Pfizer Rationalizes Obesity Pipeline: Discontinues Oral Metsera Asset and Backs Monthly Injectable Berobenatide
In August 2026, Pfizer executed a major strategic cleanup of its clinical-stage obesity pipeline, consolidating its bets following its $10 billion acquisition of biotech darling Metsera. The pharma giant discontinued two clinical obesity assets, including one of Metsera's lead oral candidates, while doubling down on its flagship monthly injectable candidate, berobenatide (PF-08653944, formerly MET-097i). This rationalization highlights the intense pressure on second-wave competitors to deliver highly differentiated clinical profiles to challenge the Lilly/Novo duopoly.
The Pipeline Clearout: MET-224o and PF-07976016 Axed
During its Q2 2026 earnings update on August 4, 2026, Pfizer revealed it had discontinued the development of two clinical-stage weight-loss candidates:
- MET-224o: An oral, fully biased, ultra-long-acting GLP-1 receptor agonist that Pfizer acquired through the Metsera transaction. This was designed as one of Metsera's primary oral candidates but was scrapped during the quarterly portfolio review.
- PF-07976016: A GIP receptor (GIPR) antagonist in Phase 2 development. It was being evaluated in combination with Pfizer’s licensed oral small-molecule GLP-1 drug from YaoPharma, PF-08642534 (formerly YP05002). The combination was discontinued following disappointing Phase 2a data on a background of liraglutide.
A Pfizer spokesperson explained the GIPR decision:
"After reviewing phase 2a data for our GIPR antagonist on background of liraglutide, Pfizer has decided to discontinue development of the molecule, though we continue to explore approaches targeting the GIP receptor."
With these cuts, PF-08642534 remains Pfizer's sole clinical oral GLP-1 candidate, though the company stated it remains committed to exploring both oral peptide and small-molecule approaches.
Backing Berobenatide (MET-097i) as a Best-in-Class Monthly Injectable
While oral assets were trimmed, Pfizer expressed high confidence in berobenatide, its ultra-long-acting injectable GLP-1 receptor agonist acquired from Metsera. Berobenatide is being positioned as a powerful, once-monthly maintenance therapy that could match the efficacy of weekly blockbusters while offering superior dosing convenience and tolerability.
At the American Diabetes Association (ADA) 2026 Scientific Sessions, Pfizer presented robust Phase 2b data validating the asset:
- VESPER-1 Trial: In a 32-week extension, patients with obesity or overweight who escalated to a 2.4 mg weekly dose of berobenatide achieved a non-placebo-adjusted weight loss of 15.9% with no weight-loss plateau observed.
- VESPER-3 Trial: This trial evaluated switching patients from weekly titration to monthly maintenance dosing. The results demonstrated that berobenatide maintains weight-loss efficacy after transitioning to once-monthly administration, with favorable gastrointestinal tolerability.
On Pfizer's Q2 2026 earnings call, Chief Scientific Officer Chris Boshoff, M.D., Ph.D., emphasized berobenatide's competitive profile:
"An analysis suggests berobenatide can deliver weight loss comparable to tirzepatide and potentially better than semaglutide. Combined with data from the extension arm of berobenatide's phase 2b Vesper-1 trial, Pfizer is increasingly confident that the candidate can potentially deliver robust efficacy and favorable gastrointestinal tolerability with the convenience of a monthly therapy."
Investor Takeaway
Pfizer's pruning of its pipeline reflects a disciplined approach to the obesity market, discarding marginal assets to focus capital on high-probability, high-differentiation candidates. By backing berobenatide, Pfizer is aiming directly at the "maintenance" market, betting that patients who achieve initial weight loss will eagerly transition to a monthly injection rather than continuing weekly shots. This positions Pfizer as a major player in the next-generation GLP-1 landscape.