Japan’s Ministry of Health, Labour and Welfare has granted marketing authorization for Rhythm Pharmaceuticals’ Imcivree (setmelanotide) to treat acquired hypothalamic obesity, marking the first approved therapy for the rare disease in the country.
The regulator’s decision follows the Phase 3 TRANSCEND trial, which enrolled 142 patients globally, including 12 from a Japanese cohort and 10 supplemental patients. In the trial, Imcivree demonstrated an 18.8% placebo-adjusted reduction in body mass index (BMI), meeting the primary efficacy endpoint.
Acquired hypothalamic obesity is a rare condition characterized by rapid weight gain due to hypothalamic damage, often resulting from craniopharyngioma, astrocytoma, or other hypothalamic-pituitary tumors. Additional causes include traumatic brain injury, stroke, infection, or inflammation. Rhythm estimates the patient population in Japan at between 5,000 and 8,000 people.
Imcivree, a melanocortin-4 receptor agonist, is designed to address hyperphagia and severe obesity. The drug has previously received approvals from the U.S. Food and Drug Administration and the European Commission for acquired hypothalamic obesity and certain genetic forms of obesity.
Rhythm Pharmaceuticals, based in Boston, plans to launch Imcivree in Japan before the end of 2026, pending final pricing determination. The company secured orphan drug designation for Imcivree from Japan’s ministry in March 2025.
