Pfizer Discontinues Clinical Development of MET-815i and PF-07976016 for Obesity
Streamlining Obesity Pipeline
Pfizer (PFE) has discontinued clinical development of MET-815i and PF-08656795, as well as PF-07976016, which were in development as chronic weight management candidates. MET-815i, a Phase 1 candidate, was a prodrug of berobenatide (PF-08653944, MET-097i), a glucagon-like peptide-1 receptor (GLP-1R) agonist, designed for once-quarterly administration. PF-07976016, a Phase 2 candidate, was an oral, small-molecule glucagon-independent polypeptide receptor (GIPR) antagonist. The decision to discontinue these programs, which offered two distinct approaches – sustained-release injection and oral combination therapy – reflects a portfolio prioritization focused on assets with a higher probability of success in later-stage clinical trials.
Focusing Resources on Berobenatide
MET-815i slowly releases berobenatide in the body, but the once-monthly berobenatide, which directly delivers the same active ingredient, is further ahead in development, having progressed to Phase 3. This created significant overlap. Pfizer is advancing over 20 obesity research programs, including berobenatide and a Phase 2, once-monthly amylin analog (MET-233i, PF-08653945), both as monotherapy and in combination. This allows the company to reduce the additional toxicity, manufacturing, and dose optimization burdens associated with the prodrug and focus resources on key assets, including patient recruitment and production. The discontinuation of PF-07976016 also means that the pipeline will no longer include a fixed-dose combination strategy of an oral GLP-1 receptor agonist and a GIPR antagonist.
Approved Products and Late-Stage Candidates Raise the Bar
The standard of care in obesity treatment is currently defined by Novo Nordisk's (NVO) Wegovy (semaglutide, a GLP-1R agonist) and Eli Lilly's (LLY) Zepbound (tirzepatide, a GIPR/GLP-1R dual agonist). The U.S. Food and Drug Administration (FDA) approved Wegovy for chronic weight management on June 4, 2021, and Zepbound on November 8, 2023; both are commercially available. Late-stage competitors include Eli Lilly's retatrutide and orforglipron, both in Phase 3, and Amgen's (AMGN) maritide, also in Phase 3. According to IQVIA, the global market for obesity treatments is projected to grow from USD 66 billion in 2025 to USD 92 billion in 2026. As a result, efficacy, as well as convenience of administration, tolerability, and manufacturing costs, will increasingly determine commercial success.
Preserving Value from the Acquisition
Pfizer completed the acquisition of Metsera on November 13, 2025, for USD 65.60 per share in cash, representing an enterprise value of approximately USD 7.0 billion, plus contingent value rights (CVRs) of up to USD 20.65 per share. The contingent payments are linked to three milestones: the initiation of a Phase 3 clinical trial of berobenatide and MET-233i in combination, and the approval of berobenatide, both as monotherapy and in combination, by the FDA. The discontinued MET-815i and PF-07976016 were not direct targets of these payments, so the core economic value of the acquisition remains intact. This is not a market withdrawal but rather a selective risk reduction, eliminating redundant assets and focusing capital on late-stage clinical success and large-scale peptide production.
The discontinuation of Phase 1 MET-815i and Phase 2 PF-07976016 signals a shift in Pfizer's obesity strategy, focusing on the Phase 3 berobenatide and Phase 2 MET-233i combination therapy. While this reduces near-term research and operational complexity, it also eliminates the potential for differentiated approaches, such as once-quarterly injections and oral GIPR antagonist combinations. The R&D organization now faces the key challenges of demonstrating the weight-loss efficacy and gastrointestinal safety of late-stage assets and scaling up production of a once-monthly peptide. With the USD 66 billion market in 2025 and competitors such as Wegovy, Zepbound, retatrutide, orforglipron, and maritide raising the bar, the clinical results of berobenatide will determine the return on the Metsera acquisition. The USD 7.0 billion acquisition price and contingent value rights of up to USD 20.65 per share, linked to the initiation of Phase 3 trials and FDA approval of key assets, support the view that this is a financially sound, selective risk reduction.