8-K

Climb Bio, Inc.

Date: June 5, 2026

/s/ Aoife Brennan

Aoife Brennan, M.B., Ch.B.

President and Chief Executive Officer

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): June 5, 2026

CLIMB BIO, INC.

(Exact Name of Registrant as Specified in its Charter)

Delaware

001-40708

83-2273741

(State or Other Jurisdiction

of Incorporation)

(Commission

File Number)

(IRS Employer

Identification No.)

20 William Street, Suite 145

Wellesley Hills, Massachusetts

02481

(Address of Principal Executive Offices)

(Zip Code)

Registrant’s Telephone Number, Including Area Code: (866) 857-2596

Not Applicable

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

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

☐	Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐	Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐	Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐	Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

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

Title of each class

Trading
Symbol(s)

Name of each exchange

on which registered

Common Stock, par value $0.0001 per share

CLYM

The Nasdaq Stock Market LLC

(The Nasdaq Global Market)

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

Emerging growth company ☒

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

Item 8.01

Other Events.

On June 5, 2026, Climb Bio, Inc. (the “Company”) announced translational pharmacometric modeling and initial Phase 1 safety data for CLYM116, its anti-APRIL monoclonal antibody:

•

A translational pharmacokinetic/pharmacodynamic model derived from pooled non-human primate (“NHP”) data projected healthy human exposure and dose-dependent IgA suppression for CLYM116, suggesting the potential for less-frequent dosing than first generation anti-APRIL approaches.

•

Literature analysis shows strong correlation in IgA reduction between NHP and healthy volunteer studies.

•

Global Phase 1 strategy, incorporating parallel healthy volunteer datasets ex-China and China (n≈80, doses 25 mg to 640 mg), expected to support a robust population pharmacokinetic foundation to inform dose selection.

•

CLYM116 has been generally well tolerated based on preliminary safety data from healthy volunteers receiving single doses up to 320 mg or placebo (n=49), with no unexpected safety findings reported to date.

No serious adverse events, dose limiting toxicities, or adverse event related discontinuations observed.

All adverse events observed were mild to moderate (Grade 1-2), transient, and self-resolving.

Injection site reactions observed in two patients, both Grade 1, and resolved without intervention.

These clinical data include results from a Phase 1 study being conducted by the Company in Australia, and a parallel ongoing Phase 1 study being conducted by the Company’s partner, Beijing Mabworks Biotech (“Mabworks”), in China. With the safety profile observed to date and supportive preclinical data, the Company plans to continue to advance CLYM116 into further clinical development, and Mabworks expects to initiate dosing in IgAN patients in the Phase 2 portion of its ongoing study in the third quarter of 2026.

Forward-Looking Statements

This Current Report on Form 8-K contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, including without limitation statements regarding: future expectations, plans and prospects for the Company; expectations regarding the therapeutic benefits, clinical potential and clinical development of CLYM116; the anticipated timelines for announcing data from the Company’s ongoing and planned clinical trials; the anticipated timelines for enrolling patients in planned clinical trials; the Company’s expectations regarding the translation of results observed in preclinical animal model models to humans; the anticipated benefits of the Company’s technology transfer and exclusive license agreement with Mabworks; and other statements containing the words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “should,” “suggest,” “target,” “would,” “will,” “working” and similar expressions. Forward-looking statements are based on management’s current expectations of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in, or implied by, such forward-looking statements. The Company may not actually achieve the plans, intentions or expectations disclosed in these forward-looking statements, and you should not place undue reliance on these forward-looking statements. These risks and uncertainties include, but are not limited to, important risks and uncertainties associated with: the ability of the Company to timely and successfully achieve or recognize the anticipated benefits of its acquisition of Tenet Medicines, Inc. and its technology transfer and exclusive license agreement with Mabworks; the Company’s ability to advance budoprutug and CLYM116 on the timelines expected or at all and to obtain and maintain necessary approvals from the U.S. Food and Drug Administration and other regulatory authorities; obtaining and maintaining the necessary approvals from investigational review boards at clinical trial sites and independent data safety monitoring boards; replicating in clinical trials positive results found in early-stage clinical trials or nonclinical studies; competing successfully with other companies that are seeking to develop treatments for primary membranous nephropathy, immune thrombocytopenia, systemic lupus erythematosus, IgA nephropathy and other immune-mediated diseases; maintaining or protecting intellectual property rights related to budoprutug, CLYM116 and/or its other product candidates; managing expenses; changes in applicable laws or regulation; the possibility that the Company may be adversely affected by other economic, business and/or competitive factors; and raising the substantial additional capital needed, on the timeline necessary, to continue development of budoprutug, CLYM116 and any other product candidates the Company may develop. For a discussion of other risks and uncertainties, and other important factors, any of which could cause the Company’s actual results to differ materially from those contained in the forward-looking statements, see the “Risk Factors” section, as well as discussions of potential risks, uncertainties and other important factors, in the Company’s most recent filings with the U.S. Securities and Exchange Commission. In addition, the forward-looking statements included in this Current Report on Form 8-K represent the Company’s views as of the date hereof and should not be relied upon as representing the Company’s views as of any date subsequent to the date hereof. The Company anticipates that subsequent events and developments will cause the Company’s views to change. However, while the Company may elect to update these forward-looking statements at some point in the future, the Company specifically disclaims any obligation to do so, except as required by law.

SIGNATURES

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

SEC Form 8-K filed by Climb Bio Inc.