▲ReadoutGlobal7 Apr 20251 min read
Setmelanotide cuts BMI by about a fifth in hypothalamic obesity
Rhythm’s MC4R agonist shows a large effect in people whose obesity follows damage to the hypothalamus, often after a childhood brain tumour.
Holds at Phase 3 The molecule is closer to patients than before.
The readThis is the clearest case on the board of a drug fixing a broken signal rather than adding a new one. A large effect in a small, well-defined group is how rare-disease drugs win.
The trial
TRANSCEND enrolled children and adults with acquired hypothalamic obesity. This condition often follows surgery or radiation for craniopharyngioma, a brain tumour near the hypothalamus. The damage breaks the MC4R pathway that tells the brain the body has enough energy, and weight rises fast despite diet.
Rhythm reported that setmelanotide reduced BMI by about 20 percent more than placebo after 52 weeks, with less hunger. The most common side effects matched what is known from its approved uses: skin darkening, injection-site reactions and nausea.
How it fits
Setmelanotide is already approved for several rare genetic obesities caused by faults in the same pathway. Hypothalamic obesity is a larger group, and it has no approved drug.
Board note
The trial result kept the molecule at phase 3 for this use. Rhythm then filed for approval, so the board now shows filed. Decision timing moved into 2026 according to the company; check the latest statement before quoting a date.
The FDA decision on the filing that followed, and the European review.
Primary sourceRhythm Pharmaceuticals press release, TRANSCEND phase 3 topline, April 2025
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