Oral GLP-1 Orforglipron for Weight Maintenance

A new phase 3 trial suggests that the investigational oral GLP-1 drug orforglipron may help people maintain weight loss after stopping injectable medications such as semaglutide and tirzepatide. The findings point to a convenient once-daily pill that could support long-term weight management for adults living with obesity.

Orforglipron is a once-daily oral glucagon-like peptide-1 (GLP-1) receptor agonist being developed by Eli Lilly for obesity and type 2 diabetes. GLP-1 receptor agonists help reduce appetite, slow gastric emptying, and improve blood sugar control, which together can drive significant weight loss. Most of the most effective GLP-1 therapies available today are injectables, creating strong interest in oral options that can sustain results.

The ATTAIN-MAINTAIN phase 3 trial focused on adults with obesity or overweight who had already lost weight while taking high-dose injectable GLP-1 therapies. These participants had completed up to 72 weeks of semaglutide (Wegovy) or tirzepatide (Zepbound) at their maximum tolerated doses in the SURMOUNT-5 head-to-head trial and had reached a stable weight plateau.

In ATTAIN-MAINTAIN, 376 adults in the United States were re-randomized in a 3:2 ratio to receive once-daily orforglipron or placebo, along with counseling on a healthy diet and regular physical activity. Doses of orforglipron were titrated every four weeks up to 36 mg or the highest dose the person could tolerate, allowing individualized dose adjustment over time.

The primary endpoint was the percentage of prior body weight reduction that participants were able to maintain over 52 weeks compared with placebo. Orforglipron met this primary endpoint and all key secondary endpoints, demonstrating superior weight maintenance versus placebo across the study population. Among adults switching from semaglutide, average weight remained close to their post-injection levels, with only minimal regain reported.

Patients who had previously taken tirzepatide also maintained a large share of their prior weight loss when switched to oral therapy, though they experienced slightly greater average regain than those who had used semaglutide. In the trial report, body weight in prior semaglutide users stayed near 95 kg, while weight in prior tirzepatide users increased from around 90.9 kg to 95.9 kg over 52 weeks. Overall, the data suggest that continuing GLP-1 therapy in an oral form can limit substantial weight regain after stopping injections.

Experts involved in the trial stressed that obesity is a chronic, progressive disease and that maintaining weight loss remains an ongoing challenge. The ability to move directly from injectable incretin therapy to an oral GLP-1 agent while preserving most of the weight lost could reshape long-term obesity treatment strategies. Kenneth Custer, PhD, executive vice president and president of Lilly Cardiometabolic Health, noted that participants were able to switch straight from their highest tolerated injectable doses to orforglipron and sustain their progress.

Safety results from ATTAIN-MAINTAIN were consistent with the broader phase 3 program for orforglipron. The most common side effects were gastrointestinal, including nausea, diarrhea, and vomiting, and were generally mild to moderate in intensity. Discontinuation due to adverse events remained relatively low, with similar rates between the orforglipron and placebo groups in both the prior semaglutide and tirzepatide cohorts.

Earlier phase 3 trials have shown that orforglipron can generate meaningful weight loss when used as primary therapy, not only as a maintenance option. In one obesity study, orforglipron produced average weight reductions of about 5.5%, 7.8%, and 10.5% at 72 weeks across increasing doses, compared with 2.2% for placebo. Up to roughly half of patients on the highest dose achieved at least a 10% reduction in baseline body weight, supporting its potential as a standalone obesity treatment.

Beyond weight loss, orforglipron has demonstrated improvements in glycemic control and cardiometabolic risk markers in adults with type 2 diabetes. Across diabetes-focused studies, hemoglobin A1c fell by about 1.2% to 1.9% from baseline levels around 8% to 8.5%, outperforming placebo and sometimes the SGLT2 inhibitor dapagliflozin. Additional benefits have included improvements in lipids, blood pressure, and inflammatory markers such as high-sensitivity C-reactive protein, which are relevant for overall cardiovascular risk.

Eli Lilly has filed a new drug application with the US Food and Drug Administration seeking approval of orforglipron for adults with obesity or overweight. The FDA has awarded a Commissioner’s National Priority Voucher for the program, underscoring the potential public health value of an effective oral GLP-1 maintenance option. Full ATTAIN-MAINTAIN data are expected to be presented at a future scientific meeting and published in a peer-reviewed journal.

If approved in the United States, orforglipron could offer a practical oral maintenance strategy for millions of Americans who want to preserve hard-earned weight loss after stopping injectable GLP-1 medications. The emerging evidence indicates that long-term obesity care may increasingly involve an optimized sequence of injectable and oral incretin therapies to support durable weight and metabolic outcomes.