BOSTON, Mass. — October 13, 2026
Rhythm Pharmaceuticals, Inc. (Nasdaq: RYTM), a commercial-stage biopharmaceutical company focused on rare neuroendocrine diseases, announced the commercial launch of IMCIVREE® (setmelanotide) in Japan for patients with acquired hypothalamic obesity (HO). The launch follows approval by Japan’s Ministry of Health, Labour and Welfare (MHLW) in August 2026 and the medicine’s inclusion on the country’s National Health Insurance (NHI) drug price list. According to Rhythm, IMCIVREE is the first approved therapy in Japan for acquired hypothalamic obesity, a rare condition associated with damage or dysfunction of the hypothalamus that can disrupt appetite regulation and contribute to severe weight gain. The launch represents a milestone in the company’s efforts to expand access to treatments for patients with rare neuroendocrine disorders.
IMCIVREE Becomes First Approved Therapy for Acquired Hypothalamic Obesity in Japan
The Japanese commercial launch follows regulatory approval supported by findings from the pivotal Phase 3 TRANSCEND clinical trial, which enrolled 142 patients with acquired hypothalamic obesity. The study included a primary cohort of 120 patients, along with 12 participants from a Japanese cohort and 10 additional supplemental participants. According to Rhythm, the global trial met its primary endpoint, demonstrating a statistically significant 18.8% placebo-adjusted reduction in body mass index (BMI). This result supported the company’s regulatory application in Japan and helped establish the clinical evidence base for the treatment. Acquired hypothalamic obesity can develop following injury or impairment affecting the hypothalamus, a brain region involved in regulating hunger, energy balance and other essential functions. Patients may experience persistent weight gain and difficulties managing body weight because of disruptions to these regulatory pathways. Rhythm estimates that approximately 5,000 to 8,000 people in Japan are living with the condition. The inclusion of IMCIVREE on Japan’s NHI drug price list marks an important step toward commercial availability under the country’s healthcare reimbursement framework.
Setmelanotide Targets Appetite Regulation Pathways
Setmelanotide is a melanocortin-4 receptor (MC4R) agonist designed to act on pathways involved in hunger and energy balance. By activating MC4R-related signaling, the medicine aims to help reduce excessive hunger and body weight in certain patients with rare obesity conditions. Rhythm is developing and commercializing setmelanotide for specific forms of obesity, including acquired hypothalamic obesity and selected genetic disorders associated with severe obesity. The company’s broader experience with the medicine across rare obesity conditions supports its strategy of targeting biological mechanisms rather than treating all forms of obesity as the same disease. However, treatment eligibility and approved indications vary by country, and the Japanese launch described in the announcement specifically concerns acquired hypothalamic obesity. The reported 18.8% placebo-adjusted BMI reduction relates to the Phase 3 TRANSCEND trial and should not be interpreted as an identical expected outcome for every patient. Individual treatment response and safety require clinical assessment. Rhythm previously received orphan drug designation from Japan’s MHLW for setmelanotide in acquired hypothalamic obesity, reflecting the rare-disease focus of the development program.
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Japan Expansion Advances Rhythm’s Rare Disease Strategy
Rhythm said the Japanese launch reflects continued investment in its international commercial capabilities and its goal of reaching patients with rare neuroendocrine diseases. The company established a local team in preparation for the launch and expects the new availability of IMCIVREE to address an unmet treatment need for people living with acquired hypothalamic obesity. Beyond Japan, setmelanotide has received regulatory approvals in other markets for specified rare obesity indications, subject to local prescribing requirements and eligibility criteria. Rhythm is also advancing investigational MC4R agonists bivamelagon and RM-718, alongside preclinical small-molecule programs targeting congenital hyperinsulinism. The company’s development strategy centers on therapies for disorders involving appetite regulation, metabolism and neuroendocrine function. Although the Japanese launch represents a significant commercial milestone, appropriate patient selection, ongoing safety monitoring and adherence to local prescribing information remain important considerations. With Japan’s regulatory approval and reimbursement listing in place, Rhythm is expanding the geographic reach of its rare-disease portfolio while bringing a new approved treatment option to patients who previously had no approved therapy for acquired hypothalamic obesity in the country.
Source::Rhythm Pharmaceuticals press release
