shares surged dramatically on Monday, September 22, 2025, following the announcement of a definitive merger agreement with pharmaceutical giant The stock jumped over 62% to $53.99 as of 11:33 AM EDT, representing one of the most significant single-day gains in the biotechnology sector this year. The acquisition, valued at $4.9 billion initially with potential additional payments bringing the total to $7.3 billion, marks Pfizer’s strategic entry into the rapidly growing obesity treatment market through Metsera’s promising portfolio of next-generation incretin and amylin therapies.
Metsera Gains Momentum With Pfizer Partnership
Under the merger terms, Pfizer will acquire all outstanding Metsera shares for $47.50 per share in cash at closing, representing the initial $4.9 billion enterprise value. Additionally, shareholders will receive contingent value rights (CVRs) worth up to $22.50 per share tied to three key milestones: $5 per share for Phase 3 trial initiation of the MET-097i+MET-233i combination, $7 per share for FDA approval of monthly MET-097i monotherapy, and $10.50 per share for FDA approval of the combination therapy.
Metsera’s portfolio includes four clinical-stage programs targeting obesity and cardiometabolic diseases, with MET-097i as a weekly and monthly injectable GLP-1 receptor agonist in Phase 2 development, and MET-233i as a monthly amylin analog in Phase 1 trials. The company also has two oral GLP-1 receptor agonist candidates expected to begin clinical trials imminently. Recent Phase 1 results for MET-233i, presented at the European Association for the Study of Diabetes meeting, demonstrated a potentially best-in-class profile that caught Pfizer’s attention.
The transaction is expected to close in Q4 2025, subject to regulatory approvals and Metsera shareholder approval. For Pfizer, this acquisition represents a strategic pivot into the obesity market, leveraging the company’s extensive cardiometabolic experience and global manufacturing capabilities to accelerate development of what CEO Albert Bourla described as “potential best-in-class injectables” with differentiated efficacy, tolerability, and monthly dosing convenience.
MTSR Stock Rockets on Heavy Trading Volume
MTSR shares opened at $52.59 and reached an intraday high of $54.46, representing a remarkable 62.06% gain from the previous close of $33.32. Trading volume exploded to over 10.3 million shares, more than seven times the average daily volume of 1.4 million shares. The stock’s 52-week range has expanded dramatically from a low of $12.30 to the current high of $54.46, reflecting the transformative nature of this acquisition.
Despite the company’s current lack of revenue and negative earnings of -$2.94 per share, investors are betting on the potential of Metsera’s obesity drug portfolio. The company maintains a strong balance sheet with $530.92 million in total cash and minimal debt, providing a solid foundation for continued research and development activities under Pfizer’s ownership.
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Metsera Buyout Confirms Obesity as Strategic Pivot for Pfizer’s Growth Story
