Pfizer’s investigational GLP‑1 peptide berobenatide achieved up to 15.9% weight loss in Phase 2b VESPER trials, with sustained efficacy, improved glycemic control, and favorable tolerability. The results support Pfizer’s extensive Phase 3 obesity program and position berobenatide as a potential first‑in‑class monthly therapy for chronic weight management.
Written By: Fariha Sameen, PharmD
Reviewed By: Pharmacally Editorial Team
Pfizer has reported detailed Phase 2b results for berobenatide (PF‑07976094/PF’3944), an investigational GLP‑1 receptor agonist peptide that could become the first approved monthly therapy in its class for chronic weight management. Data presented during a late‑breaking symposium at the American Diabetes Association (ADA) Scientific Sessions 2026 showed substantial weight loss, improved glycemic control, and favorable tolerability in adults with obesity or overweight, with and without type 2 diabetes.
The findings from the Phase 2b VESPER program support Pfizer’s planned low‑, medium‑, and high‑dose Phase 3 strategy and strengthen berobenatide’s position as a potential first‑in‑class monthly GLP‑1 receptor agonist peptide.
Clinical Impact and Differentiation
GLP‑1 receptor agonists have transformed obesity treatment by improving satiety and supporting clinically meaningful weight loss. However, treatment persistence remains a challenge due to dosing burden and tolerability concerns. Berobenatide was developed as a long‑acting peptide that transitions patients from weekly dose escalation to monthly maintenance dosing through a low‑volume 0.5 mL injection. This monthly regimen could offer a convenient alternative to more frequently administered therapies, with potential advantages for long‑term adherence and treatment persistence compared with weekly GLP‑1s such as semaglutide and tirzepatide.
Trial Highlights
The most notable findings came from the 32‑week exploratory extension of the Phase 2b VESPER‑1 study (NCT06712836), which evaluated the highest weekly dose of berobenatide reported to date. Participants who transitioned from placebo to berobenatide 2.4 mg weekly achieved a non‑placebo‑adjusted weight reduction of 15.9% at week 32, with no evidence of a weight‑loss plateau. In the Phase 2b VESPER‑2 trial (NCT06897202), adults with obesity or overweight and type 2 diabetes experienced dose‑dependent reductions in body weight and HbA1c. Patients receiving 1.6 mg weekly achieved a 2.2% reduction in HbA1c at week 28 compared with 0.2% in the placebo group. Across the VESPER studies, berobenatide demonstrated favorable tolerability, with low rates of gastrointestinal adverse events and treatment discontinuations despite rapid dose escalation.
Clinical Implications
Jim List, MD, PhD, Pfizer’s Chief Internal Medicine Officer, said the Phase 2b data demonstrated consistent weight loss across all doses selected for Phase 3 while maintaining a favorable tolerability profile during the transition from weekly to monthly dosing. He noted that the results support berobenatide’s potential to become the first monthly GLP‑1 receptor agonist peptide. John B. Buse, MD, PhD, of the University of North Carolina School of Medicine, highlighted the importance of long‑term adherence in obesity management and said monthly dosing could improve the practicality and sustainability of treatment.
Regulatory and Development Outlook
Pfizer plans to advance more than 20 obesity‑related clinical trials in 2026, including 10 Phase 3 studies evaluating berobenatide in chronic weight management and obesity‑related comorbidities such as knee osteoarthritis and obstructive sleep apnea. The Phase 3 program includes VESPER‑4 (NCT07311850), VESPER‑5 (NCT07400653), and VESPER‑6 (NCT07595549), the latter of which is currently enrolling participants for once‑monthly maintenance dosing. Pfizer is also advancing SOLIS‑1, a Phase 2b study evaluating the ultra‑long‑acting amylin analog PF’3945 alone and in combination with berobenatide, expanding its next‑generation obesity pipeline. Initial Phase 3 readouts are expected in late 2027, positioning berobenatide for potential FDA and EMA submissions as the first monthly GLP‑1 receptor agonist peptide.
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About the Writer
Fariha Sameen, PharmD (LinkedIn), is a clinical pharmacy professional with hands-on experience in patient counselling, medication review, therapeutic monitoring, and clinical documentation across multiple departments. She has experience identifying and assessing drug-related problems and supporting medication safety practices. Her interests include pharmacovigilance, ADR reporting, clinical research, and medical writing focused on clear, evidence-based communication.