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, presented data today from its Phase III program with pimavanserin for Parkinson’s disease psychosis (PDP), including data from its pivotal -020 Study and the related, open-label safety extension study, at a poster session at the 17 th International Congress of Parkinson’s Disease and Movement Disorders, which is taking place in Sydney, Australia from June 17 - 20, 2013. “Data from our open-label safety extension study indicate that long-term administration of pimavanserin is generally safe and well tolerated in PDP patients and suggest that duration of antipsychotic effect may be maintained for longer than the six weeks investigated in our pivotal -020 Study,” said Uli Hacksell, Ph.D., ACADIA's Chief Executive Officer. “The overall efficacy and safety profile observed to date shows that pimavanserin has the potential to offer a new treatment option that may provide significant advantages relative to current antipsychotics used off-label for the treatment of PDP.” Key poster presentations: 1. “Long Term Pimavanserin Treatment for Parkinson’s Disease Psychosis (PDP): An Interim Analysis of Safety and Tolerability Data from Study ACP-103-015.” The interim analysis of the Phase III open-label safety extension trial (-015 Study) reflects data assembled in the database as of March 21, 2013. A total of 458 PDP patients from 14 countries with a mean age at study-entry of 71 years had rolled over into the -015 Study from the six-week pivotal, placebo-controlled efficacy, tolerability and safety trial (-020 Study) and two earlier six-week placebo-controlled trials (-012 and -014 Studies). Study evaluations occur at week 2 and at months 1, 3, 6, 9 and 12, as well as every 6 months thereafter. About half of the patients stayed in the open-label study for more than a year. The data suggest that long-term administration of 40 mg of pimavanserin is generally safe and well tolerated in patients with PDP. In addition, the rate of discontinuation due to adverse events in the -015 Study appears to be lower than that recently reported in a third-party study of patients over 40 years old who used one of four commonly prescribed atypical antipsychotic drugs. Although there are no formal efficacy endpoints in the open-label -015 Study, antipsychotic effect was measured at one month using the SAPS-PD scale and at all study visits using the Clinical Global Impression Improvement, or CGI-I, scale, and the Clinical Global Impression Severity, or CGI-S, scale. The CGI data are intended to provide the investigator with information to determine whether patients continue to derive benefit from pimavanserin during the open-label study. Patients who entered the -015 Study from the 40 mg treatment arm of the previous six-week studies maintained about the same mean improvement in SAPS-PD scores one month later. Patients who entered the -015 Study from the placebo arm of the previous six-week studies displayed a marked improvement in mean SAPS-PD scores after one month in the -015 Study. In addition, the long-term CGI data indicate durability of treatment effect for patients remaining in the open-label study.