DEF 14A

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:

☐ Preliminary Proxy Statement

☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

☒ Definitive Proxy Statement

☐ Definitive Additional Materials

☐ Soliciting Material under §240.14a-12

LEONABIO, 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 all boxes that apply):

☒ No fee required

☐ Fee paid previously with preliminary materials

☐ Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11

February 23, 2026

Dear Fellow Stockholders:

We are pleased to invite you to attend the special meeting of stockholders and any postponement, adjournments or other delays thereof, which we refer to as the Special Meeting of LeonaBio, Inc., a Delaware corporation, or the Company. The Special Meeting will be held on March 18, 2026, at 8:00 a.m., Pacific Time. The Special Meeting will be conducted virtually via live audio webcast. You will be able to attend the Special Meeting virtually by visiting www.virtualshareholdermeeting.com/LONA2026SM, where you will be able to listen to the meeting live, submit questions and vote online. The Special Meeting will be held for the following purposes:

Proposal 1.

To approve the issuance of 5,502,402 shares of common stock, par value $0.0001 per share, or the common stock, pursuant to the exercise of a pre-funded warrant, or the Sermonix Pre-Funded Warrant, held by Sermonix Pharmaceuticals, Inc., or Sermonix, in accordance with Nasdaq Rule 5635(a)(2).

Proposal 2.

To approve the issuance of shares of common stock to Sermonix pursuant to an exercise of the Sermonix Pre-Funded Warrant if, immediately following such exercise, Sermonix, together with its affiliates and any other persons whose beneficial ownership of shares of common stock would be aggregated with Sermonix for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended, or the Exchange Act, would beneficially own in excess of 19.99% of our outstanding common stock, in accordance with Nasdaq Rule 5635(b).

Proposal 3.

To approve the issuance of shares of common stock to Perceptive Advisors or its affiliates pursuant to the exercise of warrants if, immediately following such exercise, Perceptive Advisors, together with its affiliates and any other persons whose beneficial ownership of shares of common stock would be aggregated with Perceptive Advisors for purposes of Section 13(d) of the Exchange Act, would beneficially own in excess of 19.99% of our outstanding common stock, in accordance with Nasdaq Rule 5635(b).

Proposal 4.

To approve the LeonaBio, Inc. 2026 Equity Incentive Plan.

Proposal 5.

To amend our amended and restated certificate of incorporation to increase the number of authorized shares of common stock.

Proposal 6.

To adjourn the Special Meeting, if necessary or appropriate in the view of the board of directors, including to solicit additional proxies if there are insufficient votes at the time of the Special Meeting to adopt any of Proposal 1, Proposal 2, Proposal 3, Proposal 4 or Proposal 5.

These items of business are more fully described in the attached formal meeting notice and proxy statement. The record date for the Special Meeting is January 27, 2026. Only stockholders of record at the close of business on that date are entitled to notice of and may vote at the Special Meeting or any adjournment thereof.

Your vote is important. Whether or not you attend the Special Meeting virtually, it is important that your shares be represented and voted at the Special Meeting. Therefore, we urge you to vote and submit your proxy promptly via the internet, telephone or mail.

On behalf of our board of directors, we would like to express our appreciation for your continued support of and interest in the Company.

Sincerely,

Mark J. Litton, Ph.D.

President and Chief Executive Officer

LeonaBio, Inc.

LEONABIO, INC.

18706 North Creek Parkway, Suite 104

Bothell, Washington 98011

NOTICE OF SPECIAL MEETING OF STOCKHOLDERS


Time and Date	8:00 a.m., Pacific Time, on March 18, 2026
Place	The Special Meeting will be conducted virtually via live audio webcast. You will be able to attend the Special Meeting virtually by visiting www.virtualshareholdermeeting.com/LONA2026SM, where you will be able to listen to the meeting live, submit questions and vote online during the meeting
Items of Business	• Proposal No. 1: To approve the issuance of 5,502,402 shares of common stock, par value $0.0001 per share, or the common stock, pursuant to the exercise of a pre-funded warrant, or the Sermonix Pre-Funded Warrant, held by Sermonix Pharmaceuticals, Inc., or Sermonix, in accordance with Nasdaq Rule 5635(a)(2). • Proposal No. 2: To approve the issuance of shares of common stock to Sermonix pursuant to an exercise of the Sermonix Pre-Funded Warrant if, immediately following such exercise, Sermonix, together with its affiliates and any other persons whose beneficial ownership of shares of common stock would be aggregated with Sermonix for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended, or the Exchange Act, would beneficially own in excess of 19.99% of our outstanding common stock, in accordance with Nasdaq Rule 5635(b). • Proposal No. 3: To approve the issuance of shares of common stock to Perceptive Advisors or its affiliates, who we refer to together as Perceptive, pursuant to the exercise of warrants if, immediately following such exercise, Perceptive, together with any other persons whose beneficial ownership of shares of common stock would be aggregated with Perceptive for purposes of Section 13(d) of the Exchange Act, would beneficially own in excess of 19.99% of our outstanding common stock, in accordance with Nasdaq Rule 5635(b). • Proposal No. 4: To approve the LeonaBio, Inc. 2026 Equity Incentive Plan. • Proposal No. 5: To amend our amended and restated certificate of incorporation to increase the number of authorized shares of common stock. • Proposal No. 6: To adjourn the Special Meeting, if necessary or appropriate in the view of the board of directors, including to solicit additional proxies if there are insufficient votes at the time of the Special Meeting to adopt any of Proposal 1, Proposal 2, Proposal 3, Proposal 4 or Proposal 5.
Record Date	January 27, 2026 Only stockholders of record as of January 27, 2026 are entitled to notice of and to vote at the Special Meeting. For ten days prior to the Special Meeting, a complete list of stockholders of record entitled to vote at the Special Meeting will be available for examination by any stockholder for any purpose relevant to the Special Meeting. If you would like to view the list, please contact our corporate secretary to schedule an appointment by calling (425) 620-8520 or writing to LeonaBio, Inc., 18706 North Creek Parkway, Suite 104, Bothell, Washington 98011, Attention: Corporate Secretary.
Proxy Materials	The proxy statement and accompanying proxy card were first sent or given on or about February 23, 2026 to all stockholders entitled to vote at the Special Meeting. You should have received a proxy card and postage-paid return envelope, through which your vote is being solicited on behalf of our board of directors. If your shares of common stock are held in a brokerage account or by a broker, bank or other nominee (i.e., your shares are held beneficially in “street name”), you will receive a voting instruction form from the holder of record. You must provide voting instructions by completing the voting instruction form and returning it to your broker, bank or other nominee for your shares to be voted. We recommend that you instruct your broker, bank or other nominee to vote your shares using the voting instruction form. The availability of internet and telephone voting options will depend on the voting process of your broker, bank or other nominee.
Voting	Whether or not you plan to attend the virtual Special Meeting, we urge you to submit your proxy via the internet or telephone or by mail as soon as possible.

By order of the Board of Directors,

Mark J. Litton, Ph.D.

President and Chief Executive Officer

LeonaBio, Inc.

Bothell, Washington

February 23, 2026

IMPORTANT NOTICE REGARDING THE AVAILABILITY OF PROXY MATERIALS FOR THE SPECIAL STOCKHOLDER MEETING TO BE HELD ON MARCH 18, 2026.

The proxy statement is available free of charge at www.ProxyVote.com. Information on this website, other than this proxy statement, is not a part of this proxy statement.

Please sign, date and return the enclosed proxy card in the envelope provided, or submit your proxy and voting instructions over the Internet or by telephone by following the instructions on the enclosed proxy card so that you may be represented at the special meeting.

TABLE OF CONTENTS


PROXY STATEMENT		1
QUESTIONS AND ANSWERS ABOUT THE PROXY MATERIALS AND OUR SPECIAL MEETING		1
DESCRIPTION OF THE SERMONIX TRANSACTION		8
Sermonix License		8
Sermonix Securities Issuance		9
DESCRIPTION OF THE PIPE FINANCING		10
PROPOSAL NO. 1		12
PROPOSAL NO. 2		14
PROPOSAL NO. 3		16
PROPOSAL NO. 4		18
PROPOSAL NO. 5		26
PROPOSAL NO. 6		28
EXECUTIVE COMPENSATION		29
Processes And Procedures for Compensation Decisions		29
Executive Compensation		29
2024 – 2025 Summary Compensation Table		29
Outstanding Equity Awards at December 31, 2025		30
Executive Employment Arrangements		31
Change In Control And Severance Agreements		31
Equity Awards		32
Equity Incentive Plans		34
Clawback Policy		34
Executive Incentive Compensation Plan		34
Retention Bonus Program		35
Equity Granting Practices		35
Pay Versus Performance		36
Required Disclosure of Relationships Between CAP and Financial Performance Measures		37
DIRECTOR COMPENSATION		39
Cash Compensation		39
Equity Compensation		40
SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT		41
Securities Authorized for Issuance Under Equity Compensation Plans		43
OTHER MATTERS		44
Availability of Bylaws		44
ANNEX A		A-1
ANNEX B		B-1

LEONABIO, INC.

PROXY STATEMENT

FOR SPECIAL MEETING OF STOCKHOLDERS

To be Held at 8:00 a.m., Pacific Time, on March 18, 2026

The board of directors of LeonaBio, Inc., a Delaware corporation, or the Company, is soliciting proxies to be used at our special meeting of stockholders, including any adjournments, postponements or delays thereof, which we refer to as the Special Meeting. The Special Meeting will be held on March 18, 2026, at 8:00 a.m., Pacific Time. The Special Meeting will be conducted virtually via live audio webcast. You will be able to attend the Special Meeting virtually by visiting www.virtualshareholdermeeting.com/LONA2026SM, where you will be able to listen to the meeting live, submit questions and vote online during the meeting.

This proxy statement, the accompanying notice of special meeting and proxy card are first being sent or given on or about February 23, 2026 to all stockholders of record as of January 27, 2026. The proxy materials can be accessed as of February 23, 2026 by visiting www.ProxyVote.com.

The information provided in the “question and answer” format below is for your convenience only and is merely a summary of the information contained in this proxy statement. You should read this entire proxy statement carefully.

QUESTIONS AND ANSWERS ABOUT THE PROXY MATERIALS AND OUR SPECIAL MEETING

Why am I receiving these materials?

This proxy statement and the accompanying proxy card are furnished in connection with the solicitation of proxies by our board of directors for use at the Special Meeting.

Your vote is very important. Whether or not you attend the virtual Special Meeting, it is important that your shares be represented and voted at the Special Meeting. Therefore, we urge you to vote and submit your proxy promptly via the internet, telephone or mail. Voting your shares by proxy ensures that if you are unable to attend the Special Meeting, your shares will be voted at the Special Meeting. Voting now will not limit your right to change your vote or to attend the Special Meeting.

What proposals will be voted on at the special meeting?

The following proposals will be voted on at the Special Meeting:

•

Proposal No. 1: To approve the issuance of 5,502,402 shares of common stock pursuant to the exercise of the Sermonix Pre-Funded Warrant in accordance with Nasdaq Rule 5635(a)(2).

•

Proposal No. 2: To approve the issuance of shares of common stock to Sermonix pursuant to an exercise of the Sermonix Pre-Funded Warrant if, immediately following such exercise, Sermonix, together with its affiliates and any other persons whose beneficial ownership of shares of common stock would be aggregated with Sermonix for purposes of Section 13(d) of the Exchange Act, would beneficially own in excess of 19.99% of our outstanding common stock, in accordance with Nasdaq Rule 5635(b).

•

Proposal No. 3: To approve the issuance of shares of common stock to Perceptive pursuant to the exercise of warrants if, immediately following such exercise, Perceptive, together with any other persons whose beneficial ownership of shares of common stock would be aggregated with Perceptive for purposes of Section 13(d) of the Exchange Act, would beneficially own in excess of 19.99% of our outstanding common stock, in accordance with Nasdaq Rule 5635(b).

•

Proposal No. 4: To approve the LeonaBio, Inc. 2026 Equity Incentive Plan.

•

Proposal No. 5: To amend our amended and restated certificate of incorporation to increase the number of authorized shares of common stock.

•

Proposal No. 6: To adjourn the Special Meeting, if necessary or appropriate in the view of the board of directors, including to solicit additional proxies if there are insufficient votes at the time of the Special Meeting to adopt any of Proposal 1, Proposal 2, Proposal 3, Proposal 4 or Proposal 5.

How does the board of directors recommend that I vote on these proposals?

Our board of directors recommends that you vote your shares:

•

“FOR” approval of the issuance of 5,502,402 shares of common stock pursuant to the exercise of the Sermonix Pre-Funded Warrant in accordance with Nasdaq Rule 5635(a)(2).

•

“FOR” approval of the issuance of shares of common stock to Sermonix pursuant to an exercise of the Sermonix Pre-Funded Warrant if, immediately following such exercise, Sermonix, together with its affiliates and any other persons whose beneficial ownership of shares of common stock would be aggregated with Sermonix for purposes of Section 13(d) of the Exchange Act, would beneficially own in excess of 19.99% of our outstanding common stock, in accordance with Nasdaq Rule 5635(b).

•

“FOR” approval of the issuance of shares of common stock to Perceptive pursuant to the exercise of warrants if, immediately following such exercise, Perceptive, together with any other persons whose beneficial ownership of shares of common stock would be aggregated with Perceptive for purposes of Section 13(d) of the Exchange Act, would beneficially own in excess of 19.99% of our outstanding common stock, in accordance with Nasdaq Rule 5635(b).

•

“FOR” approval of the LeonaBio, Inc. 2026 Equity Incentive Plan.

•

“FOR” the amendment of our amended and restated certificate of incorporation to increase the number of authorized shares of common stock.

•

“FOR” the adjournment of the Special Meeting, if necessary or appropriate in the view of the board of directors, including to solicit additional proxies if there are insufficient votes at the time of the Special Meeting to adopt any of Proposal 1, Proposal 2, Proposal 3, Proposal 4 or Proposal 5.

What will happen if the proposals are not approved at the special meeting?

The consequences of not obtaining approval of each of the proposals at the Special Meeting are described below.


No.	Proposal	Consequences of Failure to Obtain Approval
1	To approve the issuance of 5,502,402 shares of common stock pursuant to the exercise of the Sermonix Pre-Funded Warrant in accordance with Nasdaq Rule 5635(a)(2).	The Sermonix Pre-Funded Warrant will not be exercisable. As further described under “Proposal One—Effect of Not Obtaining the Required Vote”, we may be required to pay up to $7.5 million to redeem a portion of the shares underlying the Sermonix Pre-Funded Warrant. In addition, we will be required to bring this proposal for another vote by stockholders, as described under “Proposal No. 1—Effect of Not Obtaining the Required Vote.
2	To approve the issuance of shares of common stock to Sermonix pursuant to an exercise of the Sermonix Pre-Funded Warrant if, immediately following such exercise, Sermonix, together with its affiliates and any other persons whose beneficial ownership of shares of common stock would be aggregated with Sermonix for purposes of Section 13(d) of the Exchange Act, would beneficially own in excess of 19.99% of our outstanding common stock, in accordance with Nasdaq Rule 5635(b).	The Sermonix Pre-Funded Warrant will not be exercisable by Sermonix if, immediately following such exercise, Sermonix, together with its affiliates and any other persons whose beneficial ownership of shares of common stock would be aggregated with Sermonix for purposes of Section 13(d) of the Exchange Act, would own in excess of 19.99% of our outstanding common stock. Moreover, as further described under “Proposal Two—Effect of Not Obtaining the Required Vote”, we may be required to pay up to $7.5 million to redeem a portion of the shares underlying the Sermonix Pre-Funded Warrant. In addition, we will be required to bring this proposal for another vote by stockholders, as described under “Proposal No. 2—Effect of Not Obtaining the Required Vote.
3	To approve the issuance of shares of common stock to Perceptive pursuant to the exercise of warrants if, immediately following such exercise, Perceptive, together with any other persons whose beneficial ownership of shares of common stock would be aggregated with Perceptive for purposes of Section 13(d) of the Exchange Act, would beneficially own in excess of 19.99% of our outstanding common stock, in accordance with Nasdaq Rule 5635(b).	The warrants issued to Perceptive under the PIPE Financing, as described under “Description of the PIPE Financing,” will not be exercisable by Perceptive if, immediately following such exercise, Perceptive, together with any persons whose beneficial ownership of shares of common stock would be aggregated with Perceptive for purposes of Section 13(d) of the Exchange Act, would own in excess of 19.99% of our outstanding common stock. In addition, we will be required to bring this proposal for another vote by stockholders, as described under “Proposal No. 3—Effect of Not Obtaining the Required Vote.
4	To approve the LeonaBio, Inc. 2026 Equity Incentive Plan.	If our stockholders do not approve our 2026 Equity Incentive Plan, the 2026 Equity Incentive Plan will not come into effect


		and our 2020 Equity Incentive Plan will remain in effect through the remainder of its term.
5	To amend our amended and restated certificate of incorporation to increase the number of authorized shares of common stock.	Only 20,148,158 shares of common stock will remain unreserved and available for future issuance. Moreover, if the proposal to approve our 2026 Equity Incentive Plan is approved but the proposal to increase the number of authorized shares of common stock is not approved, only 14,448,158 shares of common stock will remain unreserved and available for future issuance.
6	To adjourn the Special Meeting, if necessary or appropriate in the view of the board of directors, including to solicit additional proxies if there are insufficient votes at the time of the Special Meeting to adopt any of Proposal 1, Proposal 2, Proposal 3, Proposal 4 or Proposal 5.	We will be unable to adjourn the Special Meeting if necessary or appropriate in the view of the board of directors. In such circumstances, we may be required to call an additional special meeting of stockholders.

Who is entitled to vote at the special meeting?

Holders of our common stock as of the close of business on January 27, 2026, the record date for the Special Meeting, may vote at the Special Meeting. As of the record date, there were 9,335,913 shares of our common stock outstanding. Each share of common stock is entitled to one vote on each matter properly brought before the Special Meeting. We do not have any outstanding shares of preferred stock.

Notwithstanding the above, and in compliance with the rules of Nasdaq, Perceptive has agreed that it will not vote 1,319,026 shares of common stock on Proposal 3. We refer to this as the Voting Restriction. Perceptive received the shares subject to the Voting Restriction pursuant to the Securities Purchase Agreement between the Company and the investors named therein, dated December 18, 2025, and further described under “Description of the PIPE Financing.”

Stockholders of Record. If your shares are registered directly in your name with our transfer agent, Computershare Inc., then you are considered the stockholder of record with respect to those shares, and this proxy statement was sent directly to you by us. As a stockholder of record, you have the right to grant your proxy directly to the individuals listed on the proxy card or to vote by ballot at the Special Meeting. Throughout this proxy statement, we refer to these holders as “stockholders of record.” Only stockholders of record as of January 27, 2026 are entitled to notice of and to vote at the Special Meeting. For ten days prior to the Special Meeting, a complete list of stockholders of record entitled to vote at the Special Meeting will be available for examination by any stockholder for any purpose relevant to the Special Meeting. If you would like to view the list, please contact our corporate secretary to schedule an appointment by calling (425) 620-8520 or writing to LeonaBio, Inc., 18706 North Creek Parkway, Suite 104, Bothell, Washington 98011, Attention: Corporate Secretary.

Street Name Stockholders. If your shares are held in a brokerage account or by a broker, bank or other nominee, then you are considered the beneficial owner of shares held in street name, and this proxy statement was forwarded to you by your broker, bank or other nominee, which is considered the stockholder of record with respect to those shares. As a beneficial owner, you have the right to direct your broker, bank or other nominee on how to vote your shares. Beneficial owners are also invited to attend the virtual Special Meeting. However, since a beneficial owner is not the stockholder of record, you may not vote your shares directly at the Special Meeting unless you follow the procedures for obtaining a legal proxy from your broker, bank or other nominee. If you request a printed copy of the proxy materials by mail, your broker, bank or other nominee will provide a voting instruction card for you to use. Throughout this proxy statement, we refer to these holders as “street name stockholders.”

How many votes are needed for approval of each proposal?

For each of the proposals submitted to the stockholders for a vote at the Special Meeting, approval will require the affirmative vote of the majority of the votes cast, affirmatively or negatively, for such proposal.

Broker non-votes and abstentions will be counted for purposes of determining the presence or absence of a quorum. However, neither broker non-votes nor abstentions will be considered votes cast for or against any proposal. Accordingly, broker non-votes and abstentions will have no impact on the outcome of any proposal.

With respect to Proposal 3 only, shares subject to the Voting Restriction are not entitled to vote on and will have no effect on the results.

What are broker non-votes?

Shares held in a brokerage account or by another nominee are considered held in “street name” by the stockholder or “beneficial owner.” A broker or nominee holding shares for a beneficial owner does not have discretion to vote on non-routine matters unless the broker or nominee receives specific voting instructions from the beneficial owner of the shares. A broker non-vote occurs when the broker or nominee does not receive voting instructions from the beneficial owner and does not have discretion to direct the voting of the

shares on a non-routine matter. Proposals 1, 2, 3, 4 and 6 are non-routine matters and therefore, brokers may not vote on such matters without specific voting instruction from the beneficial holder. Proposal 5 is a routine matter and, as a result, we do not expect broker non-votes on this proposal.

What is the quorum requirement for the special meeting?

A quorum is the minimum number of shares required to be present or represented at the Special Meeting for the meeting to be properly held under our amended and restated bylaws, or the Bylaws, and Delaware law. The presence, including virtually or by proxy, of a majority of the voting power of the capital stock of the Company issued and outstanding and entitled to vote will constitute a quorum to transact business at the Special Meeting. Abstentions and broker non-votes, if any, are counted as present and entitled to vote for purposes of determining a quorum. Whether or not a quorum exists, the chairperson of the meeting may adjourn the meeting to another time or place.

How do I vote and what are the voting deadlines?

Stockholder of Record. If you are a stockholder of record, you may vote in one of the following ways:

•

By internet following the instructions using the control number provided on your proxy card;

•

By telephone using the numbers provided on your proxy card;

•

By attending the Special Meeting virtually by visiting www.virtualshareholdermeeting.com/LONA2026SM, where you can vote during the meeting; or

•

By signing, dating and returning your proxy card following the instructions on your proxy card. Your proxy card must be received prior to the Special Meeting

Street Name Stockholders. If you are a street name stockholder, then you will receive voting instructions from your broker, bank or other nominee. You must follow the instructions provided by your broker, bank or other nominee in order to instruct them on how to vote your shares. The availability of internet and telephone voting options will depend on the voting process of your broker, bank or other nominee. As discussed above, if you are a street name stockholder, then you may not vote your shares by ballot at the Special Meeting unless you obtain a “legal proxy” from your broker, bank or other nominee.

Notwithstanding the above, no shares subject to the Voting Restriction are entitled to vote on Proposal 3 and, accordingly, any proxies that we receive through this solicitation with respect to shares subject to the Voting Restriction will not confer authority to represent or vote such shares on Proposal 3.

What if I do not specify how my shares are to be voted or fail to provide timely directions to my broker, bank or other nominee?

Stockholder of Record. If you are a stockholder of record and you submit a proxy but you do not provide voting instructions, your shares will be voted:

•

“FOR” approval of the issuance of 5,502,402 shares of common stock pursuant to the exercise of the Sermonix Pre-Funded Warrant in accordance with Nasdaq Rule 5635(a)(2);

•

“FOR” approval of the LeonaBio, Inc. 2026 Equity Incentive Plan;

•

“FOR” the amendment of our amended and restated certificate of incorporation to increase the number of authorized shares of common stock; and

•

Street Name Stockholders. Brokers, banks and other nominees holding shares of common stock in street name for customers are generally required to vote such shares in the manner directed by their customers. In the absence of timely directions, your broker, bank or other nominee will have discretion to vote your shares on our sole routine matter: the proposal to amend our amended and restated certificate of incorporation to increase the number of authorized shares of common stock. Your broker, bank or other nominee will not have discretion to vote on any other proposals, which are considered non-routine matters, absent direction from you. In the event that your broker, bank or other nominee votes your shares on our routine matters, but is not able to vote your shares on non-routine matters, then those shares will be treated as broker non-votes with respect to non-routine proposals. Accordingly, if you own shares through a nominee, such as a broker or bank, please be sure to instruct your nominee how to vote to ensure that your shares are counted on each of the proposals.

Can I change my vote or revoke my proxy?

Stockholder of Record. If you are a stockholder of record, you can change your vote or revoke your proxy before the Special Meeting by:

•

entering a new vote by internet or telephone (subject to the applicable deadlines for each method as set forth above);

•

completing and returning a later-dated proxy card, which must be received prior to the Special Meeting;

•

delivering a written notice of revocation to our corporate secretary at LeonaBio, Inc., 18706 North Creek Parkway, Suite 104, Bothell, Washington 98011, Attention: Corporate Secretary, which must be received prior to the Special Meeting; or

•

attending virtually and voting at the Special Meeting (although attendance at the Special Meeting will not, by itself, revoke a proxy).

Street Name Stockholders. If you are a street name stockholder, then your broker, bank or other nominee can provide you with instructions on how to change or revoke your proxy.

What do I need to do to attend the special meeting?

We will be hosting the Special Meeting via live webcast only. You will be able to attend the Special Meeting virtually, submit your questions during the meeting and vote your shares electronically during the meeting by visiting www.virtualshareholdermeeting.com/LONA2026SM. To participate in the Special Meeting, you will need the control number included on your proxy card. The Special Meeting webcast will begin promptly at 8:00 a.m., Pacific Time. We encourage you to access the meeting prior to the start time. Online check-in will begin at 7:45 a.m., Pacific Time, and you should allow ample time for the check-in procedures.

How can I get help if I have trouble checking in or listening to the special meeting online?

If you encounter difficulties accessing the virtual meeting during the check-in or meeting time, please call the technical support number that will be posted on the virtual meeting log-in page.

What is the effect of giving a proxy?

Proxies are being solicited by and on behalf of our board of directors. Mark Litton, our president and chief executive officer, Robert Renninger, our chief financial officer, and Mark Worthington, our general counsel, chief compliance officer and corporate secretary, have been designated as proxy holders for the Special Meeting by our board of directors. When proxies are properly dated, executed and returned, the shares represented by such proxies will be voted at the Special Meeting in accordance with the instructions of the stockholder. If the proxy card is dated and signed but no specific instructions are given, then the shares will be voted in accordance with the recommendation of our board of directors. If any other matters are properly brought before the Special Meeting, then the proxy holders will use their own judgment to determine how to vote your shares.

Who will count the votes?

A representative of Broadridge Financial Solutions, Inc. will tabulate the votes and act as inspector of election.

How can I contact LeonaBio’s transfer agent?

You may contact our transfer agent, Computershare Inc., by telephone at (800) 736-3001, or by writing Computershare Inc.,

P.O. Box 43006, Providence, RI 02940-3078. You may also access instructions with respect to certain stockholder matters (e.g., change of address) via the internet at www.computershare.com/investor.

How are proxies solicited for the special meeting and who is paying for such solicitation?

Our board of directors is soliciting proxies for use at the Special Meeting by means of these proxy materials. By signing, dating and returning the proxy card, or by submitting your proxy over the internet or by telephone using the instructions found on the proxy card, you are authorizing the persons named as proxies to vote your shares at the Special Meeting as you have instructed. Proxies will be solicited on behalf of the board of directors by our directors, and certain of our executive officers and other employees.

We will bear the cost of soliciting proxies and will reimburse brokerage firms and other custodians, nominees and fiduciaries for their reasonable out-of-pocket expenses for sending proxy materials to stockholders and obtaining their proxies. We have retained the services of Innisfree M&A Incorporated to assist in soliciting proxies from our stockholders for a fee of $25,000 plus reimbursement of reasonable expenses. In addition to soliciting the proxies by mail and the internet, certain of our directors, officers and employees, without compensation, may solicit proxies personally or by telephone, facsimile and e-mail.

We will bear the entire cost of proxy solicitation, including the preparation, assembly, printing, mailing and distribution of LeonaBio’s proxy materials. Copies of our solicitation materials will also be made available upon request to brokers, banks and other nominees to forward to the beneficial owners of the shares held of record by such brokers, banks or other nominees. The original solicitation of proxies may be supplemented by solicitation by telephone, electronic communications or other means by our directors, officers or employees. No additional compensation will be paid to these individuals for any such services, although we may reimburse such individuals for their reasonable out-of-pocket expenses in connection with such solicitation.

Could other matters be decided at the special meeting?

No business may be transacted at the Special Meeting except that referred to in this notice of special meeting and proxy statement, or in a supplemental notice given also in compliance with the provisions of the Bylaws, or such other business as may be germane or supplementary to the business that is stated in this notice of special meeting and proxy statement or any supplemental notice. We do not know of any other matters that may be presented for action at the Special Meeting other than those described in this proxy statement.

What happens if the special meeting is postponed?

The Special Meeting may be adjourned or postponed for the purpose of, among other things, soliciting additional proxies. Unless a new record date is fixed, your proxy will still be valid and may be voted at the adjourned or postponed meeting. You will still be able to change your proxy until it is voted.

Do I have appraisal rights?

Our stockholders are not entitled to dissenters’ or appraisal rights under the DGCL with respect to any of the proposals being voted on at the Special Meeting.

What is the reverse stock split?

On September 17, 2025, we effected a 10-for-1 reverse stock split of our common stock. The reverse stock split was approved by our stockholders at our 2025 annual meeting.

As a result of the reverse stock split, every ten shares of our issued and outstanding common stock were automatically combined into one issued and outstanding share of common stock, without any change in the par value per share. Any fractional shares that would otherwise be issuable as a result of the reverse stock split were paid out in cash. The total number of authorized shares of common stock under our amended and restated charter was reduced from 900,000,000 to 90,000,000 and the total number of authorized shares of our capital stock was reduced from 1,000,000,000 to 190,000,000. Proportional adjustments were made to the number of shares of common stock issuable upon the exercise or settlement of our outstanding options and restricted stock units, and the number of shares authorized and reserved for issuance pursuant to our equity incentive plans.

Unless otherwise noted, all share amounts in this proxy statement reflect the 10-for-1 reverse stock split.

Where can I find the voting results of the special meeting?

We will disclose voting results on a Current Report on Form 8-K that we will file with the Securities and Exchange Commission within four business days after the meeting. If final voting results are not available to us in time to file a Form 8-K, then we will file a Form 8-K to publish preliminary results and will provide the final results in an amendment to the Form 8-K as soon as they become available.

What does it mean if I receive more than one copy of the proxy materials?

If you receive more than one copy of the proxy materials, then your shares may be registered in more than one name and/or are registered in different accounts. Please follow the voting instructions on each proxy card to ensure that all of your shares are voted.

I share an address with another stockholder, and we received only one paper copy of the proxy materials. How may i obtain an additional copy of the proxy materials?

We have adopted a procedure called “householding,” which the Securities and Exchange Commission has approved. Under this procedure, we can deliver a single copy of the proxy materials to multiple stockholders who share the same address unless we received contrary instructions from one or more of the stockholders. This procedure reduces our printing costs, mailing costs and fees. Stockholders who participate in householding will continue to be able to access and receive separate proxy cards. Upon written or oral request, we will deliver promptly a separate copy of the proxy materials to any stockholder at a shared address to which we delivered a single copy of any of these documents. To receive a separate copy, or, if a stockholder is receiving multiple copies, to request that we only send a single copy of future Notices of Internet Availability or proxy statements and annual reports, as applicable, stockholders may contact us at the following address and telephone number:

LeonaBio, Inc.

Attention: Investor Relations

18706 North Creek Parkway, Suite 104

Bothell, Washington 98011

Tel: (425) 620-8501

Stockholders may also request additional copies of this proxy statement, or copies of the proxy statement, annual report and form of proxy relating to future stockholder meetings by (1) visiting www.ProxyVote.com, (2) calling 1-800-579-1639 or (3) sending an email to sendmaterial@proxyvote.com.

Street name stockholders may contact their broker, bank or other nominee to request information about householding.

What is the deadline to propose actions for consideration at the 2026 annual meeting of stockholders or to nominate individuals to serve as directors?

If a stockholder would like us to consider including a proposal in our proxy statement for the 2026 annual meeting of stockholders pursuant to Rule 14a-8 of the Securities Exchange Act of 1934, as amended, or the Exchange Act, then the proposal must have been received by our corporate secretary at our principal executive offices on or before December 15, 2025. In addition, stockholder proposals must comply with the requirements of Rule 14a-8 regarding the inclusion of stockholder proposals in company-sponsored proxy materials. Proposals should be addressed to:

LeonaBio, Inc.

Attention: Corporate Secretary

18706 North Creek Parkway, Suite 104

Bothell, Washington 98011

The Bylaws also establish an advance notice procedure for stockholders who wish to present a proposal or nominate a director at an annual meeting, but do not seek to include the proposal or director nominee in our proxy statement. In order to be properly brought before the 2026 annual meeting, the stockholder must provide timely written notice to our corporate secretary, at our principal executive offices, and any such proposal or nomination must constitute a proper matter for stockholder action. The written notice must contain the information specified in the Bylaws. To be timely, a stockholder’s written notice must be received by our corporate secretary at our principal executive offices:

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no earlier than 8:00 a.m., Eastern time, on January 29, 2026; and

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no later than 5:00 p.m., Eastern time, on February 28, 2026.

If we hold our 2026 annual meeting more than 25 days before or after the one-year anniversary of the 2025 annual meeting, then such written notice must be received by our corporate secretary at our principal executive offices:

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no earlier than 8:00 a.m., Eastern time, on the 120th day prior to the day of our 2026 annual meeting, and

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no later than 5:00 p.m., Eastern time, on the later of the 90th day prior to the day of the 2026 annual meeting and, if the first public announcement of the date of such annual meeting is less than 100 days prior to the date of such annual meeting, the 10th day following the day on which public announcement of the date of the annual meeting is first made by us.

In addition, stockholders who intend to solicit proxies in support of director nominees other than the Company’s nominees must also comply with the additional requirements of Rule 14a-19(b) of the Exchange Act.

If a stockholder who has notified us of his, her or its intention to present a proposal at an annual meeting of stockholders does not appear to present his, her or its proposal at such annual meeting, then we are not required to present the proposal for a vote at such annual meeting.

DESCRIPTION OF THE SERMONIX TRANSACTION

Sermonix License

On December 18, 2025, we entered into agreements with Sermonix Pharmaceuticals, Inc., or Sermonix, and Ligand Pharmaceuticals Incorporated, or Ligand, granting us exclusive licenses and rights to develop, manufacture and commercialize oral forms of the selective estrogen-receptor modulator known as lasofoxifene in all countries and territories of the world except for Asia and certain countries in the Middle East. Under the terms of our license agreement with Sermonix, or the Sermonix License, we assumed responsibility, in such countries and territories, for the ongoing global Phase 3 clinical trial of oral lasofoxifene entitled “Evaluation of Lasofoxifene in ESR1 Mutations (ELAINE-3),” or the ELAINE-3 Study, and we are coordinating with Sermonix and Shanghai Henlius Biotech, Inc., or Henlius, Sermonix’s exclusive licensee for oral lasofoxifene in Asia and certain countries in the Middle East, or the Retained Territory, with respect to Henlius’ conduct of the ELAINE-3 Study in the Retained Territory.

Licenses and Exclusivity

Under the Sermonix License, we received from Sermonix an exclusive (even as to Sermonix), sublicensable license, under relevant patents and know-how owned or in-licensed by Sermonix, to develop, manufacture, commercialize and otherwise exploit products containing lasofoxifene, or the Licensed Products, in all countries outside the Retained Territory, or the Licensed Territory. Such license does not include a sublicense under the patents and know-how that Sermonix previously in-licensed from Ligand because we entered into a direct license agreement with Ligand to replace Sermonix’s license from Ligand with respect to Licensed Products in the Licensed Territory. During the term of the Sermonix License, Sermonix and its affiliates are prohibited from developing, manufacturing, commercializing or otherwise exploiting products that selectively modulate the estrogen receptor, although Sermonix retains the ability to fulfill its obligations under its license agreement with Henlius, or the Sermonix-Henlius Agreement, with respect to the Licensed Products in the Retained Territory.

Development, Manufacture and Commercialization Activities

Under the Sermonix License, we have the sole right to conduct all development (including regulatory activities), manufacturing and commercialization of Licensed Products in the Licensed Territory, at our sole cost and expense. We are obligated to use commercially reasonable efforts to develop and obtain and maintain regulatory approval for at least one Licensed Product in the Licensed Territory and, following receipt of regulatory approval, to use commercially reasonable efforts to commercialize the applicable Licensed Product in the country of approval. We have assumed certain of Sermonix’s agreements with third parties that are conducting or supporting the ELAINE-3 Study in the Licensed Territory and certain agreements with third-party contract manufacturers that have been supplying drug substance and drug product for the ELAINE-3 Study. All of Sermonix’s existing inventory of Licensed Product drug substance and drug product will be transferred to us at no additional cost and we will provide a portion of such inventory to Henlius for use in the ELAINE-3 Study in the Retained Territory.

Financial Terms

As consideration for the rights granted to us under the Sermonix License, we agreed to issue securities to Sermonix as discussed below under “Sermonix Transaction—Sermonix Securities Issuance”, make payments to certain of Sermonix’s third-party service providers that total approximately $16.8 million, and make payments to Sermonix of $75,000 per month, subject to adjustment from time to time upon mutual agreement of the parties. We may credit the amount of such monthly payments against all milestone, royalty, and net proceed payments that become due to Sermonix under the Sermonix License, and our obligation to make such monthly payments will end upon Sermonix’s receipt of the first such milestone, royalty or net proceeds payment. If we or our affiliates achieve certain commercialization or annual net sales milestones with respect to the Licensed Products, we will make milestone payments to Sermonix up to a maximum aggregate total of $100.0 million, a portion of which may be payable in cash or shares of common stock at our discretion, with final terms to be negotiated between the parties. In addition, we are obligated to make royalty payments to Sermonix based on our and our affiliates’ annual net sales of the Licensed Products in the Licensed Territory, with the applicable royalty rates ranging from sub-single digit to low-single digit percentages, subject to customary reductions. Such royalty obligation will expire on a Licensed Product-by-Licensed Product and country-by-country basis on the latest of (i) the expiration of the last valid claim of a patent licensed to us by Sermonix that covers such Licensed Product in such country, (ii) the expiration of regulatory exclusivity of such Licensed Product in such country; and (iii) 10 years after the first commercial sale of such Licensed Product in such country. If we sublicense or divest our rights to the Licensed Products to a third party, then in lieu of the milestone and royalty payments described above, we will pay to Sermonix a percentage of the net proceeds from such sublicensing or divestiture transaction. The applicable percentage is based on the type of payment received by us from the third party as well as status of development of the Licensed Products at the time that the sublicense or divestiture transaction is entered into, with rates starting in the high-double digit and decreasing to low-double digit percentages. As consideration for our payment and other obligations under the Sermonix License, we will be eligible to receive from Henlius all milestone and royalty payments that Henlius owes to Sermonix under the Sermonix-Henlius Agreement other than royalties that Sermonix owes to Ligand on account of Sermonix’s license agreement with Ligand, and with the further exception that, if Henlius and Sermonix later agree to share the costs of developing the Licensed Products in Japan, then we will not be entitled to receive Sermonix’s share of income arising from the sublicensing of Japanese rights to the Licensed Product.

Term and Termination

The Sermonix License will remain in effect until we, our affiliates and our sublicensees are no longer developing or commercializing any Licensed Product in the Licensed Territory. Each party may terminate the Sermonix License in its entirety for the uncured material breach by or insolvency of the other party. We may terminate the Sermonix License in its entirety for safety reasons or for convenience at any time after the topline data readout of the ELAINE 3 Study. Upon termination, all rights and licenses granted to us will revert to Sermonix.

The Sermonix License includes certain other customary terms and conditions, including mutual representations and warranties, indemnification, and confidentiality provisions.

An affiliate of Perceptive held approximately 29% of the outstanding capital stock of Sermonix (excluding securities convertible into shares of capital stock) at the time of entry into the Sermonix License and Sermonix Securities Purchase Agreement. Joseph Edelman, a member of the Company’s Board, is the managing member of Perceptive Advisors LLC, the investment manager of Perceptive.

Sermonix Securities Issuance

In connection with entry into the Sermonix License, on December 18, 2025 we and Sermonix entered into a securities purchase agreement, or the Sermonix Securities Purchase Agreement, pursuant to which on December 23, 2025 we issued to Sermonix a pre-funded warrant to purchase 5,502,402 shares of common stock at an exercise price of $0.001 per share, or the Sermonix Pre-Funded Warrant. The shares issuable upon exercise of the Sermonix Pre-Funded Warrant constitute partial consideration for Sermonix’s entry into the Sermonix License.

The Sermonix Pre-Funded Warrant is subject to two restrictions on exercise:

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In compliance with Nasdaq Rule 5635(a)(2), the Sermonix Pre-Funded Warrant will not be exercisable until our stockholders approve the issuance of shares to Sermonix pursuant thereto; and

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In compliance with Nasdaq Rule 5635(b), the Sermonix Pre-Funded Warrant may not be exercised if, immediately prior to or following such exercise, Sermonix, together with its affiliates and any other persons whose beneficial ownership of shares of common stock would be aggregated with Sermonix for purposes of Section 13(d) of the Exchange Act, would beneficially own more than 19.99% of our common stock prior to receipt of the stockholder approval.

We have agreed to, no later than in connection with our 2026 annual meeting of stockholders, or the Annual Meeting, provide notice of, and solicit proxies from our stockholders to obtain approval such that the Sermonix Pre-Funded Warrant can be exercised at any time without restriction or additional stockholder approval. If such stockholder approval is not obtained at or before the Annual Meeting, we have agreed to cause an additional meeting (special or general) of stockholders to be held every 90 days thereafter for the purpose of obtaining stockholder approval until stockholder approval is obtained.

If stockholder approval has not been obtained by the first anniversary of the original issuance of the Sermonix Pre-Funded Warrant, then Sermonix will have the right at any time and from time to time prior to such time that stockholder approval is obtained thereafter, to redeem a portion of the shares underlying the Sermonix Pre-Funded Warrant, subject to certain conditions and limitations. If Sermonix exercises its redemption right, we will be required to pay an amount up to (a) $6.35 multiplied by (b) the number of shares of common stock with respect to which Sermonix is exercising the right. The redemption right will terminate on the earlier of (1) such time as we have paid an aggregate of $7.5 million to Sermonix in connection with one or more exercises of the redemption right; and (2) immediately upon receipt of stockholder approval for issuance of shares under the Sermonix Pre-Funded Warrant.

For additional information about the Sermonix License or the Sermonix Securities Purchase Agreement, see Amendment No. 1 to the Company’s Current Report on Form 8-K, filed on December 18, 2025.

DESCRIPTION OF THE PIPE FINANCING

On December 18, 2025, we entered into a securities purchase agreement, or the PIPE Securities Purchase Agreement, with a select group of investors, including Perceptive, and other accredited investors. We refer to this transaction as the PIPE Financing. Pursuant to the PIPE Securities Purchase Agreement, on December 23, 2025 we issued and sold, by way of a private placement, an aggregate of:

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5,356,547 shares of common stock, or the PIPE Initial Shares;

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pre-funded warrants, or the PIPE Pre-Funded Warrants, to purchase 8,816,684 shares of common stock;

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accompanying warrants, or the PIPE Series A Common Warrants, to purchase 23,031,494 shares of common stock and/or shares underlying pre-funded warrants, representing 162.5% of the aggregate of PIPE Initial Shares and the shares of common stock underlying the PIPE Pre-Funded Warrants; and

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accompanying warrants, or the PIPE Series B Common Warrants to purchase 21,259,842 shares of common stock and/or shares underlying pre-funded warrants, representing 150% of the aggregate of PIPE Initial Shares and the shares of common stock underlying the PIPE Pre-Funded Warrants.

The purchase price for each PIPE Initial Share (including the accompanying PIPE Series A Common Warrants and Series B Common Warrants) was $6.35 and the purchase price for each PIPE Pre-Funded Warrant (including the accompanying PIPE Series A Common Warrants and PIPE Series B Common Warrants) was $6.349 per each share underlying the PIPE Pre-Funded Warrant. Gross proceeds were approximately $90 million, excluding placement agent fees and offering expenses.

The PIPE Pre-Funded Warrants are exercisable at an exercise price of $0.001 per share, subject to customary adjustments under the terms thereof and are exercisable at any time on or after issuance, subject to the restriction discussed below.

The PIPE Series A Common Warrants have an exercise price of $6.35 per share to be paid in cash (unless a resale registration statement is unavailable at the time of exercise, in which case the PIPE Series A Common Warrants will be exercisable on a cashless net exercise basis), subject to adjustments as provided therein, and will be exercisable, subject to the restrictions discussed below, after the earlier of (1) the latest of (a) June 30, 2026, (b) the date on which we publicly announce, by means of a widely disseminated press release or a Current Report on Form 8-K, the enrollment of the 500th subject or the last subject, whichever is earlier, in the ELAINE-3 Study; provided that the total enrollment will be no less than 500 subjects unless the study’s Data Safety Monitoring Board recommends stopping enrollment at an earlier time or unless the FDA permits a different number for subject enrollment in a protocol amendment; and (c) the date on which the FDA approves or issues a complete response letter to Eli Lilly & Co.'s marketing application, including a supplement to a new drug application, for imlunestrant in combination with abemaciclib in breast cancer, and (2) October 31, 2026. The PIPE Series A Common Warrants will remain exercisable until the 30th day following their initial exercise date, except that if such initial exercise date has not occurred by December 23, 2030, then the PIPE Series A Common Warrants will terminate on December 23, 2030.

The PIPE Series B Common Warrants have an exercise price of $7.62 per share payable on a cashless net exercise basis, subject to adjustments as provided therein, and will be exercisable, subject to the restrictions discussed below, after the later of (1) June 30, 2026 and (2) the date of the completion of the public readout of topline results of the ELAINE-3 Study. The PIPE Series B Common Warrants will remain exercisable until the 30th day following their initial exercise date, except that if the initial exercise date has not occurred by December 23, 2030, then the PIPE Series B Common Warrants will terminate on December 23, 2030.

Each of the PIPE Pre-Funded Warrants, the PIPE Series A Common Warrants and the PIPE Series B Common Warrants contain a restriction on exercise such that none can be exercised if, immediately prior to or following such exercise, the applicable holder, together with its affiliates and any other persons whose beneficial ownership of shares of common stock would be aggregated with the holder for purposes of Section 13(d) of the Exchange Act, would beneficially own more than one of 4.99%, 9.99% or 19.99% of the total number of issued and outstanding shares of our common stock following the exercise. The percentage to be included in each PIPE Pre-Funded Warrant, PIPE Series A Common Warrant and PIPE Series B Common Warrant was selected by the PIPE purchaser at closing of the PIPE Financing. Such percentage may be increased or decreased by the applicable holder with 61 days’ written notice to us; provided, however, that such percentage may in no event exceed 19.99% prior to a vote of our stockholders approving the removal of such exercise limitation, in compliance with Nasdaq Rule 5635(b). Certain PIPE purchasers elected a maximum percentage of 4.99% that is not subject to increase.

Perceptive, a current stockholder of the Company, together with an affiliated fund, purchased an aggregate of $20.0 million of the securities sold in the PIPE Financing. Joseph Edelman, a member of the Company’s Board, is the managing member of Perceptive Advisors LLC, the investment manager of Perceptive.

The Company will use the net proceeds from the PIPE Financing for working capital and will not use such proceeds for (1) the repayment of borrowed debt, (2) to redeem any common stock or any securities of the Company that would entitle the holder thereof to acquire at any time common stock, subject to certain exceptions, (3) for the settlement of any litigation that is outstanding as of the closing of the PIPE Financing, and (4) to in-license or develop a drug candidate other than lasofoxifene or any drug or drug candidate in the Company’s pipeline as of the closing of the PIPE Financing until the earlier of such time as the topline results of the ELAINE-3 Study become available and the second anniversary of the effective date of the PIPE Securities Purchase Agreement.

In addition, pursuant to the terms of the PIPE Securities Purchase Agreement, for so long as funds affiliated with each of Commodore Capital LP, or Commodore, and TCG Crossover Management LLC, or TCGX, respectively, beneficially own 5% or more in the aggregate of our issued and outstanding common stock (including any shares of common stock issuable upon the exercise of any outstanding warrants issued in the PIPE Financing whose initial exercise date has occurred), each of Commodore and TCGX will be entitled to designate one member of our board of directors, and we will take all actions reasonably necessary to have such designee promptly appointed to our board of directors, including, but not limited to, increasing the size of the board of directors to accommodate the appointment of such designee, subject to specified conditions. In addition, we have agreed to use reasonable best efforts to cause the resignation of two (2) current members of the board of directors by the six-month anniversary of closing of the PIPE Financing.

For additional information about the PIPE Financing or the PIPE Securities Purchase Agreement, see Amendment No. 1 to the Company’s Current Report on Form 8-K, filed on December 18, 2025.

PROPOSAL NO. 1

A proposal to approve the issuance of 5,502,402 shares of common stock pursuant to the exercise of the Sermonix Pre-Funded Warrant in accordance with Nasdaq Rule 5635(a)(2).

DESCRIPTION OF PROPOSAL

Overview

As described above under “Description of the Sermonix Transaction,” on December 23, 2025, we issued the Sermonix Pre-Funded Warrant, representing a right to purchase 5,502,402 shares of common stock at an exercise price of $0.001 per share. Pursuant to Nasdaq Rule 5635(a)(2), the Sermonix Pre-Funded Warrant may not be exercised unless approval from our stockholders is obtained. We are seeking stockholder approval pursuant to Nasdaq Rule 5635(a)(2) for the issuance of 5,502,402 shares of common stock pursuant to the full or partial exercise of the Sermonix Pre-Funded Warrant.

Reasons for Stockholder Approval

Our common stock is listed on the Nasdaq Capital Market and, as such, we are subject to the applicable rules of Nasdaq, including Nasdaq Rule 5635(a)(2). Pursuant to Nasdaq Rule 5635(a)(2), stockholder approval is required prior to the issuance of securities in connection with the acquisition of stock or assets of another company if (1) any director, officer, or Substantial Shareholder (as defined by Nasdaq Rule 5635(e)(3)) has a 5% or greater interest (or such persons collectively have a 10% or greater interest), directly or indirectly, in the Company or assets to be acquired or in the consideration to be paid in the transaction or series of related transactions and (2) the present or potential issuance of common stock, or securities convertible into or exercisable for common stock, could result in an increase in outstanding common shares or voting power of 5% or more.

As further described under “Description of the Sermonix Transaction,” under the Sermonix License, we acquired certain rights from Sermonix relating to lasofoxifene. In addition, an affiliate of Perceptive, which at the time of entry into the Sermonix License held more than 10% of our outstanding common stock, then held approximately 29% of the outstanding capital stock of Sermonix (excluding securities convertible into shares of capital stock). Moreover, Joseph Edelman, a member of our board of directors, is the managing member of the investment manager of Perceptive. For these reasons, and because the Sermonix Pre-Funded Warrant was issued in partial consideration for the Sermonix License, the issuance of shares to the holder of the Sermonix Pre-Funded Warrant upon exercise is subject to approval by our stockholders.

The Sermonix Pre-Funded Warrant includes a restriction on exercise providing that it is not exercisable in the absence of stockholder approval. Please see “Description of the Sermonix Transaction” above for descriptions of the Sermonix License, the Sermonix Securities Purchase Agreement and the Sermonix Pre-Funded Warrant.

Effect of Vote in Favor of the Proposal

If our stockholders approve this proposal at the Special Meeting, the Sermonix Pre-Funded Warrant will become fully exercisable for an aggregate of 5,502,402 shares of common stock, subject to the restrictions of Nasdaq Rule 5635(b), the removal of which is the subject of Proposal 2 discussed below.

Effect of Not Obtaining the Required Vote

In the event our stockholders do not approve this proposal at the Special Meeting, the Sermonix Pre-Funded Warrant will not be exercisable.

As described above under “Description of the Sermonix Transaction—Sermonix Securities Issuance,” if stockholder approval has not been obtained by the first anniversary of the original issuance of the Sermonix Pre-Funded Warrant, then Sermonix will have the right at any time and from time to time prior to such time that stockholder approval is obtained thereafter, to redeem a portion of the shares underlying the Sermonix Pre-Funded Warrant, subject to certain conditions and limitations. If Sermonix exercises its redemption right, we will be required to pay an amount up to (a) $6.35 multiplied by (b) the number of shares of common stock with respect to which Sermonix is exercising the right. The redemption right will terminate on the earlier of (1) such time as we have paid an aggregate of $7.5 million to Sermonix in connection with one or more exercises of the redemption right; and (2) immediately upon receipt of stockholder approval for issuance of shares under the Sermonix Pre-Funded Warrant.

In addition, pursuant to the Sermonix Securities Purchase Agreement, if this proposal is not approved by our stockholders we will be required to submit this proposal to another vote by our stockholders at our 2026 annual meeting. If the approval of our stockholders is not obtained at the 2026 annual meeting, we will be required to cause additional meetings (special or general) of stockholders to be held every 90 days thereafter for the purpose of obtaining stockholder approval until stockholder approval is obtained.

Vote Required

The approval of this proposal requires the affirmative vote of the majority of the votes cast, affirmatively or negatively. Broker non-votes and abstentions will be counted for purposes of determining the presence or absence of a quorum. However, neither broker non-votes nor abstentions will be considered votes cast for or against this proposal. Accordingly, broker non-votes and abstentions will have no impact on the outcome of this proposal.

Board Recommendation

THE BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT STOCKHOLDERS VOTE “FOR” PROPOSAL 1.

PROPOSAL NO. 2

A proposal to approve the issuance of shares of common stock to Sermonix pursuant to an exercise of the Sermonix Pre-Funded Warrant if, immediately following such exercise, Sermonix, together with its affiliates and any other persons whose beneficial ownership of shares of common stock would be aggregated with Sermonix for purposes of Section 13(d) of the Exchange Act, would beneficially own in excess of 19.99% of our outstanding common stock, in accordance with Nasdaq Rule 5635(b).

DESCRIPTION OF PROPOSAL

Overview

As described above under “Description of Sermonix Transaction,” on December 23, 2025, we issued the Sermonix Pre-Funded Warrant, representing a right to purchase 5,502,402 shares of common stock at an exercise price of $0.001 per share. We are seeking stockholder approval for Sermonix to exercise the Sermonix Pre-Funded Warrant in the event such exercise results in Sermonix, together with its affiliates and any other persons whose beneficial ownership of shares of common stock would be aggregated with Sermonix for purposes of Section 13(d) of the Exchange Act, owning in excess of 19.99% of our outstanding common stock immediately following the exercise. Such ownership may be reached upon initial exercise of the warrant or following one or more partial exercises.

Reasons for Stockholder Approval

Our common stock is listed on the Nasdaq Capital Market and, as such, we are subject to the applicable rules of Nasdaq, including Nasdaq Rule 5635(b). Pursuant to Nasdaq Rule 5635(b), stockholder approval is required prior to the issuance of securities when the issuance or potential issuance will result in a change of control of the company. Under Nasdaq guidance, a change of control may occur when, as a result of the issuance, the recipient owns, or has the right to acquire, 20% or more of the outstanding shares of common stock or voting power of a company.

We have an aggregate of 9,335,913 shares of common stock outstanding as of the record date. As a result, assuming full exercise by Sermonix of the Sermonix Pre-Funded Warrant and no other exercises of outstanding derivative securities held by other holders, Sermonix would own approximately 37% of our common stock immediately following such exercise, which would be more than 19.99% of our outstanding common stock.

Under Nasdaq guidance, an issuance of all the shares underlying the Sermonix Pre-Funded Warrant may constitute a change of control (including, among other reasons, because such issuance may result in Sermonix owning 20% or more of our outstanding common stock). As a result, the issuance of shares to Sermonix pursuant to full exercise of the Sermonix Pre-Funded Warrant is subject to approval by our stockholders.

The Sermonix Pre-Funded Warrant includes a restriction on exercise providing that it is not exercisable if, immediately prior to or following such exercise, Sermonix, together with its affiliates and any other persons whose beneficial ownership of shares of common stock would be aggregated with Sermonix for purposes of Section 13(d) of the Exchange Act, would beneficially own more than 19.99% of our common stock prior to receipt of the stockholder approval. Please see “Description of the Sermonix Transaction” above for descriptions of the Sermonix License, the Sermonix Securities Purchase Agreement and the Sermonix Pre-Funded Warrant.

Effect of Vote in Favor of the Proposal

If our stockholders approve this proposal at the Special Meeting, the Sermonix Pre-Funded Warrant will become fully exercisable for an aggregate of 5,502,402 shares of common stock regardless of Sermonix’s ownership of our common stock immediately following such exercise.

However, if stockholders do not approve Proposal 1 at the Special Meeting, the Sermonix Pre-Funded Warrant will not be exercisable by Sermonix even if this Proposal 2 is approved. See “Proposal 2—Effect of Not Obtaining the Required Vote.”

Effect of Not Obtaining the Required Vote

In the event our stockholders do not approve this proposal at the Special Meeting, the Sermonix Pre-Funded Warrant will not be exercisable by Sermonix if, immediately following such exercise, Sermonix, together with its affiliates and any other persons whose beneficial ownership of shares of common stock would be aggregated with Sermonix for purposes of Section 13(d) of the Exchange Act, would own in excess of 19.99% of our outstanding common stock.

underlying the Sermonix Pre-Funded Warrant, subject to certain conditions and limitations. If Sermonix exercises its redemption right, we will be required to pay an amount up to (a) $6.35 multiplied by (b) the number of shares of common stock with respect to which Sermonix is exercising the right. The redemption right will terminate on the earlier of (1) such time as we have paid an aggregate of $7.5 million to Sermonix in connection with one or more exercises of the redemption right; and (2) immediately upon receipt of stockholder approval for issuance of shares under the Sermonix Pre-Funded Warrant.

Vote Required

Board Recommendation

THE BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT STOCKHOLDERS VOTE “FOR” PROPOSAL 2.

PROPOSAL NO. 3

A proposal to approve the issuance of shares of common stock to Perceptive pursuant to the exercise of warrants if, immediately following such exercise, Perceptive, together with any other persons whose beneficial ownership of shares of common stock would be aggregated with Perceptive for purposes of Section 13(d) of the Exchange Act, would beneficially own in excess of 19.99% of our outstanding common stock, in accordance with Nasdaq Rule 5635(b).

DESCRIPTION OF PROPOSAL

Overview

As described under “Description of the PIPE Financing,” on December 23, 2025, we issued and sold, by way of the Private Placement:

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5,356,547 PIPE Initial Shares, of which 1,319,026 were sold to Perceptive or an affiliate thereof;

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PIPE Pre-Funded Warrants to purchase 8,816,684 shares of common stock, of which 1,830,580 shares are subject to PIPE Pre-Funded Warrants held by Perceptive and its affiliates;

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PIPE Series A Common Warrants, to purchase 23,031,494 shares of common stock, including PIPE Series A Common Warrants to Perceptive to purchase 5,118,109 shares of common stock; and

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PIPE Series B Common Warrants to purchase 21,259,842 shares of common stock, including PIPE Series B Common Warrants to Perceptive to purchase 4,724,408 shares of common stock.

As a result of the PIPE Financing, we issued or may issue an aggregate of 12,992,123 shares of common stock to Perceptive. An affiliate of Perceptive held approximately 29% of the outstanding capital stock of Sermonix (excluding securities convertible into shares of capital stock) at the time of entry into the PIPE Securities Purchase Agreement. Joseph Edelman, a member of the Company’s Board, is the managing member of Perceptive Advisors LLC, the investment manager of Perceptive.

Reasons for Stockholder Approval

We have an aggregate of 9,335,913 shares of common stock outstanding as of the record date. As a result, assuming full exercise by Perceptive (assuming a cash exercise) of its PIPE Pre-Funded Warrants, PIPE Series A Common Warrants and PIPE Series B Common Warrants and no other exercises of outstanding derivative securities held by other holders, Perceptive would own approximately 64% of our common stock immediately following such exercise, which would be more than 19.99% of our outstanding common stock. We note that neither the PIPE Series A Common Warrants nor the PIPE Series B Common Warrants are currently exercisable pursuant to their terms and that the PIPE Series B Common Warrants are only exercisable on a net exercise basis and not for cash. As a result, Perceptive’s pro forma ownership percentage of our common stock discussed in this paragraph is illustrative only.

Under Nasdaq guidance, such issuance may constitute a change of control (including, among other reasons, because such issuance may result in Perceptive owning 20% or more of our outstanding common stock). As a result, the issuance of shares to Perceptive pursuant to full exercise of its PIPE Pre-Funded Warrants, PIPE Series A Common Warrants and PIPE Series B Common Warrants is subject to approval by our stockholders.

The PIPE Pre-Funded Warrants, PIPE Series A Common Warrants and PIPE Series B Common Warrants include a restriction on exercise providing that they are not exercisable if, immediately prior to or following such exercise, Perceptive, together with any other persons whose beneficial ownership of shares of common stock would be aggregated with Perceptive for purposes of Section 13(d) of the Exchange Act, would beneficially own more than 19.99% of our common stock prior to receipt of the stockholder approval. Please see “Description of the PIPE Financing” above for descriptions of the PIPE Securities Purchase Agreement, the PIPE Pre-Funded Warrants, the PIPE Series A Common Warrants and the PIPE Series B Common Warrants.

Effect of Vote in Favor of the Proposal

If our stockholders approve this proposal at the Special Meeting, an aggregate of 8,267,715 shares of common stock may be issued upon full exercise (assuming exercise for cash) of the PIPE Pre-Funded Warrants and PIPE Series A Common Warrants held by Perceptive. The 8,267,715 shares of common stock excludes any shares issuable upon exercise of the PIPE Series B Common Warrants, which warrants are only exercisable by way of a cashless, net exercise mechanism that references the then-current market price of the common stock. As a result, the actual number of shares of common stock to be issued upon exercise of the PIPE Series B Common Warrants cannot be confirmed at this time.

Effect of Not Obtaining the Required Vote

In the event our stockholders do not approve this proposal at the Special Meeting, the PIPE Pre-Funded Warrants, PIPE Series A Common Warrants and PIPE Series B Common Warrants will not be exercisable by Perceptive if, immediately following such exercise, Perceptive, together with any persons whose beneficial ownership of shares of common stock would be aggregated with Perceptive for purposes of Section 13(d) of the Exchange Act, would own in excess of 19.99% of our outstanding common stock.

In addition, pursuant to the PIPE Securities Purchase Agreement, if this proposal is not approved by our stockholders, we will be required to submit this proposal to another vote by our stockholders at our 2026 annual meeting. If the approval of our stockholders is not obtained at the 2026 annual meeting, we will be required to cause additional meetings (special or general) of stockholders to be held every 90 days thereafter for the purpose of obtaining stockholder approval until stockholder approval is obtained.

Vote Required

In compliance with the rules of Nasdaq, Perceptive may not vote 1,319,026 shares of common stock on Proposal 3, consisting of the shares received by Perceptive pursuant to the PIPE Securities Purchase Agreement.

Board Recommendation

THE BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT STOCKHOLDERS VOTE “FOR” PROPOSAL 3.

PROPOSAL NO. 4

A proposal to approve the LeonaBio, Inc. 2026 Equity Incentive Plan.

DESCRIPTION OF PROPOSAL

The Company’s stockholders are being asked to consider and vote upon a proposal to approve the Company’s new 2026 Equity Incentive Plan. Upon stockholder approval of the 2026 Equity Incentive Plan, our 2020 Equity Incentive Plan will terminate, and we will cease granting awards under that plan. The terms of the 2026 Equity Incentive Plan are described below and a copy of the 2026 Equity Incentive Plan is set forth in this proxy statement as Annex A.

General Information

The 2026 Equity Incentive Plan, if approved by stockholders, will allow the Company to continue providing stock-based compensation to align stockholder and participant interests and motivate, attract and retain talented service providers. If our stockholders do not approve the 2026 Equity Incentive Plan, the 2020 Equity Incentive Plan will remain in effect through the remainder of its term.

The Company’s named executive officers and directors have an interest in this proposal as they are eligible to receive equity awards under the 2026 Equity Incentive Plan.

Requested Share Reserve

If our stockholders approve the 2026 Equity Incentive Plan, subject to adjustment upon certain changes in our capitalization as described in the 2026 Equity Incentive Plan, the maximum number of shares of common stock available for grants under the 2026 Equity Incentive Plan will be: (i) 5,700,000 shares of common stock, plus (ii) any shares of common stock subject to awards granted under the 2020 Equity Incentive Plan that, on or after the stockholder approval date of the 2026 Equity Incentive Plan, are used to pay for the tax withholding related to the award or the exercise price with the award or, with respect to any options and stock appreciation rights, expire or become unexercisable without having been exercised in full, or with respect to any other types of awards under the 2020 Equity Incentive Plan, are forfeited to or repurchased by the Company due to failure to vest, or are not issued under an award due to the award being paid out in cash rather than shares of common stock, with the maximum number of shares of common stock to be added pursuant to this section (ii) equal to 1,300,000 shares, plus (iii) an annual increase commencing January 1, 2027 and continuing each January 1 until the final increase on January 1, 2036, in an amount equal to 5% of the aggregate of outstanding shares of common stock and outstanding pre-funded warrants to purchase shares of common stock, or such lower number as determined by the Board. Subject to the number of shares that may be granted under the 2026 Equity Incentive Plan as described above, the maximum number of shares of common stock that may be issued under the 2026 Equity Incentive Plan upon exercise of incentive stock options is 57,000,000 shares.

The Plan will Allow the Company to Effectively Recruit and Retain Key Talent

In determining the number of shares to request for approval under the 2026 Equity Incentive Plan, the Compensation Committee and the Board considered historical grant practices, the current stock price of the Company’s common stock and guidance from Pearl Meyer & Partners, LLC, the Compensation Committee’s independent compensation consultant. Shares of common stock remaining under the 2020 Equity Incentive Plan are expected to be insufficient to meet the Company’s compensation needs. We anticipate that shares of common stock reserved under the 2026 Equity Incentive Plan will allow us to grant equity awards at market levels and to use equity awards as an effective incentive and retention tool.

Promotion of Good Corporate Governance Practices

The Board and the Compensation Committee believe the use of stock-based incentive awards promotes best practices in corporate governance by maximizing stockholder value. By providing participants in the 2026 Equity Incentive Plan with a stake in the Company’s success, the interests of the participants are aligned with those of the Company’s stockholders. Specific features of the 2026 Equity Incentive Plan that are consistent with good corporate governance practices include, but are not limited to:

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Administration. The Board has delegated primary administration authority to the Compensation Committee, which consists entirely of independent non-employee directors.

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Annual Limits on Compensation to Non-Employee Directors. The 2026 Equity Incentive Plan sets reasonable annual limits as to the cash compensation and awards that non-employee directors may receive during each fiscal year.

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Limited transferability. Awards under the 2026 Equity Incentive Plan generally may not be sold, assigned, transferred, pledged, or otherwise alienated, unless otherwise approved by the administrator.

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Forfeiture Events. Each award under the 2026 Equity Incentive Plan will be subject to any clawback policy that the Company is required by applicable stock exchange rules or applicable laws to adopt (including any such clawback policy that is adopted after the grant of the award), and the administrator may require a participant to forfeit, return, or reimburse the Company for all or a portion of the award and any amounts paid under the award in order to comply with the clawback policy or applicable laws

Summary of the 2026 Equity Incentive Plan

The 2026 Equity Incentive Plan permits the grant of incentive stock options, within the meaning of Section 422 of the Internal Revenue Code of 1986, as amended, or the Code, to our employees and any of our parent or subsidiary corporations’ employees, and for the grant of nonstatutory stock options, restricted stock, restricted stock units, stock appreciation rights, and performance awards to our employees, directors and consultants and any of our parent or subsidiary corporations’ employees and consultants. This summary does not contain all of the terms and conditions of the 2026 Equity Incentive Plan and is qualified in its entirety by reference to the 2026 Equity Incentive Plan as set forth in Annex A.

Purposes

The purposes of the 2026 Equity Incentive Plan will be to attract and retain the best available personnel for positions of substantial responsibility with the Company or any parent or subsidiary of the Company; to provide additional incentive to eligible employees, directors, and consultants; and to promote the success of our business. These incentives will be provided through the grant of stock options, stock appreciation rights, restricted stock, restricted stock units, or RSUs, and performance awards as the administrator of the 2026 Equity Incentive Plan may determine. As of the record date, we had eight members of our Board of Directors (of whom one is an employee), approximately 21 employees (including five executive officers) and approximately seven natural person consultants, who would be eligible for grants under the 2026 Equity Incentive Plan. The basis for participation in the 2026 Equity Incentive Plan is being eligible and being selected by the administrator of the 2026 Equity Incentive Plan, in its discretion, to receive a grant thereunder.

Authorized Shares

A total of 5,700,000 shares of our common stock will be reserved for issuance pursuant to our 2026 Equity Incentive Plan. In addition, the shares reserved for issuance under our 2026 Equity Incentive Plan will include any shares subject to awards granted under the 2020 Equity Incentive Plan that, on or after the stockholder approval date of the 2026 Equity Incentive Plan, are used to pay for the tax withholding related to the award or the exercise price with the award or, with respect to any options and stock appreciation rights, expire or become unexercisable without having been exercised in full, or with respect to any other types of awards under the 2020 Equity Incentive Plan, are forfeited to or repurchased by the Company due to failure to vest, or are not issued under an award due to the award being paid out in cash rather than shares of common stock (provided that the maximum number of shares of common stock that may be added to the 2026 Equity Incentive Plan pursuant to this sentence is 1,300,000 shares).

In addition, the number of shares available for issuance under our 2026 Equity Incentive Plan also will include an annual increase on the first day of each fiscal year for a period of ten years, beginning with our fiscal year 2027, equal to the least of:

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five percent (5%) of the aggregate of outstanding shares of common stock and outstanding pre-funded warrants to purchase shares of common stock as of the last day of the immediately preceding fiscal year; or

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such number of shares as our board of directors may determine no later than the last day of our immediately preceding fiscal year.

Shares issuable under our 2026 Equity Incentive Plan will be authorized, but unissued, or reacquired shares of our common stock. If an award expires or becomes unexercisable without having been exercised in full, is surrendered pursuant to an exchange program (as described below), surrendered to pay tax withholding relating to an award or the exercise price of an award, or, with respect to restricted stock, restricted stock units, or performance awards, is forfeited to or repurchased due to failure to vest, the unpurchased shares (or for awards other than stock options or stock appreciation rights, the forfeited or repurchased shares) will become available for future grant or sale under the 2026 Equity Incentive Plan.

With respect to stock appreciation rights, the gross number of shares actually issued will cease to be available under the 2026 Equity Incentive Plan and all remaining shares under stock appreciation rights will remain available for future grant or sale under the 2026 Equity Incentive Plan. Shares that have actually been issued under the 2026 Equity Incentive Plan under any award will not be returned to the 2026 Equity Incentive Plan; except if shares issued pursuant to awards of restricted stock, restricted stock units, or performance awards are repurchased or forfeited due to failure to vest, such shares will become available for future grant under the 2026 Equity Incentive Plan. Shares used to pay the exercise price of an award or satisfy the tax withholding obligations related to an award will become available for future grant or sale under the 2026 Equity Incentive Plan. To the extent an award is paid out in cash rather than shares, such cash payment will not result in a reduction in the number of shares available for issuance under the 2026 Equity Incentive Plan.

Subject to the number of shares that may be granted under the 2026 Equity Incentive Plan as described above, the maximum number of shares of common stock that may be issued under the 2026 Equity Incentive Plan upon exercise of incentive stock options is 57,000,000 shares.

Plan Administration

Our board of directors or one or more committees appointed by our board of directors will have authority to administer our 2026 Equity Incentive Plan. The compensation committee of our board of directors initially will administer our 2026 Equity Incentive Plan. In addition,

if we determine it is desirable to qualify transactions under our 2026 Equity Incentive Plan as exempt under Rule 16b-3 of the Exchange Act, such transactions will be structured to satisfy the requirements for exemption under Rule 16b-3. Subject to the provisions of our 2026 Equity Incentive Plan, the administrator has the power to administer our 2026 Equity Incentive Plan and make all determinations deemed necessary or advisable for administering the 2026 Equity Incentive Plan, including but not limited to, the power to determine the fair market value of our common stock, select the service providers to whom awards may be granted, determine the number of shares or dollar amounts covered by each award, approve forms of award agreements for use under the 2026 Equity Incentive Plan, determine the terms and conditions of awards (including, but not limited to, the exercise price, the time or times at which awards may be exercised, any vesting acceleration or waiver or forfeiture restrictions and any restriction or limitation regarding any award or the shares relating thereto), construe and interpret the terms of our 2026 Equity Incentive Plan and awards granted under it, prescribe, amend and rescind rules relating to our 2026 Equity Incentive Plan, including creating sub-plans, modify or amend each award, and allow a participant to defer the receipt of payment of cash or the delivery of shares that otherwise would be due to such participant under an award. The administrator also has the authority to allow participants the opportunity under an exchange program to transfer outstanding awards granted under the 2026 Equity Incentive Plan to a financial institution or other person or entity selected by the administrator, and to institute an exchange program by which outstanding awards granted under the 2026 Equity Incentive Plan may be surrendered or cancelled in exchange for awards of the same type, which may have a higher or lower exercise price and/or different terms, awards of a different type and/or cash, or by which the exercise price of an outstanding award granted under the 2026 Equity Incentive Plan is reduced or increased. The administrator’s decisions, interpretations and other actions are final and binding on all participants and will be given the maximum deference permitted by applicable law.

Stock Options

Stock options may be granted under our 2026 Equity Incentive Plan. The exercise price of options granted under our 2026 Equity Incentive Plan must be equal to at least 100% of the fair market value of a share of our common stock on the date of grant. However, stock options may be granted with a per share exercise price of less than 100% of the fair market value of a Share on the date of grant pursuant to a transaction described in, and in a manner consistent with, Section 424(a) of the Code. The term of an option may not exceed ten years. With respect to any participant who owns more than 10% of the voting power of all classes of our (or any of our parent’s or subsidiary’s) outstanding stock, the term of an incentive stock option granted to such participant must not exceed five years and the per share exercise price must equal at least 110% of the fair market value of a share of our common stock on the grant date. The administrator may grant incentive stock options under the 2026 Equity Incentive Plan for a period of ten years from the earlier of the date our board of directors approves the 2026 Equity Incentive Plan or the date that our stockholders approve the 2026 Equity Incentive Plan. The administrator will determine the methods of payment of the exercise price of an option, which may include cash and cash equivalents, check, certain shares, cashless exercise, net exercise, promissory notes, as well as other types of consideration permitted by applicable law. After the termination of service of an employee, director or consultant, he or she may exercise his or her option for the period of time stated in his or her option agreement. In the absence of a specified time in an award agreement, if termination is due to death or disability, the option will remain exercisable for six months. In all other cases, in the absence of a specified time in an award agreement, the option will remain exercisable for 90 days following the termination of service. An option agreement may also provide for the tolling of the expiration of the option after the option holder’s termination of service if the exercise would result in liability under Section 16(b) of the Exchange Act or would be prohibited solely because the issuance of shares of common stock would violate the registration requirements under the Securities Act of 1933, as amended, or the Securities Act. An option, however, may not be exercised later than the expiration of its term. Subject to the provisions of our 2026 Equity Incentive Plan, the administrator determines the terms of options.

Stock Appreciation Rights

Stock appreciation rights may be granted under our 2026 Equity Incentive Plan. Stock appreciation rights allow the recipient to receive the appreciation in the fair market value of our common stock between the exercise date and the date of grant. The term of a stock appreciation right may not exceed ten years. After the termination of service of an employee, director or consultant, he or she may exercise his or her stock appreciation right for the period of time stated in his or her stock appreciation rights agreement. In the absence of a specified time in an award agreement, if termination is due to death or disability, the stock appreciation rights will remain exercisable for six months. In all other cases, in the absence of a specified time in an award agreement, the stock appreciation rights will remain exercisable for three months following the termination of service. A stock appreciation right agreement may also provide for the tolling of the expiration of the stock appreciation right after the award holder’s termination of service if the exercise would result in liability under Section 16(b) of the Exchange Act or would be prohibited solely because the issuance of shares of common stock would violate the registration requirements under the Securities Act. However, in no event may a stock appreciation right be exercised later than the expiration of its term. Subject to the provisions of our 2026 Equity Incentive Plan, the administrator determines the terms of stock appreciation rights, including when such rights become exercisable and whether to pay any increased appreciation in cash or with shares of our common stock, or a combination thereof, except that the per share exercise price for the shares to be issued pursuant to the exercise of a stock appreciation right will be no less than 100% of the fair market value per share on the date of grant. However, stock appreciation right may be granted with a per share exercise price of less than 100% of the fair market value of a share of common stock on the date of grant pursuant to a transaction described in, and in a manner consistent with, Section 424(a) of the Code.

Restricted Stock

Restricted stock may be granted under our 2026 Equity Incentive Plan. Restricted stock awards are grants of shares of our common stock that may vest in accordance with terms and conditions established by the administrator. The administrator will determine the number of shares of restricted stock granted to any employee, director or consultant and, subject to the provisions of our 2026 Equity

Incentive Plan, will determine the terms and conditions of such awards. The administrator may impose whatever vesting conditions (if any) it determines to be appropriate (for example, the administrator may set restrictions based on the achievement of specific performance goals or continued service to us), except the administrator, in its sole discretion, may accelerate the time at which any restrictions will lapse or be removed. Recipients of restricted stock awards generally will have voting and dividend rights with respect to such shares upon grant, unless the administrator provides otherwise. Shares of restricted stock that do not vest are subject to our right of repurchase or forfeiture.

Restricted Stock Units

Restricted stock units may be granted under our 2026 Equity Incentive Plan. Restricted stock units are bookkeeping entries representing an amount equal to the fair market value of one share of our common stock. Subject to the provisions of our 2026 Equity Incentive Plan, the administrator determines the terms and conditions of restricted stock units, including any vesting criteria and the form and timing of payment. The administrator may set vesting criteria based upon the achievement of company-wide, divisional, business unit, or individual goals (including, but not limited to, continued employment or service), applicable federal or state securities laws or any other basis determined by the administrator in its discretion. The administrator, in its sole discretion, may pay earned restricted stock units in the form of cash, shares, or a combination of both. Notwithstanding the foregoing, the administrator, in its sole discretion, may accelerate the time at which any restrictions will lapse or be removed.

Performance Awards

Performance awards may be granted under the 2026 Equity Incentive Plan. Performance awards are awards that may be earned in whole or in part on the attainment of performance goals or other vesting criteria that the administrator may determine, and that may be denominated in cash or stock. Subject to the terms and conditions of the 2026 Equity Incentive Plan, the administrator determines the terms and conditions of performance awards, including any vesting criteria and form and timing of payment. The administrator may set vesting criteria based upon the achievement of company-wide, divisional, business unit, or individual goals (including, but not limited to, continued employment or service), applicable federal or state securities laws or any other basis determined by the administrator in its discretion. The administrator, in its sole discretion, may pay earned performance awards in the form of cash, shares, or a combination of both. Notwithstanding the foregoing, the administrator, in its sole discretion, may accelerate the time at which any restrictions will lapse or be removed.

Outside Directors

All outside (non-employee) directors will be eligible to receive all types of awards (except for incentive stock options) under our 2026 Equity Incentive Plan. The 2026 Equity Incentive Plan provides that in any given fiscal year, no outside director may be granted awards (the value of which will be based on their grant date fair value) granted under our 2026 Equity Incentive Plan and provided any other compensation (including without limitation any cash retainers and fees) that in the aggregate exceed $500,000, provided that in the initial year of service such amount is increased to $750,000. Awards or other compensation provided to an individual for his or her services as an employee or as a consultant other than a director are excluded for purposes of these limits. The grant-date fair values of awards granted under our 2026 Equity Incentive Plan will be determined according to U.S. Generally Accepted Accounting Principles.

Non-Transferability of Awards

Unless the administrator provides otherwise, our 2026 Equity Incentive Plan generally does not allow for the transfer of awards other than by will or the laws of descent and distribution, and only the recipient of an award may exercise an award during his or her lifetime. If the administrator makes an award transferable, such award will contain such additional terms and conditions as the administrator deems appropriate.

Certain Adjustments

In the event of certain changes in our capitalization, such as a dividend or other distribution, recapitalization, stock split, reverse stock split, reorganization, merger, consolidation, split-up, spin-off, combination, reclassification, repurchase or exchange of our shares of common stock or other securities or other change in our corporate structure affecting our common stock (other than ordinary dividends or other ordinary distributions), to prevent diminution or enlargement of the benefits or potential benefits available under our 2026 Equity Incentive Plan, the administrator will adjust the number and class of shares that may be delivered under our 2026 Equity Incentive Plan and/or the number, class and price of shares covered by each outstanding award and any numerical share limits set forth in our 2026 Equity Incentive Plan.

Dissolution or Liquidation

In the event of our proposed liquidation or dissolution, the administrator will notify participants as soon as practicable and all awards will terminate immediately prior to the consummation of such proposed transaction.

Merger or Change in Control

Our 2026 Equity Incentive Plan provides that in the event of our merger or change in control, as defined in our 2026 Equity Incentive Plan, each outstanding award will be treated as the administrator determines, without a participant’s consent. For example, the

administrator may provide that awards granted under the 2026 Equity Incentive Plan will be assumed or substituted by substantially equivalent awards, be terminated immediately before the merger or change in control, become vested and exercisable or payable and be terminated in connection with the merger or change in control, be terminated in exchange for cash, other property or other consideration or any combination of the above. The administrator is not required to treat all awards, all awards held by a participant, all portions of awards, or all awards of the same type, similarly.

In the event that a successor corporation or its parent or subsidiary does not assume, continue or substitute an equivalent award for any outstanding award (or a portion of such award), then such award (or its applicable portion) will fully vest, all restrictions on such award (or its applicable portion) will lapse, all performance goals or other vesting criteria applicable to such award (or its applicable portion) will be deemed achieved at 100% of target levels and such award (or its applicable portion) will become fully exercisable, if applicable, for a specified period prior to the transaction, unless specifically provided otherwise under the applicable award agreement or other written agreement with the participant. The award (or its applicable portion) will then terminate upon the expiration of the specified period of time. If an option or stock appreciation right is not assumed or substituted, the administrator will notify the participant that such option or stock appreciation right will be exercisable for a period of time determined by the administrator in its sole discretion and the option or stock appreciation right will terminate upon the expiration of such period.

Awards granted to outside director, regardless of whether assumed or substituted for in our merger or change in control, will fully vest immediately prior to the change in control provided the participant remains an outside director through the date of such change in control, and all performance goals or other vesting criteria applicable to such awards will be deemed achieved at 100% of target levels and such awards will become fully exercisable, if applicable, unless specifically provided otherwise under the applicable award agreement or other written agreement with the outside director.

Clawback

Awards are subject to any clawback policy of ours in effect at the time of grant or that the Company is required to adopt to comply with applicable laws. The administrator may require a participant to forfeit, return or reimburse us all or a portion of the award and any amounts paid under the award in order to comply with any such clawback policy or applicable laws. The administrator also may specify in an award agreement that the participant’s rights, payments and benefits with respect to an award will be subject to reduction, cancellation, forfeiture or recoupment upon the occurrence of certain specified events.

Amendment; Termination

The administrator has the authority to amend, suspend or terminate our 2026 Equity Incentive Plan, provided such action does not materially impair the rights of any participant unless mutually agreed otherwise. Our 2026 Equity Incentive Plan will remain in effect for a term of 10 years from the date of stockholder approval of the 2026 Equity Incentive Plan, until earlier terminated in accordance with its terms.

Summary of U.S. Federal Income Tax Consequences

The following summary is intended only as a general guide to the material U.S. federal income tax consequences of participation in the 2026 Equity Incentive Plan. The summary is based on existing U.S. federal income tax laws and regulations, and there can be no assurance that those laws and regulations will not change in the future. The summary does not purport to be complete and does not discuss the tax consequences upon a participant’s death, or the provisions of the tax laws of any municipality, state or non-U.S. jurisdiction to which the participant may be subject. As a result, tax consequences for any particular participant may vary based on individual circumstances.

Options

Options granted under the 2026 Equity Incentive Plan may be either “incentive stock options,” within the meaning of Section 422 of the Code, or nonstatutory stock options.

No taxable income is reportable when an incentive stock option is granted or exercised, although the exercise may subject the participant to the alternative minimum tax or may affect the determination of the participant’s alternative minimum tax (unless the shares are sold or otherwise disposed of in the same year). If the participant exercises an incentive stock option and then later sells or otherwise disposes of the shares acquired more than two years after the grant date and more than one year after the exercise date, the difference between the sale price and the exercise price generally will be taxed as capital gain or loss. If the participant exercises the incentive stock option and then later sells or otherwise disposes of the shares before the end of the two- or one‑year holding periods described above, he or she generally will have ordinary income at the time of the sale equal to the fair market value of the shares on the exercise date (or the sale price, if less) minus the exercise price of the option. For purposes of the alternative minimum tax, the difference between the option exercise price and the fair market value of the shares on the exercise date generally is treated as an adjustment item in computing the participant’s alternative minimum taxable income in the year of exercise. In addition, special alternative minimum tax rules may apply to certain subsequent disqualifying dispositions of the shares or provide certain basis adjustments or tax credits for alternative minimum tax purposes.

Any options that do not qualify as incentive stock options are referred to as nonstatutory stock options. No taxable income is reportable when a nonstatutory stock option with a per share exercise price at least equal to the fair market value of a share of the underlying

share on the date of grant is granted to a participant. Upon exercise, the participant generally will recognize ordinary income in an amount equal to the excess of the fair market value (on the exercise date) of the shares purchased over the exercise price of the exercised shares subject to the option. Any taxable income recognized in connection with the exercise of a nonstatutory stock option by an employee is subject to tax withholding by us. Any additional gain or loss recognized upon any later disposition of the shares generally would be capital gain or loss to the participant.

Stock Appreciation Rights

No taxable income is reportable when a stock appreciation right with a per share exercise price equal to at least the fair market value of a share of the underlying share on the date of grant is granted to a participant. Upon exercise, the participant generally will recognize ordinary income in an amount equal to the amount of cash received and the fair market value of any shares received. Any taxable income recognized in connection with the exercise of a stock appreciation right by an employee is subject to tax withholding by us. Any additional gain or loss recognized upon any later disposition of the shares generally would be capital gain or loss to the participant.

Restricted Stock

No taxable income is reportable when an award of restricted stock is granted to a participant. Instead, the participant will recognize ordinary income in the first taxable year in which the shares underlying the award becomes transferable or no longer subject to a substantial risk of forfeiture at the then fair market value of the shares. However, a participant who is granted a restricted stock award may elect to recognize ordinary income at the time the participant receives shares under the award in an amount equal to the then fair market value of the shares less any amount paid for the shares. If the participant is an employee, such ordinary income generally is subject to tax withholding by us. Any gain or loss recognized upon any later disposition of shares acquired under the restricted stock generally will be treated as capital gain or loss.

Restricted Stock Units, and Performance Awards

A participant generally will not have taxable income at the time an award of RSUs or performance awards are granted. Instead, the participant will recognize ordinary income in an amount equal to the fair market value of shares issued to the participant at the end of the applicable vesting period or, if later, the settlement date of the award. If the participant is an employee, such ordinary income generally is subject to tax withholding by us. Any gain or loss recognized upon any later disposition of shares acquired under the restricted stock units or performance awards generally will be treated as capital gain or loss.

Medicare Surtax

A participant’s annual “net investment income,” as defined in Section 1411 of the Code may be subject to a 3.8% federal surtax, generally referred to as the Medicare Surtax. Net investment income may include capital gain and/or loss arising from the disposition of shares subject to a participant’s awards under the 2026 Equity Incentive Plan. Whether a participant’s net investment income will be subject to the Medicare Surtax will depend on the participant’s level of annual income and other factors.

Section 409A

Section 409A of the Code provides certain requirements for nonqualified deferred compensation arrangements with respect to an individual’s deferral and distribution elections and permissible distribution events. Awards granted under the 2026 Equity Incentive Plan with a deferral feature will be subject to the requirements of Section 409A of the Code. Section 409A also generally provides that distributions must be made on or following the occurrence of certain events (e.g., the individual’s separation from service, a predetermined date, or the individual’s death). For certain individuals who are key employees, subject to certain exceptions, Section 409A requires that distributions in connection with his or her separation from service commence no earlier than six months after such separation from service.

If an award granted under the 2026 Equity Incentive Plan is subject to and fails to satisfy the requirements of Section 409A of the Code, the recipient of that award may recognize ordinary income on the amounts deferred under the award, to the extent vested, which may be prior to when the compensation is actually or constructively received. Also, if an award that is subject to Section 409A fails to comply with Section 409A’s provisions, Section 409A imposes an additional 20% federal income tax on compensation recognized as ordinary income, as well as potential penalties and interest, on such deferred compensation. Certain states such as California have enacted laws similar to Section 409A which impose additional taxes, and potential penalties and interest, on nonqualified deferred compensation arrangements that fail to comply with such state laws. We will also have withholding and reporting requirements with respect to such amounts. The 2026 Equity Incentive Plan provides that neither we nor any of our parents or subsidiaries will have any obligation to reimburse, indemnify, or hold harmless a participant in respect of awards granted under the 2026 Equity Incentive Plan for any taxes, interest or penalties imposed, or other costs incurred, as a result of Section 409A.

Tax Effect for the Company

We generally will be entitled to a tax deduction in connection with an award under the 2026 Equity Incentive Plan in an amount equal to the ordinary income realized by a participant and at the time the participant recognizes such income (for example, the exercise of a nonstatutory stock option). Special rules limit the deductibility of compensation paid to our chief executive officer and other “covered

employees” within the meaning of Code Section 162(m). Under Code Section 162(m), the annual compensation paid to any of these specified employees will be deductible only to the extent that it does not exceed $1,000,000.

THE FOREGOING IS ONLY A SUMMARY OF THE EFFECT OF U.S. FEDERAL INCOME TAXATION UPON PARTICIPANTS AND IMMUNITYBIO WITH RESPECT TO AWARDS UNDER THE 2025 PLAN. IT DOES NOT PURPORT TO BE COMPLETE AND DOES NOT DISCUSS THE IMPACT OF EMPLOYMENT OR OTHER TAX REQUIREMENTS, THE TAX CONSEQUENCES OF A PARTICIPANT’S DEATH, OR THE PROVISIONS OF THE INCOME TAX LAWS OF ANY MUNICIPALITY, STATE, OR FOREIGN COUNTRY IN WHICH THE PARTICIPANT MAY RESIDE.

New Plan Benefits

The Company’s executive officers and directors have an interest in the approval of the 2026 Equity Incentive Plan because they are eligible to receive equity awards under the 2026 Equity Incentive Plan.

The number of awards that an employee or consultant may receive under the 2026 Equity Incentive Plan is at the discretion of the administrator and therefore cannot be determined in advance. Awards to our non-employee directors are granted automatically pursuant to our outside director compensation policy as described in our proxy statement under the heading “Director Compensation”, and such directors also are eligible for awards under the 2026 Equity Incentive Plan granted at the discretion of the administrator. The following table sets forth: (i) the aggregate number of shares of common stock subject to options granted under the 2020 Equity Incentive Plan during the fiscal year ended December 31, 2025 to each of our named executive officers; all executive officers, as a group; all directors who are not executive officers, as a group; and all employees who are not executive officers, as a group; (ii) the average per Share exercise price of such options; (iii) the aggregate number of shares of common stock subject to restricted stock units granted under the 2020 Equity Incentive Plan during the fiscal year ended December 31, 2025 to each of our named executive officers; all executive officers, as a group; all directors who are not executive officers, as a group; and all employees who are not executive officers, as a group; and (iv) the grant date value of option and restricted stock unit awards granted under the 2020 Equity Incentive Plan during the fiscal year ended December 31, 2025.


Name of Individual or Group	Shares Subject to Options Granted (#)	Average Per Share Exercise Price of Options Granted ($)	Shares Subject to Stock Awards Granted (#)	Grant Date Fair Value of Option and Stock Awards ($) (1)
Mark Litton Ph.D., President and Chief Executive Officer	166,906	3.80	22,254	601,854.36
Javier San Martin, M.D., Chief Medical Officer	55,635	4.01	7,418	210,049.50
Mark Worthington, General Counsel, Chief Compliance Officer and Corporate Secretary	42,946	4.01	5,726	162,142.13
All executive officers, as a group	356,951	3.91	45,154	1,309,153.14
All directors who are not executive officers, as a group	14,630	3.13	—	36,100.84
All employees who are not executive officers, as a group	115,999	3.98	15,742	134,649.00

(1)

Amounts shown represent the grant date fair value of option and RSU awards determined in accordance with Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) Topic 718 (ASC Topic 718), Stock Compensation.

As of the record date, the closing price of the Company’s common stock was $5.36 per share.

Effect of Vote in Favor of the Proposal

If this proposal is approved by our stockholders, our 2026 Equity Incentive Plan will come into effect.

Effect of Not Obtaining the Required Vote

If our stockholders do not approve our 2026 Equity Incentive Plan, the 2026 Equity Incentive Plan will not come into effect and our 2020 Equity Incentive Plan will remain in effect through the remainder of its term.

Vote Required

nor abstentions will be considered votes cast for or against this proposal. Accordingly, broker non-votes and abstentions will have no impact on the outcome of this proposal.

Board Recommendation

THE BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS THAT STOCKHOLDERS VOTE “FOR” PROPOSAL 4.

PROPOSAL NO. 5

A proposal to amend our amended and restated certificate of incorporation to increase the number of authorized shares of common stock.

DESCRIPTION OF PROPOSAL

Overview

We are asking our stockholders to approve an amendment of our amended and restated certificate of incorporation to increase our authorized common stock. Our authorized capital stock currently consists of 190,000,000 shares, of which 90,000,000 are common stock and 100,000,000 are preferred stock, par value $0.0001 per share. On January 26, 2026, our board of directors approved and declared advisable an amendment of our amended and restated certificate of incorporation to increase the number of authorized shares of common stock from 90,000,000 shares to 400,000,000 shares. The number of authorized shares of preferred stock would not be affected by the amendment. The board of directors further directed that the increase in common stock be submitted to stockholders for approval and adoption. The total number of authorized shares of our capital stock (which is the sum of the authorized number of shares of our common stock and our preferred stock) would, by virtue of the amendment, increase from 190,000,000 to 500,000,000.

The full text of the certificate of amendment to our amended and restated certificate of incorporation is attached to this proxy statement as Annex B. If our stockholders approve the proposal, subject to the discretion of our board of directors, we will file the certificate of amendment with the Secretary of State of the State of Delaware as soon as possible.

Reasons for Stockholder Approval

The proposed increase in the authorized number of shares of common stock is intended to ensure that we continue to have an adequate number of authorized and unissued shares of common stock for future use. The increase in authorized common stock would ensure we have sufficient additional authorized but unissued shares of common stock to permit issuances from time to time in the board of directors’ discretion in connection with future financings, investment opportunities or dividends, strategic transactions, equity incentive plan arrangements or for other corporate purposes.

As of the record date, a total of 9,335,913 shares of common stock were issued and outstanding and no shares of preferred stock were issued and outstanding. In addition, as of the record date, there were:

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1,213,464 shares of common stock issuable upon exercise of outstanding options;

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SEC Form DEF 14A filed by LeonaBio Inc.