Core Insights - Rhythm Pharmaceuticals (RYTM) shares increased by 36.6% following the announcement of positive top-line data from a Phase II study of the oral melanocortin-4 receptor (MC4R) agonist, bivamelagon, for treating acquired hypothalamic obesity [1][7]. Company Overview - Rhythm Pharmaceuticals is focused on developing treatments for obesity-related conditions, specifically acquired hypothalamic obesity, which is characterized by rapid weight gain and uncontrollable hunger due to hypothalamic damage [2][4]. - The company also markets setmelanotide, another MC4R agonist, under the brand name Imcivree for chronic weight management in patients with specific genetic conditions [4]. Study Results - The Phase II study demonstrated that bivamelagon resulted in statistically significant reductions in body mass index (BMI) after 14 weeks of treatment, with reductions of 9.3%, 7.7%, and 2.7% for the 600mg, 400mg, and 200mg doses, respectively [3][8]. - In contrast, the placebo group experienced a BMI increase of 2.2% over the same period [8]. - Patients receiving bivamelagon also reported a mean decrease of over 2.8 points in peak hunger scores on a standardized 10-point scale, indicating effective management of excessive hunger [9]. Future Development Plans - Following the encouraging Phase II results, Rhythm Pharmaceuticals plans to engage with regulatory authorities in the U.S. and EU to discuss the design of a Phase III study for bivamelagon [10]. - The company aims to request an end-of-phase II meeting with the FDA to pursue a registrational path for bivamelagon [11].