Eli Lilly's tirzepatide aces 2 more late-stage obesity trials as FDA decision nears

Eli Lilly continues to bolster the case for its dual GIP/GLP-1 agonist tirzepatide as a powerful weight loss agent.

Also known as Mounjaro in its approved type 2 diabetes indication, tirzepatide helped participants across two trials—SURMOUNT-3 and SURMOUNT-4—lose up to 26.6% of their body weight, Lilly said Thursday. Tirzepatide met all primary endpoints across both trials, Lilly said.

SURMOUNT-3 pitted tirzepatide against placebo in obese or overweight adults over a 72-week span following a 12-week intensive lifestyle intervention lead-in period. That intervention included a low-calorie diet, exercise and weekly counseling sessions, Lilly explained in a press release.

To qualify for Lilly’s trial, participants had to lose at least 5% of their body weight by the end of the 12-week lead-in.

In SURMOUNT-3, those on tirzepatide lost an additional 21.1% of their body weight from randomization, while patients on placebo experienced an average weight regain of 3.3% over 72 weeks, Lilly said.

SURMOUNT-4, meanwhile, looked at tirzepatide’s safety and efficacy over 52 weeks after a 36-week open-label tirzepatide lead-in period, during which all study participants received Lilly’s drug.

In the SURMOUNT-4 lead-in period, participants lost an average of 21.1% of their body weight, Lilly said. Those who stayed on tirzepatide lost an additional 6.7% of their body weight during the trial.

Over that same stretch, patients on placebo regained an average of 14.8% of their body weight.

Lilly plans to share full results from SURMOUNT-3 and SURMOUNT-4 at the upcoming ObesityWeek conference and the Annual Meeting of the European Association for the Study of Diabetes, respectively.

Tirzepatide’s dual trial win comes several months after the med passed the phase 3 SURMOUNT-2 study with flying colors, helping diabetic patients who are obese or overweight lose up to 15.7% of their body weight.

In that study, the drug performed significantly better than placebo on various weight loss and metabolic measurements. The SURMOUNT-2 study met its two co-primary objectives and all key secondary endpoints, Lilly said at the time.

Prior to that win, tirzepatide delivered a positive readout in SURMOUNT-1, which looked at non-diabetic patients. Lilly used results from the first two phase 3 trials to complete a rolling submission for the drug in adults with obesity or who are overweight. An approval could come as soon as this year, the company has said.

Even without an obesity nod, Mounjaro has proven immensely popular, so much so that the U.S. Food and Drug Administration recently added a fourth dose of the medication to its drug shortage database. The agency also expects supply issues with three other doses to persist longer than previously thought.

The reason listed for the supply squeeze is a demand increase. Now, supplies of Mounjaro at the 10mg dose are expected to be tight through September 2023. Issues with the 7.5mg, 12.5mg and 15mg doses are expected to be resolved by the end of July.