Metsera, Inc. — Director's Dealing 2025

Nov 17, 2025

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: Metsera, Inc. (MTSR)
CIK: 0002040807
Period of Report: 2025-11-13

Reporting Person: FMR LLC (N/A)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2025-11-13	Common Stock	J	3010	—	Disposed	0	Indirect
2025-11-13	Common Stock	J	2230450	—	Disposed	0	Indirect

Footnotes

F1: Pursuant to the Agreement and Plan of Merger dated September 21, 2025, as amended on November 7, 2025 (the "Merger Agreement"), by and among Metsera, Inc. (the "Company"), Pfizer Inc., a Delaware corporation ("Parent"), and Mayfair Merger Sub, Inc., a Delaware corporation and a wholly owned subsidiary of the Parent (the "Merger Sub"), the Merger Sub merged with and into the Company, with the Company continuing as the surviving corporation and a wholly owned subsidiary of the Parent (the "Merger"). At the Effective Time of the Merger (as defined in the Merger Agreement), each issued and outstanding share of common stock, par value $0.00001 per share of the Company (the "Common Stock") was converted automatically into the right to receive (i) cash in an amount equal to $65.60 per share without interest (the "Closing Amount"),

F2: (Continued from footnote 1) net of all applicable withholding taxes, plus (ii) one contractual contingent value right representing the right to receive contingent payments (a "CVR") in cash, without interest, upon the achievement of certain specified milestones, in accordance with the terms and conditions of the contingent value rights agreement entered into by the Parent and Equiniti Trust Company, LLC, dated November 13, 2025 (collectively, the "Merger Consideration").