Foundayo Regains Only 0.9 kg in 52 Weeks; Zepbound MTD Preserves 100% Loss
LLY•Foundayo maintained all but 0.9 kg of weight loss over 52 weeks after switching from Wegovy’s maximum tolerated dose. In SURMOUNT-MAINTAIN, Zepbound at maximum tolerated dose preserved full weight loss while a 5 mg dose retained all but 5.6 kg after 60 weeks.
1. Trial Designs and Endpoints
Two late-phase maintenance studies evaluated long-term weight-loss preservation after transitioning from injectable incretin therapies to oral GLP-1 treatment. SURMOUNT-MAINTAIN assessed percent body-weight change at week 112 following 60 weeks on Zepbound maximum tolerated or 5 mg doses, while ATTAIN-MAINTAIN measured percent maintenance of reduction at week 52 after switching to Foundayo.
2. SURMOUNT-MAINTAIN Results
Participants starting at an average 112.2–113.4 kg dropped to 89.0–89.5 kg after 60 weeks on maximum tolerated Zepbound. At week 112, those continuing maximum tolerated dose averaged 88.7 kg (100% maintenance) and those on 5 mg averaged 94.6 kg, retaining all but 5.6 kg of prior loss.
3. ATTAIN-MAINTAIN Results
In the switch to Foundayo, individuals moving from Wegovy MTD started at 95.0 kg and ended at 95.9 kg, regaining just 0.9 kg. Those switching from Zepbound MTD began at 90.9 kg and finished at 95.9 kg, regaining 5.0 kg over 52 weeks of oral therapy.
4. Safety and Outlook
Safety profiles matched prior Phase 3 data, with most common adverse events for Foundayo being nausea (18.8%), constipation (13.1%), vomiting (8.3%) and diarrhea (7.4%). Discontinuation rates remained below 8%. Lilly highlights these durable maintenance options as key additions to its cardiometabolic portfolio.
