Pfizer to acquire Metsera for $4.9 billion in obesity-drug push

Pfizer Inc. is expanding its obesity-treatment ambitions with a $4.9 billion cash deal to acquire Metsera, a development-stage drugmaker. Pfizer said it will pay $47.50 per Metsera share in cash, a premium of more than 42% to Metsera’s closing price on Friday. In addition, Metsera shareholders could receive up to $22.50 per share more, depending on how Metsera’s product pipeline develops.

Metsera has no products on the market, but its pipeline includes four programs in clinical development and one in mid-stage testing. The obesity-treatment market has drawn strong interest in recent years, with market leaders Zepbound from Eli Lilly and Wegovy from Novo Nordisk driving demand. The proposed deal underscores the continuing effort by large pharmaceutical companies to diversify portfolios in a field that has been reshaping approvals and investment priorities.

Pfizer currently has no obesity treatments on the market but has several in clinical development. Earlier this year, the company said it was ending development of a potential once-daily pill before it started late-stage testing, part of a broader review of its obesity portfolio as it prioritizes candidates with near-term potential. The Metsera acquisition adds a development-stage asset to Pfizer’s obesity ambitions, complementing programs already in the pipeline.

Market reaction to the deal underscored the shifting dynamics in the space: Pfizer shares rose modestly, climbing 31 cents to $24.33 before markets opened Monday, while Metsera’s stock advanced by roughly 60%. The cash-and-pipeline structure of the agreement reflects the high-stakes nature of obesity drug development, where early-stage programs can broaden or contract value quickly based on clinical and regulatory milestones.

The transaction illustrates the ongoing emphasis among large drugmakers on obesity therapies, a sector that has attracted significant capital as clinics see rising demand for effective weight-management treatments. Regulators will review the deal for antitrust and competitive implications, and Metsera shareholders will need to approve the transaction, with customary closing conditions expected before completion.