Natural History of Obesity Due to POMC, PCSK1, and LEPR Deficiency and the Impact of Setmelanotide

Area of Science:

• Genetics
• Endocrinology
• Obesity Research

Background:

• Rare variants in POMC, PCSK1, and LEPR genes disrupt the MC4R pathway, leading to hyperphagia and severe early-onset obesity.
• These genetic defects cause significant challenges in managing weight, with traditional interventions often proving ineffective.

Purpose of the Study:

• To characterize the historical weight trajectory in patients with obesity due to POMC, PCSK1, or LEPR deficiency.
• To evaluate the impact of setmelanotide treatment on weight and BMI trajectories in this patient population.

Main Methods:

• Analysis of data from two pivotal, single-arm, open-label, Phase 3 clinical trials (NCT02896192, NCT03287960).
• Inclusion of 17 patients with obesity due to POMC/PCSK1 or LEPR deficiency, with historical weight and height data obtained during screening.
• Patients received setmelanotide treatment, and weight/BMI trajectories were assessed over a 1-year observation period.

Main Results:

• Prior to setmelanotide treatment, patients exceeded the 95th percentile for weight throughout childhood, showing continuous gain and no long-term loss with conventional interventions.
• Setmelanotide treatment significantly attenuated weight and body mass index trajectories over the 1-year study period.
• The study included 8 patients with POMC deficiency, 1 with PCSK1 deficiency, and 8 with LEPR deficiency.

Conclusions:

• Traditional weight loss interventions have limited impact on severe early-onset obesity resulting from POMC, PCSK1, or LEPR deficiencies.
• Setmelanotide treatment effectively attenuated weight and BMI trajectories, leading to weight loss and associated health benefits in most patients.
• Setmelanotide represents a promising therapeutic option for managing severe obesity linked to MC4R pathway genetic defects.