- Design
- Phase 3, randomised, double-blind, placebo-controlled, 80 weeks
- Population
- 2,339 adults with obesity without diabetes
- Primary outcome
- Percent change in body weight; knee OA pain; apnoea-hypopnoea index
- Effect
- −23.7% (9 mg) and −25.0% (12 mg) vs −3.9% placebo; P<0.001
TRIUMPH-1 randomised 2,339 adults with obesity but without diabetes to once-weekly retatrutide at 4, 9 or 12 mg, or placebo, for 80 weeks. Retatrutide acts on three receptors: GIP, GLP-1 and glucagon.
Mean weight change was −17.6%, −23.7% and −25.0% across the three doses against −3.9% with placebo; the differences for the 9 and 12 mg doses were about 20 and 21 percentage points. In 574 participants with knee osteoarthritis, pain scores fell by about 1.4–1.6 points more than placebo on a 10-point scale. In 243 with obstructive sleep apnoea, the apnoea-hypopnoea index fell by about 22–25 more events per hour than with placebo. Gastrointestinal effects were the most common adverse events.
The weight loss approaches what has been seen after some bariatric procedures. The drug remains unapproved, and versions sold online carry unknown content and dose. For now this is a trial result, not a prescription.
- Retatrutide is not approved anywhere; it is not something to prescribe yet.
- Patients asking about it may have seen it sold online — those products are unregulated and of unknown content.
- Weight loss averaged about a quarter of body weight at the higher doses over 80 weeks.
- Knee pain and sleep apnoea severity also improved in the relevant subgroups.
- Expect gastrointestinal side effects similar to other incretin drugs.
Why it matters
It moves the ceiling for drug-induced weight loss closer to surgery, and patients are already finding it online.
Don't overread it
This trial measured weight, pain and apnoea scores — not heart attacks, strokes or deaths.
The statistics, in plain English
The differences of about 20 percentage points are relative to placebo, which itself lost 3.9%. The osteoarthritis and sleep apnoea results come from subgroups, but they were prespecified primary outcomes with their own analyses, so they are stronger than ordinary subgroup findings.
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