Eli Lilly announced on July 23 that its next-generation obesity therapy, retatrutide, achieved substantial weight loss and improved glycemic control in two late-stage clinical trials. The company now plans to file for regulatory approval in the first quarter of 2027, later than initially expected.
Retatrutide was evaluated in the Phase 3 TRIUMPH-2 trial involving patients with obesity or overweight who also have type 2 diabetes, and the TRIUMPH-3 trial focused on patients with severe obesity and established cardiovascular disease. Both studies compared weekly subcutaneous injections of retatrutide to placebo.
In TRIUMPH-2, a 12-mg dose of retatrutide resulted in a 20.8% reduction in body weight at 80 weeks compared to a 4% reduction for placebo. Lower doses showed less pronounced effects: the 9-mg dose led to a 19.1% decrease and the 4-mg dose resulted in a 12.7% drop. Glycemic control, measured by HbA1c levels, also improved among those treated with retatrutide.
TRIUMPH-3 found that patients receiving the highest dose experienced a weight loss of 22.6% at week eighty versus a decrease of just over three percent among those on placebo; similar trends were observed at lower doses. Major adverse cardiovascular events were less frequent among those taking retatrutide but did not reach statistical significance as an outcome measure.
BMO Capital Markets said, “Retatrutide’s two additional positive Phase 3 readouts reinforce its potentially best-in-class efficacy,” while noting that questions remain about long-term cardiovascular benefits. According to Eli Lilly, both studies met their primary endpoints, but detailed statistical analyses have not yet been released.
