Peptide therapeutics developer Rhythm Pharmaceuticals said today its subsidiary won a $1 million research grant from the FDA Office of Orphan Products Development toward an ongoing Phase II study of its MC4 agonist setmelanotide (RM-493).

The grant to Rhythm Metabolic will partially fund an initial proof-of-concept Phase II study in PWS—with Rhythm funding the remainder—of setmelanotide for obesity and hyperphagia in Prader-Willi syndrome (PWS).

Setmelanotide is a first-in-class MC4 agonist in development designed to treat obesity caused by genetic deficiencies in the MC4 pathway, which regulates energy expenditure, homeostasis, and appetite. Research has implicated defects in the MC4 pathway as the root cause of the weight and appetite abnormalities seen in people with PWS.

No approved treatments exist for the obesity and hyperphagia associated with PWS, a rare genetic disease whose prevalence ranges from about one in 8,000 to one in 25,000 U.S. patients.

The trial is designed to evaluate the effects of setmelanotide on weight reduction and PWS-specific food-related behavior in obese patients with PWS, The placebo-controlled study will assess the safety and efficacy of setmelanotide administered once daily by subcutaneous injection for up to 10 weeks of treatment. The trial will enroll approximately 36 obese patients with PWS, Rhythm said.

“This grant is meaningful and substantive to advance our ongoing setmelanotide program for the treatment of Prader-Willi,” Rhythm CEO Keith Gottesdiener, M.D., said in a statement. “We are extremely grateful for this grant from the FDA Office of Orphan Products Development and the important support of the Foundation for Prader-Willi Research in making it happen.”

The trial is one of two Phase II studies of setmelanotide launched in June. The other is an ongoing trial assessing the drug in Proopiomelanocortin (POMC) deficiency, in which a genetic defect in the MC4 pathway causes obesity and appetite abnormalities.

Last month, Rhythm said it completed a $40 million Series A financing for Rhythm Metabolic, with proceeds intended to advance the subsidiary’s setmelanotide program. New investors OrbiMed, Deerfield Management, Wellington Management, and an undisclosed public healthcare investment fund joined existing investors MPM Capital, New Enterprise Associates, Third Rock Ventures, Pfizer Ventures, and Ipsen.