BOSTON, MA, May 1, 2026
Rhythm Pharmaceuticals, Inc. announced that the European Commission has granted marketing authorization for IMCIVREE® (setmelanotide) for the treatment of obesity and control of hunger in patients with acquired hypothalamic obesity (HO). This milestone marks the first and only therapy authorized in both the United States and Europe for this rare neuroendocrine condition, addressing a significant unmet medical need in both adult and pediatric populations aged 4 years and older.
First Approved Therapy for Rare Hypothalamic Obesity
The EC authorization represents a major advancement for patients suffering from acquired hypothalamic obesity, a rare condition caused by damage or dysfunction of the hypothalamus, often following tumors, surgery, or brain injury. This condition leads to uncontrolled hunger (hyperphagia) and rapid, sustained weight gain, severely impacting quality of life. Until now, patients had no approved pharmacological treatment options in Europe. IMCIVREE, a melanocortin-4 receptor (MC4R) agonist, directly targets the disrupted pathway responsible for energy balance and appetite regulation. Rhythm estimates that approximately 10,000 patients in Europe are affected by this condition, highlighting the importance of this approval in expanding treatment access across the region.
Strong Phase 3 Data Supports Regulatory Approval
The approval is based on results from the Phase 3 TRANSCEND trial, which demonstrated statistically significant and clinically meaningful reductions in body mass index (BMI) among treated patients. Participants receiving IMCIVREE achieved a -16.5% reduction in BMI, compared to a +3.3% increase in the placebo group, resulting in a -19.8% placebo-adjusted difference at 52 weeks (p<0.0001). The treatment showed consistent efficacy across both adult and pediatric populations, with -19.2% and -20.2% placebo-adjusted BMI reductions, respectively. These outcomes reinforce the drug’s ability to deliver sustained weight management and appetite control in a disease driven by MC4R pathway dysfunction. Additionally, IMCIVREE demonstrated a manageable safety profile, with the most common adverse events including nausea, vomiting, diarrhea, injection site reactions, and skin hyperpigmentation.
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Commercial Rollout and Global Expansion Strategy
With the EC authorization secured, Rhythm Pharmaceuticals plans to pursue country-by-country reimbursement and access negotiations across Europe, with commercial launches expected in 2027. This follows the recent U.S. FDA approval in March 2026, strengthening the company’s global position in treating rare obesity disorders. The approval also reinforces Rhythm’s broader strategy of advancing targeted therapies for rare neuroendocrine diseases, including ongoing development of next-generation MC4R agonists. By addressing the underlying biological mechanisms of appetite dysregulation, IMCIVREE represents a precision medicine approach that could redefine treatment standards for rare obesity conditions worldwide.
This regulatory milestone underscores the growing importance of mechanism-driven therapies in rare disease treatment, particularly in conditions where traditional lifestyle or metabolic interventions are ineffective. As access expands, IMCIVREE has the potential to significantly improve long-term outcomes, reduce disease burden, and enhance quality of life for patients living with acquired hypothalamic obesity.
Source: Rhythm Pharmaceuticals press release
