The phase III TRANSCEND trial found that setmelanotide reduced body mass index (BMI) and hunger in patients with acquired hypothalamic obesity. By week 52, participants receiving setmelanotide showed a mean BMI reduction of 16.5%.

The TRANSCEND trial randomized 120 patients across 29 global sites, including the U.S., between April 2023 and March 2025. Setmelanotide is an MC4R agonist, and individuals in the active treatment arm received a daily dose of 1.5 to 3.0 mg after a dose-escalation period. In contrast, participants in the placebo group experienced a mean BMI increase of 3.3% by week 52.

Patients treated with setmelanotide shed an average of 36.4 lb by week 52, while those on placebo gained an average of 5.3 lb. The trial also demonstrated that setmelanotide treatment reduced the weekly average of maximum daily hunger scores by 2.73 points. The placebo group saw a reduction of 1.45 points in their hunger scores.

The study collected data from patients aged 4 to 66 years, with an average age of 19.9 years. All participants had a history of hypothalamic injury, and craniopharyngioma tumors caused the underlying hypothalamic damage in 78% of cases. Acquired hypothalamic obesity is characterized by rapid weight gain following damage to the hypothalamus from factors such as tumors, surgery, head injuries, or inflammation.

Adverse events in the TRANSCEND trial were generally mild to moderate. Skin hyperpigmentation was observed in 56% of participants taking setmelanotide, compared to 8% in the placebo group. Nausea affected 51% of those on setmelanotide and 31% on placebo, while vomiting occurred in 40% of the setmelanotide group versus 18% of the placebo group. Headache incidence was 38% for setmelanotide users and 31% for placebo users.

A higher occurrence of melanocytic nevi was reported with setmelanotide at 17% compared to 5% with placebo. The trial recorded one serious adverse event related to setmelanotide: a participant experienced severe drug-induced nausea and vomiting. This event prevented the participant from taking oral desmopressin, which led to hypernatremia and subsequent hospitalization.

Why It Matters

The TRANSCEND trial results indicate a potential treatment for acquired hypothalamic obesity, a condition for which few therapies currently exist. The reductions in BMI and hunger observed with setmelanotide address key challenges faced by patients with this complex condition. While adverse events occurred, they were largely mild to moderate, and a long-term extension trial is underway to further assess the drug's safety and effectiveness beyond one year.