Japan’s Ministry of Health, Labour and Welfare has granted marketing authorization for Rhythm Pharmaceuticals Inc.’s Imcivree (setmelanotide) to treat patients with acquired hypothalamic obesity, marking the first approved therapy for the rare condition in the country.
The approval applies to patients with hypothalamic obesity, a disorder characterized by rapid weight gain following injury to the hypothalamus. Rhythm estimates the condition affects between 5,000 and 8,000 people in Japan, with most cases arising from craniopharyngioma, astrocytoma, or other hypothalamic-pituitary tumors. Additional causes include traumatic brain injury, stroke, infection, or inflammation.
Imcivree, a melanocortin-4 receptor (MC4R) agonist, targets hyperphagia and severe obesity. The drug is already approved by the U.S. Food and Drug Administration and the European Commission for acquired hypothalamic obesity and certain genetic forms of obesity.
The authorization is supported by Phase 3 TRANSCEND trial results, which enrolled 142 patients globally, including 12 from a Japanese cohort and 10 supplemental patients. The study met its primary endpoint, demonstrating an 18.8% placebo-adjusted reduction in body mass index.
Rhythm received orphan drug designation for Imcivree from Japan’s health ministry in March 2025. The company expects to launch the therapy before the end of 2026, subject to final pricing determinations.
