aibioClimb Bio agrees to swap 20,440,000 RA Capital shares for a pre-funded warrant
Tickers CLYM
Climb Bio agreed on December 11, 2025 to take back 20,440,000 shares from an entity affiliated with RA Capital in exchange for a pre-funded warrant. After the exchange, RA Capital and its affiliates will hold about 23.0% of the voting power, and the filing describes no cash payment to the company.
Key facts
- Company
- Climb Bio, Inc. (NASDAQ: CLYM)
- News type
- Financings
- Primary source
- Climb Bio, Inc. Form 8-K filed December 11, 2025 (SEC EDGAR)
Climb Bio, Inc. (Nasdaq: CLYM) said on December 11, 2025 that it signed an exchange agreement with RA Capital Management, L.P. and an entity affiliated with it. The company reported the agreement in a Form 8-K under Items 1.01 and 3.02. The exchanging stockholder gives up 20,440,000 shares of common stock, par value $0.0001 per share, and receives a pre-funded warrant to buy the same number of shares. The 8-K says the stockholders received no additional consideration for the shares other than the warrants.
How the exchange works
A pre-funded warrant lets the holder buy shares at a nominal price, here $0.0001 per share, without paying the full exercise price up front. The warrant can be exercised at any time after issue. The company says the warrant shares are issued without registration under the Securities Act of 1933, in reliance on the exemption in Section 3(a)(9).
The exchange shares are retired. The 8-K says that after the exchange and retirement, 47,744,435 shares of common stock will be issued and outstanding. RA Capital and its affiliates will then beneficially own common stock representing about 23.0% of the company's voting power.
The 8-K says closing was expected on December 11, 2025, and the letter agreement sets closing for the first trading day after signing unless the parties agree another date. The stockholders instruct their broker to transfer the shares through the Deposit Withdrawal at Custodian system to Equinity Trust Company, LLC, the transfer agent. Exhibit 10.1, a letter agreement dated December 11, 2025, governs that closing.
Voting commitments and the cap
RA Capital and the exchanging stockholder agreed to vote any shares they own in excess of 33.0% of the company's total voting power in proportion to the votes of all other stockholders. They also agreed to use commercially reasonable efforts to cause Sera Medicines LLC to follow the same terms.
The warrant carries its own cap. The holder cannot exercise any part of it if the exercise would push the combined beneficial ownership of RA Capital, the holder and their affiliates above 33.00% of the shares outstanding immediately after the exercise. The holder may lower that percentage, or set it to any figure not above 33.00%. After signing, RA Capital may exchange more shares it or its affiliates hold for further pre-funded warrants, but that requires written notice to Climb and the company's written consent.
What is not in the filing
The 8-K names no placement agent, underwriter or financial advisor for the exchange. The transaction is an exchange with an existing holder under Section 3(a)(9), not a sale of new shares for cash, and the filing describes no cash payment to Climb. The 8-K does not say why the company agreed to the exchange. It also does not give the price at which the shares traded when the agreement was signed.
The company and its lead drug
Climb Bio describes itself, in its annual report for 2024 filed March 25, 2025, as a clinical-stage biotechnology company developing therapies for immune-mediated diseases. Its cornerstone candidate is budoprutug, formerly TNT119, a clinical-stage anti-CD19 monoclonal antibody designed to deplete CD19-positive B cells, including plasma blasts that secrete antibodies.
The company is developing budoprutug in three indications: primary membranous nephropathy, immune thrombocytopenia and systemic lupus erythematosus. The report says the FDA cleared a Phase 2 dose range finding trial in primary membranous nephropathy in March 2025, with first dosing expected in the second half of 2025.
The report's support for the drug in that indication rests on a small earlier study. It says a Phase 1b trial in primary membranous nephropathy produced results suggesting budoprutug "may offer the opportunity to induce remission." In that trial, three of five patients, or 60%, who received four doses and completed at least 48 weeks of follow-up achieved a complete remission of proteinuria. Five patients is a very small group, and the Phase 2 trial is a dose range finding study rather than a test of efficacy.
Who signed
President and Chief Executive Officer Aoife Brennan, M.B., Ch.B., signed the 8-K on December 11, 2025.