Orforglipron Shows Significant Weight Loss and Heart Health Benefits in Phase 3 Trial

In the 72-week phase 3 ATTAIN-1 trial, the once-daily oral GLP-1 receptor agonist orforglipron led to substantial weight loss and improved cardiovascular risk factors in 3,127 adults with obesity or overweight with related medical issues, meeting its primary endpoint.

At 72 weeks, all three doses of orforglipron, met the primary endpoint and all key secondary endpoints compared to placebo, delivering clinically meaningful weight loss as an adjunct to a healthy diet and physical activity. For the primary endpoint, orforglipron 36 mg, taken once per day without food and water restrictions, lowered weight by an average of 12.4% (27.3 lbs) compared to 0.9% (2.2 lbs) with placebo using the efficacy estimand.1=

"Obesity is one of the most pressing global health challenges of our time, driving global chronic disease burden and impacting more than one billion people worldwide," said Kenneth Custer, Ph.D., executive vice president and president of Lilly Cardiometabolic Health. "With orforglipron, we're working to transform obesity care by introducing a potential once-daily oral therapy that could support early intervention and long-term disease management, while offering a convenient alternative to injectable treatments. With these positive data in hand, we are now planning to submit orforglipron for regulatory review by year-end and are prepared for a global launch to address this urgent public health need."

In the ATTAIN-1 trial, orforglipron met the primary endpoint of superior body weight reduction compared to placebo. Participants taking the highest dose of orforglipron lost an average of 27.3 lbs (12.4%) at 72 weeks using the efficacy estimand. In a key secondary endpoint, 59.6% of participants taking the highest dose of orforglipron lost at least 10% of their body weight, while 39.6% lost at least 15% of their body weight. In addition to achieving significant weight loss, orforglipron was also associated with reductions in known markers of cardiovascular risk, including non-HDL cholesterol, triglycerides and systolic blood pressure in pooled analyses across all doses. In a pre-specified exploratory analysis, the highest dose of orforglipron reduced high-sensitivity C-reactive protein (hsCRP) levels by 47.7%.

iSuperiority test was adjusted for multiplicity.

For the treatment-regimen estimand, each dose of orforglipron led to statistically significant improvements across the primary and all key secondary endpoints.

• Percent weight reduction: -7.5% (-7.8 kg; 17.2 lbs; 6 mg), -8.4% (-8.6 kg; 19.0 lbs; 12 mg), -11.2% (-11.3 kg; 25.0 lbs; 36 mg), -2.1% (-2.4 kg; 5.3 lbs; placebo)

• Percentage of participants achieving body weight reductions of ≥10%: 33.3% (6 mg), 40.0% (12 mg), 54.6% (36 mg), 12.9% (placebo)

• Percentage of participants achieving body weight reductions of ≥15%: 15.1% (6 mg), 20.3% (12 mg), 36.0% (36 mg), 5.9% (placebo)

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 and generally mild-to-moderate in severity. The most common adverse events for participants treated with orforglipron (6 mg, 12 mg and 36 mg, respectively) were nausea (28.9%, 35.9% and 33.7%) vs. 10.4% with placebo, constipation (21.7%, 29.8% and 25.4%) vs. 9.3% with placebo, diarrhea (21.0%, 22.8% and 23.1%) vs. 9.6% with placebo, vomiting (13.0%, 21.4% and 24.0%) vs. 3.5% with placebo, and dyspepsia (13.0%, 16.2% and 14.1%) vs. 5.0% with placebo. 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) for orforglipron 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.

About orforglipron

Orforglipron (or-for-GLIP-ron) is an investigational, once-daily small molecule (non-peptide) oral glucagon-like peptide-1 receptor agonist that can be taken any time of the day without restrictions on food and water intake. Orforglipron was discovered by Chugai Pharmaceutical Co., Ltd. and licensed by Lilly in 2018. Chugai and Lilly published the preclinical pharmacology data of this molecule together. Lilly is running Phase 3 studies on orforglipron for the treatment of type 2 diabetes and for weight management in adults with obesity or overweight with at least one weight-related medical problem. It is also being studied as a potential treatment for obstructive sleep apnea (OSA) and hypertension in adults with obesity.

About ATTAIN-1 and ATTAIN clinical trial program

ATTAIN-1 (NCT05869903) is a Phase 3, 72-week, randomized, double-blind, placebo-controlled trial comparing the efficacy and safety of orforglipron 6 mg, 12 mg and 36 mg as monotherapy to placebo in adults with obesity, or overweight with at least one of the following comorbidities: hypertension, dyslipidemia, OSA or cardiovascular disease, who did not have diabetes. The trial randomized 3,127 participants across the U.S., Brazil, China, India, Japan, South Korea, Puerto Rico, Slovakia, Spain and Taiwan in 3:3:3:4 ratio to receive either 6 mg, 12 mg or 36 mg orforglipron or placebo.

The primary objective of the study was to demonstrate that orforglipron (6 mg, 12 mg, 36 mg) is superior to placebo in body weight reduction from baseline after 72 weeks in people with a BMI ≥30.0 kg/m² or a BMI ≥27.0 kg/m² with at least one weight-related comorbidity and a history of at least one self-reported unsuccessful dietary effort to lose body weight. All participants in the orforglipron treatment arms started the study at a dose of orforglipron 1 mg once-daily and then increased the dose in a step-wise approach at four-week intervals to their final randomized maintenance dose of 6 mg (via steps at 1 mg and 3 mg), 12 mg (via steps at 1 mg, 3 mg and 6 mg) or 36 mg (via steps at 1 mg, 3 mg, 6 mg, 12 mg and 24 mg). Dose reduction was only allowed for GI tolerability if other mitigations failed.

The ATTAIN Phase 3 global clinical development program for orforglipron has enrolled more than 4,500 people with obesity or overweight across two global registration trials. The program began in 2023 with additional results anticipated this year.