SEC Form DEFA14A filed by Xilio Therapeutics Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

(Amendment No. )

Filed by the Registrant ☒

Filed by a Party other than the Registrant ☐

Check the appropriate box:

XILIO THERAPEUTICS, INC.

(Name of registrant as specified in its charter)

(Name of person(s) filing proxy statement, if other than the registrant)

Payment of Filing Fee (Check the appropriate box):

828 Winter Street, Suite 300

Waltham, Massachusetts 02451

SUPPLEMENT TO NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

TO BE HELD ON JUNE 10, 2025 AND ACCOMPANYING PROXY STATEMENT

Explanatory Note

On April 28, 2025, a proxy statement, or the Proxy Statement, of Xilio Therapeutics, Inc., a Delaware corporation, or Xilio, was made available in connection with the solicitation of proxies on behalf of the board of directors of Xilio for use at the 2025 annual meeting of stockholders to be held on June 10, 2025 at 11:00 a.m., Eastern Daylight Time, virtually at www.virtualshareholdermeeting.com/XLO2025, and at any adjournment thereof. This supplement, or the Supplement, dated June 3, 2025, supplements the Proxy Statement. The Supplement should be read in conjunction with the Proxy Statement and does not change the proposals to be acted on at the annual meeting or the recommendations of the board of directors of Xilio with respect to the proposals, which are described in the Proxy Statement. Except as specifically supplemented or amended by the information contained in this Supplement, all information set forth in the Proxy Statement continues to apply. In this Supplement, unless expressly stated or the context otherwise requires, references to “Xilio,” “the company,” “we,” “us,” “our” and similar terms refer to Xilio Therapeutics, Inc. References to our website are inactive textual references only, and the contents of our website are not incorporated by reference into this Supplement.

Subsequent to the filing of the Proxy Statement, on June 3, 2025, we filed a Current Report on Form 8-K announcing that on June 2, 2025, we entered into an underwriting agreement with Leerink Partners LLC, as representative of the underwriter named therein, relating to an underwritten public offering of pre-funded warrants to purchase 66,676,000 shares of our common stock, Series A warrants to purchase 66,676,000 shares of our common stock, Series B warrants to purchase 66,676,000 shares of our common stock, and Series C warrants to purchase 66,676,000 shares of our common stock. We refer to the Series A warrants, Series B warrants, and Series C warrants, collectively, as the common stock warrants.

As described further in the Current Report on Form 8-K, our certificate of incorporation does not have a sufficient number of authorized shares of common stock for issuance upon exercise of the pre-funded warrants and common stock warrants. As a result, and as further described in the Current Report Form 8-K, the pre-funded warrants and common stock warrants cannot be exercised until we have obtained the approval of our stockholders to increase the number of authorized shares of our common stock, as discussed in the Proxy Statement, and we have filed a corresponding certificate of amendment to our certificate of incorporation, as amended from time to time.

Voting; Revocability of Proxies

This Supplement does not change the proposals to be acted upon at the annual meeting of stockholders or the recommendations of our board of directors, which are described in the Proxy Statement.

If you have already submitted your proxy, you do not need to take any action unless you wish to revoke your proxy or change your vote. If you have not yet voted, we strongly encourage you to vote as promptly as possible. Information regarding how to vote your shares or change your proxy or voting instructions is available under the sections titled “How to Vote and Voting Deadlines” and “Revoking a Proxy; Changing Your Vote” in the Proxy Statement.

Important Notice Regarding the Availability of Proxy Materials

This Supplement, the Proxy Statement, and our Annual Report on Form 10-K for the fiscal year ended December 31, 2024, as filed with the Securities and Exchange Commission, or the SEC, are available for viewing, printing and downloading at www.proxyvote.com. In addition, this Supplement, the Proxy Statement, and our Annual Report on Form 10-K are available on the SEC’s website at www.sec.gov and the “Investors & Media — Financials & Filings — SEC Filings” section of our website, which is located at https://ir.xiliotx.com.

Current Report on Form 8-K

The full text of the Current Report on Form 8-K filed on June 3, 2025 is set forth below.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of report (Date of earliest event reported): June 2, 2025

Xilio Therapeutics, Inc.

(Exact Name of Registrant as Specified in Charter)

Registrant’s telephone number, including area code: (857) 524-2466

Not applicable

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

On June 2, 2025, Xilio Therapeutics, Inc. (the “Company”) entered into an underwriting agreement (the “Underwriting Agreement”) with Leerink Partners LLC, as representative of the underwriter named therein (the “Underwriter”), relating to an underwritten public offering of pre-funded warrants (the “pre-funded warrants”) to purchase 66,676,000 shares of the Company’s common stock, par value $0.0001 per share (the “common stock”), Series A warrants to purchase 66,676,000 shares of common stock (the “Series A warrants”), Series B warrants to purchase 66,676,000 shares of common stock (the “Series B warrants”), and Series C warrants to purchase 66,676,000 shares of common stock (the “Series C warrants” and, together with the Series A warrants and Series B warrants, the “common stock warrants”). All of the pre-funded warrants and common stock warrants will be sold by the Company. The pre-funded warrants, Series A warrants, Series B warrants and Series C warrants are immediately separable and will be issued separately. Each pre-funded warrant is being offered and sold together with an accompanying Series A warrant, Series B warrant and Series C warrant at a combined offering price of $0.7499, which is equal to the combined offering price of the pre-funded warrants, Series A warrants, Series B warrants and Series C warrants, less the $0.0001 per share exercise price of the pre-funded warrants. Furthermore, to the extent that specified limitations described below restrict the exercise of the Series A warrants, Series B warrants and/or Series C warrants, a holder may choose, in lieu of receiving common stock upon exercise of such warrants, to receive a pre-funded warrant to purchase an identical number of shares of common stock it would have received upon the exercise of its Series A warrants, Series B warrants and/or Series C warrants; provided, however that the applicable exercise price shall instead be the exercise price less $0.0001 per share, and the resulting issued pre-funded warrant shall have an exercise price of $0.0001 per share.

The Company estimates that it will receive net proceeds from the offering of approximately $46.6 million, after deducting the underwriting discounts and commissions and estimated offering expenses payable by the Company and excluding the proceeds, if any, from the exercise of the common stock warrants issued in the offering. The pre-funded warrants and Series A warrants may be exercised for cash or on a net exercise or “cashless” basis, and the Series B warrants and Series C warrants may be exercised for cash or on a net exercise or “cashless” basis provided there is no effective registration statement or prospectus available which covers the Series B warrants and Series C warrants and shares of common stock issuable upon exercise of the Series B warrants and Series C warrants. There can be no assurance that any of the warrants will be exercised for cash or at all, and it is possible that the common stock warrants may expire without being exercised. If all of the Series B warrants and the Series C warrants sold in this offering were to be exercised in cash at their exercise price, the Company would receive additional gross proceeds of approximately $100.0 million.

The pre-funded warrants and the common stock warrants will be issued pursuant to a shelf registration statement on Form S-3 that was filed with the Securities and Exchange Commission (the “SEC”) on March 11, 2025, as amended on May 6, 2025, and declared effective by the SEC on May 8, 2025 (File No. 333-285703). A prospectus supplement relating to the offering has been filed with the SEC. The closing of the offering is expected to take place on or about June 5, 2025, subject to the satisfaction of customary closing conditions.

The exercisability of the pre-funded warrants and common stock warrants is subject to limitations on exercise. Specifically, the pre-funded warrants and common stock warrants are subject to a limitation on exercisability prior to the Company’s stockholders’ approval of an increase in the number of authorized shares of the Company’s common stock and the Company’s filing of an amendment to its certificate of incorporation with the Secretary of State of the State of Delaware to effect such increase, to the extent the issuance of the shares underlying such warrants would exceed the Company’s available authorized shares. In addition, a holder will be prohibited from exercising any portion of any warrant if immediately prior to or following such exercise such holder (together with its affiliates) would beneficially own more than 4.99% (or up to 19.99% at the election of the holder) of the Company’s issued and outstanding common stock immediately after giving effect to the exercise, as such percentage ownership is determined in accordance with the terms of the warrant. However, any holder of any warrant may increase or decrease such percentage to any other percentage not in excess of 19.99%, provided that any such increase will not be effective until the 61st day after notice from the holder is delivered to the Company.

At the Company’s sole discretion, each Series B warrant and Series C warrant, as well as the shares of common stock underlying each such Series B warrant and Series C warrant, shall be subject to offset and cancellation on a dollar-for-dollar basis (applied ratably amongst all warrants of the same class) against the amount of non-dilutive capital

received by the Company between the date of issuance and December 1, 2026, without any compensation paid to such holder. Non-dilutive capital consists of (i) milestone payments and option fees received by the Company pursuant to any collaboration, license or similar agreement entered into prior to the date of issuance of the warrant; (ii) upfront payments, milestone payments and option fees received by the Company pursuant to any collaboration, license or similar agreement entered into after the date of issuance; and (iii) net proceeds received by the Company pursuant to any equity issuance (subject to certain specified exceptions) after the date of issuance where the purchase price per share is above $1.50; provided, however, that that for purposes of clauses (i) and (ii) above, (A) the non-dilutive capital described shall not include any amounts received by the Company for the reimbursement of expenses or amounts intended to fund future development expenses (for example, payments intended to fund future clinical trial expenses), as reasonably determined by the Company and (B) the aggregate amount of non-dilutive capital received after the date of issuance of the warrants must be equal to at least $20 million before the offset and cancellation can be triggered.

In addition, the Company has agreed that any future equity issuance (subject to certain specified exceptions) occurring between the date of issuance of the warrants and the earlier of (i) December 1, 2026, or (ii) the expiration or exercise of all of the Series B warrants and Series C warrants issued upon the closing of the offering, shall be subject to a minimum purchase price of $1.50 per share; provided, however, that such minimum purchase price may be waived with prior approval of holders of a majority of the then-outstanding Series B warrants and Series C warrants issued upon the closing of the offering, voting together as a single series; provided, further, that if a majority of the pre-funded warrants issued upon the closing of the offering are exercised prior to December 1, 2025, such minimum purchase price shall be reduced to $1.00 per share.

Each Series A warrant will be exercisable on the earlier of (i) December 1, 2025 and (ii) the trading day immediately following a period of five consecutive trading days on which the closing sale price of the Company’s common stock is a minimum of $1.50 per share for one share of common stock and will have an exercise price of $0.75 per share of common stock. In addition, each Series A warrant will expire upon the earlier of (i) June 5, 2030 or (ii) immediately upon the exercise of the corresponding pre-funded warrant held by a holder in proportion to the extent that such corresponding pre-funded warrant is exercised prior to December 1, 2025; provided that this term will no longer apply to the Series A warrants beginning on the first trading day immediately following a period of five consecutive trading days on which the closing sale price of the Company’s common stock is a minimum of $1.50 per share for one share of common stock. Furthermore, as described above, to the extent that specified limitations restrict the exercise of the Series A warrants, the holder may choose, in lieu of receiving common stock upon exercise of a Series A warrant, to receive a pre-funded warrant to purchase an identical number of shares of common stock it would have received upon the exercise of its Series A warrants; provided, however that the applicable exercise price shall instead be the exercise price less $0.0001 per share, and the resulting issued pre-funded warrant shall have an exercise price of $0.0001 per share.

Each Series B warrant will be exercisable on or after November 1, 2025, with an exercise price of $0.75 per share of common stock, and will expire on December 2, 2025, provided that if the closing sale price of the Company’s common stock is below the exercise price on such date, the exercise price will reset to the closing sale price on December 1, 2025 and the expiration time will be extended to December 31, 2025. In addition, if the Company’s stockholders do not approve an increase in the number of authorized shares of the Company’s common stock by October 31, 2025, the expiration time will be extended to the date that is 30 days following the date of such stockholder approval. If a warrant holder seeks to exercise the Series B warrant and the Company is unable to honor such exercise due to having insufficient available authorized shares, then in lieu of delivering the warrant shares due on such exercise, the Company shall instead settle the exercise in cash by paying a cash amount equal to the fair value of the undelivered warrant shares (determined based on the value of the common stock at the closing sale price on the date of exercise) (net of the applicable exercise price), provided, however that this provision shall terminate if and upon approval of the stockholder resolution described above. Furthermore, as described above, to the extent that specified limitations restrict the exercise of the Series B warrants, the holder may choose, in lieu of receiving common stock upon exercise of a Series B warrant, to receive a pre-funded warrant to purchase an identical number of shares of common stock it would have received upon the exercise of its Series B warrants; provided, however that the applicable exercise price shall instead be the exercise price less $0.0001 per share, and the resulting issued pre-funded warrant shall have an exercise price of $0.0001 per share.

Each Series C warrant will be exercisable on or after June 1, 2026, with an exercise price of $0.75 per share of common stock, and will expire on the earlier of (i) December 2, 2026 and (ii) the expiration time of the Series B warrant held by a holder in proportion to the extent that the corresponding Series B warrant expires without being exercised. In addition, if the closing sale price of the Company’s common stock is below the exercise price on December 2, 2026, the exercise price will reset to the closing sale price on December 1, 2026 and the expiration time will be extended to December 31, 2026. Furthermore, as described above, to the extent that specified limitations restrict the exercise of the Series C warrants, the holder may choose, in lieu of receiving common stock upon exercise of a Series C warrant, to receive a pre-funded warrant to purchase an identical number of shares of common stock it would have received upon the exercise of its Series C warrants; provided, however that the applicable exercise price shall instead be the exercise price less $0.0001 per share, and the resulting issued pre-funded warrant shall have an exercise price of $0.0001 per share.

The exercise price of the pre-funded warrants and the common stock warrants and the number of shares of the Company’s common stock issuable upon exercise of the pre-funded warrants and common stock warrants are subject to appropriate adjustment in the event of certain stock dividends and distributions, stock splits, stock combinations, reclassifications or similar events affecting the Company’s common stock, as well as upon certain pro rata distributions to the Company’s stockholders for no consideration. The exercise price of the pre-funded warrants and the common stock warrants will not be adjusted below the par value of the Company’s common stock.

In the event of certain fundamental transactions, each holder of the pre-funded warrants and the common stock warrants has the right to receive, upon exercise of such warrant, the same amount and kind of securities, cash or property as such holder would have been entitled to receive upon the occurrence of such fundamental transaction if it had been, immediately prior to such fundamental transaction, the holder of the number of shares of common stock underlying such holder’s warrant without regard to any limitations on exercise contained in such holder’s warrant. In addition, the holders of Series A warrants will be entitled to receive consideration in an amount equal to the Black Scholes value of the unexercised portion of such holder’s Series A warrants.

The Underwriting Agreement contains customary representations, warranties and agreements by the Company, customary conditions to closing, indemnification obligations of the Company and the Underwriter, including for liabilities under the Securities Act of 1933, as amended (the “Securities Act”), and other obligations of the parties and termination provisions. The representations, warranties and covenants contained in the Underwriting Agreement were made only for purposes of such agreement and as of specific dates, were solely for the benefit of the parties to such agreement, and may be subject to limitations agreed upon by the contracting parties, including being qualified by confidential disclosures exchanged between the parties in connection with the execution of the Underwriting Agreement.

The foregoing descriptions of the terms of the Underwriting Agreement, the pre-funded warrants and the common stock warrants do not purport to be complete and each is qualified in its entirety by reference to the Underwriting Agreement, the form of pre-funded warrant and the form of common stock warrant, respectively, which are filed as Exhibit 1.1, Exhibit 4.1 and Exhibit 4.2 hereto and incorporated by reference herein.

The legal opinion of Wilmer Cutler Pickering Hale and Dorr LLP, counsel to the Company, relating to the pre-funded warrants, the common stock warrants and the shares of common stock underlying the pre-funded warrants and the common stock warrants is filed as Exhibit 5.1 to this Current Report on Form 8-K.

The full text of the press release announcing the pricing of the underwritten public offering on June 2, 2025 is attached as Exhibit 99.1 hereto and is incorporated herein by reference.

The information in this Current Report on Form 8-K under Item 7.01, including the information contained in Exhibit 99.1, is being furnished to the SEC and shall not be deemed to be “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, and shall not be deemed to be incorporated by reference into any filing under the Securities Act or the Exchange Act, except as shall be expressly set forth by a specific reference in such filing.

Cash Runway

Based on the Company’s current plans, the Company estimates that the Company’s existing cash and cash equivalents, together with the $46.6 million net proceeds from the underwritten public offering, but excluding any potential payments under the Company’s existing collaboration and partnership agreements with AbbVie Group Holdings Limited and Gilead Sciences, Inc., will enable the Company to fund its operating expenses and capital expenditure requirements through the end of the third quarter of 2026. The Company has based this estimate on assumptions that may prove to be wrong, and the Company could exhaust its available capital resources sooner than it anticipates.

Cautionary Note Regarding Forward-Looking Statements

This Current Report on Form 8-K contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including, without limitation, statements regarding the satisfaction of customary closing conditions relating to the underwritten public offering, the expected closing of the underwritten public offering and the Company’s anticipated cash runway. The words “aim,” “may,” “will,” “could,” “would,” “should,” “expect,” “plan,” “anticipate,” “intend,” “believe,” “estimate,” “predict,” “project,” “potential,” “continue,” “seek,” “target” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Any forward-looking statements in this Current Report on Form 8-K are based on management’s current expectations and beliefs and are subject to a number of important risks, uncertainties and other factors that may cause actual events or results to differ materially from those expressed or implied by any forward-looking statements contained in this Current Report on Form 8-K, including, without limitation, risks and uncertainties related to market and other conditions, the satisfaction of customary closing conditions related to the underwritten public offering and the impact of general economic, industry or political conditions in the United States or internationally. These and other risks and uncertainties are described in greater detail in the section entitled “Risk Factors” in the Company’s filings with the SEC, including the Company’s most recent Quarterly Report on Form 10-Q, the Company’s prospectus supplement filed with the SEC on June 2, 2025 and any other filings that the Company has made or may make with the SEC in the future. Any forward-looking statements contained in this Current Report on Form 8-K represent the Company’s views only as of the date hereof and should not be relied upon as representing its views as of any subsequent date. Except as required by law, the Company explicitly disclaims any obligation to update any forward-looking statements.

(d) Exhibits.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Exhibit 1.1

PRE-FUNDED WARRANTS TO PURCHASE 66,676,000 SHARES OF COMMON STOCK

SERIES A WARRANTS TO PURCHASE 66,676,000 SHARES OF COMMON STOCK (OR, IN LIEU OF COMMON STOCK, PRE-FUNDED WARRANTS TO PURCHASE COMMON STOCK)

SERIES B WARRANTS TO PURCHASE 66,676,000 SHARES OF COMMON STOCK (OR, IN LIEU OF COMMON STOCK, PRE-FUNDED WARRANTS TO PURCHASE COMMON STOCK)

SERIES C WARRANTS TO PURCHASE 66,676,000 SHARES OF COMMON STOCK (OR, IN LIEU OF COMMON STOCK, PRE-FUNDED WARRANTS TO PURCHASE COMMON STOCK)

XILIO THERAPEUTICS, INC.

UNDERWRITING AGREEMENT

June 2, 2025

June 2, 2025

Leerink Partners LLC

As Representative of the Underwriter named in Schedule I hereto

c/o Leerink Partners LLC

 1301 Avenue of the Americas, 5th Floor

 New York, NY 10019

Ladies and Gentlemen:

Xilio Therapeutics, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the several Underwriters named in Schedule I hereto (the “Underwriters” or, each underwriter individually, an “Underwriter,” provided that, if only Leerink Partners LLC is listed on Schedule I, any references to Underwriters shall exclusively refer to Leerink Partners LLC), for whom you are acting as representative (the “Representative”) an aggregate of (i) pre-funded warrants to purchase up to 66,676,000 shares of the Company’s common stock, $0.0001 par value per share, of the Company (the “Common Stock”), substantially in the form of Annex A hereto, with an exercise price of $0.0001 per share (the “Pre-Funded Warrants”), (ii) series A common stock warrants, substantially in the form as set forth on Annex B hereto, to purchase an aggregate of 66,676,000 shares of Common Stock (or, in lieu of Common Stock, Pre-Funded Warrants to purchase Common Stock) with an initial exercise price of $0.75 per share (“Series A Warrants”), (iii) series B common stock warrants, substantially in the form as set forth on Annex B hereto, to purchase an aggregate of 66,676,000 shares of Common Stock (or, in lieu of Common Stock, Pre-Funded Warrants to purchase Common Stock) with an initial exercise price of $0.75 per share (“Series B Warrants”) and (iv) series C common stock warrants, substantially in the form as set forth on Annex B hereto, to purchase an aggregate of 66,676,000 shares of Common Stock (or, in lieu of Common Stock, Pre-Funded Warrants to purchase Common Stock) with an exercise price of $0.75 per shares (“Series C Warrants” and, together with the Series A Warrants and the Series B Warrants, the “Common Warrants”; and the Common Warrants, together with the Pre-Funded Warrants, the “Securities”) as set forth in Schedule II hereto. The shares of Common Stock issuable upon the exercise of the Securities are herein referred to as the “Warrant Shares.”

The Company has filed with the Securities and Exchange Commission (the “Commission”) a registration statement on Form S-3 (File No. 333-285703), as amended, including a preliminary prospectus, relating to the Securities and the Warrant Shares. The registration statement as amended at the time it became effective, including the information (if any) deemed to be part of the registration statement at the time of effectiveness pursuant to Rule 430A or 430B under the Securities Act of 1933, as amended (the “Securities Act”), is hereinafter referred to as the “Registration Statement”; the prospectus in the form first used to confirm sales of the Securities (or in

the form first made available to the Underwriters by the Company to meet requests of purchasers pursuant to Rule 173 under the Securities Act) is hereinafter referred to as the “Prospectus.” If the Company has filed an abbreviated registration statement to register additional shares of Common Stock pursuant to Rule 462(b) under the Securities Act (a “Rule 462 Registration Statement”), then any reference herein to the term “Registration Statement” shall be deemed to include such Rule 462 Registration Statement.

For purposes of this Agreement, “free writing prospectus” has the meaning set forth in Rule 405 under the Securities Act, “preliminary prospectus” shall mean each prospectus used prior to the effectiveness of the Registration Statement, and each prospectus that omitted information pursuant to Rule 430A under the Securities Act that was used after such effectiveness and prior to the execution and delivery of this Agreement, “Time of Sale Prospectus” means the preliminary prospectus contained in the Registration Statement at the time of its effectiveness together with the documents and pricing information set forth in Schedule II hereto, and “broadly available road show” means a “bona fide electronic road show” as defined in Rule 433(h)(5) under the Securities Act that has been made available without restriction to any person. As used herein, the terms “Registration Statement,” “preliminary prospectus,” “Time of Sale Prospectus” and “Prospectus” shall include the documents, if any, incorporated by reference therein as of the date hereof. The terms “supplement,” “amendment” and “amend” as used herein with respect to the Registration Statement, the Prospectus or the Time of Sale Prospectus shall include all documents subsequently filed by the Company with the Commission pursuant to the Securities Exchange Act of 1934, as amended (the “Exchange Act”), that are deemed to be incorporated by reference therein prior to the Closing Date (as defined in Section 4).

1. Representations and Warranties. The Company represents and warrants to and agrees with each of the Underwriters that:

(a) The Registration Statement has become effective; no stop order suspending the effectiveness of the Registration Statement is in effect, and no proceedings for such purpose or pursuant to Section 8A under the Securities Act are pending before or, to the Company’s knowledge, threatened by the Commission.

(b) (i) Each document, if any, filed or to be filed pursuant to the Exchange Act and incorporated by reference in the Time of Sale Prospectus or the Prospectus prior to the Closing Date complied or will comply when so filed in all material respects with the Exchange Act and the applicable rules and regulations of the Commission thereunder, (ii) the Registration Statement, when it became effective, did not contain and, as amended or supplemented, if applicable, as of the date of such amendment or supplement, will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading, (iii) the Registration Statement and the Prospectus comply and, as amended or supplemented, if applicable, as of the date of such amendment or supplement, will comply in all

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material respects with the Securities Act and the applicable rules and regulations of the Commission thereunder, (iv) the Time of Sale Prospectus does not, and at the time of sale of the Securities in connection with the offering when the Prospectus is not yet available to prospective purchasers and at the Closing Date (as defined in Section 4), the Time of Sale Prospectus, as then amended or supplemented by the Company, if applicable, will not, contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading, (v) each broadly available road show, if any, when considered together with the Time of Sale Prospectus, does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading and (vi) the Prospectus does not contain and, as amended or supplemented, if applicable, as of the date of such amendment or supplement, will not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading, except that the representations and warranties set forth in this paragraph do not apply to statements or omissions in the Registration Statement, the Time of Sale Prospectus or the Prospectus based upon information relating to any Underwriter furnished to the Company in writing by such Underwriter through the Representative expressly for use therein, it being understood and agreed upon that only such information in the Prospectus: furnished on behalf of each Underwriter is the statements concerning the Underwriters contained in the second and third paragraphs under the caption “Underwriting – Price Stabilization, Short Positions and Penalty Bids.” (the “Underwriter Information”).

(c) The Company is not an “ineligible issuer” in connection with the offering pursuant to Rules 164, 405 and 433 under the Securities Act. Any free writing prospectus that the Company is required to file pursuant to Rule 433(d) under the Securities Act has been, or will be, filed with the Commission in accordance with the requirements of the Securities Act and the applicable rules and regulations of the Commission thereunder. Each free writing prospectus that the Company has filed, or is required to file, pursuant to Rule 433(d) under the Securities Act or that was prepared by or on behalf of or used or referred to by the Company complies or will comply in all material respects with the requirements of the Securities Act and the applicable rules and regulations of the Commission thereunder. Except for the free writing prospectuses, if any, identified in Schedule II hereto, and electronic road shows, if any, each furnished to the Representative before first use, the Company has not prepared, used or referred to, and will not, without the Representative’s prior consent, prepare, use or refer to, any free writing prospectus.

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(d) The Company has been duly incorporated, is validly existing as a corporation in good standing under the laws of the State of Delaware, has the corporate power and authority to own or lease its property and to conduct its business as described in each of the Registration Statement, the Time of Sale Prospectus and the Prospectus and is duly qualified to transact business and is in good standing in each jurisdiction in which the conduct of its business or its ownership or leasing of property requires such qualification, except to the extent that the failure to be so qualified or be in good standing would not reasonably be expected to, singly or in the aggregate, result in a Material Adverse Change (as defined below) of the Company and its subsidiaries, taken as a whole.

(e) Each subsidiary of the Company has been duly incorporated, organized or formed, is validly existing as a corporation or other business entity in good standing under the laws of the jurisdiction of its incorporation, organization or formation, has the corporate or other business entity power and authority to own or lease its property and to conduct its business as described in each of the Registration Statement, the Time of Sale Prospectus and the Prospectus and is duly qualified to transact business and is in good standing in each jurisdiction in which the conduct of its business or its ownership or leasing of property requires such qualification, except to the extent that the failure to be so qualified or be in good standing would not, singly or in the aggregate, reasonably be expected to result in a Material Adverse Change of the Company and its subsidiaries, taken as a whole; all of the issued shares of capital stock or other equity interests of each subsidiary of the Company have been duly and validly authorized and issued, are fully paid and non-assessable and are owned directly or indirectly by the Company, free and clear of all liens, encumbrances, equities or claims. The Company does not own or control, directly or indirectly, any corporation, association or other entity other than the subsidiaries listed in Exhibit 21.2 to the Company’s Annual Report on Form 10-K for the most recently ended fiscal year and other than (i) those subsidiaries not required to be listed on Exhibit 21.1 by Item 601 of Regulation S-K under the Exchange Act and (ii) those subsidiaries formed since the last day of the most recently ended fiscal year.

(f) This Agreement has been duly authorized, executed and delivered by the Company.

(g) The authorized capital stock of the Company conforms in all material respects as to legal matters to the description thereof contained under the heading “Description of Capital Stock” in each of the Registration Statement, the Time of Sale Prospectus and the Prospectus.

(h) The shares of Common Stock outstanding prior to the issuance of the Securities have been duly authorized and are validly issued, fully paid and non-assessable.

(i) The Securities have been duly authorized and, when executed and delivered by the Company in accordance with this Agreement, will be valid and legally binding agreements of the Company, enforceable against the Company in accordance with their terms except as the enforcement thereof may be limited by applicable bankruptcy, insolvency, reorganization, moratorium or other similar laws relating to or affecting the rights and remedies of creditors or by general

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equitable principles. The Warrant Shares to be issued by the Company upon exercise of the Securities in accordance with their terms will have been duly authorized and will be reserved for issuance upon exercise of the Securities in a number sufficient to meet the current exercise requirements. The Warrant Shares, when issued and delivered upon exercise of the Securities in accordance therewith, will be validly issued, fully paid and nonassessable, and the issuance of the Warrant Shares is not subject to any preemptive or similar rights not otherwise validly waived or satisfied.

(j) The execution and delivery by the Company of, and the performance by the Company of its obligations under, this Agreement will not contravene any provision of (i) applicable law, (ii) the restated certificate of incorporation, as amended, or the bylaws of the Company, (iii) any agreement or other instrument binding upon the Company or any of its subsidiaries that is material to the Company and its subsidiaries, taken as a whole, or (iv) any judgment, order or decree of any governmental body, agency or court having jurisdiction over the Company or any subsidiary, except as would not, singly or in the aggregate, reasonably be expected to result in a Material Adverse Change of the Company and its subsidiaries, taken as a whole, or on the power and ability of the Company to perform its obligations under this Agreement. No consent, approval, authorization or order of, or qualification with, any governmental body, agency or court is required for the performance by the Company of its obligations under this Agreement, except such as have already been obtained or made or as may be required by the securities or Blue Sky laws of the various states or the rules and regulations of the Financial Industry Regulatory Authority or the Nasdaq Global Market in connection with the offer and sale of the Securities.

(k) There has not occurred any Material Adverse Change, or any development that would reasonably be expected to result in a Material Adverse Change, in the condition, financial or otherwise, or in the earnings, business, prospects or operations of the Company and its subsidiaries, taken as a whole, from that set forth in the Time of Sale Prospectus. Subsequent to the respective dates as of which information is given in each of the Registration Statement, the Time of Sale Prospectus and the Prospectus, (i) there has been no material adverse change, or any development that could reasonably be expected to result in a material adverse change, in the condition, financial or otherwise, or in the earnings, business, operations or prospects, whether or not arising from transactions in the ordinary course of business, of the Company and its subsidiaries, considered as one entity (any such change is called a “Material Adverse Change”), (ii) the Company and its subsidiaries, taken as a whole, have not incurred any material liability or obligation, direct or contingent, nor entered into any material transaction; (iii) the Company has not purchased any of its outstanding capital stock (other than from its employees or other service providers in connection with the termination of the service pursuant to plans or agreements, as applicable), nor declared, paid or otherwise made any dividend or distribution of any kind on its capital stock other than ordinary and customary dividends; and (iv) there has not been any material change in the capital stock, short-term debt or long-term debt of the Company and its subsidiaries, taken as a whole, except in each case as described in the Time of Sale Prospectus.

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(l) There are no legal or governmental proceedings pending or, to the Company’s knowledge, threatened to which the Company or any of its subsidiaries is a party or to which any of the properties of the Company or any of its subsidiaries is subject (i) other than proceedings described in each of the Registration Statement, the Time of Sale Prospectus and the Prospectus and proceedings that would not, singly or in the aggregate, result in a Material Adverse Change of the Company and its subsidiaries, taken as a whole, or on the power or ability of the Company to perform its obligations under this Agreement or to consummate the transactions contemplated by each of the Registration Statement, the Time of Sale Prospectus and the Prospectus or (ii) that are required to be described in the Registration Statement, the Time of Sale Prospectus or the Prospectus and are not so described in all material respects; and there are no contracts or other documents to which the Company or its subsidiaries are subject or bound that are required to be described in the Registration Statement, the Time of Sale Prospectus or the Prospectus or to be filed or incorporated by reference as exhibits to the Registration Statement that are not described in all material respects or filed or incorporated by reference as required.

(m) Each preliminary prospectus filed as part of the Registration Statement as originally filed or as part of any amendment thereto, or filed pursuant to Rule 424 under the Securities Act, complied when so filed in all material respects with the Securities Act and the applicable rules and regulations of the Commission thereunder.

(n) The Company is not, and immediately after giving effect to the offering and sale of the Securities and the application of the proceeds thereof as described in each of the Registration Statement, the Time of Sale Prospectus and the Prospectus will not be, required to register as an “investment company” as such term is defined in the Investment Company Act of 1940, as amended.

(o) The Company and each of its subsidiaries (i) are in compliance with any and all applicable foreign, federal, state and local laws and regulations relating to the protection of human health and safety, the environment or hazardous or toxic substances or wastes, pollutants or contaminants (“Environmental Laws”), (ii) have received all permits, licenses or other approvals required of them under applicable Environmental Laws to conduct their respective businesses and (iii) are in compliance with all terms and conditions of any such permit, license or approval, except where such noncompliance with Environmental Laws, failure to receive required permits, licenses or other approvals or failure to comply with the terms and conditions of such permits, licenses or approvals would not, singly or in the aggregate, reasonably be expected to result in a Material Adverse Change of the Company and its subsidiaries, taken as a whole.

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(p) There are no costs or liabilities associated with Environmental Laws (including, without limitation, any capital or operating expenditures required for clean-up, closure of properties or compliance with Environmental Laws or any permit, license or approval, any related constraints on operating activities and any potential liabilities to third parties) which would, singly or in the aggregate, reasonably be expected to result in a Material Adverse Change of the Company and its subsidiaries, taken as a whole.

(q) There are no contracts, agreements or understandings between the Company and any person granting such person the right to require the Company to file a registration statement under the Securities Act with respect to any securities of the Company or to require the Company to include such securities with the Securities registered pursuant to the Registration Statement, except those contracts, agreements and understandings described in the Time of Sale Prospectus and the Prospectus, all of which have been validly waived or complied with in connection with the issuance and sale of the Securities contemplated hereby.

(r) (i) None of the Company or any of its subsidiaries or controlled affiliates, or any director, officer or employee thereof, or, to the Company’s knowledge, any agent or representative of the Company or of any of its subsidiaries or controlled affiliates, has taken or will take any action in furtherance of an offer, payment, promise to pay, or authorization or approval of the payment, giving or receipt of money, property, gifts or anything else of value, directly or indirectly, to any government official (including any officer or employee of a government or government-owned or controlled entity or of a public international organization, or any person acting in an official capacity for or on behalf of any of the foregoing, or any political party or party official or candidate for political office) in order to improperly influence official action, or to any person in violation of any applicable anti-corruption laws; (ii) the Company and each of its subsidiaries and controlled affiliates have conducted their businesses in compliance with applicable anti-corruption laws and instituted at the time of the offering and will maintain policies and procedures reasonably designed to promote and achieve compliance with such laws and with the representations and warranties contained herein; and (iii) neither the Company nor any of its subsidiaries will use, directly or indirectly, the proceeds of the offering in furtherance of an offer, payment, promise to pay, or authorization of the payment or giving of money, or anything else of value, to any person in violation of any applicable anti-corruption laws.

(s) The operations of the Company and each of its subsidiaries are and have been conducted at all times in material compliance with all applicable financial recordkeeping and reporting requirements, including those of the Bank Secrecy Act, as amended by Title III of the Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism Act of 2001 (USA PATRIOT Act), and the applicable anti-money laundering statutes of jurisdictions where the Company and each of its subsidiaries conduct business,

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the rules and regulations thereunder and any related or similar rules, regulations or guidelines, issued, administered or enforced by any governmental agency having jurisdiction over the Company or its subsidiaries (collectively, the “Anti-Money Laundering Laws”), and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or any of its subsidiaries with respect to the Anti-Money Laundering Laws is pending or, to the knowledge of the Company, threatened.

(t) (i) None of the Company, any of its subsidiaries, or any director, officer, or employee thereof, or, to the Company’s knowledge, any agent, affiliate or representative of the Company or any of its subsidiaries, is an individual or entity (“Person”) that is, or is owned or controlled by one or more Persons that are:

(A) the subject of any sanctions administered or enforced by the U.S. Department of the Treasury’s Office of Foreign Assets Control, the United Nations Security Council, the European Union, His Majesty’s Treasury, or other relevant sanctions authority (collectively, “Sanctions”), or

(B) located, organized or resident in a country or territory that is the subject of Sanctions (including, without limitation, Crimea, the so-called Donetsk People’s Republic, the so-called Luhansk People’s Republic, Cuba, Iran, North Korea and Syria).

(ii) The Company will not, directly or indirectly, use the proceeds of the offering, or lend, contribute or otherwise make available such proceeds to any subsidiary, joint venture partner or other Person:

(A) to fund or facilitate any activities or business of or with any Person or in any country or territory that, at the time of such funding or facilitation, is the subject of Sanctions; or

(B) in any other manner that will result in a violation of Sanctions by any Person (including any Person participating in the offering, whether as underwriter, advisor, investor or otherwise).

(iii) The Company and each of its subsidiaries have not knowingly engaged in, are not now knowingly engaged in, and will not knowingly engage in, any dealings or transactions with any Person, or in any country or territory, that at the time of the dealing or transaction is or was the subject of Sanctions.

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(u) The Company and each of its subsidiaries have good and marketable title to all real property owned by them and good and marketable title to all personal property owned by them, in each case, which is material to the business of the Company and its subsidiaries, and in each case, free and clear of all liens, encumbrances and defects, except such as are described in each of the Registration Statement, the Time of Sale Prospectus and the Prospectus or such as do not materially affect the value of such property and do not interfere in any material respect with the use made and proposed to be made of such property by the Company and its subsidiaries; and any real property and buildings held under lease by the Company and its subsidiaries are held by them, as applicable, under valid, subsisting and enforceable leases with such exceptions as are not material and do not interfere in any material respect with the use made and proposed to be made of such property and buildings by the Company and its subsidiaries.

(v) (i) The Company and its subsidiaries own or have a valid license to all pending patent applications and issued patents, inventions, copyrights, know how (including trade secrets and other unpatented and/or unpatentable proprietary or confidential information, systems or procedures), trademarks, service marks and trade names (collectively, “Intellectual Property Rights”) used in or reasonably necessary to the conduct of their businesses in the manner described in the Time of Sale Prospectus; (ii) the Intellectual Property Rights owned by the Company and its subsidiaries and, to the Company’s knowledge, the Intellectual Property Rights licensed to the Company and its subsidiaries, are valid, subsisting and enforceable, and there is no pending or, to the Company’s knowledge, threatened action, suit, proceeding or claim by others challenging the validity, scope or enforceability of any such Intellectual Property Rights; (iii) neither the Company nor any of its subsidiaries has received any notice alleging any infringement, misappropriation or other violation of Intellectual Property Rights which, singly or in the aggregate, if the subject of an unfavorable decision, ruling or finding, would result in a Material Adverse Change of the Company and its subsidiaries, taken as a whole, and, to the Company’s knowledge, none of the licensors, in relation to the Intellectual Property Rights licensed to the Company and its subsidiaries, have received any notice alleging any infringement, misappropriation or other violation of Intellectual Property Rights licensed to the Company and its subsidiaries which, singly or in the aggregate, if the subject of an unfavorable decision, ruling or finding, would result in a Material Adverse Change of the Company and its subsidiaries, taken as a whole; (iv) to the Company’s knowledge, no third party is infringing, misappropriating or otherwise violating, or has infringed, misappropriated or otherwise violated, any Intellectual Property Rights owned by the Company or any of its subsidiaries, and any Intellectual Property Rights licensed to the Company and its subsidiaries, that would materially adversely affect the Company and its subsidiaries, taken as a whole; (v) neither the Company nor any of its subsidiaries infringes, misappropriates or otherwise violates, or has infringed, misappropriated or otherwise violated, any Intellectual Property Rights of a third party in any material respect; (vi) all employees or contractors engaged in the development of material Intellectual Property Rights on behalf of the Company or any subsidiary of the Company have executed an invention assignment agreement whereby such employees or contractors presently assign all of their right, title and interest in and

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to such Intellectual Property Rights to the Company or the applicable subsidiary, and to the Company’s knowledge no such agreement has been breached or violated; (vii) the Company and its subsidiaries use, and have used, commercially reasonable efforts to appropriately maintain all information intended to be maintained as a trade secret; and (viii) all employees or contractors engaged in the development of material trade secrets on behalf of the Company or any subsidiary of the Company have executed a confidentiality agreement with the Company or any subsidiary of the Company.

(w) (i) The Company and its subsidiaries use and have used any and all software and other materials distributed under a “free,” “open source,” or similar licensing model (including but not limited to the MIT License, Apache License, GNU General Public License, GNU Lesser General Public License and GNU Affero General Public License) (“Open Source Software”) in compliance with all license terms applicable to such Open Source Software; and (ii) neither the Company nor any of its subsidiaries uses or distributes or has used or distributed any Open Source Software in any manner that requires or has required (A) the Company or any of its subsidiaries to permit reverse engineering of any software code or other technology owned by the Company or any of its subsidiaries or (B) any software code or other technology owned by the Company or any of its subsidiaries to be (1) disclosed or distributed in source code form, (2) licensed for the purpose of making derivative works or (3) redistributed at no charge.

(x) (i) The Company and each of its subsidiaries have complied and are presently in material compliance with all internal and external privacy policies, contractual obligations, industry standards, applicable laws, statutes, judgments, orders, rules and regulations of any court or arbitrator or other governmental or regulatory authority with jurisdiction over the Company, in each case, relating to the collection, use, transfer, import, export, storage, protection, disposal and disclosure by the Company or any of its subsidiaries of personal, personally identifiable, household, sensitive, confidential or regulated data (“Data Security Obligations”, and such data, “Data”); (ii) the Company has not received any notification of or complaint regarding and is unaware of any other facts that, singly or in the aggregate, would reasonably indicate material non-compliance with any Data Security Obligation; and (iii) there is no action, suit or proceeding by or before any court or governmental agency, authority or body pending or, to the Company’s knowledge, threatened alleging material non-compliance with any Data Security Obligation.

(y) The Company and each of its subsidiaries have taken reasonable technical, physical and organizational measures to protect the information technology systems and Data used in connection with the operation of the Company’s and its subsidiaries’ businesses. Without limiting the foregoing, the Company and its subsidiaries have used reasonable efforts to establish and maintain, and have established, maintained, implemented and complied with, reasonable information technology, information security, cyber security and data protection controls, policies and procedures, including oversight, access controls,

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technological and physical safeguards and business continuity/disaster recovery and security plans that are designed to protect against and prevent breach, destruction, loss, unauthorized distribution, use, access, disablement, misappropriation or modification, or other compromise or misuse of or relating to any information technology system or Data used in connection with the operation of the Company’s and its subsidiaries’ businesses (“Breach”). To the Company’s knowledge, there has been no such Breach, and the Company and its subsidiaries have no knowledge of any event or condition that would reasonably be expected to result in any such Breach.

(z) No material labor dispute with the employees of the Company or any of its subsidiaries exists, or, to the knowledge of the Company, is imminent; and the Company is not aware of any existing, threatened or imminent labor disturbance by the employees of any of its principal suppliers, manufacturers or contractors that could, singly or in the aggregate, result in a Material Adverse Change of the Company and its subsidiaries, taken as a whole.

(aa) The Company and each of its subsidiaries are insured by insurers of recognized financial responsibility against such losses and risks and in such amounts as, in the Company’s reasonable judgment, are prudent and customary in the businesses in which they are engaged; neither the Company nor any of its subsidiaries has been refused any insurance coverage sought or applied for; and neither the Company nor any of its subsidiaries has any reason to believe that it will not be able to renew its existing insurance coverage as and when such coverage expires or to obtain similar coverage from similar insurers as may be necessary to continue its business at a cost that would not reasonably be expected to, singly or in the aggregate, result in a Material Adverse Change of the Company and its subsidiaries, taken as a whole.

(bb) The Company has operated at all times and is currently in compliance in all material respects with all applicable statutes, rules and regulations of the U.S. Food and Drug Administration (the “FDA”), and applicable foreign regulatory authorities, including the European Medicines Agency and the UK Medicines & Healthcare products Regulatory Agency (collectively, the “Regulatory Authorities”), except where failure to be in compliance would not be expected reasonably to result in a Material Adverse Change of the Company and its subsidiaries, taken as a whole. For purposes of this Agreement, “Health Care Laws” means:

(i) the Federal Food, Drug, and Cosmetic Act and the regulations promulgated thereunder;

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(ii) all applicable federal, state, local and foreign health care laws, including, without limitation, the U.S. Anti-Kickback Statute (42 U.S.C. Section 1320a-7b(b)), the Civil Monetary Penalties Law (42 U.S.C. § 1320a-7a), the U.S. Civil False Claims Act (31 U.S.C. Section 3729 et seq.), all applicable federal, state, local and all foreign criminal laws relating to health care fraud and abuse, including but not limited to the U.S. False Statements Law (42 U.S.C. Section 1320a-7b(a)), 18 U.S.C. Sections 286 and 287, and the health care fraud criminal provisions under the U.S. Health Insurance Portability and Accountability Act of 1996 (“HIPAA”) (42 U.S.C. Section 1320d et seq.), the U.S. Physician Payments Sunshine Act (42 U.S.C. Section 1320a-7h), the exclusions law, the statutes and regulations of applicable government funded or sponsored healthcare programs, and the regulations promulgated pursuant to such statutes;

(iii) HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act (42 U.S.C. Section 17921 et seq.), and the regulations promulgated thereunder and any state or non-U.S. counterpart thereof to which the Company is subject, the purpose of which is to protect the privacy of individuals or prescribers;

(iv) the Patient Protection and Affordable Care Act of 2010, as amended by the Health Care and Education Reconciliation Act of 2010, the regulations promulgated thereunder;

(v) all other local, state, federal, national, supranational and foreign laws, relating to the regulation of the Company and the ownership, testing, development, manufacture, packaging, processing, use, distribution, marketing, labeling, promotion, sale, offer for sale, storage, import, export or disposal of any product under development, manufactured or distributed by the Company.

(cc) (i) the preclinical studies, research tests and clinical trials conducted by or on behalf of or sponsored by the Company or in which the Company has participated that are described or referred to in the Registration Statement and the Time of Sale Prospectus, were, and if still pending are, being conducted in all material respects in accordance with standard medical and experimental protocols, procedures and controls pursuant to all applicable Health Care Laws, the rules and regulations of the Regulatory Authorities and current Good Clinical Practices and Good Laboratory Practices; (ii) the descriptions of the results of such studies and trials contained in the Registration Statement, the Time of Sale Prospectus or the Prospectus are accurate in all material respects and fairly present the data derived from such trials and studies; (iii) the Company has no knowledge of any other preclinical studies, research tests or clinical trials not described in the Registration Statement, the Time of Sale Prospectus and the Prospectus, the results of which are materially inconsistent with or call into question in any material respect the results described or referred to in the Registration Statement, the Time of Sale Prospectus and the Prospectus; (iv) the Company has provided the Underwriters with all substantive and material written notices, correspondence and summaries of all other communications provided to the Company or its subsidiaries from the Regulatory Authorities; and (v) the Company has not received any written and material notices, correspondence or

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other communications from any Regulatory Authority requiring or threatening the termination, material modification or suspension of any studies or trials that are described in the Registration Statement, the Time of Sale Prospectus and the Prospectus or the results of which are referred to in the Registration Statement, the Time of Sale Prospectus and the Prospectus, and, to the Company’s knowledge, there are no reasonable grounds for the same.

(dd) (i) Except as would not, singly or in the aggregate, result in a Material Adverse Change of the Company and its subsidiaries, taken as a whole, the Company has filed, obtained, maintained or submitted all reports, documents, forms, notices, applications, records, claims, submissions and supplements or amendments as required by any Health Care Laws, and, all such reports, documents, forms, notices, applications, records, claims, submissions and supplements or amendments were timely, complete, accurate and not misleading in all material respects on the date filed (or were corrected or supplemented by a subsequent submission); (ii) the Company has not received written notice of any claim, action, suit, proceeding, hearing, enforcement, investigation, arbitration or other action from any court or arbitrator or Regulatory Authority or other governmental entity alleging that the Company is in material violation of any Health Care Laws, including, without limitation, any FDA Form 483, notice of adverse finding, warning letter, untitled letter from the FDA or any other Regulatory Authority or governmental entity, nor, to the Company’s knowledge, is any such claim, action, suit, proceeding, hearing, enforcement, investigation, arbitration or other action threatened; (iii) the Company is not a party to any corporate integrity agreements, monitoring agreements, consent decrees, settlement orders, or similar agreements with or imposed by any Regulatory Authority or other governmental entity; and (iv) neither the Company nor any of its employees, officers or directors has been excluded, suspended or debarred from participation in any U.S. federal health care program or human clinical research or, to the knowledge of the Company, is subject to an inquiry, investigation, proceeding or other similar action by a Regulatory Authority or other governmental entity that could reasonably be expected to result in debarment, suspension, or exclusion.

(ee) The Company and its subsidiaries possess all certificates, authorizations and permits issued by the appropriate federal, state or foreign regulatory authorities necessary to conduct their respective businesses, including, without limitation, from the Regulatory Authorities, and neither the Company nor any of its subsidiaries has received any notice of proceedings relating to the revocation or modification of any such certificate, authorization or permit which, singly or in the aggregate, if the subject of an unfavorable decision, ruling or finding, would result in a Material Adverse Change of the Company and its subsidiaries, taken as a whole, except as described in the Time of Sale Prospectus.

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(ff) Except as would not, singly or in the aggregate, reasonably be expected to result in a Material Adverse Change of the Company and its subsidiaries, taken as a whole, (i) each employee benefit plan, within the meaning of Section 3(3) of the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), that is sponsored, maintained, administered or contributed to by the Company has been maintained in material compliance with its terms and the requirements of any applicable statutes, orders, rules and regulations, including but not limited to ERISA and the Internal Revenue Code of 1986, as amended (the “Code”), and (ii) neither the Company nor any member of its “Controlled Group” (defined as any trade or business, whether or not incorporated, that would be regarded as a single employer with the Company under Section 414 of the Code) (x) has ever sponsored, maintained, contributed to or has had any obligation to contribute to, any employee benefit plan that is subject to Title IV of ERISA or any “multiemployer plan” as defined in Section 3(37) of ERISA or (y) has incurred, or reasonably expects to incur, any liability under Title IV of ERISA.

(gg) The financial statements included or incorporated by reference in each of the Registration Statement, the Time of Sale Prospectus and the Prospectus, together with the related notes thereto, comply as to form in all material respects with the applicable accounting requirements of the Securities Act and present fairly the consolidated financial position of the Company and its subsidiaries as of the dates shown and its results of operations and comprehensive loss, statements of convertible preferred units and convertible preferred stock and members’ and stockholders’ deficit and cash flows for the periods shown, and such financial statements have been prepared in conformity with generally accepted accounting principles in the United States (“U.S. GAAP”) applied on a consistent basis throughout the periods covered thereby, except for any normal year-end adjustments in the Company’s quarterly financial statements. The other financial information included or incorporated by reference in each of the Registration Statement, the Time of Sale Prospectus and the Prospectus has been derived from the accounting records of the Company and its consolidated subsidiaries and presents fairly in all material respects the information shown thereby.

(hh) The statistical, industry-related and market-related data included or incorporated by reference in each of the Registration Statement, the Time of Sale Prospectus and the Prospectus are based on or derived from sources which the Company reasonably and in good faith believes are reliable and accurate and such data is consistent with the sources from which they are derived, in each case in all material respects. No other financial statements or supporting schedules are required to be included in the Registration Statement, the Prospectus or the Time of Sale Prospectus.

(ii) Ernst & Young LLP or other accountants who have certified certain financial statements of the Company and its subsidiaries filed with the Commission and included or incorporated by reference in each of the Registration Statement, the Time of Sale Prospectus and the Prospectus, is an independent registered public accounting firm with respect to the Company within the meaning of the Securities Act and the applicable rules and regulations thereunder adopted by the Commission and the Public Company Accounting Oversight Board (United States).

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(jj) The Company and each of its subsidiaries maintain a system of internal accounting controls sufficient to provide reasonable assurance that (i) transactions are executed in accordance with management’s general or specific authorizations; (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with U.S. GAAP and to maintain asset accountability; (iii) access to assets is permitted only in accordance with management’s general or specific authorization; (iv) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences and (v) the interactive data in the eXtensible Business Reporting Language included or incorporated by reference in the Registration Statement fairly presents the information called for in all material respects and is prepared in accordance with the Commission’s rules and guidelines applicable thereto. Since the end of the Company’s most recent audited fiscal year, there has been (i) no material weakness in the Company’s internal control over financial reporting (whether or not remediated) and (ii) no change in the Company’s internal control over financial reporting that has materially affected, or is reasonably likely to materially affect, the Company’s internal control over financial reporting.

(kk) The Company has not sold, issued or distributed any shares of Common Stock during the six-month period preceding the date hereof, including any sales pursuant to Rule 144A under, or Regulation D or S of, the Securities Act, other than shares issued pursuant to employee benefit plans, qualified stock option plans or other employee compensation plans or pursuant to outstanding options, rights or warrants.

(ll) The Company and each of its subsidiaries have filed all federal, state, local and foreign tax returns required to be filed through the date of this Agreement or have requested extensions thereof (except where the failure to file would not, singly or in the aggregate, reasonably be expected to result in a Material Adverse Change of the Company and its subsidiaries, taken as a whole) and have paid all taxes required to be paid thereon (except for cases in which the failure to file or pay would not, singly or in the aggregate, reasonably be expected to result in a Material Adverse Change of the Company and its subsidiaries, taken as a whole, or, except as currently being contested in good faith and for which reserves required by U.S. GAAP have been created in the financial statements of the Company), and no tax deficiency has been determined adversely to the Company or any of its subsidiaries which, singly or in the aggregate, has resulted in (nor does the Company nor any of its subsidiaries have any notice or knowledge of any tax deficiency which could reasonably be expected to be determined adversely to the Company or its subsidiaries and which could reasonably be expected to have) a Material Adverse Change of the Company and its subsidiaries, taken as a whole.

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(mm) From the time of initial confidential submission of the Company’s Registration Statement on Form S-1 (File No. 333-259973) to the Commission through the date hereof, the Company has been and is an “emerging growth company,” as defined in Section 2(a) of the Securities Act (an “Emerging Growth Company”).

(nn) The interactive data in eXtensible Business Reporting Language included or incorporated by reference in the Registration Statement fairly presents the information called for in all material respects and has been prepared in accordance with the Commission’s rules and guidelines applicable thereto.

(oo) The Company has not taken and will not take, directly or indirectly, any action designed to or that might be reasonably expected to cause or result in stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Securities.

(pp) The Company (i) has not alone engaged in any Testing-the-Waters Communication with any person and (ii) has not authorized anyone other than the Representative to engage in Testing-the-Waters Communications. The Company reconfirms that the Representative has been authorized to act on its behalf in undertaking Testing-the-Waters Communications. The Company has not distributed any Testing-the-Waters Communication that is a written communication within the meaning of Rule 405 under the Securities Act other than those listed on Schedule III hereto. “Testing-the-Waters Communication” means any communication with potential investors undertaken in reliance on Section 5(d) or Rule 163B of the Securities Act.

(qq) As of the time of sale of the Securities in connection with the offering when the Prospectus is not yet available to prospective purchasers, none of (A) the Time of Sale Prospectus, (B) any free writing prospectus, when considered together with the Time of Sale Prospectus, and (C) any individual Testing-the-Waters Communication, when considered together with the Time of Sale Prospectus, included, includes or will include an untrue statement of a material fact or omitted, omits or will omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading.

(rr) There are (and prior to the Closing Date, will be) no debt securities, convertible securities or preferred stock issued or guaranteed by the Company that are rated by a “nationally recognized statistical rating organization”, as such term is defined in Section 3(a)(62) under the Exchange Act.

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(ss) The Company maintains disclosure controls and procedures (as such is defined in Rule 13a-15(e) under the Exchange Act) that comply with the requirements of the Exchange Act; such disclosure controls and procedures have been designed to ensure that information required to be disclosed by the Company in reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the Commission’s rules and forms, including controls and procedures designed to ensure that such information is accumulated and communicated to the Company’s management to allow timely decisions regarding disclosures. The Company has conducted evaluations of the effectiveness of their disclosure controls as required by Rule 13a-15 of the Exchange Act.

(tt) The Company is subject to and in compliance in all material respects with the reporting requirements of Section 13 or Section 15(d) of the Exchange Act. Except as disclosed in the Registration Statement, the Common Stock is registered pursuant to Section 12(b) or Section 12(g) of the Exchange Act and is listed on Nasdaq, and the Company has taken no action designed to, or reasonably likely to have the effect of, terminating the registration of the Common Stock under the Exchange Act or delisting the Common Stock from Nasdaq, nor has the Company received any notification that the Commission or Nasdaq is contemplating terminating such registration or listing. Except as disclosed in the Registration Statement, the Company has submitted a Listing of Additional Shares Notification Form with Nasdaq covering all of the Securities, including the Warrant Shares; the Company has taken all reasonably necessary actions to ensure that it will be in compliance with all applicable corporate governance requirements set forth in Nasdaq’s listing rules that are then in effect.

(uu) The Company has not relied upon Leerink Partners LLC or legal counsel for Leerink Partners LLC for any legal, tax or accounting advice in connection with the offering and sale of the Securities.

(vv) No forward-looking statement (within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act) included in any of the Registration Statement or the Time of Sale Prospectus has been made or reaffirmed without a reasonable basis or has been disclosed other than in good faith.

(ww) There are no persons (as such term is defined in Rule 1-02 of Regulation S-X promulgated under the Securities Act) with registration or other similar rights to have any equity or debt securities of the Company registered for sale under the Registration Statement or included in the offering contemplated by this Agreement, except for such rights as have been duly waived in a writing.

(xx) Neither the Company nor any of its subsidiaries is a “covered foreign person”, as that term is defined in 31 C.F.R. § 850.209. Neither the Company nor any of its subsidiaries currently engages, or has plans to engage, directly or indirectly, in a “covered activity”, as that term is defined in 31 C.F.R. § 850.208 (“Covered Activity”). The Company does not have any joint venture that engages in or plans to engage in any Covered Activity. The Company also does not, directly or indirectly, hold a board seat on, have a voting or equity interest in, or have any contractual power to direct or cause the direction of the management or policies of any person or persons that engages or plans to engage in any Covered Activity.

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2. Agreements to Sell and Purchase. The Company hereby agrees to sell to the several Underwriters, and each Underwriter, upon the basis of the representations and warranties herein contained, but subject to the terms and conditions hereinafter stated, agrees, severally and not jointly, to purchase from the Company the respective numbers of Securities set forth in Schedule I hereto opposite its name. The combined purchase price to be paid by the several Underwriters to the Company per Pre-Funded Warrant and accompanying Common Warrants shall be $0.7049.

3. Terms of Public Offering. The Company is advised by the Representative that the Underwriters propose to make a public offering of their respective portions of the Securities as soon after the Registration Statement and this Agreement have become effective as in the Representative’s judgment is advisable. The Company is further advised by the Representative that each Pre-Funded Warrant and accompanying Common Warrants is to be offered to the public initially at a combined public offering price of $0.74990 (the “Public Offering Price”).

4. Payment and Delivery. Payment for the Securities shall be made to the Company in Federal or other funds immediately available in New York City against delivery of the Securities for the respective accounts of the several Underwriters at 10:00 a.m., New York City time, on June 5, 2025, or at such other time on the same or such other date, not later than June 12, 2025, as shall be designated in writing by the Representative. The time and date of such payment are hereinafter referred to as the “Closing Date.”

At the Closing Date, the Company shall physically deliver, or cause to be delivered, the Securities as set forth below according to the instructions of the Representative at or prior to the Closing Time.

Notwithstanding the foregoing, the Company and the Representative shall instruct purchasers of the Securities in the public offering to make payment for the Securities at the Public Offering Price on the Closing Date to the Company by wire transfer in immediately available funds to the account specified by the Company, in lieu of payment by the Underwriters for such Securities, and the Company shall deliver such Securities to such purchasers on the Closing Date in the definitive form against such payment, in lieu of the Company’s obligation to deliver such Securities to the Underwriters. On the Closing Date, payment shall be made to the Representative by wire transfer of immediately available funds to a bank account designated by the Representative in an amount equal to $0.045 per Pre-Funded Warrant and accompanying Common Warrants.

In addition to the foregoing, while any Common Warrants remain outstanding, no later than three business days following the end of each calendar quarter, the Company shall (i) deliver to the Representative a report detailing exercises of Common Warrants and the aggregate amount of cash proceeds received by the Company during the then- ended quarter and (ii) pay to the Underwriters a fee equal to 6.0% of such aggregate cash proceeds.

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5. Conditions to the Underwriters’ Obligations. The obligations of the Company to sell the Securities to the Underwriters and the several obligations of the Underwriters to purchase and pay for the Securities on the Closing Date are subject to the condition that the Registration Statement shall have become effective not later than 5:00 p.m. (New York City time) on the date hereof.

The several obligations of the Underwriters are subject to the following further conditions:

(a) Subsequent to the execution and delivery of this Agreement and prior to the Closing Date:

(i) no order suspending the effectiveness of the Registration Statement shall be in effect, and no proceeding for such purpose or pursuant to Section 8A under the Securities Act shall be pending before or threatened by the Commission; and

(ii) there shall not have occurred any change in the condition, financial or otherwise, or in the earnings, business or operations of the Company and its subsidiaries, taken as a whole, from that set forth in the Time of Sale Prospectus that, in the Representative’s judgment, is material and adverse and that makes it, in the Representative’s judgment, impracticable to market the Securities on the terms and in the manner contemplated in the Time of Sale Prospectus.

(b) The Underwriters shall have received on the Closing Date a certificate, dated the Closing Date and signed by an executive officer of the Company on behalf of the Company, to the effect set forth in Sections 5(a)(i) and 5(a)(ii) above and to the effect that the representations and warranties of the Company contained in this Agreement are true and correct as of the Closing Date and that the Company has complied with all of the agreements and satisfied all of the conditions on its part to be performed or satisfied hereunder on or before the Closing Date.

The executive officer signing and delivering such certificate on behalf of the Company may rely upon his or her knowledge as to proceedings threatened.

(c) The Underwriters shall have received on the Closing Date an opinion and negative assurance letter of Wilmer Cutler Pickering Hale and Dorr LLP, outside counsel for the Company, in form and substance reasonably satisfactory to the Representative.

(d) The Underwriters shall have received on the Closing Date an opinion of Proskauer Rose LLP, outside intellectual property counsel for the Company, dated the Closing Date, in form and substance reasonably satisfactory to the Representative.

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(e) The Underwriters shall have received on the Closing Date an opinion and negative assurance letter of Cooley LLP, counsel for the Underwriters, dated the Closing Date, in form and substance reasonably satisfactory to the Representative.

With respect to the negative assurance letters to be delivered pursuant to Sections 5(c) and 5(e) above, Wilmer Cutler Pickering Hale and Dorr LLP and Cooley LLP may state that their opinions and beliefs are based upon their participation in the preparation of the Registration Statement, the Time of Sale Prospectus and the Prospectus and any amendments or supplements thereto and review and discussion of the contents thereof, but are without independent check or verification, except as specified.

The opinions of Wilmer Cutler Pickering Hale and Dorr LLP, Proskauer Rose LLP and Cooley LLP described in Sections 5(c), 5(d) and 5(e) above shall be rendered to the Underwriters at the request of the Company and shall so state therein.

(f) The Underwriters shall have received, on each of the date hereof and the Closing Date, a letter dated the date hereof or the Closing Date, as the case may be, in form and substance reasonably satisfactory to the Underwriters, from Ernst & Young LLP, independent public accountants, containing statements and information of the type ordinarily included in accountants’ “comfort letters” to underwriters with respect to the financial statements and certain financial information contained in the Registration Statement, the Time of Sale Prospectus and the Prospectus; provided that the letter delivered on the Closing Date shall use a “cut-off date” not earlier than the date hereof.

(g) The “lock-up” agreements, each substantially in the form of Exhibit A hereto, between the Representative and each of the officers and directors of the Company relating to restrictions on sales and certain other dispositions of shares of Common Stock or certain other securities, delivered to the Representative on or before the date hereof, shall be in full force and effect on the Closing Date.

6. Covenants of the Company. The Company covenants with each Underwriter as follows:

(a) To furnish upon request to the Representative, without charge, two signed copies of the Registration Statement (including exhibits thereto and documents incorporated by reference therein) and for delivery to each other Underwriter a conformed copy of the Registration Statement (without exhibits thereto, but including documents incorporated by reference therein) and to furnish to the Representative in New York City, without charge, prior to 10:00 a.m. New York City time on the business day next succeeding the date of this Agreement and during the period mentioned in Section 6(e) or 6(f) below, as many copies of the Time of Sale Prospectus, the Prospectus, and any documents incorporated by reference therein and any supplements and amendments thereto or to the Registration Statement as the Representative may reasonably request.

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(b) Before amending or supplementing the Registration Statement, the Time of Sale Prospectus or the Prospectus, to furnish to the Representative a copy of each such proposed amendment or supplement and not to file any such proposed amendment or supplement to which the Representative reasonably objects in a timely manner, and to file with the Commission within the applicable period specified in Rule 424(b) under the Securities Act any prospectus required to be filed pursuant to such Rule.

(c) To furnish to the Representative a copy of each proposed free writing prospectus to be prepared by or on behalf of, used by, or referred to by the Company and not to use or refer to any proposed free writing prospectus to which the Representative reasonably objects.

(d) Not to take any action that would result in an Underwriter or the Company being required to file with the Commission pursuant to Rule 433(d) under the Securities Act a free writing prospectus prepared by or on behalf of the Underwriter that the Underwriter otherwise would not have been required to file thereunder.

(e) If the Time of Sale Prospectus is being used to solicit offers to buy the Securities at a time when the Prospectus is not yet available to prospective purchasers and any event shall occur or condition exist as a result of which it is necessary to amend or supplement the Time of Sale Prospectus in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, or if any event shall occur or condition exist as a result of which the Time of Sale Prospectus conflicts with the information contained in the Registration Statement then on file, or if, in the opinion of counsel for the Underwriters, it is necessary to amend or supplement the Time of Sale Prospectus to comply with applicable law, forthwith to prepare, file with the Commission and furnish, at its own expense, to the Underwriters and to any dealer upon request, either amendments or supplements to the Time of Sale Prospectus so that the statements in the Time of Sale Prospectus as so amended or supplemented will not, in the light of the circumstances when the Time of Sale Prospectus is delivered to a prospective purchaser, be misleading or so that the Time of Sale Prospectus, as amended or supplemented, will no longer conflict with the Registration Statement, or so that the Time of Sale Prospectus, as amended or supplemented, will comply with applicable law.

(f) If, during such period after the first date of the public offering of the Securities and at any time prior to the date on which the Warrants are no longer outstanding, as in the opinion of counsel for the Underwriters, the Prospectus (or in lieu thereof the notice referred to in Rule 173(a) of the Securities Act) is required by law to be delivered in connection with sales by an Underwriter

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or dealer, any event shall occur or condition exist as a result of which it is necessary to amend or supplement the Prospectus in order to make the statements therein, in the light of the circumstances when the Prospectus (or in lieu thereof the notice referred to in Rule 173(a) of the Securities Act) is delivered to a purchaser, not misleading, or if, in the opinion of counsel for the Underwriters, it is necessary to amend or supplement the Prospectus to comply with applicable law, forthwith to prepare, file with the Commission and furnish, at its own expense, to the Underwriters and to the dealers (whose names and addresses the Representative will furnish to the Company) to which Securities may have been sold by the Representative on behalf of the Underwriters and to any other dealers upon request, either amendments or supplements to the Prospectus so that the statements in the Prospectus as so amended or supplemented will not, in the light of the circumstances when the Prospectus (or in lieu thereof the notice referred to in Rule 173(a) of the Securities Act) is delivered to a purchaser, be misleading or so that the Prospectus, as amended or supplemented, will comply with applicable law.

(g) If required by applicable law, to endeavor to qualify the Securities for offer and sale under the securities or Blue Sky laws of such jurisdictions as the Representative shall reasonably request; provided, however, that nothing contained herein shall require the Company to do business in any jurisdiction, to execute a general consent of service of process in any jurisdiction or to subject itself to taxation in any jurisdiction in which it is not otherwise subject.

(h) To make generally available to the Company’s security holders and to the Representative as soon as reasonably practicable an earnings statement covering a period of at least twelve months beginning with the first fiscal quarter of the Company occurring after the date of this Agreement which shall satisfy the provisions of Section 11(a) of the Securities Act and the rules and regulations of the Commission thereunder; provided however, that the Company will be deemed to have furnished such statement to its security holders to the extent it is filed on the Commission’s Electronic Data Gathering, Analysis and Retrieval System.

(i) Whether or not the transactions contemplated in this Agreement are consummated or this Agreement is terminated, to pay or cause to be paid all expenses incident to the performance of its obligations under this Agreement, including: (i) the fees, disbursements and expenses of the Company’s counsel and the Company’s accountants in connection with the registration and delivery of the Securities and Warrant Shares under the Securities Act, including the costs of reproducing and distributing each of the Warrants, and all other fees or expenses in connection with the preparation and filing of the Registration Statement, any preliminary prospectus, the Time of Sale Prospectus, the Prospectus, any free writing prospectus prepared by or on behalf of, used by, or referred to by the Company and amendments and supplements to any of the foregoing, including all printing costs associated therewith, and the mailing and delivering of copies thereof to the Underwriters and dealers, in the quantities hereinabove specified, (ii) all costs and expenses related to the transfer and delivery of the Securities to

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the Underwriters, including any transfer or other taxes payable thereon, (iii) the cost of printing or producing any Blue Sky memorandum in connection with the offer and sale of the Securities under state securities laws and all expenses in connection with the qualification of the Securities for offer and sale under state securities laws as provided in Section 6(g) hereof, including filing fees and the reasonable and documented fees and disbursements of counsel for the Underwriters in connection with such qualification and in connection with the Blue Sky memorandum (provided that the amount payable by the Company with respect to the fees and disbursements of counsel for the Underwriters pursuant to clause (iii) shall not exceed $3,500 in the aggregate), (iv) all filing fees and the reasonable fees and disbursements of counsel to the Underwriters incurred in connection with the review and qualification of the offering of the Securities by the Financial Industry Regulatory Authority (provided that the amount payable by the Company with respect to the fees and disbursements of counsel for the Underwriters pursuant to clause (iv) shall not exceed $20,000 in the aggregate, (v) all costs and expenses incident to listing the Warrant Shares on the Nasdaq Global Market, (vi) the cost of printing certificates representing the Securities, (vii) the costs and charges of any transfer agent, registrar or depositary, (viii) the costs and expenses of the Company relating to investor presentations on any “road show” undertaken in connection with the marketing of the offering of the Securities, including, without limitation, expenses associated with the preparation or dissemination of any electronic road show, expenses associated with the production of road show slides and graphics, fees and expenses of any consultants engaged in connection with the road show presentations with the prior approval of the Company, travel and lodging expenses of the representatives and officers of the Company and any such consultants, and 50% of the cost of any aircraft or other transportation chartered in connection with the road show (the remaining 50% of the cost of such aircraft to be paid by the Underwriters), if applicable, (ix) the document production charges and expenses associated with printing this Agreement and (x) all other costs and expenses incident to the performance of the obligations of the Company hereunder for which provision is not otherwise made in this Section. It is understood, however, that except as provided in this Section, Section 8 entitled “Indemnity and Contribution” and the last paragraph of Section 10 below, the Underwriters will pay all of their costs and expenses, including fees and disbursements of their counsel, stock transfer taxes payable on resale of any of the Securities by them and any advertising expenses connected with any offers they may make.

(j) The Company will promptly notify the Representative if the Company ceases to be an Emerging Growth Company at any time prior to the later of (i) completion of the distribution of the Securities within the meaning of the Securities Act and (ii) completion of the Restricted Period (as defined in this Section 6).

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(k) If at any time following the distribution of any Testing-the-Waters Communication that is a written communication within the meaning of Rule 405 under the Securities Act there occurred or occurs an event or development as a result of which such Testing-the-Waters Communication included or would include an untrue statement of a material fact or omitted or would omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances existing at that subsequent time, not misleading, the Company will promptly notify the Representative and will promptly amend or supplement, at its own expense, such Testing-the-Waters Communication to eliminate or correct such untrue statement or omission.

(l) The Company shall, at all times while any Warrants are outstanding: (i) use reasonable best efforts to maintain a registration statement covering the issue and sale of the Warrant Shares upon exercise of the Warrants such that the Warrant Shares, when issued, will not be subject to resale restrictions under the Securities Act except to the extent that the Warrant Shares are owned by affiliates, and (ii) reserve and keep available out of the aggregate of its authorized but unissued and otherwise unreserved shares of Common Stock, the number of Warrant Shares that are initially issuable and deliverable upon the exercise of the then-outstanding Warrants, solely for the purpose of enabling it to issue Warrant Shares upon exercise of such Warrants. Notwithstanding this clause 6(l), as further described in the forms of such Warrants appended to this Agreement, the Company does not currently have adequate authorized but unissued shares to cover the Warrant Shares that are expected to be issuable upon issuance of the Warrants on the Closing Date.

The Company also covenants with each Underwriter that, without the prior written consent of the Representative on behalf of the Underwriters, it will not, and will not publicly disclose an intention to, during the period ending 90 days after the date of the Prospectus (the “Restricted Period”), (1) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock or (2) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of Common Stock, whether any such transaction described in clause (1) or (2) above is to be settled by delivery of Common Stock or such other securities, in cash or otherwise, or (3) file any registration statement with the Commission relating to the offering of any shares of Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock other than as any registration statement required to be filed as disclosed in the Registration Statement.

The restrictions contained in the preceding paragraph shall not apply to (A) the Securities to be sold hereunder, including, for the avoidance of doubt, the issuance by the Company of Warrant Shares upon the exercise of the Warrants (B) the issuance by the Company of shares of Common Stock upon the exercise of an option or warrant or the conversion of a security outstanding on the date hereof as described in each of the Time of Sale Prospectus and Prospectus, (C) facilitating the establishment of a trading plan on behalf of a stockholder, officer or director of the Company pursuant to Rule 10b5-1 under the Exchange Act for the transfer of shares of Common Stock, provided that (i) such plan

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does not provide for the transfer of Common Stock during the Restricted Period and (ii) to the extent a public announcement or filing under the Exchange Act, if any, is required of or voluntarily made by the Company regarding the establishment of such plan, such announcement or filing shall include a statement to the effect that no transfer of Common Stock may be made under such plan during the Restricted Period, (D) the grant of any options to purchase shares of Common Stock or other awards granted under a stock incentive plan or stock purchase plan described in the Registration Statement, Time of Sale Prospectus and the Prospectus, and the issuance by the Company of shares of Common Stock upon the exercise thereof, provided that each newly appointed director or officer (including a newly appointed director or officer that is appointed during the Restricted Period) that is a recipient of such securities shall execute and deliver to the Representative a lock-up agreement substantially in the form of Exhibit A hereto covering the remainder of the Restricted Period, (E) the filing by the Company of any registration statement on Form S-8 or a successor form thereto relating to the shares of Common Stock granted pursuant to or reserved for issuance under a stock incentive plan or stock purchase plan described in the Registration Statement, Time of Sale Prospectus and the Prospectus, or (F) shares of Common Stock or other securities issued in connection with a transaction with an unaffiliated third party that includes a debt financing or a bona fide commercial relationship (including joint ventures, marketing or distribution arrangements, collaboration agreements, or intellectual property license agreements) or any acquisition of assets or acquisition of not less than a majority or controlling portion of the equity of another entity, provided that (x) the aggregate number of shares issued pursuant to this clause (F) shall not exceed 5% of the total number of outstanding shares of Common Stock immediately following the issuance and sale of the Securities to be sold hereunder (giving effect to the Warrant Shares issuable upon the exercise of the Warrants) and (y) the recipient of any such shares of Common Stock and securities issued pursuant to this clause (F) during the 90-day restricted period described above shall enter into an agreement substantially in the form of Exhibit A hereto on or prior to such issuance.

7. Covenants of the Underwriters. Each Underwriter, severally and not jointly, covenants with the Company not to take any action that would result in the Company being required to file with the Commission under Rule 433(d) a free writing prospectus prepared by or on behalf of such Underwriter that otherwise would not be required to be filed by the Company thereunder, but for the action of the Underwriter.

8. Indemnity and Contribution. (a) The Company agrees to indemnify and hold harmless each Underwriter, each person, if any, who controls any Underwriter within the meaning of either Section 15 of the Securities Act or Section 20 of the Exchange Act and each affiliate of any Underwriter within the meaning of Rule 405 under the Securities Act from and against any and all losses, claims, damages and liabilities (including, without limitation, any legal or other expenses reasonably incurred in connection with defending or investigating any such action or claim) that arise out of, or are based upon, any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement or any amendment thereof, any preliminary prospectus, the Time of Sale Prospectus or any amendment or supplement thereto, any issuer free writing prospectus as defined in Rule 433(h) under the Securities Act, any

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Company information that the Company has filed, or is required to file, pursuant to Rule 433(d) under the Securities Act, any “road show” as defined in Rule 433(h) under the Securities Act (a “road show”), the Prospectus or any amendment or supplement thereto, or any Testing-the-Waters Communication, or arise out of, or are based upon, any omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, except insofar as such losses, claims, damages or liabilities arise out of, or are based upon, any such untrue statement or omission or alleged untrue statement or omission made in reliance upon and in conformity with any information relating to any Underwriter furnished to the Company in writing by such Underwriter through the Representative expressly for use therein, it being understood and agreed that the only such information furnished by the Underwriters through the Representative consists of the Underwriter Information.

(b) Each Underwriter agrees, severally and not jointly, to indemnify and hold harmless the Company, its directors, its officers who sign the Registration Statement and each person, if any, who controls the Company within the meaning of either Section 15 of the Securities Act or Section 20 of the Exchange Act to the same extent as the foregoing indemnity from the Company to such Underwriter, but only with reference to information relating to such Underwriter furnished to the Company in writing by such Underwriter through the Representative expressly for use in the Registration Statement, any preliminary prospectus, the Time of Sale Prospectus, any issuer free writing prospectus, road show or the Prospectus or any amendment or supplement thereto, it being understood and agreed that the only such information furnished by the Underwriters consists of the Underwriter Information.

(c) In case any proceeding (including any governmental investigation) shall be instituted involving any person in respect of which indemnity may be sought pursuant to Section 8(a) or 8(b), such person (the “indemnified party”) shall promptly notify the person against whom such indemnity may be sought (the “indemnifying party”) in writing and the indemnifying party, upon request of the indemnified party, shall retain counsel reasonably satisfactory to the indemnified party to represent the indemnified party and any others the indemnifying party may designate in such proceeding and shall pay the reasonably incurred and fees and disbursements of such counsel related to such proceeding. In any such proceeding, any indemnified party shall have the right to retain its own counsel, but the fees and expenses of such counsel shall be at the expense of such indemnified party unless (i) the indemnifying party and the indemnified party shall have mutually agreed to the retention of such counsel or (ii) the named parties to any such proceeding (including any impleaded parties) include both the indemnifying party and the indemnified party and representation of both parties by the same counsel would be inappropriate due to actual or potential differing interests between them. It is understood that the indemnifying party shall not, in respect of the legal expenses of any indemnified party in connection with any proceeding or related proceedings in the same jurisdiction, be liable for the reasonably incurred fees and expenses of more than one separate firm (in addition to any local counsel) for all such indemnified parties and that all such reasonably

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incurred fees and expenses shall be reimbursed as they are incurred. Such firm shall be designated in writing by the Representative, in the case of parties indemnified pursuant to Section 8(a), and by the Company, in the case of parties indemnified pursuant to Section 8(b). The indemnifying party shall not be liable for any settlement of any proceeding effected without its written consent, but if settled with such consent or if there be a final judgment for the plaintiff, the indemnifying party agrees to indemnify the indemnified party from and against any loss or liability by reason of such settlement or judgment. Notwithstanding the foregoing sentence, if at any time an indemnified party shall have requested an indemnifying party to reimburse the indemnified party for fees and expenses of counsel as contemplated by the second and third sentences of this paragraph, the indemnifying party agrees that it shall be liable for any settlement of any proceeding effected without its written consent if (i) such settlement is entered into more than 30 days after receipt by such indemnifying party of the aforesaid request and (ii) such indemnifying party shall not have reimbursed the indemnified party in accordance with such request prior to the date of such settlement. No indemnifying party shall, without the prior written consent of the indemnified party, effect any settlement of any pending or threatened proceeding in respect of which any indemnified party is or could have been a party and indemnity could have been sought hereunder by such indemnified party, unless such settlement (x) includes an unconditional release of such indemnified party from all liability on claims that are the subject matter of such proceeding and (y) does not include a statement admitting fault, culpability or a failure to act, by or on behalf of any indemnified party.

(d) To the extent the indemnification provided for in Section 8(a) or 8(b) is unavailable to an indemnified party or insufficient in respect of any losses, claims, damages or liabilities referred to therein, then each indemnifying party under such paragraph, in lieu of indemnifying such indemnified party thereunder, shall contribute to the amount paid or payable by such indemnified party as a result of such losses, claims, damages or liabilities (i) in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and the Underwriters on the other hand from the offering of the Securities or (ii) if the allocation provided by clause 8(d)(i) above is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause 8(d)(i) above but also the relative fault of the Company on the one hand and of the Underwriters on the other hand in connection with the statements or omissions that resulted in such losses, claims, damages or liabilities, as well as any other relevant equitable considerations. The relative benefits received by the Company on the one hand and the Underwriters on the other hand in connection with the offering of the Securities shall be deemed to be in the same respective proportions as the net proceeds from the offering of the Securities (before deducting expenses) received by the Company and the total underwriting discounts and commissions received by the Underwriters, in each case as set forth in the table on the cover of the Prospectus, bear to the aggregate Public Offering Price. The relative fault of the Company on

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the one hand and the Underwriters on the other hand shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company or by the Underwriters and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission. The Underwriters’ respective obligations to contribute pursuant to this Section 8 are several in proportion to the respective number of Securities they have purchased hereunder, and not joint.

(e) The Company and the Underwriters agree that it would not be just or equitable if contribution pursuant to this Section 8 were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation that does not take account of the equitable considerations referred to in Section 8(d). The amount paid or payable by an indemnified party as a result of the losses, claims, damages and liabilities referred to in Section 8(d) shall be deemed to include, subject to the limitations set forth above, any legal or other expenses reasonably incurred by such indemnified party in connection with investigating or defending any such action or claim. Notwithstanding the provisions of this Section 8, no Underwriter shall be required to contribute any amount in excess of the amount by which the total price at which the Securities underwritten by it and distributed to the public were offered to the public exceeds the amount of any damages that such Underwriter has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The remedies provided for in this Section 8 are not exclusive and shall not limit any rights or remedies which may otherwise be available to any indemnified party at law or in equity.

(f) The indemnity and contribution provisions contained in this Section 8 and the representations, warranties and other statements of the Company contained in this Agreement shall remain operative and in full force and effect regardless of (i) any termination of this Agreement, (ii) any investigation made by or on behalf of any Underwriter, any person controlling any Underwriter or any affiliate of any Underwriter or by or on behalf of the Company, its officers or directors or any person controlling the Company and (iii) acceptance of and payment for any of the Securities.

9. Termination. The Underwriters may terminate this Agreement by notice given by the Representative to the Company, if after the execution and delivery of this Agreement and prior to or on the Closing Date, (i) trading generally shall have been suspended or materially limited on, or by, as the case may be, either the New York Stock Exchange or the Nasdaq Global Market, (ii) trading of any securities of the Company shall have been suspended on any exchange or in any over-the-counter market, (iii) a material disruption in securities settlement, payment or clearance services in the United States shall have occurred, (iv) any moratorium on commercial banking activities shall

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have been declared by Federal or New York State authorities or (v) there shall have occurred any outbreak or escalation of hostilities, or any change in financial markets or any calamity or crisis that, in the Representative’s judgment, is material and adverse and which, singly or together with any other event specified in this clause (v), makes it, in the Representative’s judgment, impracticable or inadvisable to proceed with the offer, sale or delivery of the Securities on the terms and in the manner contemplated in the Time of Sale Prospectus or the Prospectus.

10. Effectiveness; Defaulting Underwriters. This Agreement shall become effective upon the execution and delivery hereof by the parties hereto.

If, on the Closing Date, any one or more of the Underwriters shall fail or refuse to purchase Securities that it has or they have agreed to purchase hereunder on such date, and the aggregate number of Securities which such defaulting Underwriter or Underwriters agreed but failed or refused to purchase is not more than one-tenth of the aggregate number of the Securities to be purchased on such date, the other Underwriters shall be obligated severally in the proportions that the number of Securities set forth opposite their respective names in Schedule I bears to the aggregate number of Securities set forth opposite the names of all such non-defaulting Underwriters, or in such other proportions as the Representative may specify, to purchase the Securities which such defaulting Underwriter or Underwriters agreed but failed or refused to purchase on such date; provided that in no event shall the number of Securities that any Underwriter has agreed to purchase pursuant to this Agreement be increased pursuant to this Section 10 by an amount in excess of one-ninth of such number of Securities without the written consent of such Underwriter. If, on the Closing Date, any Underwriter or Underwriters shall fail or refuse to purchase Securities and the aggregate number of Securities with respect to which such default occurs is more than one-tenth of the aggregate number of Securities to be purchased on such date, and arrangements satisfactory to the Representative and the Company for the purchase of such Securities are not made within 36 hours after such default, this Agreement shall terminate without liability on the part of any non-defaulting Underwriter or the Company. In any such case either the Representative or the Company shall have the right to postpone the Closing Date, but in no event for longer than seven days, in order that the required changes, if any, in the Registration Statement, in the Time of Sale Prospectus, in the Prospectus or in any other documents or arrangements may be effected.

If this Agreement shall be terminated by the Underwriters, or any of them, because of any failure or refusal on the part of the Company to comply with the terms or to fulfill any of the conditions of this Agreement, or if for any reason the Company shall be unable to perform its obligations under this Agreement, other than by reason of a default by the Underwriters or following termination of this Agreement pursuant to clauses (i), (iii), (iv) or (v) of Section 9, the Company will reimburse the non-defaulting Underwriters or such Underwriters as have so terminated this Agreement with respect to themselves, severally, for all out-of-pocket expenses (including the reasonably incurred and documented fees and disbursements of their counsel) reasonably incurred and documented by such Underwriters in connection with this Agreement or the offering contemplated hereunder.

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11. Entire Agreement. (a) This Agreement, together with any contemporaneous written agreements and any prior written agreements (to the extent not superseded by this Agreement) that relate to the offering of the Securities, represents the entire agreement between the Company and the Underwriters with respect to the preparation of any preliminary prospectus, the Time of Sale Prospectus, the Prospectus, the conduct of the offering, and the purchase and sale of the Securities.

(b) The Company acknowledges that in connection with the offering of the Securities: (i) the Underwriters have acted at arm’s length, are not agents of, and owe no fiduciary duties to, the Company or any other person, (ii) the Underwriters owe the Company only those duties and obligations set forth in this Agreement, any contemporaneous written agreements and prior written agreements (to the extent not superseded by this Agreement), if any, (iii) the Underwriters may have interests that differ from those of the Company, and (iv) none of the activities of the Underwriters in connection with the transactions contemplated herein constitutes a recommendation, investment advice, or solicitation of any action by the Underwriters with respect to any entity or natural person. The Company waives to the full extent permitted by applicable law any claims it may have against the Underwriters arising from an alleged breach of fiduciary duty in connection with the offering of the Securities.

12. Recognition of the U.S. Special Resolution Regimes. (a) In the event that any Underwriter that is a Covered Entity becomes subject to a proceeding under a U.S. Special Resolution Regime, the transfer from such Underwriter of this Agreement, and any interest and obligation in or under this Agreement, will be effective to the same extent as the transfer would be effective under the U.S. Special Resolution Regime if this Agreement, and any such interest and obligation, were governed by the laws of the United States or a state of the United States.

(b) In the event that any Underwriter that is a Covered Entity or a BHC Act Affiliate of such Underwriter becomes subject to a proceeding under a U.S. Special Resolution Regime, Default Rights under this Agreement that may be exercised against such Underwriter are permitted to be exercised to no greater extent than such Default Rights could be exercised under the U.S. Special Resolution Regime if this Agreement were governed by the laws of the United States or a state of the United States.

For purposes of this Section a “BHC Act Affiliate” has the meaning assigned to the term “affiliate” in, and shall be interpreted in accordance with, 12 U.S.C. § 1841(k). “Covered Entity” means any of the following: (i) a “covered entity” as that term is defined in, and interpreted in accordance with, 12 C.F.R. § 252.82(b); (ii) a “covered bank” as that term is defined in, and interpreted in accordance with, 12 C.F.R. § 47.3(b); or (iii) a “covered FSI” as that term is defined in, and interpreted in accordance with, 12 C.F.R. § 382.2(b). “Default Right” has the meaning assigned to that term in, and shall be interpreted in accordance with, 12 C.F.R. §§ 252.81, 47.2 or 382.1, as applicable. “U.S. Special Resolution Regime” means each of (i) the Federal Deposit Insurance Act and the regulations promulgated thereunder and (ii) Title II of the Dodd-Frank Wall Street Reform and Consumer Protection Act and the regulations promulgated thereunder.

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13. Counterparts. This Agreement may be signed in two or more counterparts, each of which shall be an original, with the same effect as if the signatures thereto and hereto were upon the same instrument. This Agreement may be delivered via facsimile, electronic mail (including pdf or any electronic signature complying with the U.S. federal ESIGN Act of 2000, e.g., www.docusign.com) or other transmission method and any counterpart so delivered shall be deemed to have been duly and validly delivered and be valid and effective for all purposes.

14. Applicable Law. This Agreement shall be governed by and construed in accordance with the internal laws of the State of New York.

15. Headings. The headings of the sections of this Agreement have been inserted for convenience of reference only and shall not be deemed a part of this Agreement.

16. Notices. All communications hereunder shall be in writing and effective only upon receipt and if to the Underwriters shall be delivered, mailed or sent to the Representative in care of Leerink Partners LLC, 1301 Avenue of the Americas, 5th Floor, New York, NY 10019, Attention: Stuart R. Nayman; and if to the Company shall be delivered, mailed or sent to Xilio Therapeutics, Inc., 828 Winter Street, Suite 300, Waltham, MA 02451, Attention: Chief Legal Officer.

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[Signature Page to Underwriting Agreement]

[Signature Page to Underwriting Agreement]

SCHEDULE I

I-1

SCHEDULE II

Time of Sale Prospectus

Preliminary Prospectus dated June 2, 2025.

Securities to be Sold:

Pre-Funded Warrants to Purchase 66,676,000 shares of Common Stock.

Series A Warrants to Purchase 66,676,000 shares of Common Stock (or, in lieu of Common Stock, Pre-Funded Warrants to purchase Common Stock); Exercise price of $0.75 per underlying share of Common Stock.

Series B Warrants to Purchase 66,676,000 shares of Common Stock (or, in lieu of Common Stock, Pre-Funded Warrants to purchase Common Stock); Exercise price of $0.75 per underlying share of Common Stock.

Series C Warrants to Purchase 66,676,000 shares of Common Stock (or, in lieu of Common Stock, Pre-Funded Warrants to purchase Common Stock); Exercise price of $0.75 per underlying share of Common Stock.

Public Offering Price:

$0.74990 per Pre-Funded Warrant and accompanying Common Warrants.

Underwriting Discounts and Commissions: $0.045 per Pre-Funded Warrant and accompanying Common Warrants.

Estimated net proceeds to the Company (after underwriting discounts and commissions, but before transaction expenses, and assuming no exercise of Common Warrants): $47.0 million.

II-1

SCHEDULE III

Written Testing-the-Waters Communications

None.

III-1

EXHIBIT A

FORM OF LOCK-UP AGREEMENT

_____________, 2025

LEERINK PARTNERS LLC

As Representative of the several Underwriters

1301 Avenue of the Americas, 5th Floor

New York, New York 10019

Ladies and Gentlemen:

This letter agreement (this “Agreement”) is being delivered to you in connection with the proposed underwritten offering (the “Offering”) of (i) shares of common stock, par value of $0.0001 per share (the “Common Stock”), (ii) pre-funded warrants to purchase shares of Common Stock and (iii) accompanying warrants to purchase shares of Common Stock, of Xilio Therapeutics, Inc., a Delaware corporation (the “Company”), for which Leerink Partners LLC is acting as representative of a group of underwriters (the “Representative”) pursuant to the underwriting agreement (the “Underwriting Agreement”) to be entered into in connection with the Offering.

The undersigned recognizes that the Offering will benefit each of the Company and the undersigned. The undersigned acknowledges that the Representative is relying on the representations and agreements of the undersigned contained in this Agreement and other arrangements with the Company with respect to the Offering. For good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the undersigned hereby agrees that, during the period beginning on the date hereof and ending 60 days after the date of the final prospectus (the “Restricted Period”) relating to the Offering, the undersigned will not, and will not cause or direct any of its affiliates to, without the prior written consent of the Representative, directly or indirectly (1) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock beneficially owned (as such term is used in Rule 13d-3 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”)), by the undersigned or any other securities so owned convertible into or exercisable or exchangeable for Common Stock, or (2) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of the Common Stock, whether any such transaction described in clause (1) or (2) above is to be settled by delivery of Common Stock or such other securities, in cash or otherwise. The foregoing sentence shall not apply to the following:

(a) transactions relating to shares of Common Stock or other securities acquired in the Offering or in open market transactions after the completion of the Offering, provided that no filing under Section 16(a) of the Exchange Act shall be required or shall be voluntarily made during the Restricted Period in connection with subsequent sales of Common Stock or other securities acquired in the Offering or such open market transactions;

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(b) transfers of shares of Common Stock or any security convertible into or exercisable or exchangeable for Common Stock as a bona fide gift or gifts, or for bona fide estate planning purposes;

(c) transfers or dispositions of shares of Common Stock or any security convertible into or exercisable or exchangeable for Common Stock to any member of the immediate family of the undersigned or any trust for the direct or indirect benefit of the undersigned or the immediate family of the undersigned, or if the undersigned is a trust, to any beneficiary (including such beneficiary’s estate) of the undersigned, in a transaction not involving a disposition for value;

(d) transfers or dispositions of shares of Common Stock or any security convertible into or exercisable or exchangeable for Common Stock to any corporation, partnership, limited liability company or other entity all of the beneficial ownership interests of which are held by the undersigned or a member of the immediate family of the undersigned;

(e) transfers or dispositions of shares of Common Stock or any security convertible into or exercisable or exchangeable for Common Stock (i) by will, other testamentary document or intestate succession to the legal representative, heir, beneficiary or a member of the immediate family of the undersigned upon the death of the undersigned or (ii) in connection with a divorce settlement or solely by operation of law, such as pursuant to a qualified domestic order or court order;

(f) if the undersigned is an entity, transfers or distributions of shares of Common Stock or any security convertible into Common Stock to general or limited partners, members or stockholders of the undersigned, its direct or indirect affiliates (as defined in Rule 405 promulgated under the Securities Act of 1933, as amended) or to an investment fund or other entity that controls or manages, or is under common control with, the undersigned;

provided that in the case of any transfer, disposition or distribution pursuant to clause (b), (c), (d), (e) or (f), (A) each transferee, donee or distributee shall sign and deliver a lock-up agreement substantially in the form of this Agreement, and (B) no public announcement shall be made and no filing under Section 16(a) of the Exchange Act, reporting a reduction in beneficial ownership of shares of Common Stock, shall be required or shall be voluntarily made during the Restricted Period (other than, in the case of a transfer or other disposition pursuant to clause (b), (c) or (e) above, any Form 4 or Form 5 required to be filed under the Exchange Act if the undersigned is subject to Section 16 reporting with respect to the Company under the Exchange Act and indicating by footnote disclosure or otherwise the nature of the transfer or disposition);

(g) transfers or dispositions of shares of Common Stock or any security convertible into or exercisable or exchangeable for Common Stock to the Company pursuant to any contractual arrangement in effect on the date of this Agreement and disclosed to the Representative that provides for the repurchase of the undersigned’s Common Stock or other securities by the Company or in connection with the termination of the undersigned’s employment with or service

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to the Company; provided that no filing under Section 16(a) of the Exchange Act reporting a reduction in beneficial ownership of shares of Common Stock shall be required or shall be voluntarily made during the Restricted Period in connection with any such transfers or dispositions (other than any Form 4 or Form 5 required to be filed under the Exchange Act if the undersigned is subject to Section 16 reporting with respect to the Company under the Exchange Act and indicating by footnote disclosure or otherwise the nature of the transfer or disposition);

(h) the exercise of stock options to purchase shares of Common Stock, granted under any equity incentive plan described in the Company’s Exchange Act filings and any related transfer to the Company of shares of Common Stock (including by way of “net” or “cashless” exercise solely to cover withholding tax obligations in connection with such exercise and any transfer to the Company for the payment of taxes as a result of such exercise); provided that any shares of Common Stock received upon exercise shall be subject to the restrictions on transfer set forth in this Agreement; provided, further, that no filing under Section 16(a) of the Exchange Act reporting a reduction in beneficial ownership of shares of Common Stock shall be required or shall be voluntarily made during the Restricted Period (other than a filing on a Form 4 that reports such disposition under the transaction code “F”);

(i) transfers or dispositions of shares of Common Stock in connection with the vesting or settlement of restricted stock units, so long as such sale is effected pursuant to the Company’s sell to cover policy solely in an amount sufficient to cover withholding taxes due in connection with such restricted stock units; provided that (i) any filing under Section 16(a) of the Exchange Act shall indicate in the footnotes thereto that the filing relates to the applicable circumstances described in this clause and (ii) no other public announcement shall be required or shall be made voluntarily in connection with such transfer;

(j) the establishment of a trading plan pursuant to Rule 10b5-1 under the Exchange Act for the transfer of shares of Common Stock, provided that (i) such plan does not provide for the transfer of Common Stock during the Restricted Period and (ii) to the extent a public announcement or filing under the Exchange Act, if any, is required of or voluntarily made by or on behalf of the undersigned or the Company regarding the establishment of such plan, such announcement or filing shall include a statement to the effect that no transfer of Common Stock may be made under such plan during the Restricted Period; or

(k) (A) transfers of shares of Common Stock (or any securities convertible into or exercisable or exchangeable for Common Stock) pursuant to a bona fide third-party tender offer for shares of the Company’s capital stock made to all holders of the Company’s securities, merger, consolidation or other similar transaction approved by the Company’s board of directors the result of which is that any person (as defined in Section 13(d)(3) of the Exchange Act), or group of persons, other than the Company, becomes the beneficial owner (as defined in Rules 13d-3 and 13d-5 of the Exchange Act) of more than 50% of the total voting power of the voting stock of the Company and (B) entry into any lock-up, voting or similar agreement pursuant to which the undersigned may agree to transfer, sell, tender or otherwise dispose of shares of Common Stock or such other securities in connection with a transaction described in (A) above; provided that in the event that such change of control transaction is not completed, the Common Stock (or any security convertible into or exercisable or exchangeable for Common Stock) owned by the undersigned shall remain subject to the restrictions contained in this Agreement.

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For purposes of this Agreement, “immediate family” shall mean any relationship by blood, marriage, domestic partnership or adoption, not more remote than first cousin.

In addition, the undersigned agrees that, without the prior written consent of the Representative, it will not, during the Restricted Period, make any demand for or exercise any right with respect to, the registration of any shares of Common Stock or any security convertible into or exercisable or exchangeable for Common Stock. The undersigned also agrees and consents to the entry of stop transfer instructions with the Company’s transfer agent and registrar against the transfer of the undersigned’s shares of Common Stock except in compliance with the foregoing restrictions.

The undersigned understands that this Agreement is irrevocable and shall be binding upon the undersigned’s heirs, legal representatives, successors and assigns.

The undersigned acknowledges and agrees that the Representative has not made any recommendation or provided any investment or other advice to the undersigned with respect to this Agreement or the subject matter hereof, nor has the Representative solicited any action from the undersigned with respect to the Offering and the undersigned has consulted their own legal, accounting, financial, regulatory, tax and other advisors with respect to this Agreement and the subject matter hereof to the extent deemed appropriate. The undersigned further acknowledges and agrees that, although the Representative may provide certain Regulation Best Interest and Form CRS disclosures or other related documentation to you in connection with the Offering, the Representative is not making a recommendation to you to participate in the Offering or sell any Shares at the price determined in the Offering and nothing set forth in such disclosures or documentation is intended to suggest that the Representative is making such a recommendation.

The undersigned acknowledges and agrees that the foregoing precludes the undersigned from engaging in any hedging or other transaction designed or intended, or which could reasonably be expected to lead to or result in, a sale or disposition of any shares of Common Stock, or any securities convertible into or exercisable or exchangeable for Common Stock, even if any such sale or disposition transaction or transactions would be made or executed by or on behalf of someone other than the undersigned.

If (i) the Company notifies the Representative in writing that it does not intend to proceed with the Offering, (ii) the Underwriting Agreement (other than the provisions thereof which survive termination) shall terminate or be terminated prior to payment for and delivery of the securities to be sold thereunder, or (iii) the Underwriting Agreement is not executed by June 30, 2025, then this Agreement shall immediately be terminated and the undersigned shall automatically be released from all of his, her or its obligations under this Agreement. The undersigned acknowledges and agrees that whether or not any offering of securities actually occurs depends on a number of factors, including market conditions.

This Agreement shall be governed by and construed in accordance with the laws of the State of New York.

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4

Exhibit 4.1

THE ISSUER HAS FILED A REGISTRATION STATEMENT (INCLUDING A PROSPECTUS) WITH THE COMMISSION FOR THE OFFERING TO WHICH THIS COMMUNICATION RELATES. BEFORE YOU INVEST, YOU SHOULD READ THE PROSPECTUS IN THAT REGISTRATION STATEMENT AND OTHER DOCUMENTS THE ISSUER HAS FILED WITH THE COMMISSION FOR MORE COMPLETE INFORMATION ABOUT THE ISSUER AND THIS OFFERING. YOU MAY GET THESE DOCUMENTS FOR FREE BY VISITING EDGAR ON THE COMMISSION WEB SITE AT WWW.SEC.GOV.

XILIO THERAPEUTICS, INC.

FORM OF PRE-FUNDED WARRANT TO PURCHASE COMMON STOCK

Number of Warrant Shares: [_________]

(subject to adjustment)

Xilio Therapeutics, Inc., a Delaware corporation (the “Company”), hereby certifies that, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, [___________] or its permitted assigns (the “Holder”), is entitled, subject to the terms set forth below, to purchase from the Company up to a total of [______] shares of common stock, $0.0001 par value per share (the “Common Stock”), of the Company (each such share, a “Warrant Share” and all such shares, the “Warrant Shares”) at an exercise price per share equal to $0.0001 per share (as adjusted from time to time as provided in Section 9 herein, the “Exercise Price”), upon surrender of this Pre-Funded Warrant to Purchase Common Stock (including any Warrants to Purchase Common Stock issued in exchange, transfer or replacement hereof, the “Warrant”) at any time and from time to time on or after the date hereof (the “Original Issue Date”), and until the Warrant is exercised in full (the “Termination Date”), subject to the following terms and conditions:

1. Definitions. For purposes of this Warrant, the following terms shall have the following meanings:

(a) “Affiliate” means any Person that, directly or indirectly through one or more intermediaries, controls or is controlled by or is under common control with, a Holder, as such terms are used in and construed under Rule 405 under the Securities Act, but only for so long as such control shall continue.

(b) “Attribution Parties” means, collectively, the following Persons and entities: (i) any direct or indirect Affiliates of the Holder, (ii) any Person acting or who reasonably could be deemed to be acting as a Group together with the Holder or any of the foregoing and (iii) any other Persons whose beneficial ownership of the Company’s Common Stock reasonably could be aggregated with the Holder’s and the other Attribution Parties for purposes of Section 13(d) or Section 16 of the Exchange Act. For clarity, the purpose of the foregoing is to subject collectively the Holder and all other Attribution Parties to the Maximum Percentage.

(c) “Available Shares” means authorized but unissued shares of Common Stock that are available for issuance by the Company (excluding any shares that are issuable upon exercise, conversion or exchange of outstanding options, warrants or other securities or are reserved under any equity plan maintained by the Company).

(d) “Commission” means the United States Securities and Exchange Commission.

(e) “Closing Sale Price” means, for any security as of any date, the last trade price for such security on the Principal Trading Market for such security, as reported by Bloomberg Financial Markets, or, if such Principal Trading Market begins to operate on an extended hours basis and does not designate the last trade price, then the last trade price of such security prior to 4:00 P.M., New York City time, as reported by Bloomberg Financial Markets, or if the foregoing do not apply, the last trade price of such security in the over-the-counter market on the electronic bulletin board for such security as reported by Bloomberg Financial Markets, or, if no last trade price is reported for such security by Bloomberg Financial Markets, the average of the bid and ask prices of any market makers for such security as reported in the OTC Link or “pink sheets” by OTC Markets Group Inc. (formerly OTC Markets Inc.) as of 4:00 P.M., New York City time on such date. If the Closing Sale Price cannot be calculated for a security on a particular date on any of the foregoing bases, the Closing Sale Price of such security on such date shall be the fair market value as mutually determined by the Company and the Holder. If the Company and the Holder are unable to agree upon the fair market value of such security, then the Board of Directors of the Company shall use its good faith judgment to determine the fair market value. The determination of the Board of Directors of the Company shall be binding upon all parties absent demonstrable error. All such determinations shall be appropriately adjusted for any stock dividend, stock split, stock combination or other similar transaction during the applicable calculation period.

(f) “Exchange Act” means the Securities Exchange Act of 1934, as amended.

(g) “Group” shall have the meaning ascribed to it in Section 13(d) of the Exchange Act, and all related rules, regulations and jurisprudence.

(h) “Person” means an individual, a limited liability company, a partnership, a joint venture, a corporation, a trust, an unincorporated organization, any other entity and a government or any department or agency thereof.

(i) “Principal Trading Market” means the national securities exchange or other trading market on which the Common Stock is primarily listed on and quoted for trading, which, as of the Original Issue Date shall be the Nasdaq Global Select Market.

(j) “Registration Statement” means the Company’s Registration Statement on Form S-3 (File No. 333-285703), that became effective on May 8, 2025.

(k) “Securities Act” means the Securities Act of 1933, as amended.

(l) “Standard Settlement Period” means the standard settlement period, expressed in a number of Trading Days, for the Company’s primary trading market or quotation system with respect to the Common Stock that is in effect on the date of delivery of an applicable Exercise Notice, which as of the Original Issue Date was “T+1”.

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(m) “Trading Day” means any weekday on which the Principal Trading Market is open for trading. If the Common Stock is not listed or admitted for trading, “Trading Day” means any day except any Saturday, any Sunday, any day which is a federal legal holiday in the United States or any day on which banking institutions in New York City are authorized or required by law or other governmental action to close.

(n) “Transfer Agent” means Computershare Trust Company, N.A., the Company’s transfer agent and registrar for the Common Stock, and any successor appointed in such capacity, or if none, the Company.

2. Issuance of Securities; Registration of Warrants. The Warrant, as initially issued by the Company, is offered and sold pursuant to the Registration Statement. As of the Original Issue Date, the Warrant Shares are issuable under the Registration Statement. Accordingly, the Warrant and, assuming issuance pursuant to the Registration Statement or an exchange meeting the requirements of Section 3(a)(9) of the Exchange Act as in effect on the Original Issue Date, the Warrant Shares are not “restricted securities” under Rule 144 promulgated under the Securities Act. The Company shall register ownership of this Warrant, upon records to be maintained by the Company for that purpose (the “Warrant Register”), in the name of the record Holder (which shall include the initial Holder or, as the case may be, any assignee to which this Warrant is permissibly assigned hereunder) from time to time. The Company may deem and treat the registered Holder of this Warrant as the absolute owner and holder hereof for the purpose of any exercise hereof or any distribution to the Holder, and for all other purposes, absent actual notice to the contrary.

3. Registration of Transfers. Subject to compliance with all applicable securities laws, the Company shall, or will cause its Transfer Agent to, register the transfer of all or any portion of this Warrant in the Warrant Register, upon surrender of this Warrant, and payment for all applicable transfer taxes (if any) by the Holder or any subsequent Holder. Upon any such registration or transfer, a new warrant to purchase Common Stock in substantially the form of this Warrant (any such new warrant, a “New Warrant”) evidencing the portion of this Warrant so transferred shall be issued to the transferee, and a New Warrant evidencing the remaining portion of this Warrant not so transferred, if any, shall be issued to the transferring Holder. The acceptance of the New Warrant by the transferee thereof shall be deemed the acceptance by such transferee of all of the rights and obligations in respect of the New Warrant that the Holder has in respect of this Warrant. The Company shall, or will cause its Transfer Agent to, prepare, issue and deliver at the Company’s own expense any New Warrant under this Section 3. Until due presentment for registration of transfer, the Company may deem and treat the registered Holder hereof as the owner and holder for all purposes, and the Company shall not be affected by any notice to the contrary.

4. Exercise and Duration of Warrants.

(a) All or any part of this Warrant shall be exercisable by the registered Holder in the manner set forth herein (including in Section 10) at any time and from time to time on or after the Original Issue Date and on or before the Termination Date, subject to the limitations set forth in Section 11 of this Warrant.

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(b) The Holder may exercise this Warrant by delivering to the Company (i) an exercise notice, in the form attached as Schedule 1 hereto (the “Exercise Notice”), completed and duly signed, and (ii) payment of the Exercise Price for the number of Warrant Shares as to which this Warrant is being exercised (which may take the form of a “cashless exercise” if so indicated in the Exercise Notice pursuant to Section 10 below), and the date on which the last of such items is delivered to the Company (as determined in accordance with the notice provisions hereof) is an “Exercise Date.” The Holder shall not be required to deliver the original Warrant in order to effect an exercise hereunder. Execution and delivery of the Exercise Notice shall have the same effect as cancellation of the original Warrant and issuance of a New Warrant evidencing the right to purchase the remaining number of Warrant Shares, if any. The Holder and any assignee, by acceptance of this Warrant, acknowledge and agree that, by reason of the provisions of this paragraph, following the purchase of a portion of the Warrant Shares hereunder, the number of Warrant Shares available for purchase hereunder at any given time may be less than the amount stated on the face hereof.

5. Delivery of Warrant Shares.

(a) Upon exercise of this Warrant in accordance with the terms of this Warrant (including Section 10), the Company shall promptly (but in no event later than the number of Trading Days comprising the Standard Settlement Period following the Exercise Date), upon the request of the Holder, credit or instruct the Transfer Agent to credit such aggregate number of shares of Common Stock to which the Holder is entitled pursuant to such exercise to the Holder’s or its designee’s balance account with The Depository Trust Company (“DTC”) through its Deposit Withdrawal At Custodian system, provided that the Transfer Agent is then a participant in the DTC Fast Automated Securities Transfer (“FAST”) Program and either (i) there is an effective registration statement permitting the issuance of such Warrant Shares to or resale of such Warrant Shares by the Holder or (ii) such Warrant Shares are eligible for resale under Rule 144(b)(1) promulgated under the Securities Act, and otherwise issue such Warrant Shares in the name of the Holder or its designee in restricted book-entry form in the Company’s share register. The Company agrees to maintain a transfer agent that is a participant in the FAST program so long as this Warrant remains outstanding and exercisable. The Holder, or any Person permissibly so designated by the Holder to receive Warrant Shares, shall be deemed to have become the holder of record of such Warrant Shares as of the Exercise Date, irrespective of the date such Warrant Shares are credited to the Holder’s or its designee’s DTC account or the date of the book-entry positions evidencing such Warrant Shares, as the case may be. The Holder acknowledges that the Warrant Shares acquired upon the exercise of this Warrant, if issued in restricted book-entry form, will contain a customary legend to the effect that the Warrant Shares are not registered.

(b) If within the Standard Settlement Period after the Exercise Date, the Company fails to deliver to the Holder or its designee the required number of Warrant Shares in the manner required pursuant to Section 5(a) or fails to credit the Holder’s or its designee’s balance account with DTC for such number of Warrant Shares to which the Holder is entitled, and if after such number of Trading Days comprising the Standard Settlement Period and prior to the receipt of such Warrant Shares, the Holder purchases (in an open market transaction or otherwise) shares of Common Stock to deliver in satisfaction of a sale by the Holder of the Warrant Shares which the Holder anticipated receiving upon such exercise (a “Buy-In”), then the Company shall,

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within two (2) Trading Days after the Holder’s request promptly honor its obligation to deliver to the Holder or its designee such Warrant Shares and pay cash to the Holder in an amount equal to the excess (if any) of Holder’s total purchase price (including brokerage commissions, if any) for the shares of Common Stock so purchased in the Buy-In less the product of (i) the number of shares of Common Stock purchased in the Buy-In, times (ii) the Closing Sale Price of a share of Common Stock on the Exercise Date.

(c) To the extent permitted by law and subject to Section 5(b), the Company’s obligations to issue and deliver Warrant Shares in accordance with and subject to the terms hereof (including the limitations set forth in Section 11 below) are absolute and unconditional, irrespective of any action or inaction by the Holder to enforce the same, any waiver or consent with respect to any provision hereof, the recovery of any judgment against any Person or any action to enforce the same, or any setoff, counterclaim, recoupment, limitation or termination, or any breach or alleged breach by the Holder or any other Person of any obligation to the Company or any violation or alleged violation of law by the Holder or any other Person, and irrespective of any other circumstance that might otherwise limit such obligation of the Company to the Holder in connection with the issuance of Warrant Shares. Subject to Section 5(b), nothing herein shall limit the Holder’s right to pursue any other remedies available to it hereunder, at law or in equity including, without limitation, a decree of specific performance and/or injunctive relief with respect to the Company’s failure to timely deliver shares of Common Stock upon exercise of the Warrant as required pursuant to the terms hereof.

6. Charges, Taxes and Expenses. Issuance and delivery of shares of Common Stock upon exercise of this Warrant shall be made without charge to the Holder for any issue or transfer tax, transfer agent fee or other incidental tax or expense (excluding any applicable stamp duties) in respect of the issuance of such shares, all of which taxes and expenses shall be paid by the Company; provided, however, that the Company shall not be required to pay any tax that may be payable in respect of any transfer involved in the registration of any Warrant Shares or the Warrants in a name other than that of the Holder or an Affiliate thereof. The Holder shall be responsible for all other tax liability that may arise as a result of holding or transferring this Warrant or receiving Warrant Shares upon exercise hereof.

7. Replacement of Warrant. If this Warrant is mutilated, lost, stolen or destroyed, the Company shall issue or cause to be issued in exchange and substitution for and upon cancellation hereof, or in lieu of and substitution for this Warrant, a New Warrant, but only upon receipt of evidence reasonably satisfactory to the Company of such loss, theft or destruction (in such case) and, in each case, a customary and reasonable indemnity and surety bond, if requested by the Company. Applicants for a New Warrant under such circumstances shall also comply with such other reasonable regulations and procedures and pay such other reasonable third-party costs as the Company may prescribe. If a New Warrant is requested as a result of a mutilation of this Warrant, then the Holder shall deliver such mutilated Warrant to the Company as a condition precedent to the Company’s obligation to issue the New Warrant.

8. Reservation of Warrant Shares.

(a) The Company covenants that, subject to Section 8(b) hereof, it will, at all times while this Warrant is outstanding, reserve and keep available out of the aggregate of its authorized but unissued and otherwise unreserved Common Stock, solely for the purpose of enabling it to issue

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Warrant Shares upon exercise of this Warrant as herein provided, the number of Warrant Shares that are issuable and deliverable upon the exercise of this entire Warrant (the “Number of Warrant Shares”), free from preemptive rights or any other contingent purchase rights of Persons other than the Holder (taking into account the adjustments and restrictions of Section 9). The failure of the Company to reserve and keep available out of the aggregate of its authorized but unissued and otherwise unreserved Common Stock a sufficient number of shares of Common Stock to enable it to issue Warrant Shares upon exercise of this Warrant as herein provided is referred to herein as an “Authorized Share Failure.” The Company covenants that all Warrant Shares so issuable and deliverable shall, upon issuance and the payment of the applicable Exercise Price in accordance with the terms hereof, be duly and validly authorized, issued and fully paid and non-assessable. The Company will take all such action as may be reasonably necessary to assure that such shares of Common Stock may be issued as provided herein without violation of any applicable law or regulation, or of any requirements of any securities exchange or automated quotation system upon which the Common Stock may be listed. The Company further covenants that it will not, without the prior written consent of the Holder, take any actions to increase the par value of the Common Stock at any time while this Warrant is outstanding. In furtherance of the Company’s obligations set forth in this Section 8, as soon as practicable after the date of the occurrence of an Authorized Share Failure, but in no event later than ninety (90) days after the occurrence of such Authorized Share Failure, the Company shall hold a meeting of its stockholders for the approval of an increase in the number of authorized shares of Common Stock. In connection with such meeting, the Company shall provide each stockholder with a proxy statement and shall use its reasonable best efforts to solicit its stockholders’ approval of such increase in authorized shares of Common Stock and to cause its Board of Directors to recommend to the stockholders that they approve such proposal. Notwithstanding the foregoing, if at any such time of an Authorized Share Failure, the Company is able to obtain the written consent of a majority of the shares of its issued and outstanding shares of Common Stock to approve the increase in the number of authorized shares of Common Stock, the Company may satisfy this obligation by obtaining such consent and submitting for filing with the Commission an Information Statement on Schedule 14C.

(b) Notwithstanding Section 8(a) above, the Holder acknowledges and agrees that, as of the Original Issue Date, the Company does not have sufficient Available Shares for the purpose of issuing all of the Warrant Shares which may be issued upon the exercise of this Warrant. Therefore, as soon as practicable after the date hereof, but in any event, no later than one hundred and eighty (180) days following the Original Issue Date, the Company shall hold a meeting of its stockholders for the approval of an increase in the number of authorized shares of Common Stock (the “Stockholder Resolution”). In connection with such meeting, the Company shall provide each stockholder with a proxy statement and shall use its reasonable best efforts to solicit its stockholders’ approval of such increase in authorized shares of Common Stock and to cause its Board of Directors to recommend to the stockholders that they approve the Stockholder Resolution. If, despite the Company’s reasonable best efforts, approval of the Stockholder Resolution is not obtained by October 31, 2025, the Company shall cause an additional stockholder meeting to be held every one hundred and eighty (180) calendar days thereafter until approval of the Stockholder Resolution is obtained. As soon as practicable following the approval of the Stockholder Resolution by the Company’s stockholders, the Company shall amend its certificate of incorporation to effect such increase to its authorized shares.

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9. Certain Adjustments. The Exercise Price and the Number of Warrant Shares issuable upon exercise of this Warrant are subject to adjustment from time to time as set forth in this Section 9.

(a) Stock Dividends and Splits. If the Company, at any time while this Warrant is outstanding, (i) pays a stock dividend on its Common Stock or otherwise makes a distribution on any class of capital stock issued and outstanding on the Original Issue Date and in accordance with the terms of such stock on the Original Issue Date or as amended, that is payable in shares of Common Stock, (ii) subdivides its outstanding shares of Common Stock into a larger number of shares of Common Stock, (iii) combines its outstanding shares of Common Stock into a smaller number of shares of Common Stock or (iv) issues by reclassification of shares of capital stock any additional shares of Common Stock, then in each such case the Number of Warrant Shares shall be multiplied by a fraction, the numerator of which shall be the number of shares of Common Stock outstanding immediately after such event and the denominator of which shall be the number of shares of Common Stock outstanding immediately before such event. Any adjustment made pursuant to clause (i) of this paragraph shall become effective immediately after the record date for the determination of stockholders entitled to receive such dividend or distribution, provided, however, that if such record date shall have been fixed and such dividend is not fully paid on the date fixed therefor, the Number of Warrant Shares shall be recomputed accordingly as of the close of business on such record date and thereafter the Number of Warrant Shares shall be adjusted pursuant to this paragraph as of the time of actual payment of such dividends. Any adjustment pursuant to clause (ii), (iii) or (iv) of this paragraph shall become effective immediately after the effective date of such subdivision, combination or re-classification.

(b) Pro Rata Distributions. If the Company, at any time while this Warrant is outstanding, distributes to all holders of Common Stock for no consideration (i) evidences of its indebtedness, (ii) any security (other than a distribution of Common Stock covered by the preceding paragraph), (iii) rights or warrants to subscribe for or purchase any security (including Common Stock), or (iv) cash or any other asset (in each case, a “Distribution”), other than a reclassification as to which Section 9(c) applies, then in each such case, the Holder shall be entitled to participate in such Distribution to the same extent that the Holder would have participated therein if the Holder had held the number of shares of Common Stock acquirable upon complete exercise of this Warrant (without regard to any limitations or restrictions on exercise of this Warrant, including without limitation, the Maximum Percentage (as defined below)) immediately before the date on which a record is taken for such Distribution, or, if no such record is taken, the date as of which the record holders of shares of Common Stock are to be determined for the participation in such Distribution; provided, that to the extent that the Holder’s right to participate in any such Distribution would result in the Holder and the other Attribution Parties exceeding the Maximum Percentage, then the Holder shall not be entitled to participate in such Distribution to such extent (and shall not be entitled to beneficial ownership of such shares of Common Stock as a result of such Distribution (and beneficial ownership) to such extent) and the portion of such Distribution shall be held in abeyance for the benefit of the Holder until such time or times as (all or a portion) its right thereto would not result in the Holder and the other Attribution Parties exceeding the Maximum Percentage, at which time or times the Holder shall be granted (all or such portion of) such Distribution (and any Distributions declared or made on such initial Distribution or on any subsequent Distribution held similarly in abeyance) to the same extent as if there had been no such limitation.

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(c) Fundamental Transactions. If, at any time while this Warrant is outstanding (i) the Company effects any merger or consolidation of the Company with or into another Person, in which the Company is not the surviving entity or the stockholders of the Company immediately prior to such merger or consolidation do not own, directly or indirectly, at least 50% of the voting power of the surviving entity immediately after such merger or consolidation, (ii) the Company effects any sale to another Person of all or substantially all of its assets in one transaction or a series of related transactions, (iii) pursuant to any tender offer or exchange offer (whether by the Company or another Person), holders of capital stock tender shares representing more than 50% of the voting power of the capital stock of the Company and the Company or such other Person, as applicable, accepts such tender for payment, (iv) the Company consummates a stock purchase agreement or other business combination (including, without limitation, a reorganization, recapitalization, spin-off or scheme of arrangement) with another Person whereby such other Person acquires more than the 50% of the voting power of the capital stock of the Company (except for any such transaction in which the stockholders of the Company immediately prior to such transaction maintain, in substantially the same proportions, the voting power of such Person immediately after the transaction) or (v) the Company effects any reclassification of the Common Stock or any compulsory share exchange pursuant to which the Common Stock is effectively converted into or exchanged for other securities, cash or property (other than as a result of a subdivision or combination of shares of Common Stock covered by Section 9(a) above) (in any such case, a “Fundamental Transaction”), then following such Fundamental Transaction but prior to the Termination Date the Holder shall have the right to receive, upon exercise of this Warrant, the same amount and kind of securities, cash or property as it would have been entitled to receive upon the occurrence of such Fundamental Transaction if it had been, immediately prior to such Fundamental Transaction, the holder of the Number of Warrant Shares without regard to any limitations on exercise contained herein (in the case of clause (iii) above, assuming it had tendered, and the offeror had accepted, such Warrant Shares) (the “Alternate Consideration”). The Company shall not effect any Fundamental Transaction in which the Company is not the surviving entity or the Alternate Consideration includes securities of another Person unless (i) the Alternate Consideration is solely cash and the Company provides for the simultaneous “cashless exercise” of this Warrant pursuant to Section 10 below or (ii) prior to or simultaneously with the consummation thereof, any successor to the Company, surviving entity or other Person (including any purchaser of assets of the Company) shall assume the obligation to deliver to the Holder such Alternate Consideration as, in accordance with the foregoing provisions, the Holder may be entitled to receive, and the other obligations under this Warrant. The provisions of this paragraph (c) shall similarly apply to subsequent transactions analogous of a Fundamental Transaction type.

(d) Exercise Price. Simultaneously with any adjustment to the Number of Warrant Shares pursuant to Section 9, the Exercise Price shall be increased or decreased proportionately, so that after such adjustment, the aggregate Exercise Price payable hereunder for the increased or decreased Number of Warrant Shares shall be the same as the aggregate Exercise Price in effect immediately prior to such adjustment. Notwithstanding the foregoing, in no event may the Exercise Price be adjusted below the par value of the Common Stock then in effect.

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(e) Calculations. All calculations under this Section 9 shall be made to the nearest one-hundredth of one cent or the nearest whole share, as applicable.

(f) Notice of Adjustments. Upon the occurrence of each adjustment pursuant to this Section 9, the Company at its expense will, at the written request of the Holder, promptly compute such adjustment, in good faith, in accordance with the terms of this Warrant and prepare a certificate setting forth such adjustment, including a statement of the adjusted Exercise Price and adjusted number or type of Warrant Shares or other securities issuable upon exercise of this Warrant (as applicable), describing the transactions giving rise to such adjustments and showing in detail the facts upon which such adjustment is based. Upon written request, the Company will promptly deliver a copy of each such certificate to the Holder and to the Transfer Agent.

(g) Notice of Corporate Events. If, while this Warrant is outstanding, the Company (i) declares a dividend or any other distribution of cash, securities or other property in respect of its Common Stock, including, without limitation, any granting of rights or warrants to subscribe for or purchase any capital stock of the Company or any subsidiary, (ii) authorizes or approves, enters into any agreement contemplating or solicits stockholder approval for any Fundamental Transaction or (iii) authorizes the voluntary dissolution, liquidation or winding up of the affairs of the Company, then, except if such notice and the contents thereof shall be deemed to constitute material non-public information, the Company shall deliver to the Holder a notice of such transaction at least ten (10) days prior to the applicable record or effective date on which a Person would need to hold Common Stock in order to participate in or vote with respect to such transaction; provided, however, that the failure to deliver such notice or any defect therein shall not affect the validity of the corporate action required to be described in such notice. In addition, if while this Warrant is outstanding, the Company authorizes or approves, enters into any agreement contemplating or solicits stockholder approval for any Fundamental Transaction contemplated by Section 9(c), other than a Fundamental Transaction under clause (iii) of Section 9(c), then, except if such notice and the contents thereof shall be deemed to constitute material non-public information, the Company shall deliver to the Holder a notice of such Fundamental Transaction at least ten (10) days prior to the date such Fundamental Transaction is consummated.

10. Exercise. Notwithstanding anything contained herein to the contrary, the Holder may, in its sole discretion, exercise this Warrant, whether in whole or in part, and in lieu of making the cash payment otherwise contemplated to be made to the Company upon such exercise in payment of the Exercise Price, through a “cashless exercise.” Upon such cashless exercise, the Company shall issue to the Holder the number of Warrant Shares in an exchange of securities effected pursuant to Section 3(a)(9) of the Securities Act, determined as follows:

X = Y [(A-B)/A]

where:

“X” equals the number of Warrant Shares to be issued to the Holder;

“Y” equals the total number of Warrant Shares with respect to which this Warrant is then being exercised;

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“A” equals the Closing Sale Price per share of Common Stock (as reported by Bloomberg Financial Markets) as of the Trading Day on the date immediately preceding the Exercise Date; and

“B” equals the Exercise Price per Warrant Share then in effect on the Exercise Date.

For purposes of Rule 144 promulgated under the Securities Act, it is intended, understood and acknowledged that the Warrant Shares issued in such a “cashless exercise” transaction shall be deemed to have been acquired by the Holder, the Warrant Shares shall take on the registered characteristics of the Warrants being exercised, and the holding period for the Warrant Shares shall be deemed to have commenced, on the date this Warrant was originally issued (provided that the Commission continues to take the position that such treatment is proper at the time of such exercise).

11. Limitations on Exercise.

(a) The Holder shall be prohibited from exercising this Warrant if, immediately prior to or following such exercise (or portion of such exercise thereof), the Holder, together with its Attribution Parties, collectively beneficially owns or would beneficially own as determined in accordance with Section 13(d) of the Exchange Act more than [4.99]/[9.99][19.99]% (the “Maximum Percentage”) of the issued and outstanding Common Stock or any other class of equity security (other than an exempted security) of the Company that is registered pursuant to Section 12 of the Exchange Act immediately after giving effect to such exercise. For purposes of calculating beneficial ownership, the aggregate number of shares of Common Stock beneficially owned by the Holder, together with its Attribution Parties, shall include the number of shares of Common Stock held by the Holder and all other Attribution Parties plus the number of shares of Common Stock issuable upon exercise of this Warrant with respect to which the determination is being made, but shall exclude the number of shares of Common Stock which are issuable upon (i) exercise of the remaining, unexercised portion of this Warrant beneficially owned by the Holder, together with its Attribution Parties, and (ii) exercise or conversion of the unexercised or unconverted portion of any other securities of the Company beneficially owned by the Holder, together with its Attribution Parties (including, without limitation, any convertible notes, convertible stock or warrants) that are subject to a limitation on conversion or exercise analogous to the limitation contained herein. For purposes of this Section 11(a), beneficial ownership shall be calculated and determined in accordance with Section 13(d) of the Exchange Act and the rules promulgated thereunder, it being acknowledged and agreed that the Holder is solely responsible for any schedules required to be filed in accordance therewith. For purposes of this Warrant, in determining the number of outstanding shares of Common Stock, the Holder may rely on the number of outstanding shares of Common Stock as reflected in (1) the Company’s most recent Annual Report on Form 10-K, Quarterly Report on Form 10-Q, Current Report on Form 8-K or other public filing with the Commission, as the case may be, (2) a more recent public announcement by the Company or (3) any other written notice by the Company or the Transfer Agent setting forth the number of shares of Common Stock outstanding (the “Reported Outstanding Share Number”). If the Company receives an Exercise Notice from the Holder at a time when the actual number of outstanding shares of Common Stock is less than the Reported Outstanding Share Number, the Company shall (i) notify the Holder in writing of the number of shares of Common Stock then outstanding and, to the extent that such Exercise Notice would

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otherwise cause the Holder’s beneficial ownership, as determined pursuant to this Section 11(a), to exceed the Maximum Percentage, the Holder must notify the Company of a reduced number of Warrant Shares to be purchased pursuant to such Exercise Notice (the number of shares by which such purchase is reduced, the “Reduction Shares”) and (ii) as soon as reasonably practicable, the Company shall return to the Holder any exercise price paid by the Holder for the Reduction Shares. For any reason at any time, upon the written request of the Holder, the Company shall within one (1) Trading Day confirm to the Holder the number of shares of Common Stock then outstanding. In any case, the number of outstanding shares of Common Stock shall be determined after giving effect to the conversion or exercise of securities of the Company, including this Warrant, by the Holder and any other Attribution Party since the date as of which the Reported Outstanding Share Number was reported. In the event that the issuance of Common Stock to the Holder upon exercise of this Warrant results in the Holder and the other Attribution Parties being deemed to beneficially own, in the aggregate, more than the Maximum Percentage of the number of outstanding shares of Common Stock (as determined under Section 13(d) of the Exchange Act), the number of shares so issued by which the Holder’s and the other Attribution Parties’ aggregate beneficial ownership exceeds the Maximum Percentage (the “Excess Shares”) shall be deemed null and void and shall be cancelled ab initio, and the Holder shall not have the power to vote or to transfer the Excess Shares. As soon as reasonably practicable after the issuance of the Excess Shares has been deemed null and void, the Company shall return to the Holder the exercise price paid by the Holder for the Excess Shares. By written notice to the Company, the Holder may from time to time increase or decrease the Maximum Percentage to any other percentage (not in excess of 19.99% if exceeding that limit would result in a change of control under Nasdaq Listing Rule 5635(b) or any successor rule) specified in such notice; provided that any increase in the Maximum Percentage will not be effective until the sixty-first (61st) day after such notice is delivered to the Company.

(b) Notwithstanding anything herein to the contrary, the Company shall not issue, and the Holder may not acquire, a number of Warrant Shares upon exercise of this Warrant, and the Company shall not otherwise deliver any Warrant Shares pursuant to this Warrant, to the extent that the issuance of such Warrant Shares would exceed the number of Available Shares (the “Available Shares Ownership Cap”), except that such limitation shall not apply in the event that the Company obtains approval of the Stockholder Resolution and files an amendment to its certificate of incorporation with the Secretary of State of the State of Delaware to effect an increase in its authorized shares to cover the issuance of such Warrant Shares.

(c) For purposes of clarity, the shares of Common Stock issuable pursuant to the terms of this Warrant in excess of the Maximum Percentage or the Available Shares Ownership Cap shall not be deemed to be beneficially owned by the Holder for any purpose including for purposes of Section 13(d) of the Exchange Act or Rule 16a-1(a)(1) promulgated under the Exchange Act. No prior inability to exercise this Warrant pursuant to this Section 11 shall have any effect on the applicability of the provisions of this Section 11 with respect to any subsequent determination of exercisability. The provisions of this Section 11 shall be construed and implemented in a manner otherwise than in strict conformity with the terms of this Section 11 to the extent necessary to correct this section or any portion hereof that may be defective or inconsistent with the intended limitations contained in this Section 11 or to make changes or supplements necessary or desirable to properly give effect to such limitations. The limitations contained in this Section 11 may not be waived and shall apply to a successor holder of this Warrant.

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(d) Section 11(a) shall not restrict the number of shares of Common Stock which a Holder may receive or beneficially own in order to determine the amount of securities or other consideration that such Holder may receive in the event of a Fundamental Transaction as contemplated in Section 9(c) of this Warrant.

12. No Fractional Shares. No fractional Warrant Shares will be issued in connection with any exercise of this Warrant. In lieu of any fractional shares that would otherwise be issuable, the number of Warrant Shares to be issued shall be rounded down to the next whole number.

13. Notices. Any and all notices or other communications or deliveries hereunder (including, without limitation, any Exercise Notice) shall be in writing and shall be deemed given and effective on the earliest of (i) the date of transmission, if such notice or communication is delivered via confirmed e-mail prior to 5:30 P.M., New York City time, on a Trading Day, (ii) the next Trading Day after the date of transmission, if such notice or communication is delivered via confirmed e-mail on a day that is not a Trading Day or later than 5:30 P.M., New York City time, on any Trading Day, (iii) the Trading Day following the date of mailing, if sent by nationally recognized overnight courier service specifying next business day delivery, or (iv) upon actual receipt by the Person to whom such notice is required to be given, if by hand delivery. The addresses and e-mail addresses for such communications shall be:

If to the Company, to:

Xilio Therapeutics, Inc.

828 Winter Street, Suite 300

Waltham, MA 02451

Attention: Chief Financial Officer and Chief Operating Officer

Email: [email protected]

with a copy (which shall not constitute notice) to:

Wilmer Cutler Pickering Hale and Dorr LLP

60 State Street

Boston, MA 02109

Attention: Cynthia T. Mazareas

Email: [email protected]

If to the Holder, at such address or other contact information delivered by the Holder to the Company or as is on the books and records of the Company.

Or, in each of the above instances, to such other address or e-mail address as the recipient party has specified by written notice given to each other party at least five (5) days prior to the effectiveness of such change.

14. Warrant Agent. The Company shall initially serve as warrant agent under this Warrant. Upon ten (10) days’ notice to the Holder, the Company may appoint a new warrant agent. Any entity into which the Company or any new warrant agent may be merged or any entity resulting from any consolidation to which the Company or any new warrant agent shall be a party or any

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entity to which the Company or any new warrant agent transfers substantially all of its corporate trust or shareholders services business shall be a successor warrant agent under this Warrant without any further act. Any such successor warrant agent shall promptly cause notice of its succession as warrant agent to be mailed (by first class mail, postage prepaid) to the Holder at the Holder’s last address as shown on the Warrant Register.

15. Miscellaneous.

(a) Minimum Price Floor Requirement. The Company covenants that any future equity issuance occurring between the Original Issue Date and the earlier of (i) December 1, 2026, or (ii) the expiration or exercise of all of the Series B Warrants and Series C Warrants to Purchase Common Stock issued on the Original Issue Date, shall be subject to a minimum purchase price of $1.50 per share (the “Minimum Price Floor”); provided, however, that the Minimum Price Floor may be waived with prior approval of holders of a majority of the then-outstanding Series B Warrants and Series C Warrants to Purchase Common Stock issued on the Original Issue Date, voting together as a single series; provided, further, that if a majority of all of the Pre-Funded Warrants to Purchase Common Stock issued on the Original Issue Date are exercised prior to December 1, 2025, the Minimum Price Floor shall be $1.00 per share.

(b) No Rights as a Stockholder. Except as otherwise set forth in this Warrant, the Holder, solely in such Person’s capacity as a holder of this Warrant, shall not be entitled to vote or receive dividends or be deemed the holder of share capital of the Company for any purpose, nor shall anything contained in this Warrant be construed to confer upon the Holder, solely in such Person’s capacity as the Holder of this Warrant, any of the rights of a stockholder of the Company or any right to vote, give or withhold consent to any corporate action (whether any reorganization, issue of stock, reclassification of stock, consolidation, merger, amalgamation, conveyance or otherwise), receive notice of meetings, receive dividends or subscription rights, or otherwise, prior to the issuance to the Holder of the Warrant Shares which such Person is then entitled to receive upon the due exercise of this Warrant. In addition, nothing contained in this Warrant shall be construed as imposing any liabilities on the Holder to purchase any securities (upon exercise of this Warrant or otherwise) or as a stockholder of the Company, whether such liabilities are asserted by the Company or by creditors of the Company.

(c) Authorized Shares. Except and to the extent as waived or consented to by the Holder, the Company shall not by any action, including, without limitation, amending its certificate or articles of incorporation or through any reorganization, transfer of assets, consolidation, merger, dissolution, issue or sale of securities or any other voluntary action, avoid or seek to avoid the observance or performance of any of the terms of this Warrant, but will at all times in good faith assist in the carrying out of all such terms and in the taking of all such actions as may be necessary or appropriate to protect the rights of Holder as set forth in this Warrant against impairment. Without limiting the generality of the foregoing, the Company will (a) not increase the par value of any Warrant Shares above the amount payable therefor upon such exercise immediately prior to such increase in par value, (b) take all such action as may be necessary or appropriate in order that the Company may validly and legally issue fully paid and non-assessable Warrant Shares upon the exercise of this Warrant, and (c) use commercially reasonable efforts to obtain all such authorizations, exemptions or consents from any public regulatory body having jurisdiction thereof as may be necessary to enable the Company to perform its obligations under this Warrant.

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(d) Successors and Assigns. Subject to compliance with applicable securities laws, this Warrant may be transferred or assigned by the Holder. This Warrant may not be assigned by the Company without the written consent of the Holder, except to a successor in the event of a Fundamental Transaction. This Warrant shall be binding on and inure to the benefit of the Company and the Holder and their respective successors and assigns. Subject to the preceding sentence, nothing in this Warrant shall be construed to give to any Person other than the Company and the Holder any legal or equitable right, remedy or cause of action under this Warrant. This Warrant may be amended only in writing signed by the Company and the Holder, or their successors and assigns.

(e) Amendment and Waiver. Except as otherwise provided herein, this Warrant may be modified or amended or the provisions hereof waived with the written consent of the Company and the Holder.

(f) Acceptance. Receipt of this Warrant by the Holder shall constitute acceptance of and agreement to all of the terms and conditions contained herein.

(g) Governing Law; Jurisdiction. ALL QUESTIONS CONCERNING THE CONSTRUCTION, VALIDITY, ENFORCEMENT AND INTERPRETATION OF THIS WARRANT SHALL BE GOVERNED BY AND CONSTRUED AND ENFORCED IN ACCORDANCE WITH THE LAWS OF THE STATE OF DELAWARE WITHOUT REGARD TO THE PRINCIPLES OF CONFLICTS OF LAW THEREOF. EACH OF THE COMPANY AND THE HOLDER HEREBY IRREVOCABLY SUBMITS TO THE EXCLUSIVE JURISDICTION OF THE STATE AND FEDERAL COURTS SITTING IN THE STATE OF DELAWARE, FOR THE ADJUDICATION OF ANY DISPUTE HEREUNDER OR IN CONNECTION HEREWITH OR WITH ANY TRANSACTION CONTEMPLATED HEREBY OR DISCUSSED HEREIN (INCLUDING WITH RESPECT TO THE ENFORCEMENT OF ANY OF THE TRANSACTION DOCUMENTS), AND HEREBY IRREVOCABLY WAIVES, AND AGREES NOT TO ASSERT IN ANY SUIT, ACTION OR PROCEEDING, ANY CLAIM THAT IT IS NOT PERSONALLY SUBJECT TO THE JURISDICTION OF ANY SUCH COURT. EACH OF THE COMPANY AND THE HOLDER HEREBY IRREVOCABLY WAIVES PERSONAL SERVICE OF PROCESS AND CONSENTS TO PROCESS BEING SERVED IN ANY SUCH SUIT, ACTION OR PROCEEDING BY MAILING A COPY THEREOF VIA REGISTERED OR CERTIFIED MAIL OR OVERNIGHT DELIVERY (WITH EVIDENCE OF DELIVERY) TO SUCH PERSON AT THE ADDRESS IN EFFECT FOR NOTICES TO IT AND AGREES THAT SUCH SERVICE SHALL CONSTITUTE GOOD AND SUFFICIENT SERVICE OF PROCESS AND NOTICE THEREOF. NOTHING CONTAINED HEREIN SHALL BE DEEMED TO LIMIT IN ANY WAY ANY RIGHT TO SERVE PROCESS IN ANY MANNER PERMITTED BY LAW. EACH OF THE COMPANY AND THE HOLDER HEREBY WAIVES ALL RIGHTS TO A TRIAL BY JURY.

(h) Headings. The headings herein are for convenience only, do not constitute a part of this Warrant and shall not be deemed to limit or affect any of the provisions hereof.

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(i) Severability. In case any one or more of the provisions of this Warrant shall be invalid or unenforceable in any respect, the validity and enforceability of the remaining terms and provisions of this Warrant shall not in any way be affected or impaired thereby, and the Company and the Holder will attempt in good faith to agree upon a valid and enforceable provision which shall be a commercially reasonable substitute therefor, and upon so agreeing, shall incorporate such substitute provision in this Warrant.

[REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

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IN WITNESS WHEREOF, the Company has caused this Warrant to be duly executed by its authorized officer as of the date first indicated above.

[Signature Page to the Warrant Agreement]

SCHEDULE 1

FORM OF EXERCISE NOTICE

[To be executed by the Holder to purchase shares of Common Stock under the Warrant]

XILIO THERAPEUTICS, INC.

Ladies and Gentlemen:

(1) The undersigned is the Holder of Pre-Funded Warrant to Purchase Common Stock No. ___ (the “Warrant”) issued by Xilio Therapeutics, Inc., a Delaware corporation (the “Company”). Capitalized terms used herein and not otherwise defined herein have the respective meanings set forth in the Warrant.

(2) The undersigned hereby exercises its right to purchase ___________ Warrant Shares pursuant to the Warrant.

(3) Payment of the Exercise Price shall take the form of (check applicable box):

☐ Cash exercise in lawful money of the United States (wire transfer or cashier’s check drawn on a United States bank); or

☐ a “Cashless Exercise” under Section 10 of the Warrant.

(4) Pursuant to this Exercise Notice, the Company shall deliver to the Holder the applicable number of Warrant Shares determined in accordance with the terms of the Warrant. The Warrant Shares shall be delivered to the following DWAC Account number:

(5) By its delivery of this Exercise Notice, the undersigned represents and warrants to the Company that in giving effect to the exercise evidenced hereby the Holder will not beneficially own in excess of the number of shares of Common Stock (as determined in accordance with Section 13(d) of the Securities Exchange Act of 1934, as amended) permitted to be owned under Section 11(a) of the Warrant to which this notice relates.

(Signature must conform in all respects to name of Holder as specified on the face of the Warrant)

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Exhibit 4.2

THE ISSUER HAS FILED A REGISTRATION STATEMENT (INCLUDING A PROSPECTUS) WITH THE COMMISSION FOR THE OFFERING TO WHICH THIS COMMUNICATION RELATES. BEFORE YOU INVEST, YOU SHOULD READ THE PROSPECTUS IN THAT REGISTRATION STATEMENT AND OTHER DOCUMENTS THE ISSUER HAS FILED WITH THE COMMISSION FOR MORE COMPLETE INFORMATION ABOUT THE ISSUER AND THIS OFFERING. YOU MAY GET THESE DOCUMENTS FOR FREE BY VISITING EDGAR ON THE COMMISSION WEB SITE AT WWW.SEC.GOV.

XILIO THERAPEUTICS, INC.

FORM OF SERIES [A]/[B]/[C] WARRANT TO PURCHASE COMMON STOCK

Xilio Therapeutics, Inc., a Delaware corporation (the “Company”), hereby certifies that, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, [___________] or its permitted assigns (the “Holder”), is entitled, subject to the terms set forth below, to purchase from the Company up to a total of [______] shares of common stock, $0.0001 par value per share (the “Common Stock”), of the Company (each such share, a “Warrant Share” and all such shares, the “Warrant Shares”) at an exercise price per share equal to $0.75 per share (as adjusted from time to time as provided in Section 9 and Section 1(g) herein, the “Exercise Price”), upon surrender of this Warrant to Purchase Common Stock (including any Warrants to Purchase Common Stock issued in exchange, transfer or replacement hereof, the “Warrant”) at any time and from time to time on or after the Initial Exercise Date and at or prior to the Expiration Time, subject to the following terms and conditions:

1. Definitions. For purposes of this Warrant, the following terms shall have the following meanings:

(a) “Affiliate” means any Person that, directly or indirectly through one or more intermediaries, controls or is controlled by or is under common control with, a Holder, as such terms are used in and construed under Rule 405 under the Securities Act, but only for so long as such control shall continue.

(b) “Attribution Parties” means, collectively, the following Persons and entities: (i) any direct or indirect Affiliates of the Holder, (ii) any Person acting or who could be deemed to be acting as a Group together with the Holder or any of the foregoing and (iii) any other Persons whose beneficial ownership of the Common Stock could be aggregated with the Holder’s and the other Attribution Parties for purposes of Section 13(d) or Section 16 of the Exchange Act. For clarity, the purpose of the foregoing is to subject collectively the Holder and all other Attribution Parties to the Maximum Percentage.

(c) “Available Shares” means authorized but unissued shares of Common Stock that are available for issuance by the Company (excluding any shares that are issuable upon exercise, conversion or exchange of outstanding options, warrants or other securities or are reserved under any equity plan maintained by the Company).

(d) “Commission” means the United States Securities and Exchange Commission.

(e) “Closing Sale Price” means, for any security as of any date, the last trade price for such security on the Principal Trading Market for such security, as reported by Bloomberg Financial Markets, or, if such Principal Trading Market begins to operate on an extended hours basis and does not designate the last trade price, then the last trade price of such security prior to 4:00 P.M., New York City time, as reported by Bloomberg Financial Markets, or if the foregoing do not apply, the last trade price of such security in the over-the-counter market on the electronic bulletin board for such security as reported by Bloomberg Financial Markets, or, if no last trade price is reported for such security by Bloomberg Financial Markets, the average of the bid and ask prices of any market makers for such security as reported in the OTC Link or “pink sheets” by OTC Markets Group Inc. (formerly OTC Markets Inc.) as of 4:00 P.M., New York City time on such date. If the Closing Sale Price cannot be calculated for a security on a particular date on any of the foregoing bases, the Closing Sale Price of such security on such date shall be the fair market value as mutually determined by the Company and the Holder. If the Company and the Holder are unable to agree upon the fair market value of such security, then the Board of Directors of the Company shall use its good faith judgment to determine the fair market value. The determination of the Board of Directors of the Company shall be binding upon all parties absent demonstrable error. All such determinations shall be appropriately adjusted for any stock dividend, stock split, stock combination or other similar transaction during the applicable calculation period.

(f) “Exchange Act” means the Securities Exchange Act of 1934, as amended.

(g) “Expiration Time” means [SERIES A: the earlier of (i) 5:00 P.M. New York City time on June [ ], 2030 or (ii) immediately upon the exercise of the Holder’s Pre-Funded Warrants to Purchase Common Stock issued on the Original Issue Date, if such exercise is prior to December 1, 2025, provided that if such Pre-Funded Warrant is not exercised in full, this Warrant shall expire with respect to only that number of Warrant Shares that is equal to the number of shares of Common Stock with respect to which the Pre-Funded Warrant is then exercised, and, provided, further, that prior to December 1, 2025, with respect to only that number of Warrant Shares that is equal to the number of shares of Common stock with respect to which the Pre-Funded Warrant remains unexercised, beginning on the first Trading Day immediately following a period of five (5) consecutive Trading Days on which the Closing Sale Price of the Common Stock is a minimum of $1.50 per share, “Expiration Time” shall instead mean 5:00 P.M. New York City time on June [ ], 2030.] / [SERIES B: 5:00 P.M. New York City time on December 2, 2025, provided, however, that if the Closing Sale Price is below the Exercise Price at such Expiration Time, the Exercise Price shall reset to the Closing Sale Price as of December 1, 2025 and the Expiration Time shall be extended to December 31, 2025, and provided, further, that if the Stockholder Resolution is not obtained by the Outside Approval Date (as defined below), the Expiration Time shall be extended to the date that is [thirty] days following the date of approval of the Stockholder Resolution.] / [SERIES C: the earlier of (i) 5:00 P.M. New York City time on December 2, 2026 or (ii) if the Holder’s Series B Warrant to Purchase Common Stock (the “Series B Warrant”) issued on the Original Issue Date expires without being exercised at the “Expiration Time” as defined in such Series B Warrant, at such “Expiration Time”; provided that

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this Warrant shall expire with respect to only that number of Warrant Shares that is equal to the number of shares of Common Stock with respect to which the Series B Warrant expires unexercised; provided, further, that if the Closing Sale Price is below the Exercise Price at such Expiration Time, the Exercise Price shall reset to the Closing Sale Price as of December 1, 2026 and the Expiration Time shall be extended to December 31, 2026.]

(h) “Group” shall have the meaning ascribed to it in Section 13(d) of the Exchange Act, and all related rules, regulations and jurisprudence.

(i) “Initial Exercise Date” means [SERIES A: the earlier of (i) December 1, 2025 and (ii) the Trading Day immediately following a period of five (5) consecutive Trading Days on which the Closing Sale Price of the Common Stock is a minimum of $1.50 per share] / [SERIES B: November 1, 2025] / [SERIES C: June 1, 2026].

(j) “Original Issue Date” means the date hereof.

(k) “Person” means an individual, a limited liability company, a partnership, a joint venture, a corporation, a trust, an unincorporated organization, any other entity and a government or any department or agency thereof.

(l) “Principal Trading Market” means the national securities exchange or other trading market on which the Common Stock is primarily listed on and quoted for trading, which, as of the Original Issue Date shall be the Nasdaq Global Select Market.

(m) “Registration Statement” means the Company’s Registration Statement on Form S-3 (File No. 333-285703), that became effective on May 8, 2025.

(n) “Securities Act” means the Securities Act of 1933, as amended.

(o) “Standard Settlement Period” means the standard settlement period, expressed in a number of Trading Days, for the Company’s primary trading market or quotation system with respect to the Common Stock that is in effect on the date of delivery of an applicable Exercise Notice, which as of the Original Issue Date was “T+1”.

(p) “Trading Day” means any weekday on which the Principal Trading Market is open for trading. If the Common Stock is not listed or admitted for trading, “Trading Day” means any day except any Saturday, any Sunday, any day which is a federal legal holiday in the United States or any day on which banking institutions in New York City are authorized or required by law or other governmental action to close.

(q) “Transfer Agent” means Computershare Trust Company, N.A., the Company’s transfer agent and registrar for the Common Stock, and any successor appointed in such capacity, or if none, the Company.

2. Issuance of Securities; Registration of Warrants. The Warrant, as initially issued by the Company, is offered and sold pursuant to the Registration Statement. As of the Original Issue Date, the Warrant Shares are issuable under the Registration Statement. Accordingly, the Warrant and, assuming issuance pursuant to the Registration Statement or an exchange meeting the requirements of Section 3(a)(9) of the Exchange Act as in effect on the Original Issue Date, the Warrant Shares are not “restricted securities” under Rule 144 promulgated under the

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Securities Act. The Company shall register ownership of this Warrant, upon records to be maintained by the Company for that purpose (the “Warrant Register”), in the name of the record Holder (which shall include the initial Holder or, as the case may be, any assignee to which this Warrant is permissibly assigned hereunder) from time to time. The Company may deem and treat the registered Holder of this Warrant as the absolute owner and holder hereof for the purpose of any exercise hereof or any distribution to the Holder, and for all other purposes, absent actual notice to the contrary.

3. Registration of Transfers. Subject to compliance with all applicable securities laws, the Company shall, or will cause its Transfer Agent to, register the transfer of all or any portion of this Warrant in the Warrant Register, upon surrender of this Warrant, and payment for all applicable transfer taxes (if any) by the Holder or any subsequent Holder. Upon any such registration or transfer, a new warrant to purchase Common Stock in substantially the form of this Warrant (any such new warrant, a “New Warrant”) evidencing the portion of this Warrant so transferred shall be issued to the transferee, and a New Warrant evidencing the remaining portion of this Warrant not so transferred, if any, shall be issued to the transferring Holder. The acceptance of the New Warrant by the transferee thereof shall be deemed the acceptance by such transferee of all of the rights and obligations in respect of the New Warrant that the Holder has in respect of this Warrant. The Company shall, or will cause its Transfer Agent to, prepare, issue and deliver at the Company’s own expense any New Warrant under this Section 3. Until due presentment for registration of transfer, the Company may deem and treat the registered Holder hereof as the owner and holder for all purposes, and the Company shall not be affected by any notice to the contrary.

4. Exercise and Duration of Warrants.

(a) All or any part of this Warrant shall be exercisable by the registered Holder in the manner set forth herein (including in Section 10 [SERIES B/C:, if applicable,] and Section 4(b)) at any time and from time to time on or after the Initial Exercise Date and through and including the Expiration Time, subject to the limitations set forth in Section 11 of this Warrant.

(b) [SERIES A: The Holder may exercise this Warrant by delivering to the Company (i) an exercise notice, in the form attached as Schedule 1 hereto (the “Exercise Notice”), completed and duly signed, and (ii) payment of the Exercise Price for the number of Warrant Shares as to which this Warrant is being exercised (which may take the form of a “cashless exercise” as so indicated in the Exercise Notice pursuant to Section 10 below), and the date on which the last of such items is delivered to the Company (as determined in accordance with the notice provisions hereof) is an “Exercise Date.” The Holder shall not be required to deliver the original Warrant in order to effect an exercise hereunder. Execution and delivery of the Exercise Notice shall have the same effect as cancellation of the original Warrant and issuance of a New Warrant evidencing the right to purchase the remaining number of Warrant Shares, if any.] / [SERIES B/C: The Holder may exercise this Warrant by delivering to the Company an exercise notice, in the form attached as Schedule 1 hereto (the “Exercise Notice”), completed and duly signed, and payment of the Exercise Price for the number of Warrant Shares as to which this Warrant is being exercised by wire transfer to the Company (which may take the form of a “cashless exercise” as permitted pursuant to Section 10 below). The date on which the last of such items is delivered to the Company (as determined in accordance with the notice provisions hereof) is an “Exercise Date.” The Holder shall not be required to deliver the original Warrant in order to

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effect an exercise hereunder. Execution and delivery of the Exercise Notice (provided that payment of the Exercise Price has then been received by the Company) shall have the same effect as cancellation of the original Warrant and issuance of a New Warrant evidencing the right to purchase the remaining number of Warrant Shares, if any.] The Holder and any assignee, by acceptance of this Warrant, acknowledge and agree that, by reason of the provisions of this paragraph, following the purchase of a portion of the Warrant Shares hereunder, the number of Warrant Shares available for purchase hereunder at any given time may be less than the amount stated on the face hereof.

[SERIES B/C: (c) At the sole discretion of the Company, this Warrant and the corresponding Warrant Shares shall be subject to offset and cancellation on a dollar-for-dollar basis (applied ratably among all Warrants of the same class) against the amount of Non-Dilutive Capital received by the Company between the Original Issue Date and December 1, 2026, without any compensation paid to the Holder (the “Warrant Cancellation”). For the purposes of this Section 4(c), “Non-Dilutive Capital” shall consist of (i) milestone payments and option fees received by the Company pursuant to any collaboration, license or similar agreement entered into prior to the Original Issue Date; (ii) upfront payments, milestone payments and option fees received by the Company pursuant to any collaboration, license or similar agreement entered into after the Original Issue Date; and (iii) net proceeds received by the Company pursuant to any equity issuance (other than the issuance of shares of Common Stock or grant of any options to purchase shares of Common Stock or other awards granted or issued to employees, directors, consultants and advisors pursuant to a plan, agreement or arrangement and disclosed in the Registration Statement) after the Original Issue Date where the sale price per share is above $1.50; provided, however, that for purposes of clauses (i) and (ii) above, (A) Non-Dilutive Capital shall not include any amounts received by the Company for the reimbursement of expenses or amounts intended to fund future development expenses (e.g., payments intended to fund future clinical trial expenses), as reasonably determined by the Company and (B) the aggregate amount of Non-Dilutive Capital received after the Original Issue Date must be equal to at least $20 million before the Warrant Cancellation may be triggered. For illustration purposes only, if the Company receives $1,000,000 in Non-Dilutive Capital between the Original Issue Date and December 1, 2026, the Company may elect to offset and cancel a portion of this Warrant in an amount equivalent to the ratable portion of $1,000,000 worth of Warrant Shares (allocated ratably among all Warrant Holders) valued at the Exercise Price[; provided that [SERIES B: the Warrant Cancellation shall first apply to the Holder’s Series C Warrants to Purchase Common Stock issued on the Original Issue Date, ensuring the full outstanding amount of such warrants is offset and cancelled against the amount of Non-Dilutive Capital before any Warrant Cancellation is applied to this Warrant]/[SERIES C: the Warrant Cancellation shall first apply to this Warrant, ensuring the full outstanding amount of this Warrant is offset and cancelled against the amount of Non-Dilutive Capital before any Warrant Cancellation is applied to the Holder’s other warrants]].]

5. Delivery of Warrant Shares.

(a) Upon exercise of this Warrant in accordance with the terms of this Warrant [SERIES A: (including Section 10[SERIES B/C:, if applicable,]), the Company shall promptly (but in no event later than the number of Trading Days comprising the Standard Settlement Period following the Exercise Date), upon the request of the Holder, credit or instruct the Transfer Agent to credit such aggregate number of shares of Common Stock to which the Holder is

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entitled pursuant to such exercise to the Holder’s or its designee’s balance account with The Depository Trust Company (“DTC”) through its Deposit Withdrawal At Custodian system, provided that the Transfer Agent is then a participant in the DTC Fast Automated Securities Transfer (“FAST”) Program and either (i) there is an effective registration statement permitting the issuance of such Warrant Shares to or resale of such Warrant Shares by the Holder or (ii) such Warrant Shares are eligible for resale under Rule 144(b)(1) promulgated under the Securities Act, and otherwise issue such Warrant Shares in the name of the Holder or its designee in restricted book-entry form in the Company’s share register. The Company agrees to maintain a transfer agent that is a participant in the FAST program so long as this Warrant remains outstanding and exercisable. The Holder, or any Person permissibly so designated by the Holder to receive Warrant Shares, shall be deemed to have become the holder of record of such Warrant Shares as of the Exercise Date, irrespective of the date such Warrant Shares are credited to the Holder’s or its designee’s DTC account or the date of the book-entry positions evidencing such Warrant Shares, as the case may be. The Holder acknowledges that the Warrant Shares acquired upon the exercise of this Warrant, if issued in restricted book-entry form, will contain a customary legend to the effect that the Warrant Shares are not registered.

(b) If within the Standard Settlement Period after the Exercise Date, the Company fails to deliver to the Holder or its designee the required number of Warrant Shares in the manner required pursuant to Section 5(a) or fails to credit the Holder’s or its designee’s balance account with DTC for such number of Warrant Shares to which the Holder is entitled, and if after such number of Trading Days comprising the Standard Settlement Period and prior to the receipt of such Warrant Shares, the Holder purchases (in an open market transaction or otherwise) shares of Common Stock to deliver in satisfaction of a sale by the Holder of the Warrant Shares which the Holder anticipated receiving upon such exercise (a “Buy-In”), then the Company shall, within two (2) Trading Days after the Holder’s request promptly honor its obligation to deliver to the Holder or its designee such Warrant Shares and pay cash to the Holder in an amount equal to the excess (if any) of Holder’s total purchase price (including brokerage commissions, if any) for the shares of Common Stock so purchased in the Buy-In less the product of (i) the number of shares of Common Stock purchased in the Buy-In, times (ii) the Closing Sale Price of a share of Common Stock on the Exercise Date.

(c) To the extent permitted by law and subject to Section 5(b), the Company’s obligations to issue and deliver Warrant Shares in accordance with and subject to the terms hereof (including the limitations set forth in Section 11 below) are absolute and unconditional, irrespective of any action or inaction by the Holder to enforce the same, any waiver or consent with respect to any provision hereof, the recovery of any judgment against any Person or any action to enforce the same, or any setoff, counterclaim, recoupment, limitation or termination, or any breach or alleged breach by the Holder or any other Person of any obligation to the Company or any violation or alleged violation of law by the Holder or any other Person, and irrespective of any other circumstance that might otherwise limit such obligation of the Company to the Holder in connection with the issuance of Warrant Shares. Subject to Section 5(b), nothing herein shall limit the Holder’s right to pursue any other remedies available to it hereunder, at law or in equity including, without limitation, a decree of specific performance and/or injunctive relief with respect to the Company’s failure to timely deliver shares of Common Stock upon exercise of the Warrant as required pursuant to the terms hereof.

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6. Charges, Taxes and Expenses. Issuance and delivery of shares of Common Stock upon exercise of this Warrant shall be made without charge to the Holder for any issue or transfer tax, transfer agent fee or other incidental tax or expense (excluding any applicable stamp duties) in respect of the issuance of such shares, all of which taxes and expenses shall be paid by the Company; provided, however, that the Company shall not be required to pay any tax that may be payable in respect of any transfer involved in the registration of any Warrant Shares or the Warrants in a name other than that of the Holder or an Affiliate thereof. The Holder shall be responsible for all other tax liability that may arise as a result of holding or transferring this Warrant or receiving Warrant Shares upon exercise hereof.

7. Replacement of Warrant. If this Warrant is mutilated, lost, stolen or destroyed, the Company shall issue or cause to be issued in exchange and substitution for and upon cancellation hereof, or in lieu of and substitution for this Warrant, a New Warrant, but only upon receipt of evidence reasonably satisfactory to the Company of such loss, theft or destruction (in such case) and, in each case, a customary and reasonable indemnity and surety bond, if requested by the Company. Applicants for a New Warrant under such circumstances shall also comply with such other reasonable regulations and procedures and pay such other reasonable third-party costs as the Company may prescribe. If a New Warrant is requested as a result of a mutilation of this Warrant, then the Holder shall deliver such mutilated Warrant to the Company as a condition precedent to the Company’s obligation to issue the New Warrant.

8. Reservation of Warrant Shares.

(a) The Company covenants that, subject to Section 8(b) hereof, it will, at all times while this Warrant is outstanding, reserve and keep available out of the aggregate of its authorized but unissued and otherwise unreserved Common Stock, solely for the purpose of enabling it to issue Warrant Shares upon exercise of this Warrant as herein provided, the number of Warrant Shares that are issuable and deliverable upon the exercise of this entire Warrant (the “Number of Warrant Shares”), free from preemptive rights or any other contingent purchase rights of Persons other than the Holder (taking into account the adjustments and restrictions of Section 9). The failure of the Company to reserve and keep available out of the aggregate of its authorized but unissued and otherwise unreserved Common Stock a sufficient number of shares of Common Stock to enable it to issue Warrant Shares upon exercise of this Warrant as herein provided is referred to herein as an “Authorized Share Failure.” The Company covenants that all Warrant Shares so issuable and deliverable shall, upon issuance and the payment of the applicable Exercise Price in accordance with the terms hereof, be duly and validly authorized, issued and fully paid and non-assessable. The Company will take all such action as may be reasonably necessary to assure that such shares of Common Stock may be issued as provided herein without violation of any applicable law or regulation, or of any requirements of any securities exchange or automated quotation system upon which the Common Stock may be listed. The Company further covenants that it will not, without the prior written consent of the Holder, take any actions to increase the par value of the Common Stock at any time while this Warrant is outstanding. In furtherance of the Company’s obligations set forth in this Section 8, as soon as practicable after the date of the occurrence of an Authorized Share Failure, but in no event later than ninety (90) days after the occurrence of such Authorized Share Failure, the Company shall hold a meeting of its stockholders for the approval of an increase in the number of authorized shares of Common Stock. In connection with such meeting, the Company shall provide each stockholder with a proxy statement and shall use its reasonable best efforts to solicit its stockholders’ approval of

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such increase in authorized shares of Common Stock and to cause its Board of Directors to recommend to the stockholders that they approve such proposal. Notwithstanding the foregoing, if at any such time of an Authorized Share Failure, the Company is able to obtain the written consent of a majority of the shares of its issued and outstanding shares of Common Stock to approve the increase in the number of authorized shares of Common Stock, the Company may satisfy this obligation by obtaining such consent and submitting for filing with the Commission an Information Statement on Schedule 14C.

(b) Notwithstanding Section 8(a) above, the Holder acknowledges and agrees that, as of the Original Issue Date, the Company does not have sufficient Available Shares for the purpose of issuing all of the Warrant Shares which may be issued upon the exercise of this Warrant. Therefore, as soon as practicable after the date hereof, but in any event, no later than one hundred and eighty (180) days following the Original Issue Date, the Company shall hold a meeting of its stockholders for the approval of an increase in the number of authorized shares of Common Stock (the “Stockholder Resolution”). In connection with such meeting, the Company shall provide each stockholder with a proxy statement and shall use its reasonable best efforts to solicit its stockholders’ approval of such increase in authorized shares of Common Stock and to cause its Board of Directors to recommend to the stockholders that they approve the Stockholder Resolution. If, despite the Company’s reasonable best efforts, approval of the Stockholder Resolution is not obtained by October 31, 2025 (the “Outside Approval Date”), the Company shall cause an additional stockholder meeting to be held every one hundred and eighty (180) calendar days thereafter until approval of the Stockholder Resolution is obtained. As soon as practicable following the approval of the Stockholder Resolution by the Company’s stockholders, the Company shall amend its certificate of incorporation to effect such increase to its authorized shares.

(c) [Series B: To the extent that any Holder seeks to exercise this Warrant after the Initial Exercise Date and the Company is unable to honor such exercise due to having insufficient Available Shares, then in lieu of delivering the Warrant Shares due on such exercise, the Company shall instead settle the exercise in cash, delivering within the Standard Settlement Period a cash amount equal to the fair value of the undelivered Warrant Shares (net of the applicable Exercise Price) provided, however that this Section 8(c) shall terminate upon approval of the Stockholder Resolution. For purposes of this Section 8(c), the amount of the cash payment will be determined valuing the Common Stock at the Closing Sale Price on the date of exercise.]

9. Certain Adjustments. The Exercise Price and the Number of Warrant Shares issuable upon exercise of this Warrant are subject to adjustment from time to time as set forth in this Section 9.

(a) Stock Dividends and Splits. If the Company, at any time while this Warrant is outstanding, (i) pays a stock dividend on its Common Stock or otherwise makes a distribution on any class of capital stock issued and outstanding on the Original Issue Date and in accordance with the terms of such stock on the Original Issue Date or as amended, that is payable in shares of Common Stock, (ii) subdivides its outstanding shares of Common Stock into a larger number of shares of Common Stock, (iii) combines its outstanding shares of Common Stock into a smaller number of shares of Common Stock or (iv) issues by reclassification of shares of capital stock any additional shares of Common Stock, then in each such case the Number of Warrant Shares shall be multiplied by a fraction, the numerator of which shall be the number of shares of

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Common Stock outstanding immediately after such event and the denominator of which shall be the number of shares of Common Stock outstanding immediately before such event. Any adjustment made pursuant to clause (i) of this paragraph shall become effective immediately after the record date for the determination of stockholders entitled to receive such dividend or distribution, provided, however, that if such record date shall have been fixed and such dividend is not fully paid on the date fixed therefor, the Number of Warrant Shares shall be recomputed accordingly as of the close of business on such record date and thereafter the Number of Warrant Shares shall be adjusted pursuant to this paragraph as of the time of actual payment of such dividends. Any adjustment pursuant to clause (ii), (iii) or (iv) of this paragraph shall become effective immediately after the effective date of such subdivision, combination or re-classification.

(b) Pro Rata Distributions. If the Company, at any time while this Warrant is outstanding, distributes to all holders of Common Stock for no consideration (i) evidences of its indebtedness, (ii) any security (other than a distribution of Common Stock covered by the preceding paragraph), (iii) rights or warrants to subscribe for or purchase any security (including Common Stock), or (iv) cash or any other asset (in each case, a “Distribution”), other than a reclassification as to which Section 9(c) applies, then in each such case, the Holder shall be entitled to participate in such Distribution to the same extent that the Holder would have participated therein if the Holder had held the number of shares of Common Stock acquirable upon complete exercise of this Warrant (without regard to any limitations or restrictions on exercise of this Warrant, including without limitation, the Maximum Percentage (as defined below)) immediately before the date on which a record is taken for such Distribution, or, if no such record is taken, the date as of which the record holders of shares of Common Stock are to be determined for the participation in such Distribution; provided, that to the extent that the Holder’s right to participate in any such Distribution would result in the Holder and the other Attribution Parties exceeding the Maximum Percentage, then the Holder shall not be entitled to participate in such Distribution to such extent (and shall not be entitled to beneficial ownership of such shares of Common Stock as a result of such Distribution (and beneficial ownership) to such extent) and the portion of such Distribution shall be held in abeyance for the benefit of the Holder until such time or times as (all or a portion) its right thereto would not result in the Holder and the other Attribution Parties exceeding the Maximum Percentage, at which time or times the Holder shall be granted (all or such portion of) such Distribution (and any Distributions declared or made on such initial Distribution or on any subsequent Distribution held similarly in abeyance) to the same extent as if there had been no such limitation.

(c) Fundamental Transactions. If, at any time while this Warrant is outstanding (i) the Company effects any merger or consolidation of the Company with or into another Person, in which the Company is not the surviving entity or the stockholders of the Company immediately prior to such merger or consolidation do not own, directly or indirectly, at least 50% of the voting power of the surviving entity immediately after such merger or consolidation, (ii) the Company effects any sale to another Person of all or substantially all of its assets in one transaction or a series of related transactions, (iii) pursuant to any tender offer or exchange offer (whether by the Company or another Person), holders of capital stock tender shares representing more than 50% of the voting power of the capital stock of the Company and the Company or such other Person, as applicable, accepts such tender for payment, (iv) the Company consummates a stock purchase agreement or other business combination (including, without limitation, a reorganization, recapitalization, spin-off or scheme of arrangement) with another

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Person whereby such other Person acquires more than 50% of the voting power of the capital stock of the Company (except for any such transaction in which the stockholders of the Company immediately prior to such transaction maintain, in substantially the same proportions, the voting power of such Person immediately after the transaction) or (v) the Company effects any reclassification of the Common Stock or any compulsory share exchange pursuant to which the Common Stock is effectively converted into or exchanged for other securities, cash or property (other than as a result of a subdivision or combination of shares of Common Stock covered by Section 9(a) above) (in any such case, a “Fundamental Transaction”), then following such Fundamental Transaction but prior to the Expiration Time the Holder shall have the right to receive, upon exercise of this Warrant, the same amount and kind of securities, cash or property as it would have been entitled to receive upon the occurrence of such Fundamental Transaction if it had been, immediately prior to such Fundamental Transaction, the holder of the Number of Warrant Shares without regard to any limitations on exercise contained herein (in the case of clause (iii) above, assuming it had tendered, and the offeror had accepted, such Warrant Shares) (the “Alternate Consideration”). The Company shall not effect any Fundamental Transaction in which the Company is not the surviving entity or the Alternate Consideration includes securities of another Person unless (i) the Alternate Consideration is solely cash and, notwithstanding the provisions herein, the Company provides for the simultaneous “cashless exercise” of this Warrant pursuant to Section 10 below or (ii) prior to or simultaneously with the consummation thereof, any successor to the Company, surviving entity or other Person (including any purchaser of assets of the Company) shall assume the obligation to deliver to the Holder such Alternate Consideration as, in accordance with the foregoing provisions, the Holder may be entitled to receive, and the other obligations under this Warrant. The provisions of this paragraph (c) shall similarly apply to subsequent transactions analogous of a Fundamental Transaction type.

[SERIES A: Notwithstanding anything to the contrary, in the event of a Fundamental Transaction (other than (x) any stock split or reverse stock split, (y) any transaction effected solely for the purpose of changing the jurisdiction of incorporation of the Company, or (z) any holding company reorganization or parent-subsidiary merger not requiring stockholder approval pursuant to Sections 251(g) or 253 of the General Corporation Law of the State of Delaware (or any successor provisions thereof)), the Company or any Successor Entity (as defined below) shall, at the Holder’s option, exercisable at any time concurrently with, or within 30 days after, the consummation of the Fundamental Transaction (or, if later, the date of the public announcement of the applicable Fundamental Transaction), purchase this Warrant from the Holder by paying to the Holder an amount of cash equal to the Black Scholes Value (as defined below) of the remaining unexercised portion of this Warrant on the later of the date that is five days after the consummation of such Fundamental Transaction or such election by the Holder, provided, however, that, if the Fundamental Transaction is not within the Company’s control, including not approved by the Company’s Board of Directors, the Holder shall only be entitled to receive from the Company or any Successor Entity the same type or form of consideration (and in the same proportion) at the Black Scholes Value of the unexercised portion of this Warrant, that is being offered and paid to the holders of Common Stock of the Company in connection with the Fundamental Transaction, whether that consideration be in the form of cash, stock or any combination thereof, or whether the holders of Common Stock are given the choice to receive from among alternative forms of consideration in connection with the Fundamental Transaction; provided, further, that if holders of Common Stock of the Company are not offered or paid any consideration in such Fundamental Transaction, such holders of Common Stock will

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be deemed to have received common stock of the Successor Entity (which entity may be the Company following such Fundamental Transaction) in such Fundamental Transaction. “Black-Scholes Value” means the value of this Warrant based on the Black-Scholes Option Pricing Model obtained from the “OV” function on Bloomberg Financial Markets determined as of the day of consummation of the applicable Fundamental Transaction for pricing purposes and reflecting (A) a risk-free interest rate corresponding to the U.S. Treasury rate for a period equal to the time between the date of the public announcement of the applicable Fundamental Transaction and the Expiration Time, (B) an expected volatility equal to the greater of (i) 100% and (ii) the 100 day volatility, each obtained from the “HVT” function on Bloomberg Financial Markets (determined utilizing a 365 day annualization factor) as of the Trading Day immediately following the public announcement of the applicable Fundamental Transaction, (C) the underlying price per share used in such calculation shall be the greater of (i) the sum of the price per share being offered in cash, if any, plus the value of any non-cash consideration, if any, being offered in such Fundamental Transaction and (ii) the greater of (x) the last volume weighted average price (“VWAP”) immediately prior to the public announcement of such Fundamental Transaction and (y) the last VWAP immediately prior to the consummation of the Fundamental Transaction, (D) a remaining option time equal to the time between the date of the public announcement of the applicable Fundamental Transaction and the Expiration Time and (E) a zero cost of borrow. The payment of the Black Scholes Value will be made by wire transfer of immediately available funds within five Trading Days of the Holder’s election (or, if later, on the effective date of the Fundamental Transaction). The terms of any agreement pursuant to which a Fundamental Transaction is effected shall include terms requiring any such successor or surviving entity to comply with the provisions of this Section 9(c) and ensuring that this Warrant (or any such replacement security) will be similarly adjusted upon any subsequent Fundamental Transaction. The Company shall cause any successor entity in a Fundamental Transaction in which the Company is not the survivor (the “Successor Entity”) to assume in writing all of the obligations of the Company under this Warrant in accordance with the provisions of this Section 9(c) pursuant to written agreements in form and substance reasonably satisfactory to the Holder and approved by the Holder (without unreasonable delay) prior to such Fundamental Transaction and shall, at the option of the Holder, deliver to the Holder in exchange for this Warrant a security of the Successor Entity evidenced by a written instrument substantially similar in form and substance to this Warrant which is exercisable for a corresponding number of shares of capital stock of such Successor Entity (or its parent entity) equivalent to the shares of Common Stock acquirable and receivable upon exercise of this Warrant (without regard to any limitations on the exercise of this Warrant) prior to such Fundamental Transaction, and with an exercise price which applies the exercise price hereunder to such shares of capital stock (but taking into account the relative value of the shares of Common Stock pursuant to such Fundamental Transaction and the value of such shares of capital stock, such adjustments to the number of shares of capital stock and such exercise price being for the purpose of protecting the economic value of this Warrant immediately prior to the consummation of such Fundamental Transaction), and which is reasonably satisfactory in form and substance to the Holder. Upon the occurrence of any such Fundamental Transaction, the Successor Entity shall succeed to, and be substituted for the Company (so that from and after the date of such Fundamental Transaction, the provisions of this Warrant referring to the “Company” shall refer instead to the Successor Entity), and may exercise every right and power of the Company and shall assume all of the obligations of the Company under this Warrant with the same effect as if such Successor Entity had been named as the Company herein. Notwithstanding the foregoing, and without limiting Section 11 hereof, the Holder may elect, at its sole option, by delivery of written notice to the Company to waive this Section 9(c) to permit a Fundamental Transaction without the assumption of this Warrant.]

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(d) Exercise Price. Simultaneously with any adjustment to the Number of Warrant Shares pursuant to Section 9, the Exercise Price shall be increased or decreased proportionately, so that after such adjustment, the aggregate Exercise Price payable hereunder for the increased or decreased Number of Warrant Shares shall be the same as the aggregate Exercise Price in effect immediately prior to such adjustment. Notwithstanding the foregoing, in no event may the Exercise Price be adjusted below the par value of the Common Stock then in effect.

(e) Calculations. All calculations under this Section 9 shall be made to the nearest one-hundredth of one cent or the nearest whole share, as applicable.

(f) Notice of Adjustments. Upon the occurrence of each adjustment pursuant to this Section 9, the Company at its expense will, at the written request of the Holder, promptly compute such adjustment, in good faith, in accordance with the terms of this Warrant and prepare a certificate setting forth such adjustment, including a statement of the adjusted Exercise Price and adjusted number or type of Warrant Shares or other securities issuable upon exercise of this Warrant (as applicable), describing the transactions giving rise to such adjustments and showing in detail the facts upon which such adjustment is based. Upon written request, the Company will promptly deliver a copy of each such certificate to the Holder and to the Transfer Agent.

(g) Notice of Corporate Events. If, while this Warrant is outstanding, the Company (i) declares a dividend or any other distribution of cash, securities or other property in respect of its Common Stock, including, without limitation, any granting of rights or warrants to subscribe for or purchase any capital stock of the Company or any subsidiary, (ii) authorizes or approves, enters into any agreement contemplating or solicits stockholder approval for any Fundamental Transaction or (iii) authorizes the voluntary dissolution, liquidation or winding up of the affairs of the Company, then, except if such notice and the contents thereof shall be deemed to constitute material non-public information, the Company shall deliver to the Holder a notice of such transaction at least ten (10) days prior to the applicable record or effective date on which a Person would need to hold Common Stock in order to participate in or vote with respect to such transaction; provided, however, that the failure to deliver such notice or any defect therein shall not affect the validity of the corporate action required to be described in such notice. In addition, if while this Warrant is outstanding, the Company authorizes or approves, enters into any agreement contemplating or solicits stockholder approval for any Fundamental Transaction contemplated by Section 9(c), other than a Fundamental Transaction under clause (iii) of Section 9(c), then, except if such notice and the contents thereof shall be deemed to constitute material non-public information, the Company shall deliver to the Holder a notice of such Fundamental Transaction at least ten (10) days prior to the date such Fundamental Transaction is consummated.

10. [SERIES A: Exercise. Notwithstanding anything contained herein to the contrary, the Holder may, in its sole discretion, exercise this Warrant, whether in whole or in part, and in lieu of making the cash payment otherwise contemplated to be made to the Company upon such exercise in payment of the Exercise Price,]SERIES B/C: Exercise. Notwithstanding anything contained herein to the contrary, if at the time of exercise hereof there is no effective registration statement registering, or the prospectus contained therein is not available for the issuance or resale of the Warrant Shares to or by the Holder, then this Warrant may also be exercised, whether in whole or in part, at such time,] through a “cashless exercise.” Upon such cashless exercise, the Company shall issue to the Holder the number of Warrant Shares in an exchange of securities effected pursuant to Section 3(a)(9) of the Securities Act, determined as follows:

X = Y [(A-B)/A]

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where:

“X” equals the number of Warrant Shares to be issued to the Holder;

“Y” equals the total number of Warrant Shares with respect to which this Warrant is then being exercised;

“A” equals the Closing Sale Price per share of Common Stock (as reported by Bloomberg Financial Markets) as of the Trading Day on the date immediately preceding the Exercise Date; and

“B” equals the Exercise Price per Warrant Share then in effect on the Exercise Date.

For purposes of Rule 144 promulgated under the Securities Act, it is intended, understood and acknowledged that the Warrant Shares issued in such a “cashless exercise” transaction shall be deemed to have been acquired by the Holder, the Warrant Shares shall take on the registered characteristics of the Warrants being exercised, and the holding period for the Warrant Shares shall be deemed to have commenced, on the date this Warrant was originally issued (provided that the Commission continues to take the position that such treatment is proper at the time of such exercise).

11. Limitations on Exercise.

(a) The Holder shall be prohibited from exercising this Warrant if, immediately prior to or following such exercise (or portion of such exercise thereof), the Holder, together with its Attribution Parties, collectively beneficially owns or would beneficially own as determined in accordance with Section 13(d) of the Exchange Act more than [4.99]/[9.99]/[19.99]%¹ (the “Maximum Percentage”) of the issued and outstanding Common Stock or any other class of equity security (other than an exempted security) of the Company that is registered pursuant to Section 12 of the Exchange Act immediately after giving effect to such exercise. For purposes of calculating beneficial ownership, the aggregate number of shares of Common Stock beneficially owned by the Holder, together with its Attribution Parties, shall include the number of shares of Common Stock held by the Holder and all other Attribution Parties plus the number of shares of Common Stock issuable upon exercise of this Warrant with respect to which the determination is being made, but shall exclude the number of shares of Common Stock which are issuable upon (i) exercise of the remaining, unexercised portion of this Warrant beneficially owned by the Holder, together with its Attribution Parties, and (ii) exercise or conversion of the unexercised or unconverted portion of any other securities of the Company beneficially owned by the Holder, together with its Attribution Parties (including, without limitation, any convertible notes, convertible stock or warrants) that are subject to a limitation on conversion or exercise analogous

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to the limitation contained herein. For purposes of this Section 11(a), beneficial ownership shall be calculated and determined in accordance with Section 13(d) of the Exchange Act and the rules promulgated thereunder, it being acknowledged and agreed that the Holder is solely responsible for any schedules required to be filed in accordance therewith. For purposes of this Warrant, in determining the number of outstanding shares of Common Stock, the Holder may rely on the number of outstanding shares of Common Stock as reflected in (1) the Company’s most recent Annual Report on Form 10-K, Quarterly Report on Form 10-Q, Current Report on Form 8-K or other public filing with the Commission, as the case may be, (2) a more recent public announcement by the Company or (3) any other written notice by the Company or the Transfer Agent setting forth the number of shares of Common Stock outstanding (the “Reported Outstanding Share Number”). If the Company receives an Exercise Notice from the Holder at a time when the actual number of outstanding shares of Common Stock is less than the Reported Outstanding Share Number, the Company shall (i) notify the Holder in writing of the number of shares of Common Stock then outstanding and, to the extent that such Exercise Notice would otherwise cause the Holder’s beneficial ownership, as determined pursuant to this Section 11(a), to exceed the Maximum Percentage, the Holder must notify the Company of a reduced number of Warrant Shares to be purchased pursuant to such Exercise Notice (the number of shares by which such purchase is reduced, the “Reduction Shares”) and (ii) as soon as reasonably practicable, the Company shall return to the Holder any exercise price paid by the Holder for the Reduction Shares. For any reason at any time, upon the written request of the Holder, the Company shall within one (1) Trading Day confirm to the Holder the number of shares of Common Stock then outstanding. In any case, the number of outstanding shares of Common Stock shall be determined after giving effect to the conversion or exercise of securities of the Company, including this Warrant, by the Holder and any other Attribution Party since the date as of which the Reported Outstanding Share Number was reported. In the event that the issuance of Common Stock to the Holder upon exercise of this Warrant results in the Holder and the other Attribution Parties being deemed to beneficially own, in the aggregate, more than the Maximum Percentage of the number of outstanding shares of Common Stock (as determined under Section 13(d) of the Exchange Act), the number of shares so issued by which the Holder’s and the other Attribution Parties’ aggregate beneficial ownership exceeds the Maximum Percentage (the “Excess Shares”) shall be deemed null and void and shall be cancelled ab initio, and the Holder shall not have the power to vote or to transfer the Excess Shares. As soon as reasonably practicable after the issuance of the Excess Shares has been deemed null and void, the Company shall return to the Holder the exercise price paid by the Holder for the Excess Shares. By written notice to the Company, the Holder may from time to time increase or decrease the Maximum Percentage to any other percentage (not in excess of 19.99% if exceeding that limit would result in a change of control under Nasdaq Listing Rule 5635(b) or any successor rule) specified in such notice; provided that any increase in the Maximum Percentage will not be effective until the sixty-first (61st) day after such notice is delivered to the Company.

(b) Notwithstanding anything herein to the contrary, the Company shall not issue, and the Holder may not acquire, a number of Warrant Shares upon exercise of this Warrant, and the Company shall not otherwise deliver any Warrant Shares pursuant to this Warrant, to the extent that the issuance of such Warrant Shares would exceed the Available Shares (the “Available Shares Ownership Cap”), except that such limitation shall not apply in the event that the Company obtains approval of the Stockholder Resolution and files an amendment to its certificate of incorporation with the Secretary of State of the State of Delaware to effect an increase in its authorized shares to cover the issuance of such Warrant Shares.

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(c) For purposes of clarity, the shares of Common Stock issuable pursuant to the terms of this Warrant in excess of the Maximum Percentage or the Available Shares Ownership Cap shall not be deemed to be beneficially owned by the Holder for any purpose including for purposes of Section 13(d) of the Exchange Act or Rule 16a-1(a)(1) promulgated under the Exchange Act. No prior inability to exercise this Warrant pursuant to this Section 11 shall have any effect on the applicability of the provisions of this Section 11 with respect to any subsequent determination of exercisability. The provisions of this Section 11 shall be construed and implemented in a manner otherwise than in strict conformity with the terms of this Section 11 to the extent necessary to correct this section or any portion hereof that may be defective or inconsistent with the intended limitations contained in this Section 11 or to make changes or supplements necessary or desirable to properly give effect to such limitations. The limitations contained in this Section 11 may not be waived and shall apply to a successor holder of this Warrant.

(d) Section 11(a) shall not restrict the number of shares of Common Stock which a Holder may receive or beneficially own in order to determine the amount of securities or other consideration that such Holder may receive in the event of a Fundamental Transaction as contemplated in Section 9(c) of this Warrant.

12. No Fractional Shares. No fractional Warrant Shares will be issued in connection with any exercise of this Warrant. In lieu of any fractional shares that would otherwise be issuable, the number of Warrant Shares to be issued shall be rounded down to the next whole number.

13. Notices. Any and all notices or other communications or deliveries hereunder (including, without limitation, any Exercise Notice) shall be in writing and shall be deemed given and effective on the earliest of (i) the date of transmission, if such notice or communication is delivered via confirmed e-mail prior to 5:30 P.M., New York City time, on a Trading Day, (ii) the next Trading Day after the date of transmission, if such notice or communication is delivered via confirmed e-mail on a day that is not a Trading Day or later than 5:30 P.M., New York City time, on any Trading Day, (iii) the Trading Day following the date of mailing, if sent by nationally recognized overnight courier service specifying next business day delivery, or (iv) upon actual receipt by the Person to whom such notice is required to be given, if by hand delivery. The addresses and e-mail addresses for such communications shall be:

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If to the Holder, at such address or other contact information delivered by the Holder to the Company or as is on the books and records of the Company.

Or, in each of the above instances, to such other address or e-mail address as the recipient party has specified by written notice given to each other party at least five (5) days prior to the effectiveness of such change.

14. Warrant Agent. The Company shall initially serve as warrant agent under this Warrant. Upon ten (10) days’ notice to the Holder, the Company may appoint a new warrant agent. Any entity into which the Company or any new warrant agent may be merged or any entity resulting from any consolidation to which the Company or any new warrant agent shall be a party or any entity to which the Company or any new warrant agent transfers substantially all of its corporate trust or shareholders services business shall be a successor warrant agent under this Warrant without any further act. Any such successor warrant agent shall promptly cause notice of its succession as warrant agent to be mailed (by first class mail, postage prepaid) to the Holder at the Holder’s last address as shown on the Warrant Register.

15. Miscellaneous.

(a) Minimum Price Floor Requirement. The Company covenants that any future equity issuance (including the issuance of securities convertible into capital stock but excluding the issuance of shares of Common Stock or grant of any options to purchase shares of Common Stock or other awards granted or issued to employees, directors, consultants and advisors pursuant to a plan, agreement or arrangement and disclosed in the Registration Statement) occurring between the Original Issue Date and the earlier of (i) December 1, 2026, or (ii) the expiration or exercise of all of the Series B Warrants and Series C Warrants to Purchase Common Stock issued on the Original Issue Date, shall be subject to a minimum purchase price of $1.50 per share of Common Stock (calculated on an as-converted per-share basis), which for the avoidance of doubt shall not be calculated on an average or weighted-average basis (the “Minimum Price Floor”); provided, however, that the Minimum Price Floor may be waived with prior approval of holders of a majority of the then-outstanding Series B Warrants and Series C Warrants to Purchase Common Stock issued on the Original Issue Date, voting together as a single series; provided, further, that if a majority of the Pre-Funded Warrants to Purchase Common Stock issued on the Original Issue Date are exercised prior to December 1, 2025, then the Minimum Price Floor shall thereafter be $1.00 per share.

(b) No Rights as a Stockholder. Except as otherwise set forth in this Warrant, the Holder, solely in such Person’s capacity as a holder of this Warrant, shall not be entitled to vote or receive dividends or be deemed the holder of share capital of the Company for any purpose, nor shall anything contained in this Warrant be construed to confer upon the Holder, solely in such Person’s capacity as the Holder of this Warrant, any of the rights of a stockholder of the Company or any right to vote, give or withhold consent to any corporate action (whether any reorganization, issue of stock, reclassification of stock, consolidation, merger, amalgamation, conveyance or otherwise), receive notice of meetings, receive dividends or subscription rights, or

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otherwise, prior to the issuance to the Holder of the Warrant Shares which such Person is then entitled to receive upon the due exercise of this Warrant. In addition, nothing contained in this Warrant shall be construed as imposing any liabilities on the Holder to purchase any securities (upon exercise of this Warrant or otherwise) or as a stockholder of the Company, whether such liabilities are asserted by the Company or by creditors of the Company.

(c) Authorized Shares. Except and to the extent as waived or consented to by the Holder, the Company shall not by any action, including, without limitation, amending its certificate or articles of incorporation or through any reorganization, transfer of assets, consolidation, merger, dissolution, issue or sale of securities or any other voluntary action, avoid or seek to avoid the observance or performance of any of the terms of this Warrant, but will at all times in good faith assist in the carrying out of all such terms and in the taking of all such actions as may be necessary or appropriate to protect the rights of Holder as set forth in this Warrant against impairment. Without limiting the generality of the foregoing, the Company will (a) not increase the par value of any Warrant Shares above the amount payable therefor upon such exercise immediately prior to such increase in par value, (b) take all such action as may be necessary or appropriate in order that the Company may validly and legally issue fully paid and non-assessable Warrant Shares upon the exercise of this Warrant, and (c) use commercially reasonable efforts to obtain all such authorizations, exemptions or consents from any public regulatory body having jurisdiction thereof as may be necessary to enable the Company to perform its obligations under this Warrant.

(d) Successors and Assigns. Subject to compliance with applicable securities laws, this Warrant may be transferred or assigned by the Holder. This Warrant may not be assigned by the Company without the written consent of the Holder, except to a successor in the event of a Fundamental Transaction. This Warrant shall be binding on and inure to the benefit of the Company and the Holder and their respective successors and assigns. Subject to the preceding sentence, nothing in this Warrant shall be construed to give to any Person other than the Company and the Holder any legal or equitable right, remedy or cause of action under this Warrant. This Warrant may be amended only in writing signed by the Company and the Holder, or their successors and assigns.

(e) Amendment and Waiver. Except as otherwise provided herein, this Warrant may be modified or amended or the provisions hereof waived with the written consent of the Company and the Holder.

(f) Acceptance. Receipt of this Warrant by the Holder shall constitute acceptance of and agreement to all of the terms and conditions contained herein.

(g) Governing Law; Jurisdiction. ALL QUESTIONS CONCERNING THE CONSTRUCTION, VALIDITY, ENFORCEMENT AND INTERPRETATION OF THIS WARRANT SHALL BE GOVERNED BY AND CONSTRUED AND ENFORCED IN ACCORDANCE WITH THE LAWS OF THE STATE OF DELAWARE WITHOUT REGARD TO THE PRINCIPLES OF CONFLICTS OF LAW THEREOF. EACH OF THE COMPANY AND THE HOLDER HEREBY IRREVOCABLY SUBMITS TO THE EXCLUSIVE JURISDICTION OF THE STATE AND FEDERAL COURTS SITTING IN THE STATE OF DELAWARE, FOR THE ADJUDICATION OF ANY DISPUTE HEREUNDER OR IN CONNECTION HEREWITH OR WITH ANY TRANSACTION CONTEMPLATED HEREBY OR DISCUSSED HEREIN (INCLUDING WITH RESPECT TO THE ENFORCEMENT OF

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ANY OF THE TRANSACTION DOCUMENTS), AND HEREBY IRREVOCABLY WAIVES, AND AGREES NOT TO ASSERT IN ANY SUIT, ACTION OR PROCEEDING, ANY CLAIM THAT IT IS NOT PERSONALLY SUBJECT TO THE JURISDICTION OF ANY SUCH COURT. EACH OF THE COMPANY AND THE HOLDER HEREBY IRREVOCABLY WAIVES PERSONAL SERVICE OF PROCESS AND CONSENTS TO PROCESS BEING SERVED IN ANY SUCH SUIT, ACTION OR PROCEEDING BY MAILING A COPY THEREOF VIA REGISTERED OR CERTIFIED MAIL OR OVERNIGHT DELIVERY (WITH EVIDENCE OF DELIVERY) TO SUCH PERSON AT THE ADDRESS IN EFFECT FOR NOTICES TO IT AND AGREES THAT SUCH SERVICE SHALL CONSTITUTE GOOD AND SUFFICIENT SERVICE OF PROCESS AND NOTICE THEREOF. NOTHING CONTAINED HEREIN SHALL BE DEEMED TO LIMIT IN ANY WAY ANY RIGHT TO SERVE PROCESS IN ANY MANNER PERMITTED BY LAW. EACH OF THE COMPANY AND THE HOLDER HEREBY WAIVES ALL RIGHTS TO A TRIAL BY JURY.

(h) Headings. The headings herein are for convenience only, do not constitute a part of this Warrant and shall not be deemed to limit or affect any of the provisions hereof.

(i) Severability. In case any one or more of the provisions of this Warrant shall be invalid or unenforceable in any respect, the validity and enforceability of the remaining terms and provisions of this Warrant shall not in any way be affected or impaired thereby, and the Company and the Holder will attempt in good faith to agree upon a valid and enforceable provision which shall be a commercially reasonable substitute therefor, and upon so agreeing, shall incorporate such substitute provision in this Warrant.

(j) Pre-Funded Warrants in lieu of Common Stock. Notwithstanding anything to the contrary in this Warrant, to the extent the limitations set forth in Section 11 hereof restrict the exercise of this Warrant into Warrant Shares, the Holder may choose, in lieu of receiving Warrant Shares upon exercise of this Warrant, to receive a Pre-Funded Warrant to purchase an identical number of shares of Common Stock that it would have received upon the exercise of this Warrant for shares of Common Stock; provided, however that the Exercise Price shall instead be the Exercise Price less $0.0001 per share, and the resulting issued Pre-Funded Warrant shall have an exercise price of $0.0001 per share.

[REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

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IN WITNESS WHEREOF, the Company has caused this Warrant to be duly executed by its authorized officer as of the date first indicated above.

[Signature Page to the Warrant Agreement]

SCHEDULE 1

FORM OF EXERCISE NOTICE

[To be executed by the Holder to purchase shares of Common Stock under the Warrant]

XILIO THERAPEUTICS, INC.

Ladies and Gentlemen:

(1) The undersigned is the Holder of Warrant to Purchase Common Stock No. ___ (the “Warrant”) issued by Xilio Therapeutics, Inc., a Delaware corporation (the “Company”). Capitalized terms used herein and not otherwise defined herein have the respective meanings set forth in the Warrant.

(2) The undersigned hereby exercises its right to purchase ___________ Warrant Shares pursuant to the Warrant.

(3) Payment of the Exercise Price shall take the form of (check applicable box):

☐ Cash exercise in lawful money of the United States (wire transfer or cashier’s check drawn on a United States bank); or

☐ a “Cashless Exercise” under Section 10 of the Warrant [SERIES B/C: (only in the event that there is no effective registration statement for the issuance of the Warrant Shares to the Holder)].

(4) Pursuant to this Exercise Notice, the Company shall deliver to the Holder the applicable number of Warrant Shares determined in accordance with the terms of the Warrant. The Warrant Shares shall be delivered to the following DWAC Account number:

(5) By its delivery of this Exercise Notice, the undersigned represents and warrants to the Company that in giving effect to the exercise evidenced hereby the Holder will not beneficially own in excess of the number of shares of Common Stock (as determined in accordance with Section 13(d) of the Securities Exchange Act of 1934, as amended) permitted to be owned under Section 11(a) of the Warrant to which this notice relates.

(Signature must conform in all respects to name of Holder as specified on the face of the Warrant)

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Exhibit 5.1

June 3, 2025

+1 617 526 6000 (t)

+1 617 526 5000 (f)

wilmerhale.com

Xilio Therapeutics, Inc.

828 Winter Street, Suite 300

Waltham, Massachusetts 02451

Ladies and Gentlemen:

This opinion is being furnished to you in connection with (i) the Registration Statement on Form S-3 (File No. 333-285703) (the “Registration Statement”) filed by Xilio Therapeutics, Inc., a Delaware corporation (the “Company”), with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Securities Act”), for the registration of, among other things, warrants to purchase shares of common stock, $0.0001 par value per share, of the Company (the “Common Stock”), which may be issued from time to time on a delayed or continuous basis pursuant to Rule 415 under the Securities Act at an aggregate initial offering price not to exceed $250,000,000, as set forth in the Registration Statement and the prospectus contained therein (the “Base Prospectus”), and (ii) the prospectus supplement, dated June 2, 2025 (the “Prospectus Supplement” and, together with the Base Prospectus, the “Prospectus”), relating to the issuance and sale by the Company pursuant to the Registration Statement of (w) pre-funded warrants (the “Pre-Funded Warrants”) to purchase 66,676,000 shares of Common Stock (the “Pre-Funded Warrant Shares”), (x) Series A warrants (the “Series A Warrants”) to purchase 66,676,000 shares of Common Stock (or, in certain circumstances, Pre-Funded Warrants) (the “Series A Warrants Shares”), (y) Series B warrants (the “Series B Warrants”) to purchase 66,676,000 shares of Common Stock (or, in certain circumstances, Pre-Funded Warrants) (the “Series B Warrant Shares”), and (z) Series C warrants (the “Series C Warrants” and together with the Pre-Funded Warrants, the Series A Warrants and the Series B Warrants, the “Warrants”) to purchase 66,676,000 shares of Common Stock (or, in certain circumstances, Pre-Funded Warrants) (the “Series C Warrant Shares” and together with the Pre-Funded Warrant Shares, the Series A Warrant Shares and the Series B Warrant Shares, the “Warrant Shares”).

The Warrants are to be offered and sold by the Company pursuant to an underwriting agreement, dated June 2, 2025 (the “Underwriting Agreement”), entered into by and between the Company and Leerink Partners LLC, as representative of the several underwriters named in the Underwriting Agreement, which is being filed as Exhibit 1.1 to the Company’s Current Report on Form 8-K, filed on the date hereof.

We are acting as counsel for the Company in connection with the issue and sale by the Company of the Warrants. We have examined and relied upon a signed copy of the Registration Statement and a copy of the Prospectus, each as filed with the Commission. We have also examined and relied upon the Underwriting Agreement, the forms of Warrants, minutes of meetings and actions of the stockholders and the Board of Directors of the Company, including the committees thereof, as provided to us by the Company, the Restated Certificate of Incorporation and Second Amended and Restated Bylaws of the Company, each as restated and/or amended to date, and such other documents as we have deemed necessary for purposes of rendering the opinions hereinafter set forth.

In our examination of the foregoing documents, we have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as originals, the conformity to original documents of all documents submitted to us as copies, the authenticity of the originals of such latter documents and the legal competence of all signatories to such documents.

Our opinions set forth below are qualified to the extent that they may be subject to or affected by (i) applicable bankruptcy, insolvency, reorganization, receivership, moratorium, fraudulent transfer, fraudulent conveyance or similar laws relating to or affecting the rights or remedies of creditors generally, (ii) statutory or decisional law concerning recourse by creditors to security in the absence of notice or hearing, (iii) duties and standards imposed on creditors and parties to contracts, including, without limitation, requirements of good faith, reasonableness and fair dealing, and (iv) general equitable principles. We express no opinion as to the availability of any equitable or specific remedy upon any breach of any of the agreements as to which we are opining herein, or any of the agreements, documents or obligations referred to therein, or to the successful assertion of any equitable defenses, inasmuch as the availability of such remedies or the success of any equitable defense may be subject to the discretion of a court.

We also express no opinion herein as to any provision of any agreement (a) which may be deemed to or construed to waive any right of the Company, (b) to the effect that rights and remedies are not exclusive, that every right or remedy is cumulative and may be exercised in addition to or with any other right or remedy and does not preclude recourse to one or more other rights or remedies, (c) relating to the effect of invalidity or unenforceability of any provision of the Warrants on the validity or enforceability of any other provision thereof, (d) which is in violation of public policy, including, without limitation, any provision relating to indemnification and contribution with respect to securities law matters, (e) which provides that the terms of the Warrants may not be waived or modified except in writing or (f) relating to choice of law or consent to jurisdiction.

We also express no opinion herein as to the laws of any state or jurisdiction other than the state laws of the State of New York and the General Corporation Law of the State of Delaware.

Based upon and subject to the foregoing, we are of the opinion that:

Please note that we are opining only as to the matters expressly set forth herein, and no opinion should be inferred as to any other matters. This opinion is based upon currently existing statutes, rules, regulations and judicial decisions, and we disclaim any obligation to advise you of any change in any of these sources of law or subsequent legal or factual developments which might affect any matters or opinions set forth herein.

We hereby consent to the filing of this opinion with the Commission, in accordance with the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act, as an exhibit to the Current Report on Form 8-K to be filed by the Company on the date hereof in connection with the issuance and sale of the Warrants and to the use of our name therein and in the related Prospectus Supplement under the caption “Legal Matters.” In giving such consent, we do not hereby admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission.

Very truly yours,

/s/ WILMER CUTLER PICKERING HALE AND DORR LLP  

WILMER CUTLER PICKERING HALE AND DORR LLP

Exhibit 99.1

Xilio Therapeutics Announces Pricing of $50.0 Million Public Offering

WALTHAM, Mass., June 2, 2025 — Xilio Therapeutics, Inc. (Nasdaq: XLO), a clinical-stage biotechnology company discovering and developing tumor-activated immuno-oncology therapies for people living with cancer, today announced the pricing of an underwritten public offering of pre-funded warrants to purchase 66,676,000 shares of common stock (the “pre-funded warrants”), accompanied by Series A warrants to purchase 66,676,000 shares of common stock (or, in certain circumstances, pre-funded warrants) (the “Series A warrants”), Series B warrants to purchase 66,676,000 shares of common stock (or, in certain circumstances, pre-funded warrants) (the “Series B warrants”) and Series C warrants to purchase 66,676,000 shares of common stock (or, in certain circumstances, pre-funded warrants) (the “Series C warrants”). The combined public offering price of one pre-funded warrant, one Series A warrant, one Series B warrant and one Series C warrant, which are being sold together but are immediately separable, is $0.7499, which is equal to the combined offering price of the pre-funded warrants, Series A warrants, Series B warrants and Series C warrants, less the $0.0001 per share exercise price of the pre-funded warrants. The offering is expected to close on or about June 5, 2025, subject to satisfaction of customary closing conditions. All of the securities are being offered by Xilio.

The pre-funded warrants will be exercisable immediately and will be exercisable until all of the pre-funded warrants are exercised in full. The Series A warrants will be exercisable the earlier of (i) December 1, 2025 and (ii) the trading day immediately following a period of five consecutive trading days on which the closing sale price of our common stock is a minimum of $1.50 per share, with an exercise price of $0.75 per share of common stock, and will expire five years from the date of issuance. In addition, each Series A warrant will immediately expire in proportion to the extent that the corresponding pre-funded warrant offered hereby is exercised on or prior to December 1, 2025; provided that this term will no longer apply to the Series A warrants beginning on the first the trading day immediately following a period of five consecutive trading days on which the closing sale price of our common stock is a minimum of $1.50 per share. The Series B Warrants will be exercisable on or after November 1, 2025, with an exercise price of $0.75 per share of common stock, and will expire on December 2, 2025, subject to certain extensions. The Series C Warrants will be exercisable on or after June 1, 2026, with an exercise price of $0.75 per share of common stock, and will expire on the earlier of (i) December 2, 2026 and (ii) the expiration time of the Series B warrant held by a holder in proportion to the extent that the corresponding Series B warrant expires without being exercised, subject to certain extensions.

The initial gross proceeds from the offering are expected to be approximately $50.0 million before deducting underwriting discounts and commissions and offering expenses. The pre-funded warrants and Series A warrants may be exercised for cash or on a net exercise or “cashless” basis, and the Series B warrants and Series C warrants may be exercised for cash or on a net exercise or “cashless” basis provided there is no effective registration statement or prospectus available which covers the Series B warrants and Series C warrants and shares of common stock issuable upon exercise of the Series B warrants and Series C warrants. If all of the Series B warrants and Series C warrants are exercised in cash at their exercise price, the Company may receive additional gross proceeds from the offering of up to approximately $100.0 million before deducting underwriting discounts and commissions and offering expenses.

Xilio intends to use the net proceeds received from the offering to advance the development of its product candidates and for working capital requirements and other general corporate purposes.

Leerink Partners is acting as the sole bookrunner for the offering.

A shelf registration statement on Form S-3 (File No. 333-285703), as amended, relating to the securities to be offered in the public offering was initially filed with the Securities and Exchange Commission (the “SEC”) on March 11, 2025, and declared effective on May 8, 2025. The offering was made only by means of a prospectus supplement and accompanying prospectus that form a part of the registration statement. A preliminary prospectus supplement relating to and describing the terms of the offering has been filed with the SEC and may be obtained for free by visiting the SEC’s website at www.sec.gov. A final prospectus supplement relating to the offering will be filed with the SEC. When available, copies of the preliminary prospectus supplement and final prospectus supplement relating to the offering may also be obtained by contacting Leerink Partners LLC, Syndicate Department, 53 State Street, 40th Floor, Boston, MA 02109, or by telephone at (800) 808-7525 ext. 6105, or by email at [email protected].

This press release shall not constitute an offer to sell, or a solicitation of an offer to buy these securities, nor shall there be any sale of, these securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

About Xilio Therapeutics

Xilio Therapeutics is a clinical-stage biotechnology company discovering and developing tumor-activated, or masked, immuno-oncology (I-O) therapies with the goal of significantly improving outcomes for people living with cancer without the systemic side effects of current I-O treatments. The company is leveraging its proprietary platform to advance a pipeline of novel, tumor-activated I-O molecules that are designed to optimize the therapeutic index by localizing anti-tumor activity within the tumor microenvironment.

Cautionary Note Regarding Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including, without limitation, statements regarding the satisfaction of customary closing conditions relating to the offering and the expected closing of the public offering. The words “aim,” “may,” “will,” “could,” “would,” “should,” “expect,” “plan,” “anticipate,” “intend,” “believe,” “estimate,” “predict,” “project,” “potential,” “continue,” “seek,” “target” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Any forward-looking statements in this press release are based on management’s current expectations and beliefs and are subject to a number of important risks, uncertainties and other factors that may cause actual events or results to differ materially from those expressed or implied by any forward-looking statements contained in this press release, including, without limitation, the satisfaction of customary closing conditions related to the public offering. These and other risks and uncertainties are described in greater detail in the sections entitled “Risk Factor Summary” and “Risk Factors” in Xilio’s filings with the SEC, including Xilio’s most recent Quarterly Report on Form 10-Q and any other filings that Xilio has made or may make with the SEC in the future. Any forward-looking statements contained in this press release represent Xilio’s views only as of the date hereof and should not be relied upon as representing its views as of any subsequent date. Except as required by law, Xilio explicitly disclaims any obligation to update any forward-looking statements.

Investor and Media Contact

Scott Young

Vice President, Investor Relations and Corporate Communications

[email protected]