Pfizer (PFE) announced on Tuesday that a mid-stage trial evaluating a monthly maintenance dosing regimen of its experimental obesity drug indicated that the GLP-1 receptor agonist PF’3944 (MET-097i) caused up to 12% weight loss over roughly seven months.
Citing topline data from its Phase 2b VESPER-3 study, the company said that the long-acting injectable led to statistically significant weight reduction in the study, which targeted obese or overweight adults without type 2 diabetes.
Pfizer (PFE) shares slipped ~1% after the readout, which came ahead of the company’s Q4 2025 results, as the drug’s efficacy trailed those of blockbuster weight loss medications marketed by rivals Novo Nordisk (NVO) and Eli Lilly (LLY), whose GLP-1s have generated 15% – 20% of weight loss.
“These topline results from the Phase 2b VESPER-3 study reinforce the potential of PF’3944 as a monthly treatment with competitive efficacy,” Chief Internal Medicine Officer Jim List added.
The New York-based pharma giant added PF’3944 to its pipeline following its recent acquisition of weight loss drug developer Metsera.