SURMOUNT-5: tirzepatide beats semaglutide on weight loss in head-to-head trial

Eli Lilly reported topline results from the open-label phase 3b SURMOUNT-5 trial in 751 adults with obesity or overweight without diabetes. At 72 weeks, tirzepatide (10 or 15 mg) produced an average weight loss of 20.2% versus 13.7% with semaglutide (1.7 or 2.4 mg), a 47% greater relative reduction. It was the first head-to-head obesity trial of the two leading incretin drugs, and full results were later published in the New England Journal of Medicine.