Metsera, Inc. (MTSR)

Metsera, Inc. was a clinical-stage biopharmaceutical company headquartered in New York City that focused on next-generation medicines for obesity and other cardiometabolic diseases. The company was launched in 2022 by Population Health Partners and ARCH Venture Partners and spent most of its early life as a privately held company. Its stated goal was to develop weight-management therapies with convenient dosing, good tolerability and the potential to preserve lean mass.

The pipeline was built around incretin and amylin pathways. Its lead candidate, MET-097i, is an injectable GLP-1 receptor agonist engineered for extended duration so that it could eventually be dosed as infrequently as once a month. MET-233i is a long-acting amylin analog that Metsera evaluated both alone and in combination with MET-097i. The company also worked on oral and other injectable candidates intended to broaden its portfolio beyond a single product.

Metsera became a public company in January 2025, when its common stock began trading on the Nasdaq Global Select Market under the ticker MTSR following an initial public offering that raised roughly $275 million. The proceeds were directed at advancing the clinical programs, including a Phase 2b study of MET-097i in adults with obesity and early-stage studies of MET-233i. As a development-stage company, Metsera had no approved products and no product revenue.

On September 22, 2025, Metsera announced a definitive agreement under which Pfizer Inc. would acquire the company, a move that gave Pfizer a larger presence in the obesity market. The initial terms provided for cash plus a contingent value right. In late October, Novo Nordisk made an unsolicited competing proposal, and a contested process followed that included litigation between Pfizer and Metsera in Delaware and a review of the competing offer by Metsera's board of directors.

Pfizer ultimately raised its offer to $65.60 per share in cash at closing, plus a non-transferable contingent value right worth up to $20.65 per share in cash, payable if specified development milestones are achieved. Together these terms valued the transaction at up to $86.25 per share, or roughly $10 billion in total. Metsera's board supported the revised terms, and the company's stockholders approved the merger.

The acquisition closed on November 13, 2025, and Metsera became a wholly owned subsidiary of Pfizer. Trading of MTSR on the Nasdaq Global Select Market ended, and a Form 25 delisting notice was filed with the Securities and Exchange Commission the same day. Because Metsera no longer exists as an independent listed company, its former shareholders hold no continuing equity interest other than the contingent value rights.