Pfizer (PFE) Study update summary

Study design and population

• Berobenatide was evaluated in multiple Phase IIb trials (VESPER-1, -2, -3) in adults aged 18–75 years with overweight/obesity, with and without type 2 diabetes, using weekly and monthly dosing regimens.

• Trials included randomized, placebo-controlled periods and open-label extensions, with primary endpoints focused on percent change in body weight.

Key study results and efficacy insights

• Phase IIb trials showed monthly berobenatide achieved weight loss on par with weekly tirzepatide and potentially superior to semaglutide at matched time points and doses.

• At the medium Phase III dose (4.8 mg monthly), berobenatide delivered up to 12.3% placebo-corrected weight loss at week 28 in VESPER-3; VESPER-1 OLE showed 10.3–14.9% weight reduction at week 60, and placebo switchers achieved 15.9–16.8%.

• VESPER-2 (type 2 diabetes): up to 10.2% weight loss and 2.2% HbA1c reduction at 28 weeks; dose-dependent reductions in both body weight and HbA1c observed.

• High-dose extension data (2.4 mg weekly) showed mean weight loss of ~16% at 32 weeks, with modeling predicting even greater loss at higher doses.

• Model-based meta-analysis using data from 69 trials and 32,000+ patients supports berobenatide's efficacy and aligns with observed results, predicting monthly efficacy similar to tirzepatide and potentially better than semaglutide at 72 weeks.

Safety and tolerability

• Across studies, most gastrointestinal adverse events were mild or moderate; 96% of participants had no or only mild GI adverse events in VESPER-1 extension.

• No treatment discontinuations due to GI events in any arm; discontinuation due to AEs was ≤14.8% in any group, and vomiting rates were under 20% at high doses.

• Tolerability improved with gradual titration; phase III will use smaller dose increments and allow down-titration for GI events.

• Mild, transient increases in GI events occurred at the weekly-to-monthly transition but resolved quickly.

• In VESPER-3, 83% reported no or mild GI AEs; discontinuation due to GI AEs was <10%.