ACADIA Pharmaceuticals Inc. (NASDAQ: ACAD), a biopharmaceutical company focused on innovative treatments that address unmet medical needs in neurological and related central nervous system disorders, today announced the publication of data from its pivotal Phase III -020 Study with pimavanserin in patients with Parkinson’s disease psychosis (PDP) in the November 1, 2013 online issue of The Lancet. In the -020 Study, pimavanserin demonstrated significant and clinically meaningful benefits and was safe and well tolerated in patients with PDP. Pimavanserin significantly reduced psychosis and maintained motor control in patients with PDP. Significant benefits were also observed in exploratory measures of nighttime sleep, daytime wakefulness and caregiver burden. “Among Parkinson’s patients, psychosis causes great distress for patients and caregivers and is the leading cause of institutionalization,” said Jeffrey Cummings, M.D., Sc.D., Director of Cleveland Clinic Lou Ruvo Center for Brain Health, and lead author. “These data indicate that pimavanserin, a selective 5-HT 2A inverse agonist, confers a meaningful clinical benefit in patients with PDP and has the potential to be an important new treatment option for this condition for which there is no approved therapy in the U.S.” Pimavanserin met the primary endpoint in the -020 Study by demonstrating highly significant improvement in psychosis compared to placebo on the 9-item SAPS-PD scale (p=0.001), which was assessed by central, independent raters. The mean change in SAPS-PD score represented a 37% improvement for pimavanserin versus 14% for placebo (p<0.001). Pimavanserin also demonstrated significant improvement on the full 20-item SAPS (hallucinations plus delusions) measure (p=0.001) and on each of the separate hallucinations and delusions domains in supportive analyses. Significant improvements were observed for pimavanserin over placebo on additional investigator-assessed secondary measures of psychosis benefit, including the Clinical Global Impression Severity, or CGI-S, scale (p<0.001), and the Clinical Global Impression Improvement, or CGI-I, scale (p=0.001). The proportion of CGI-I responders was also higher for pimavanserin versus placebo, (49% vs. 26%, p=0.002). Pimavanserin met the key secondary endpoint for motoric tolerability as measured using Parts II and III of the Unified Parkinson’s Disease Rating Scale, or UPDRS. Caregivers in the pimavanserin group also reported significant reduction in caregiver burden (p=0.002), and participants reported significant improvements on nighttime sleep (p=0.045) and daytime wakefulness (p=0.012) for pimavanserin over placebo in exploratory analyses.