Pfizer reported up to 12.3% placebo-adjusted weight loss at 28 weeks in a phase 2b trial of PF-08653944 (formerly MET-097i), a GLP-1 receptor agonist acquired through its $10 billion Metsera deal.
In the Vesper-3 trial (~250 adults with obesity or overweight without diabetes), patients transitioned from weekly dosing to higher monthly maintenance injections. Weight loss continued after the switch, with no plateau observed at Week 28.
Key highlights:
- 10%–12.3% placebo-adjusted weight loss on phase 3–bound doses
- Modeling predicts nearly 16% at higher planned phase 3 dosing
- Mostly mild-to-moderate GI adverse events
- Monthly format may offer differentiation vs. weekly competitors
The data place Pfizer within the competitive range reported by obesity drug rivals (9%–13% placebo-adjusted at 28 weeks), while offering the potential convenience advantage of monthly dosing.
The stakes are high: Pfizer is pursuing obesity as a growth engine ahead of a looming patent cliff, targeting a 2028 launch.