SAN DIEGO—(BUSINESS WIRE)—Sep. 24, 2025—Acadia Pharmaceuticals Inc. (Nasdaq: ACAD) today announced top-line results from the Phase 3 COMPASS PWS trial evaluating the efficacy and safety of intranasal carbetocin (ACP-101) in patients with hyperphagia in Prader-Willi syndrome (PWS). Intranasal carbetocin did not demonstrate a statistically significant improvement over placebo on the study’s primary endpoint, change from baseline to Week 12 on the Hyperphagia Questionnaire for Clinical Trials (HQ-CT), nor was there separation from placebo on any secondary endpoint. The safety and tolerability profile of intranasal carbetocin was consistent with previous clinical trials, showing a low rate of adverse events.
“We are disappointed by these findings, especially for Prader-Willi syndrome patients, their families and the entire community,” said Elizabeth H.Z. Thompson, Ph.D., Acadia’s Head of Research and Development. “I want to thank the many patients, families, study site personnel, and physicians who participated in the COMPASS PWS study as well as the intranasal carbetocin clinical development program, for their dedication and contributions in this important study. We are committed to sharing a summary of the data in the future to ensure learning for the PWS community; however, given these results, we do not intend to investigate intranasal carbetocin any further.”
COMPASS PWS was a 12-week, double-blind, randomized, placebo-controlled global Phase 3 trial evaluating the efficacy and safety of intranasal carbetocin 3.2 mg three times daily (TID) in 175 enrolled children and adults aged five to 30 years with PWS.
“Despite this disappointment, Acadia is well-positioned to deliver long-term, sustainable growth supported by two approved products projected to generate over $1 billion in net sales in 2025, and a robust pipeline that includes eight disclosed and multiple undisclosed programs,” said Catherine Owen Adams, Acadia’s Chief Executive Officer. “Looking ahead, we anticipate seven Phase 2 or 3 study starts through 2026 and four data readouts by the end of 2027. For more details on our programs, I encourage you to revisit our recent R&D Day presentation on our website.”
About Acadia Pharmaceuticals
Acadia is advancing breakthroughs in neurological and rare diseases to elevate life. Since our founding we have been working at the forefront of healthcare to bring vital solutions to people who need them most. We developed and commercialized the first and only FDA-approved drug to treat hallucinations and delusions associated with Parkinson’s disease psychosis and the first and only approved drug in the United States and Canada for the treatment of Rett syndrome. Our clinical-stage development efforts are focused on Alzheimer’s disease psychosis, Lewy Body Demetia psychosis and multiple other programs targeting neuroscience and neuro-rare diseases.