Lilly’s Retatrutide Yields 28.3% Loss; Mounjaro Tops Q1 Sales
Participants on 12 mg retatrutide lost 70.3 lbs (28.3%) at 80 weeks in the TRIUMPH-1 trial, with 45.3% achieving ≥30% weight loss and extension subjects losing up to 85.0 lbs (30.3%) at 104 weeks. In Q1, Lilly’s Mounjaro became the top-selling drug, overtaking pembrolizumab.
1. Pivotal TRIUMPH-1 Trial Results
In the TRIUMPH-1 Phase 3 trial, adults receiving 4 mg, 9 mg or 12 mg of retatrutide achieved mean weight reductions of 19.0%, 25.9% and 28.3% respectively at 80 weeks, with 45.3% of the 12 mg cohort losing at least 30% of body weight. The 4 mg dose required only a single escalation step and showed fewer discontinuations from adverse events versus placebo.
2. 104-Week Extension Outcomes
In a blinded extension of participants with baseline BMI ≥35, those maintained on a 12 mg regimen lost an average of 30.3% of body weight (85.0 lbs) by week 104, alongside reductions in waist circumference, non-HDL cholesterol, triglycerides, systolic blood pressure and hsCRP, indicating broad cardiometabolic benefits.
3. Q1 Sales and Pipeline Implications
During Q1, Lilly’s weight-loss portfolio drove revenue growth as Mounjaro became the quarter’s top-selling drug, surpassing pembrolizumab. This shift underscores the increasing market dominance of obesity therapies and accentuates the urgency of addressing upcoming patent expirations across the pipeline.