Rhythm Pharmaceuticals Inc.'s experimental obesity drug setmelanotide reduced body weight and insatiable hunger, meeting the main goals of two late-stage trials.
The Boston-based company's stock was up approximately 18.6% to $22.53, as of 1:43 p.m. ET on Aug. 7.
In the phase 3 trials, setmelanotide's effect on two rare types of genetic obesity — pro-opiomelanocortin, or POMC, and leptin receptor, or LEPR, deficiency — was examined in patients six years or older, Rhythm said in its Aug. 7 press release.
In the POMC trial, 8 out of the 10 enrolled patients achieved at least a 10% change in body weight at week 52 of treatment with setmelanotide, meeting the study's main goal. The study met all its key secondary goals as well, including body weight loss and reduction in hunger.
POMC-deficient patients saw a mean reduction in body weight of 25.4%, which translates to an average weight loss of 70.2 pounds, or 31.9 kilograms. Participants also reported a 27.8% reduction in hunger, and 50% of patients met or exceeded a 25% reduction in hunger.
In the LEPR trial, five out of 11 patients met the primary goal of 10% change in body weight, which Stifel analyst Derek Archila said is clinically meaningful. The trial also met its secondary goals, as LEPR-deficient patients experienced a 12.5% reduction in body weight of about 38 pounds, or 17 kilograms, as well as a 41.9% mean reduction in hunger. According to Rhythm, 72.7% of the LEPR patients experienced a 25% or more reduction in self-reported hunger.
A total of 20 of the 21 patients in the two trials lost weight, Archila said.
Rhythm also conducted a four-week treatment period with placebo after 12 weeks of treatment with setmelanotide, during which participants almost immediately gained weight and reported an increase in insatiable hunger. Across both trials, patients saw an average weight increase of more than 11 pounds, or about 5 kilograms, during placebo treatment. Rhythm said the trend reversed once patients went back on setmelanotide.
The drug was also well-tolerated, with no new safety issues reported. Consistent with previous studies, treatment-related adverse events were injection site reactions, nausea and vomiting, and increased hyperpigmentation, or darkening of the skin. One LEPR patient discontinued the study in week seven due to a blood condition, which Rhythm said was unrelated to therapy.
Rhythm, which is enrolling supplemental POMC and LEPR patients, will present full data from the phase 3 trials at an upcoming medical meeting. The company plans to submit an application for priority review for setmelanotide's approval in both types of obesities to the U.S. Food and Drug Administration in the fourth fiscal quarter of 2019. Setmelanotide will also be submitted for European approval.
Setmelanotide has been granted priority medicines status by the European Medicines Agency and received breakthrough therapy designation from the U.S. FDA.