Setmelanotide significantly reduces BMI by 16.5% and hunger in acquired hypothalamic obesity patients

Acquired hypothalamic obesity (aHO) is a severe and challenging condition resulting from damage to the hypothalamus, often due to tumors, lesions, or injury. This damage disrupts normal energy balance, leading to profound hyperphagia and rapid weight gain, for which current treatments are largely ineffective. Patients experience significant morbidity and a reduced quality of life. Setmelanotide, a potent melanocortin-4 receptor (MC4R) agonist, targets a critical pathway in central appetite regulation. Previous phase 2 data showed promise, but robust phase 3 evidence was needed to confirm its efficacy and safety in this specific, high-need population.

This phase 3 randomized controlled trial assigned 120 participants (age 4 to 66 years) in a 2:1 ratio to receive either setmelanotide or placebo. After a dose-escalation period, participants received setmelanotide at a dose of 1.5 to 3.0 mg administered subcutaneously (SC) once daily for 52 weeks. Eligibility required a diagnosis of acquired hypothalamic obesity, defined by a body-mass index (BMI) at or above the 95th percentile for age and sex (for those <18 years) or at least 30 (for those ≥18 years), alongside a history of hypothalamic damage. The primary endpoint was the mean percent change in BMI from baseline to 52 weeks, while secondary endpoints included changes in maximal daily hunger scores, assessed in participants aged 12 years or older.

A total of 81 participants received setmelanotide and 39 received placebo. At 52 weeks, setmelanotide demonstrated a statistically significant reduction in BMI compared to placebo. The least-squares mean (LSM) change in BMI was -16.5% (95% confidence interval [CI], -19.3 to -13.8) in the setmelanotide group, versus a 3.3% increase (95% CI, -0.6 to 7.2) in the placebo group (P<0.001). This represents a substantial and clinically meaningful difference.

Setmelanotide treatment led to a 16.5% reduction in BMI, a stark contrast to the 3.3% increase observed with placebo (P<0.001). Furthermore, setmelanotide significantly improved hyperphagia, a hallmark symptom of aHO. The LSM change in the weekly average of maximal daily hunger scores was -2.73 (95% CI, -3.28 to -2.18) in the setmelanotide group, compared to -1.45 (95% CI, -2.23 to -0.67) in the placebo group (P=0.009). The abstract noted that adverse events were reported, but specific details were not provided.