Rhythm Pharmaceuticals Stock Rises After Positive Study Data For Setmelanotide In Treating Genetic Disorder

The company was studying the therapy in Prader-Willi Syndrome, a rare genetic disorder requiring lifelong management.

• The company said that reduction in body mass index as well as hyperphagia or extreme, insatiable, or excessive hunger that does not go away after eating was observed at month 3 and month 6 in the trial.
• The company said that the results are supportive of a late-stage registrational trial. 
• Bank of America subsequently raised its price target on Rhythm to $140 from $127 while keeping a ‘Buy’ rating on the shares.

Shares of Rhythm Pharmaceuticals, Inc. (RYTM) jumped 14% on Thursday after the company announced that its mid-stage study evaluating Setmelanotide in Prader-Willi Syndrome patients showed reduction in weight and hyperphagia.

The company said that the reduction in body mass index as well as hyperphagia or extreme, insatiable, or excessive hunger that does not go away after eating was observed at the third and sixth-month mark in the trial. The company said that the results are supportive of a late-stage registrational trial.

Trial Design

The company enrolled 18 patients with Prader-Willi Syndrome (PWS) in the ongoing 52 week trial. Of this, 17 patients remain enrolled on active Setmelanotide therapy and the company will share additional data in the first half of 2026, it added.

PWS is a rare genetic disorder requiring lifelong management and causing poor muscle tone and feeding issues in infancy, followed by relentless hunger (hyperphagia) and severe obesity in childhood, alongside developmental delays, learning disabilities, and distinctive behavioral problems. PWS is estimated to affect approximately 400,000 people worldwide and approximately 20,000 people in the United States, as per Rhythm.

The company said that safety and tolerability profile of Setmelanotide therapy in the trial was consistent with the drug’s established clinical profile. In the United States, Setmelanotide is already indicated to reduce excess body weight and maintain weight reduction long term in adult and pediatric patients 2 years of age and older with syndromic or monogenic obesity due to certain conditions including Bardet-Biedl syndrome.

Rhythm is also looking to evaluate its experimental therapy RM-718 in PWS and expects the first patient with PWS to enter screening for this study in December.

Expert Take

Bank of America subsequently raised its price target on Rhythm to $140 from $127 while keeping a ‘Buy’ rating on the shares. The firm, which is "encouraged" by the preliminary update, argues that a successful late-stage study in PWS would "offer an attractive commercial opportunity."

How Did Stocktwits Users React?

On Stocktwits, retail sentiment around RYTM jumped from ‘bullish’ to ‘extremely bullish’ territory over the past 24 hours, while message volume rose from ‘normal’ to ‘extremely high’ levels.

RYTM stock has more than doubled this year. 

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