Rhythm Drug Fails in Phase 3 Study in Genetic Obesity

Rare Daily Staff

Rhythm Pharmaceuticals said that its late-stage study of its drug setmelanotide for rare genetic forms of obesity did not achieve its primary endpoints across four substudies.

Setmelanotide is already approved for some rare genetic obesity conditions, and Rhythm has been working to expand its use to additional patient groups.

The trial tested setmelanotide in people whose obesity is linked to changes in specific genes. Researchers divided participants into four groups based on their genetic profiles and followed them for one year.

At the end of the study, none of the four groups met the trial’s main goal, which was to show a statistically significant improvement in body mass index (BMI) compared with placebo.

However, in further analyses using alternative statistical methods, researchers found that some patients did benefit from treatment. In two of the genetic groups, patients who received the drug lost more weight than those given placebo, with average reductions of about five to six percent after one year. Among patients who completed the full study, weight loss was greater, reaching nearly ten percent in one group.

The company said these findings could help it better identify which patients are most likely to respond to treatment, and it plans to continue developing newer versions of the drug aimed at specific genetic subtypes.

No new safety concerns were reported. The most common side effects included skin darkening, nausea, headache, and reactions at the injection site.

“This is a difficult outcome, but we’re seeing signals that could guide future treatments,” said Rhythm CEO David Meeker. He said that people with these rare forms of obesity currently have very limited treatment options.

Photo: Rhythm CEO David Meeker