Dual activation of MC3R and MC4R drives weight loss and reduces food intake in male primates with obesity

The melanocortin system plays a central role in regulating hunger and satiety, making it an attractive target for treating metabolic disease. However, the limited clinical success of selective melanocortin-4 receptor (MC4R) agonists has prompted investigation into whether concurrent melanocortin-3 receptor (MC3R) and MC4R activation may more effectively engage this pathway for the treatment of general obesity. Here we show that selective MC3R agonism modulates food intake in a state-dependent manner, and that co-agonism of MC3R and MC4R produces greater metabolic effects than selective MC4R agonism alone, consistent with non-redundant and cooperative roles. Using novel peptides in male nonhuman primates and rodents, we develop 710GO, an orally available MC3R/MC4R dual agonist that induces significant weight loss in primates with diet-induced obesity. Oral 710GO demonstrates limited weight rebound, compatibility with GLP-1–based therapies, and a favorable preclinical safety profile. These findings support combined MC3R/MC4R agonism as a promising approach for next-generation obesity therapeutics. Melanocortin receptor agonists are an alternative to GLP-1s for weight loss. The study showed that activating MC3R & MC4R together demonstrated strong weight loss, limited rebound, and a clean safety profile in primates.