NEJM publishes Phase 3 TRANSCEND trial results showing setmelanotide delivers significant BMI reduction and hunger control in acquired hypothalamic obesity.
Written By: Mayuresh Salvi, PharmD
Reviewed By: Pharmacally Editorial Team
Rhythm Pharmaceuticals announced that results from its pivotal Phase 3 TRANSCEND trial evaluating setmelanotide (IMCIVREE®) in patients with acquired hypothalamic obesity (HO) have been published in The New England Journal of Medicine (NEJM). The peer-reviewed publication highlights clinically meaningful reductions in body mass index (BMI) and improvements in hunger among adults and children aged 4 years and older, further supporting the efficacy of the melanocortin-4 receptor (MC4R) agonist in this rare neuroendocrine disorder.
The TRANSCEND trial is the largest and longest randomized, double-blind, placebo-controlled Phase 3 study conducted in patients with acquired hypothalamic obesity, addressing a disease with few effective therapeutic options.
Clinical Trial Design
TRANSCEND was a global, randomized, double-blind, placebo-controlled Phase 3 trial (NCT05774756) that enrolled 120 patients aged 4 years and older with acquired hypothalamic obesity. Participants were randomized in a 2:1 ratio to receive once-daily subcutaneous setmelanotide (n=81) or placebo (n=39) for 52 weeks. The primary endpoint was the mean percentage change in BMI from baseline after one year of treatment.
Key Efficacy Findings
The study met its primary endpoint, demonstrating statistically significant and clinically meaningful reductions in BMI with setmelanotide compared with placebo.
After 52 weeks:
Patients receiving setmelanotide achieved a 16.5% mean reduction in BMI from baseline compared with a 3.3% increase in the placebo group (p<0.0001).
The treatment produced a 19.8% placebo-adjusted difference in BMI reduction.
80% of patients treated with setmelanotide achieved at least a 5% reduction in BMI.
Setmelanotide also produced clinically meaningful improvements in hunger scores, an important therapeutic outcome given the persistent hyperphagia associated with hypothalamic injury.
These findings confirm that restoring MC4R pathway signalling can improve both weight management and appetite control in patients with acquired hypothalamic obesity.
Safety Findings
Setmelanotide was generally well tolerated, and no new safety signals were identified during the study. Adverse events leading to treatment discontinuation were comparable between the treatment and placebo groups.
The most frequently reported adverse reactions included skin hyperpigmentation, injection-site reactions, nausea, headache, diarrhoea, abdominal pain, vomiting, depression, and spontaneous penile erections. The prescribing information also highlights warnings regarding serious hypersensitivity reactions, depression and suicidal ideation, skin pigmentation changes, acute adrenal insufficiency in susceptible patients, and sodium imbalance in patients with concomitant central diabetes insipidus.
Clinical Significance
Senior author Dr. Christian Roth, paediatric endocrinologist at Seattle Children’s Research Institute, stated that patients with acquired hypothalamic obesity and their families have long faced an urgent need for effective treatment options. He noted that the TRANSCEND trial demonstrated meaningful and consistent reductions in BMI together with improvements in hunger, representing a potentially transformative therapeutic advancement for patients experiencing rapid and sustained weight gain following hypothalamic injury.
David Meeker, M.D., Chairman, President and Chief Executive Officer of Rhythm Pharmaceuticals, said that publication of the TRANSCEND results in The New England Journal of Medicine underscores the strength of the clinical evidence supporting setmelanotide. He added that, following regulatory approvals in the United States and Europe, the company remains focused on expanding access to the therapy globally, including through an ongoing regulatory review in Japan.
Mechanism of Action
Setmelanotide is a melanocortin-4 receptor (MC4R) agonist that restores signalling within the MC4R pathway, a critical regulator of appetite and energy balance. Damage to the hypothalamus reduces alpha-melanocyte-stimulating hormone (α-MSH) signalling, leading to hyperphagia, decreased energy expenditure, and progressive obesity. Setmelanotide improve appetite regulation and promote sustained weight reduction.
Regulatory Status
In March 2026, the U.S. Food and Drug Administration (FDA) approved IMCIVREE® (setmelanotide) as the first and only therapy indicated to reduce excess body weight and maintain long-term weight reduction in adults and children aged 4 years and older with acquired hypothalamic obesity.
In May 2026, the European Commission granted marketing authorization for IMCIVREE for the treatment of obesity and the control of hunger in adults and children aged 4 years and older with acquired hypothalamic obesity due to hypothalamic injury or impairment. A regulatory submission remains under review in Japan.
Reference
About the Writer
Mayuresh Sunil Salvi (Linkedin) is a PharmD professional and healthcare writer with a strong interest in pharmacovigilance, drug safety, and emerging medical research. He is passionate about exploring new drug discoveries, clinical research, and advances in evidence-based medicine. His interests also include ward rounds, prescription audits, and treatment analysis to support rational pharmacotherapy and improved patient care.