Lilly’s Retatrutide Shows Strong Phase III Results, Forecast for Blockbuster Sales

Eli Lilly’s triple hormone agonist retatrutide has delivered strong Phase III results, reinforcing expectations that it could become a major player in the obesity market. In the TRIUMPH-4 trial, once-weekly retatrutide achieved up to 28.7% average weight loss after 68 weeks in adults with obesity or overweight and knee osteoarthritis, significantly outperforming placebo. Patients also experienced meaningful reductions in pain and improvements in physical function, meeting all primary and key secondary endpoints.

Retatrutide, which targets GIP, GLP-1 and glucagon receptors, also improved cardiovascular risk markers and reduced systolic blood pressure at higher doses. Safety findings were consistent with other incretin therapies, with gastrointestinal side effects being most common.

GlobalData forecasts a 2027 approval and predicts retatrutide could generate $15.6bn in annual sales by 2031. With multiple Phase III readouts expected in 2026, Lilly’s leadership in the rapidly expanding obesity market continues to strengthen.

18-12-2025