ACADIA Pharmaceuticals Announces Positive Top-Line Results From Phase II Study of Pimavanserin for Alzheimer’s Disease Psychosis

Data Support Moving Forward With Further Development inAlzheimer’s Disease Psychosis

Conference Call and Webcast to Be Held Today, December 20, 2016,at 8:30 a.m. Eastern Time

SAN DIEGO—(BUSINESS WIRE)—Dec. 20, 2016—ACADIA Pharmaceuticals Inc. (NASDAQ: ACAD) today announced positivetop-line results from its Phase II exploratory study (-019 Study) ofpimavanserin in patients with Alzheimer’s disease psychosis (ADPsychosis). As a selective serotonin inverse agonist (SSIA)preferentially targeting 5-HT_2A receptors, pimavanserin has adifferent biological mechanism than other marketed antipsychotics.Pimavanserin has been approved by the United States Food and DrugAdministration (FDA) for hallucinations and delusions associated withParkinson’s disease psychosis and currently is being studied in severalother disease states, including AD Psychosis. The FDA has not approvedany drug to treat AD Psychosis.

In this Phase II exploratory study, pimavanserin met the primaryendpoint showing a statistically significant reduction in psychosisversus placebo as measured by the Neuropsychiatric Inventory-NursingHome (NPI-NH) Psychosis score at week 6 of dosing (p=0.0451).Pimavanserin was generally well tolerated and the safety profile wasconsistent with what has been observed in previous studies.

“Alzheimer’s disease patients suffer from a number of debilitatingsymptoms, of which psychosis carries a poor prognosis and is associatedwith earlier placement into nursing homes,” said Steve Davis, ACADIA’sPresident and Chief Executive Officer. “Data from the -019 Study providesolid evidence that pimavanserin can improve psychosis in another majorneurological disorder and provide strategic momentum for the furtherdevelopment of pimavanserin to address the needs of AD Psychosispatients.”

About the Phase II -019 Study
The Phase II -019 Study was adouble-blind, placebo-controlled exploratory trial designed to evaluatethe efficacy and safety of pimavanserin as a treatment for patients withAD Psychosis. A total of 181 patients were enrolled in the study in theUnited Kingdom and randomized on a one-to-one basis to receive either 34mg of pimavanserin or placebo once daily. The primary endpoint of thestudy was antipsychotic efficacy as measured by the mean change in theNPI-NH Psychosis score (combined hallucinations and delusions domains)from baseline to week 6 of dosing. Patients continued dosing throughweek 12 to gather information on secondary endpoints, including changesin cognition.

Pimavanserin demonstrated efficacy on the primary endpoint of the -019Study with a 3.76 point improvement in psychosis at week 6 compared to a1.93 point improvement for placebo, representing a statisticallysignificant treatment improvement in the NPI-NH Psychosis score(p=0.0451). Baseline mean scores for the pimavanserin and placebotreated groups were 9.52 and 10.00, respectively.

Atypical antipsychotics have been associated with a statisticallysignificant worsening of cognitive function in patients with Alzheimer’sdisease. In the -019 Study, over the course of 12 weeks of treatment,pimavanserin did not impair cognition as measured by the Mini-MentalState Examination (MMSE) score and was similar to placebo. On thesecondary endpoint of mean change in NPI-NH Psychosis score at week 12,pimavanserin maintained the improvement on psychosis observed at theweek 6 primary endpoint, but did not statistically separate from placebo.

In the -019 Study, pimavanserin was generally well tolerated and thesafety profile was consistent with what has been observed in previousstudies. Based on a preliminary analysis of safety data, the most commonadverse events reported were falls, urinary tract infection and agitation.The mortality rate was the same in the pimavanserin and placebotreatment groups. The mean age of patients in the study was 86 years.

The data analysis of the Phase II -019 Study is ongoing and ACADIA plansto present data from this study at a future medical conference.

Conference Call and Webcast Information
ACADIA will host aconference call and webcast today, December 20, 2016 at 8:30 a.m.Eastern Time to discuss top-line results from its Phase II trial withpimavanserin in patients with Alzheimer’s disease psychosis. Theconference call can be accessed by dialing 844-821-1109 for participantsin the U.S. and Canada and 830-865-2550 for international callers(reference passcode 43052480). The conference call will be webcast liveon ACADIA’s website, www.acadia-pharm.com,under the investors section and will be archived there until January 3,2017. A telephone replay also may be accessed through January 3, 2017 bydialing 855-859-2056 for participants in the U.S. and Canada and404-537-3406 for international callers (reference passcode 43052480).

About Alzheimer’s Disease Psychosis (AD Psychosis)
Accordingto the Alzheimer’s Association, around 5.4 million people in the UnitedStates are living with Alzheimer’s disease and approximately half arediagnosed with the disease. Studies suggest that 25 to 50 percent ofpatients diagnosed with Alzheimer’s disease may develop psychosis,commonly consisting of hallucinations and delusions. AD Psychosis isassociated with more rapid cognitive and functional decline, greatercaregiver burden, and earlier institutionalization. The FDA has notapproved any drug to treat AD Psychosis.

About Pimavanserin
Pimavanserin is a selective serotonininverse agonist (SSIA) preferentially targeting 5-HT_2Areceptors. These receptors are thought to play an important role in ADPsychosis. Pimavanserin is being evaluated in an extensive clinicaldevelopment program by ACADIA across multiple other indicationsincluding Alzheimer’s disease agitation, schizophrenia – inadequateresponse, schizophrenia – negative symptoms, and major depressivedisorder. Pimavanserin (34 mg) was approved for the treatment ofhallucinations and delusions associated with Parkinson’s diseasepsychosis by the FDA in April 2016 under the trade name NUPLAZID^®.NUPLAZID is not approved for patients with AD Psychosis.

About ACADIA Pharmaceuticals
ACADIA is a biopharmaceuticalcompany focused on the development and commercialization of innovativemedicines to address unmet medical needs in central nervous systemdisorders. ACADIA maintains a website at www.acadia-pharm.comto which we regularly post copies of our press releases as well asadditional information and through which interested parties cansubscribe to receive e-mail alerts.

Forward-Looking Statements
Statements in this press releasethat are not strictly historical in nature are forward-lookingstatements. These statements include but are not limited to statementsrelated to the progress and timing of ACADIA’s drug discovery anddevelopment programs; the benefits to be derived from NUPLAZID(pimavanserin) and ACADIA’s product candidates, including whetherpimavanserin can improve psychosis in another major neurologicaldisorder or be used to treat AD Psychosis; whether the data from the-019 Study support moving forward with further development in ADPsychosis or provide strategic momentum for the further development ofpimavanserin to address the needs of AD Psychosis patients; and ACADIA’splans to present data from the -019 Study. These statements are onlypredictions based on current information and expectations and involve anumber of risks and uncertainties. Actual events or results may differmaterially from those projected in any of such statements due to variousfactors, including the risks and uncertainties inherent in drugdiscovery, development, approval and commercialization, and incollaborations with others, and the fact that past results of clinicaltrials may not be indicative of future trial results. For a discussionof these and other factors, please refer to ACADIA’s annual report onForm 10-K for the year ended December 31, 2015 as well as ACADIA’ssubsequent filings with the Securities and Exchange Commission. You arecautioned not to place undue reliance on these forward-lookingstatements, which speak only as of the date hereof. This caution is madeunder the safe harbor provisions of the Private Securities LitigationReform Act of 1995. All forward-looking statements are qualified intheir entirety by this cautionary statement and ACADIA undertakes noobligation to revise or update this press release to reflect events orcircumstances after the date hereof, except as required by law.

Important Safety Information and Indication forNUPLAZID (pimavanserin) tablets

WARNING: INCREASED MORTALITY IN ELDERLY PATIENTS WITHDEMENTIA-RELATED PSYCHOSIS
Elderly patients withdementia-related psychosis treated with antipsychotic drugs are at anincreased risk of death. NUPLAZID is not approved for the treatment ofpatients with dementia-related psychosis unrelated to the hallucinationsand delusions associated with Parkinson’s disease psychosis.

NUPLAZID is an atypical antipsychotic indicated for the treatment ofhallucinations and delusions associated with Parkinson’s diseasepsychosis.

QT Interval Prolongation: NUPLAZID prolongs the QT interval. The use ofNUPLAZID should be avoided in patients with known QT prolongation or incombination with other drugs known to prolong QT interval includingClass 1A antiarrhythmics or Class 3 antiarrhythmics, certainantipsychotic medications, and certain antibiotics. NUPLAZID should alsobe avoided in patients with a history of cardiac arrhythmias, as well asother circumstances that may increase the risk of the occurrence oftorsade de pointes and/or sudden death, including symptomaticbradycardia, hypokalemia or hypomagnesemia, and presence of congenitalprolongation of the QT interval.

Adverse Reactions: The most common adverse reactions (≥2% for NUPLAZIDand greater than placebo) were peripheral edema (7% vs 2%), nausea (7%vs 4%), confusional state (6% vs 3%), hallucination (5% vs 3%),constipation (4% vs 3%), and gait disturbance (2% vs <1%).

Drug Interactions: Strong CYP3A4 inhibitors (eg, ketoconazole) increaseNUPLAZID concentrations. Reduce the NUPLAZID dose by one-half. StrongCYP3A4 inducers may reduce NUPLAZID exposure, monitor for reducedefficacy. Increase in NUPLAZID dosage may be needed.

Renal Impairment: No dosage adjustment for NUPLAZID is needed inpatients with mild to moderate renal impairment. Use of NUPLAZID is notrecommended in patients with severe renal impairment.

Hepatic Impairment: Use of NUPLAZID is not recommended in patients withhepatic impairment. NUPLAZID has not been evaluated in this patientpopulation.

Pregnancy: Use of NUPLAZID in pregnant women has not been evaluated andshould therefore be used in pregnancy only if the potential benefitjustifies the potential risk to the mother and fetus.

Pediatric Use: Safety and efficacy have not been established inpediatric patients.

Dosage and Administration: Recommended dose: 34 mg per day, taken orallyas two 17-mg tablets once daily, without titration.

For additional Important Safety Information, including boxed warning,please see the full Prescribing Information for NUPLAZID at https://www.nuplazid.com/pdf/NUPLAZID_Prescribing_Information.pdf.

Source: ACADIA Pharmaceuticals Inc.

Investor Contact:
ACADIA Pharmaceuticals Inc.
Lisa Barthelemy,(858) 558-2871
ir@acadia-pharm.com
or
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