Pfizer Inc. presented detailed results from multiple Phase 2b studies of berobenatide (PF?3944), an investigational, potential first-in-class monthly GLP-1 receptor agonist (GLP-1 RA) peptide, during a late-breaking expert symposium at the 86th Scientific Sessions of the American Diabetes Association (ADA). The objectives for the Phase 2 studies were to identify the right doses for Phase 3 and to test escalation schemes. Across both weekly and monthly dosing in participants with obesity or overweight, with and without type 2 diabetes, the data from the Phase 2b VESPER-1, 2 and 3 studies provide proof of concept for berobenatide as a potential first-in-class monthly GLP-1 RA peptide that can deliver competitive weight loss; show favorable tolerability for berobenatide, including low gastrointestinal (GI) adverse events and discontinuations despite rapid dose escalation and no allowed step-down; and highlight the potential for monthly delivery in a patient-friendly presentation with a very low 0.5 mL injection volume that provides convenience and scalability advantages.
Results from a 32-week exploratory extension (Part B) of the Phase 2b VESPER-1 study showed a non-placebo-adjusted weight loss of 15.9%* with no plateau observed at 32 weeks on berobenatide (Week 60 of the overall study), in participants who escalated from placebo to 2.4 mg weekly berobenatide. VESPER-1 is evaluating once-weekly berobenatide in adults with obesity or overweight, including Part B to assess the durability of weight loss and the impact of transitioning from once-weekly to less frequent dosing regimens, including once-monthly. Detailed results from the previously reported Phase 2b VESPER-3 study are also being presented, which is evaluating monthly maintenance dosing of berobenatide in adults with obesity or overweight without type 2 diabetes.
Data from the Phase 2b VESPER-2 study, which evaluated weekly dosing of berobenatide in adults with obesity or overweight and type 2 diabetes, showed dose dependent reductions from baseline were observed with berobenatide for both body weight and HbA1c. There was a 2.2%** reduction in HbA1c achieved with berobenatide 1.6 mg weekly at week 28 (on treatment [efficacy] estimand), compared to a reduction of 0.2% in the placebo group. The VESPER-6 pivotal Phase 3 study investigating monthly maintenance dosing for berobenatide in adults with obesity or overweight is open for enrollment, as well as the SOLIS-1 Phase 2b study investigating weekly and monthly maintenance dosing of an ultra-long-acting amylin analog (PF'3945) as a monotherapy and in combination with berobenatide.
Pfizer plans to advance 20+ trials for obesity and related comorbidities in 2026. This includes 10 ongoing and planned Phase 3 trials for berobenatide (PF?3944), an investigational, potential first-in-class monthly GLP-1 receptor agonist (GLP-1 RA) peptide being studied for chronic weight management and obesity-related comorbidities including knee osteoarthritis and obstructive sleep apnea. The growing body of evidence supports advancing an extensive development program for berobenatide as a monotherapy and in combination with various Nutrient-Stimulated Hormone (NuSH) peptides including amylin analogs.
The VESPER clinical development program is a comprehensive global program evaluating berobenatide across a range of patient populations and dosing regimens in chronic weight management. Phase 2b VESPER studies include: VESPER-1: A Phase 2b trial in adults with obesity or overweight evaluating once-weekly berobenatide, including a 32-week exploratory extension (Part B) assessing the durability of weight loss and the impact of transitioning from once-weekly to less frequent dosing regimens, including once-monthly administration. Part A was the initial 28-week double-blind placebo-controlled portion of the study.
VESPER-2: A Phase 2b randomized, double-blind, placebo-controlled trial evaluating once-weekly berobenatide in adults with obesity or overweight and type 2 diabetes, designed to assess weight loss, glycemic control and safety in this population. VESPER-3 is an ongoing 64-week, randomized, double-blind, placebo-controlled study in participants with obesity or overweight without type 2 diabetes. The study is designed to evaluate weekly (QW) titration phase to monthly (QM) dosing of berobenatide in four different titration and QM dose arms, compared to placebo.
Phase 3 VESPER studies include: VESPER-4 is an ongoing Phase 3 pivotal study investigating once-weekly berobenatide in adults with obesity or overweight and without type 2 diabetes. VESPER-5 is an ongoing Phase 3 pivotal study investigating once-weekly berobenatide in adults with obesity or overweight and type 2 diabetes. A higher weekly dose of berobenatide (2.4 mg) is currently being evaluated in Phase 3. VESPER-6 is a Phase 3 pivotal study investigating once-monthly berobenatide in adults with obesity or overweight.
The study is now open for enrollment. Seven additional planned Phase 3 studies of berobenatide are designed to target comorbidities and increase patient optionality and access.
