RA Capital Increases Stake in Climb Bio, Inc. via $20M Private Placement Investment

On April 27, 2026, RA Capital Management, L.P., along with its affiliates Peter Kolchinsky, Rajeev Shah, and several managed funds, entered into a Securities Purchase Agreement with Climb Bio, Inc. (formerly known as Sera Medicines, LLC) as part of a private placement. RA Capital Healthcare Fund purchased 2,106,000 Pre-Funded Warrants for $20,006,789.40. Following the transaction, the reporting persons collectively beneficially own 22,631,401 shares of common stock, representing 33.0% of the class. This ownership includes common stock held directly by various funds, pre-funded warrants, and vested stock options. The Pre-Funded Warrants include a beneficial ownership blocker that limits the reporting persons' aggregate ownership to 33.0% of the outstanding common stock. Additionally, Sera Medicines, LLC ceased to be a 5% beneficial owner due to dilution from the private placement. As part of the deal, the Issuer entered into a Registration Rights Agreement to register the resale of the shares and warrant shares issued in this private placement.