Topline Results of the CARE-PWS Phase 3 Study: Intranasal Carbetocin Improves Hyperphagia and Anxiety and Distress Symptoms in Prader-Willi Syndrome (PWS)

Prader-Willi syndrome (PWS) is a complex genetic disorder associated with multiple neuroendocrine abnormalities including significantly decreased hypothalamic oxytocin levels, resulting in symptoms of severe hyperphagia (an unrelenting false sense of starvation) and multiple severe neuropsychiatric and behavioral issues. CARE-PWS, a multi-center, randomized, double-blind, placebo-controlled phase 3 study, has evaluated the efficacy, safety, and tolerability of intranasal carbetocin, a selective oxytocin receptor agonist, in participants with PWS. Eligible participants aged 7 through 18 with genetically confirmed PWS were randomized in equal proportions to three treatment arms for the 8-week placebo-controlled period of the study: carbetocin 9.6 mg, carbetocin 3.2 mg, or a matching placebo, administered by nasal spray three times a day with meals. The primary endpoint assessed changes from baseline to week 8 in Hyperphagia Questionnaire for Clinical Trials (HQ-CT) or Children’s Yale-Brown Obsessive Compulsive Scale (CY-BOCS) scores for the carbetocin 9.6 mg arm vs placebo, and the first secondary endpoint assessed changes from baseline to week 8 in HQ-CT or CY-BOCS scores for the carbetocin 3.2 mg arm vs placebo. Additional secondary endpoints included changes from baseline to week 8 in PWS Anxiety and Distress Questionnaire (PADQ) scores, and Clinical Global Impression of Change (CGI-C) scores evaluating the overall change in severity of PWS symptoms at week 8. Due to COVID-19, enrollment was closed early with 119 evaluable participants for the primary analysis. In the carbetocin 9.6 mg arm, trends toward numerically greater improvements in HQ-CT and CGI-C scores relative to placebo were observed but did not reach statistical significance; however, the carbetocin 3.2 mg arm demonstrated a significant improvement in HQ-CT scores (LS mean improvement vs placebo -3.14 points, p=0.016). In the 3.2 mg arm, additional consistent evidence of improvements versus placebo was seen in multiple secondary endpoints, including CGI-C (p=0.027) and PADQ (p=0.027). Numeric trends toward improvement in CY-BOCS scores were observed in each dose arm, but did not reach statistical significance versus placebo. During the subsequent long-term follow-up period of the study, both carbetocin arms have experienced continued numeric improvements from baseline across multiple endpoints. Intranasal carbetocin was generally well-tolerated; the most frequently reported adverse event was flushing, which was generally mild and transient. In conclusion, results of the CARE-PWS study support that intranasal carbetocin appears to be safe and well tolerated, and reduces hyperphagia and anxiety and distress behaviors in PWS.