RA CAPITAL MANAGEMENT, L.P. - 11 Dec 2025 Form 4 Insider Report for Climb Bio, Inc. (CLYM)

Signature
/s/ Peter Kolchinsky, Manager of RA Capital Management, L.P.
Issuer symbol
CLYM
Transactions as of
11 Dec 2025
Net transactions value
+$754,737
Form type
4
Filing time
15 Dec 2025, 19:55:04 UTC
Previous filing
10 Dec 2025
Next filing
19 Dec 2025

Reporting Owners (7)

Name Relationship Address Signature Signature date CIK
RA CAPITAL MANAGEMENT, L.P. Director, 10%+ Owner 200 BERKELEY STREET, 18TH FLOOR, BOSTON /s/ Peter Kolchinsky, Manager of RA Capital Management, L.P. 15 Dec 2025 0001346824
RA Capital Healthcare Fund LP Director, 10%+ Owner 200 BERKELEY STREET, 18TH FLOOR, BOSTON /s/ Peter Kolchinsky, Manager of RA Capital Healthcare Fund GP, LLC the General Partner of RA Capital Healthcare Fund, L.P. 15 Dec 2025 0001315082
RA Capital Nexus Fund, L.P. Director 200 BERKELEY STREET, 18TH FLOOR, BOSTON /s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund GP, LLC, the General Partner of RA Capital Nexus Fund, L.P. 15 Dec 2025 0001780117
RA Capital Nexus Fund II, L.P. Director 200 BERKELEY STREET, 18TH FLOOR, BOSTON /s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund II GP, LLC, the General Partner of RA Capital Nexus Fund II, L.P. 15 Dec 2025 0001825376
RA Capital Nexus Fund III, L.P. Director, 10%+ Owner 200 BERKELEY STREET, 18TH FLOOR, BOSTON /s/ Peter Kolchinsky, Manager of RA Capital Nexus Fund III GP, LLC, the General Partner of RA Capital Nexus Fund III, L.P. 15 Dec 2025 0001883840
Kolchinsky Peter Director, 10%+ Owner C/O RA CAPITAL MANAGEMENT, L.P., 200 BERKELEY STREET, 18TH FLOOR, BOSTON /s/ Peter Kolchinsky, individually 15 Dec 2025 0001384859
Shah Rajeev M. Director, 10%+ Owner C/O RA CAPITAL MANAGEMENT, L.P., 200 BERKELEY STREET, 18TH FLOOR, BOSTON /s/ Rajeev Shah, individually 15 Dec 2025 0001619841

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction CLYM Common Stock Disposed to Issuer $0 -20,440,000 -87% $0.000000 3,081,757 11 Dec 2025 See footnotes F1, F2, F3
transaction CLYM Common Stock Purchase $464,556 +213,099 +6.9% $2.18 3,294,856 11 Dec 2025 See footnotes F2, F3, F4
transaction CLYM Common Stock Purchase $290,181 +101,462 +3.1% $2.86 3,396,318 12 Dec 2025 See footnotes F2, F3, F5
holding CLYM Common Stock 2,479,872 11 Dec 2025 See footnotes F3, F6
holding CLYM Common Stock 1,226,497 11 Dec 2025 See footnotes F3, F7
holding CLYM Common Stock 483,679 11 Dec 2025 See footnotes F3, F8
holding CLYM Common Stock 2,866,375 11 Dec 2025 See footnotes F3, F9
holding CLYM Common Stock 841,087 11 Dec 2025 See footnotes F3, F10

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction CLYM Pre-Funded Warrants (Right to Buy) Award +20,440,000 20,440,000 11 Dec 2025 Common Stock 20,440,000 $0.000100 See footnotes F1, F2, F3, F11
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 On December 11, 2025, RA Capital Healthcare Fund, L.P. (the "Fund") entered into an Exchange Agreement with the Issuer pursuant to which the Fund exchanged, for no additional consideration, 20,440,000 shares of the Issuer's Common Stock for a pre-funded warrant exercisable for up to 20,440,000 shares of the Issuer's Common Stock at an exercise price of $0.0001 per share.
F2 These securities are held directly by RA Capital Healthcare Fund, L.P. (the "Fund").
F3 RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund, RA Capital Nexus Fund, L.P. (the "Nexus Fund"), RA Capital Nexus II Fund, L.P. (the "Nexus Fund II"), RA Capital Nexus III Fund, L.P. (the "Nexus Fund III") and a separately managed account (the "Account"). The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. The Fund and the Nexus Fund III collectively own approximately 75% of the outstanding equity interests of Sera Medicines, LLC ("Sera"). Accordingly, each of the Fund, the Nexus Fund III and the Adviser may be deemed to beneficially own the securities held by Sera. The Adviser, the Adviser GP, the Fund, the Nexus Fund, the Nexus Fund II, the Nexus Fund III, Dr. Kolchinsky and Mr. Shah disclaim beneficial ownership of the reported securities, except to the extent of their respective pecuniary interest therein.
F4 The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $2.11 to $2.20 inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote.
F5 The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $2.32 to $3.00 inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote.
F6 These securities are held directly by Sera.
F7 These securities are held directly by the Nexus Fund.
F8 These securities are held directly by the Nexus Fund II.
F9 These securities are held directly by Nexus Fund III.
F10 These securities are held directly by the Account.
F11 The Pre-Funded Warrants have no expiration date and are exercisable immediately. Notwithstanding the foregoing, the Reporting Persons shall not be entitled to exercise the Pre-Funded Warrant if it would cause the aggregate number of shares of Common Stock beneficially owned by the Reporting Persons, their affiliates and any persons who are members of a Section 13(d) group with the Reporting Persons or their affiliates to exceed 33.0% of the total number of issued and outstanding shares of Common Stock of the Issuer following such exercise.

Remarks:

Dr. Andrew Levin, a Partner and Managing Director of the Adviser, serves on the Issuer's board of directors.