ACADIA Pharmaceuticals Announces Multiple Presentations of Data from Phase III Pimavanserin Program at the 17th International Congress of Parkinson’s Disease and Movement Disorders

SAN DIEGO—(BUSINESS WIRE)—Jun. 18, 2013—ACADIA Pharmaceuticals Inc. (NASDAQ: ACAD), a biopharmaceutical companyfocused on innovative treatments that address unmet medical needs inneurological and related central nervous system disorders, presenteddata today from its Phase III program with pimavanserin for Parkinson’sdisease psychosis (PDP), including data from its pivotal -020 Study andthe related, open-label safety extension study, at a poster session atthe 17^th International Congress of Parkinson’s Disease andMovement Disorders, which is taking place in Sydney, Australia from June17 - 20, 2013.

“Data from our open-label safety extension study indicate that long-termadministration of pimavanserin is generally safe and well tolerated inPDP patients and suggest that duration of antipsychotic effect may bemaintained 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 thatpimavanserin has the potential to offer a new treatment option that mayprovide significant advantages relative to current antipsychotics usedoff-label for the treatment of PDP.”

Key poster presentations:

1. “Long Term Pimavanserin Treatment for Parkinson’s DiseasePsychosis (PDP): An Interim Analysis of Safety and Tolerability Datafrom Study ACP-103-015.” The interim analysis of the Phase IIIopen-label safety extension trial (-015 Study) reflects data assembledin the database as of March 21, 2013. A total of 458 PDP patients from14 countries with a mean age at study-entry of 71 years had rolled overinto the -015 Study from the six-week pivotal, placebo-controlledefficacy, tolerability and safety trial (-020 Study) and two earliersix-week placebo-controlled trials (-012 and -014 Studies). Studyevaluations occur at week 2 and at months 1, 3, 6, 9 and 12, as well asevery 6 months thereafter. About half of the patients stayed in theopen-label study for more than a year. The data suggest that long-termadministration of 40 mg of pimavanserin is generally safe and welltolerated in patients with PDP. In addition, the rate of discontinuationdue to adverse events in the -015 Study appears to be lower than thatrecently reported in a third-party study of patients over 40 years oldwho used one of four commonly prescribed atypical antipsychotic drugs.

Although there are no formal efficacy endpoints in the open-label -015Study, antipsychotic effect was measured at one month using the SAPS-PDscale and at all study visits using the Clinical Global ImpressionImprovement, or CGI-I, scale, and the Clinical Global ImpressionSeverity, or CGI-S, scale. The CGI data are intended to provide theinvestigator with information to determine whether patients continue toderive benefit from pimavanserin during the open-label study. Patientswho entered the -015 Study from the 40 mg treatment arm of the previoussix-week studies maintained about the same mean improvement in SAPS-PDscores one month later. Patients who entered the -015 Study from theplacebo arm of the previous six-week studies displayed a markedimprovement in mean SAPS-PD scores after one month in the -015 Study. Inaddition, the long-term CGI data indicate durability of treatment effectfor patients remaining in the open-label study.

2. “Improved Nighttime Sleep and Increased Daytime Wakefulness inPatients with PD Psychosis Treated with Pimavanserin.” In additionto the assessments of antipsychotic efficacy, effects on sleep anddaytime wakefulness were assessed in the previously reported six-weekpivotal -020 Study. Although the study did not require sleep impairmentat entry, pimavanserin demonstrated a significant improvement innighttime sleep at weeks 4 and 6 compared to placebo. Consistent withprevious pimavanserin studies, this sleep improvement was notaccompanied by any sedation or “hang-over effect.” Instead, pimavanserinproduced a significant improvement in daytime wakefulness at week 6compared to placebo. Patients who entered the -020 Study with severenighttime disturbances (i.e., those having a baseline score of at least7 on the Scales for Outcome in Parkinson’s Disease - Nighttime Sleep, orSCOPA-NS) benefitted the most from pimavanserin therapy and showedhighly significant nighttime sleep improvements at weeks 2, 4 and 6compared to placebo. The positive effect of pimavanserin on nighttimesleep and daytime wakefulness did not correlate with antipsychoticmeasures, thus indicating that the sleep and wakefulness improvements ofpimavanserin seen in the -020 Study may represent treatment benefitsindependent from the antipsychotic efficacy.

About Pimavanserin

Pimavanserin is ACADIA’s proprietary small molecule that actsselectively as an antagonist/inverse agonist on serotonin 5-HT_2Areceptors and is in Phase III development as a potential first-in-classtreatment for Parkinson’s disease psychosis. Pimavanserin can be takenorally as a tablet once-a-day. ACADIA discovered pimavanserin and holdsworldwide rights to this new chemical entity.

ACADIA has reported results from its pivotal Phase III -020 Studyevaluating the efficacy, tolerability, and safety of pimavanserin inpatients with PDP. Results of the study showed that pimavanserindemonstrated highly significant antipsychotic efficacy in patients withPDP and allowed for maintained motor control. Pimavanserin also showedsignificant improvements in all secondary efficacy measures and on theexploratory measures of nighttime sleep, daytime wakefulness, andcaregiver burden. Consistent with previous studies, pimavanserin wassafe and well tolerated in the -020 Study.

In April 2013, ACADIA announced an expedited path to a New DrugApplication (NDA) filing for pimavanserin following a meeting with theFood and Drug Administration (FDA). ACADIA is currently focused oncompleting the remaining elements of its pimavanserin PDP program and istargeting an NDA submission near the end of 2014.

About Parkinson’s Disease Psychosis

According to the National Parkinson’s Foundation, about one millionpeople in the United States and from four to six million peopleworldwide suffer from Parkinson’s disease. Parkinson’s disease psychosis(PDP) is a debilitating disorder that develops in up to 60 percent ofpatients with Parkinson’s disease. Currently, there is no FDA-approvedtherapy to treat PDP in the United States. PDP, commonly consisting ofvisual hallucinations and delusions, substantially contributes to theburden of Parkinson’s disease and deeply affects the quality of life ofpatients. PDP is associated with increased caregiver stress and burden,nursing home placement, and increased morbidity and mortality. There isa large unmet medical need for new therapies that will effectively treatPDP without compromising motor control in patients with Parkinson’sdisease.

About ACADIA Pharmaceuticals

ACADIA is a biopharmaceutical company focused on innovative treatmentsthat address unmet medical needs in neurological and related centralnervous system disorders. ACADIA has a pipeline of product candidatesled by pimavanserin, which is in Phase III development as a potentialfirst-in-class treatment for Parkinson's disease psychosis. ACADIA alsohas clinical-stage programs for chronic pain and glaucoma incollaboration with Allergan, Inc. and two advanced preclinical programsdirected at Parkinson’s disease and other neurological disorders. Allproduct candidates are small molecules that emanate from discoveriesmade at ACADIA. ACADIA maintains a website at www.acadia-pharm.comto which ACADIA regularly posts copies of its press releases as well asadditional information and through which interested parties cansubscribe to receive email alerts.

Forward-Looking Statements

Statements in this press release that are not strictly historical innature are forward-looking statements. These statements include but arenot limited to statements related to the progress and timing of ACADIA’sdrug discovery and development programs, either alone or with a partner,including clinical trials and timing of filing an NDA, the benefits tobe derived from ACADIA’s product candidates, in each case includingpimavanserin, the potential sleep improvements or long-termantipsychotic benefits from treatment with pimavanserin, and thepotential benefits of pimavanserin in comparison to off-label use ofcurrent antipsychotics and in comparison to commonly prescribed atypicalantipsychotics. These statements are only predictions based on currentinformation and expectations and involve a number of risks anduncertainties. Actual events or results may differ materially from thoseprojected in any of such statements due to various factors, includingthe risks and uncertainties inherent in drug discovery, development andcommercialization, and collaborations with others, and the fact thatpast results of clinical trials may not be indicative of future trialresults. For a discussion of these and other factors, please refer toACADIA’s annual report on Form 10-K for the year ended December 31, 2012as well as ACADIA’s subsequent filings with the Securities and ExchangeCommission. You are cautioned not to place undue reliance on theseforward-looking statements, which speak only as of the date hereof. Thiscaution is made under the safe harbor provisions of the PrivateSecurities Litigation Reform Act of 1995. All forward-looking statementsare qualified in their entirety by this cautionary statement and ACADIAundertakes no obligation to revise or update this press release toreflect events or circumstances after the date hereof, except asrequired by law.

Source: ACADIA Pharmaceuticals Inc.

ACADIA Pharmaceuticals Inc.
Uli Hacksell, Ph.D., ChiefExecutive Officer
Lisa Barthelemy, Director of InvestorRelations
(858) 558-2871