INDIANAPOLIS, May 12, 2026
Eli Lilly and Company has reported positive results from two major late-phase obesity trials showing that patients were able to maintain significant long-term weight loss after switching from higher-dose injectable incretin therapies to either oral Foundayo™ (orforglipron) or lower-dose Zepbound® (tirzepatide). The findings from the SURMOUNT-MAINTAIN and ATTAIN-MAINTAIN studies were presented at the European Congress on Obesity (ECO) 2026 and published in leading scientific journals, further strengthening Lilly’s growing position in the rapidly expanding obesity therapeutics market. The studies demonstrated that both therapies successfully supported durable weight maintenance after patients transitioned from maximum tolerated doses of injectable GLP-1 and dual agonist treatments.
Lilly Highlights Strong Weight Maintenance Results
According to data from the ATTAIN-MAINTAIN trial, patients who switched from Wegovy® (semaglutide) to oral Foundayo maintained nearly all of their previous weight reduction, regaining only an average of 0.9 kilograms after one year. Participants transitioning from higher-dose Zepbound® to Foundayo also maintained most of their weight reduction, regaining only about 5 kilograms on average over the maintenance period.
Meanwhile, the SURMOUNT-MAINTAIN trial demonstrated that patients who continued receiving maximum tolerated doses of Zepbound maintained virtually all of their prior weight loss after an additional year of therapy. Even participants who reduced their dose to Zepbound 5 mg successfully maintained the majority of their weight reduction. Researchers emphasized that these findings address one of the biggest challenges in obesity management: long-term maintenance after substantial weight loss has already been achieved.
Obesity specialists involved in the studies noted that biological mechanisms often drive patients toward weight regain after treatment interruptions or therapy adjustments. The ability of both Foundayo and lower-dose Zepbound to maintain clinically meaningful weight reduction may therefore represent an important advancement in chronic obesity management and long-term metabolic disease treatment strategies.
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Foundayo Expands Oral GLP-1 Treatment Opportunities
The new data also strengthen the commercial and scientific importance of Foundayo, Lilly’s once-daily oral GLP-1 receptor agonist. Unlike injectable incretin therapies, Foundayo is a small-molecule oral medication that can be taken without food or water restrictions, making it a potentially attractive option for patients seeking easier long-term obesity treatment solutions. Lilly executives stated that obesity is a chronic disease requiring sustained therapy and broader patient access to flexible treatment options.
Clinical investigators highlighted that both trials met their primary and key secondary endpoints while maintaining safety profiles consistent with earlier Phase 3 obesity studies. The most common adverse events included nausea, diarrhea, constipation, vomiting, and gastrointestinal discomfort, which are commonly associated with incretin-based therapies. Importantly, discontinuation rates due to adverse events remained relatively low across both studies, supporting the tolerability profile of the treatments.
The findings are particularly significant because the obesity therapeutics market has become one of the most competitive sectors in global biopharma, with pharmaceutical companies racing to develop next-generation GLP-1, GIP, and dual agonist medicines capable of delivering sustained weight reduction and long-term metabolic benefits.
Lilly Strengthens Leadership in Obesity Therapeutics
The positive SURMOUNT-MAINTAIN and ATTAIN-MAINTAIN results reinforce Lilly’s leadership ambitions in obesity and cardiometabolic disease treatment. The company continues expanding the clinical development of both tirzepatide and orforglipron across multiple indications including obesity, type 2 diabetes, obstructive sleep apnea, osteoarthritis-related complications, hypertension, and cardiovascular risk management.
Industry analysts believe the latest maintenance-focused data could play a critical role in future obesity treatment strategies, especially as healthcare providers increasingly recognize obesity as a chronic disease requiring lifelong management rather than short-term intervention. With oral obesity medicines attracting major global attention, Lilly’s Foundayo may emerge as a significant competitor in the next phase of the GLP-1 treatment revolution.
Source: Eli Lilly press release
