Chugai Pharmaceutical Co., Ltd. announced that Eli Lilly and Company issued a press release on August 7, 2025 (local time) regarding the positive topline Phase 3 results from ATTAIN-1, evaluating the efficacy and safety of orforglipron compared to placebo in adults with obesity, or overweight with a weight-related medical problem and without diabetes. In the first Phase 3 trial of the ATTAIN program, ATTAIN-1 trial (n=3,127), orforglipron, taken once per day without food and water restrictions, achieved the primary and all key secondary endpoints compared to placebo. Participants taking the highest dose of orforglipron lost an average of 27.3 lbs (12.4kg) (12.4%) at 72 weeks using the efficacy estimand.
In a key secondary endpoint, 59.6% of participants taking the highest dose of or forglipron lost at least 10% of their body weight, while 39.6% lost at least 15% of their body weight. The overall safety profile of orforglipron in ATTAIN-1 was consistent with the established GLP-1 receptor agonist class. The most commonly reported adverse events were gastrointestinal-related (nausea, constipation, diarrhea, vomiting, dyspepsia) and generally mild to moderate in severity.
Treatment discontinuation rates due to adverse events were 5.1% (6 mg), 7.7% (12 mg) and 10.3% (36 mg) for orforglipron vs. 2.6% with placebo. The overall treatment discontinuation rates were 21.9% (6 mg), 22.5% (12 mg) and 24.4% (36 mg) fororforglipron vs.
29.9% with placebo. No hepatic safety signal was observed. The detailed ATTAIN-1 results will be presented next month at the European Association for the Study of Diabetes (EASD) Annual Meeting 2025 and published in a peer-reviewed journal.
More results from the ATTAIN Phase 3 clinical trial program will be shared later this year, along with findings from the ACHIEVE Phase 3 clinical trial program evaluating orforglipron for adults with type 2 diabetes. Eli Lilly expects to submit orforglipron for weight management to global regulatory agencies by the end of this year.
