Phase 2 trial testing setmelanotide for PWS set to start soon
Therapy already approved in US, EU for treating obesity
Rhythm Pharmaceuticals plans to start a new Phase 2 clinical study in the first quarter of 2025 to test setmelanotide in adults and children with Prader-Willi syndrome (PWS).
An investigational therapy for PWS, setmelanotide is approved in the U.S. to treat certain types of genetic obesity under the brand name Imcivree. The main goal of the new study (NCT06772597), which will take place at a single site in the U.S., is to assess how safe and well tolerated setmelanotide is in up to 20 patients, ages 6-65, with PWS and obesity. The patients will gradually increase their dose to 5 mg/day, as tolerated, for up to 26 weeks, or about six months.
Other goals include testing the therapy’s pharmacokinetics, that is, how it moves into, through, and out of the body, and its effects on weight, excessive eating, called hyperphagia, and behavior. It will be an open-label study, meaning everyone will know they are receiving the treatment.
Testing setmelanotide for PWS
In an earlier Phase 2 clinical study (NCT02311673) involving 40 adults and adolescents with PWS, setmelanotide injected under the skin, that is, subcutaneously, reduced hyperphagia and resulted in clinically meaningful weight loss, but only at the highest dose of 2.5 mg daily, and for the longest period of time, just over two months.
“Based on the unmet need and severity of Prader-Willi syndrome (PWS) and learnings from our initial study, we plan to initiate an exploratory Phase 2 study with higher doses of setmelanotide over a longer duration of [six] months,” David Meeker, MD, Rhythm’s chairman, CEO, and president, said in a company press release.
Usually starting in childhood, PWS causes patients to feel constantly hungry and obsessed with food. This results in a need to eat all the time, which often leads to gaining too much weight or becoming obese. There are no approved treatments for PWS that can reduce hyperphagia.
Setmelanotide is designed to bind to and activate a protein called melanocortin-4 receptor (MC4R), which is normally activated by hormones that signal a feeling of fullness after eating. By activating MC4R itself, setmelanotide should reduce appetite and help patients lose weight or keep weight off.
In the U.S., setmelanotide as Imcivree is approved to reduce excess body weight and maintain weight reduction long term in adults and children, ages 2 and older, with obesity due to certain genetic diseases. In the European Union, Imcivree is approved for the same indications to treat obesity and help control hunger.
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