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According to Lilly's announcement, patients taking the top dose of retatrutide shed an average of 70.3 pounds over 80 weeks, representing a 28.3% reduction in body weight, and close to half of those patients reached the 30% weight loss mark.
The TRIUMPH-1 trial enrolled 2,339 adults with obesity or overweight and tested three doses of retatrutide against placebo. By the 80-week mark, roughly 65.3% of those on the 12 mg dose had crossed below a BMI of 30, the cutoff used to define obesity, Lilly reported. In a study extension running to 104 weeks, a subset of patients whose BMI was at least 35 — a level associated with elevated cardiovascular and metabolic risk — dropped an average of 85 pounds, equal to 30.3% of their starting weight.
Lilly also tested a lower 4 mg dose not previously used in other trials. Over the same 80-week period, people assigned to that dose dropped an average of 47.2 pounds, a reduction of 19% from their baseline weight. Lilly noted that discontinuations driven by adverse events were actually lower among 4 mg participants — at roughly 4% — than among those receiving placebo, where the figure was close to 5%.
Lilly's chief scientific and product officer Dan Skovronsky described the 30% figure as extraordinary, saying such outcomes had until now been the exclusive territory of bariatric surgery. "We haven't seen that level of weight loss before with these kinds of medicines," Dan Skovronsky told CNBC.
