ADA 2026 spotlights three obesity paths, with Pfizer betting on a “foundational” monthly drug

New weight-loss data presented around the American Diabetes Association’s 2026 Scientific Sessions did not erase the market’s central question: will the next generation of obesity medicines meaningfully outperform, or at least differentiate from, Eli Lilly’s dominant franchise. In coverage of the meeting, BioPharma Dive characterized Lilly’s “triple G” retatrutide as the clearest step toward a new standard, while positioning Pfizer’s berobenatide as a potentially “foundational” option that could become a backbone for combinations and Roche’s enicepatide as a “me-too” alternative that may arrive after the most entrenched competitors.

Lilly’s retatrutide is designed to activate three gut hormone receptors, rather than the two targeted by many existing incretin-based therapies. In Lilly’s published results for the Phase 3 TRIUMPH-1 program, people taking retatrutide 12 mg averaged about 70.3 pounds of weight loss, or 28.3%, over 80 weeks, and a majority reached a body mass index below 30. BioPharma Dive added that retatrutide’s benefits came with ongoing questions about how and where it fits once the market already includes multiple highly effective injectables and emerging oral options.

Pfizer is trying to secure a different kind of advantage: dosing convenience. At the ADA meeting, Pfizer shared detailed updates from Phase 2b studies of berobenatide (PF’3944), describing it as an investigational GLP-1 receptor agonist peptide that it hopes could be administered on a monthly schedule. In Pfizer’s June 6 investor materials tied to the ADA symposium, the company said its Phase 2b VESPER-1 study showed non-placebo-adjusted weight loss of 15.9% after 32 weeks on 2.4 mg weekly berobenatide, in an exploratory extension where participants moved from placebo to the active dose.

Pfizer also indicated where it believes berobenatide could compete if approved. In a broader set of ADA updates covered by BioPharma Dive, one trial showed about 16% weight loss by 60 weeks at a higher weekly dose, while another evaluation of maintenance dosing produced around 12% placebo-adjusted weight loss after 28 weeks. For people with obesity and type 2 diabetes, BioPharma Dive reported weight loss of roughly 10 percentage points better than placebo, as summarized by RBC’s Trung Huynh. Pfizer’s own release emphasized tolerability and scalability, including the aim of low injection volume for monthly delivery, but analysts in the ADA wrap still flagged tolerability concerns as a key risk.

Those concerns focused on gastrointestinal side effects and discontinuation rates. BioPharma Dive said that in Pfizer’s studies, discontinuation rates were reported to be as high as 21% in a trial evaluating monthly doses, and that nausea, vomiting, and diarrhea occurred more often in Pfizer’s studies than what investigators have observed in testing of Lilly’s Zepbound. The market interpretation, as described by analysts cited in the reporting, was that berobenatide could be “in line” on efficacy for now, but would need phase 3 monthly data to prove it can sustain weight loss with an acceptable side-effect profile at scale.

Roche’s presence at ADA underscored the reality that obesity drug developers are still searching for differentiation as efficacy bars rise. BioPharma Dive described enicepatide (CT-388) as a “me-too” option, citing placebo-adjusted weight-loss results from ADA presentations that were in the high-teens range depending on the measure and that appeared only modestly worse on tolerability than what competing products show. Separately, Roche said in its June 1 update that enicepatide and petrelintide data at ADA reinforce the strength of its obesity portfolio, and that Roche is moving both programs into Phase 3 development.

For Pfizer, the company laid out an execution timeline tied to what markets usually want most from competitors to the leaders: late-stage evidence that directly supports a dosing and differentiation story. BioPharma Dive said Pfizer could announce first late-stage results in the second half of 2027, with initial late-stage data for a monthly regimen expected in 2028. That leaves multiple uncertainties open, particularly how well cross-trial comparisons will hold up once phase 3 results are available for berobenatide and once Roche’s Phase 3 program produces its own head-to-head positioning.

The remaining gap is not simply efficacy, it is durability, adherence, and patient tolerability across the range of future prescribing choices. While Lilly’s published Phase 3 results suggest retatrutide can achieve large average weight losses, the evidence base for how clinicians will sequence and select between products, and how quickly safety and tolerability findings translate into real-world persistence, is still developing. The next set of ADA-adjacent catalysts is therefore likely to come from phase 3 readouts and from updates that clarify the role of “foundational” combination backbones, monthly dosing strategies, and late-entry differentiation claims.