ACADIA Pharmaceuticals Initiates Phase II Trial of Pimavanserin for Adjunctive Treatment in Patients With Major Depressive Disorder

SAN DIEGO—(BUSINESS WIRE)—Dec. 1, 2016—ACADIA Pharmaceuticals Inc. (NASDAQ: ACAD), a biopharmaceutical companyfocused on innovative treatments that address unmet medical needs incentral nervous system (CNS) disorders, today announced the initiationof CLARITY, a Phase II study to evaluate pimavanserin for adjunctivetreatment in patients with major depressive disorder (MDD) who have aninadequate response to first-line therapies for clinical depression.Pimavanserin is a selective serotonin inverse agonist (SSIA)preferentially targeting 5-HT_2A receptors that may play arole in depression.

“Major depressive disorder affects millions of people in the UnitedStates every year and many do not respond adequately to currentlyavailable treatments,” said Professor Maurizio Fava, M.D., ExecutiveVice Chair, Department of Psychiatry, Massachusetts General Hospital(MGH) and Associate Dean for Clinical & Translational Research, HarvardMedical School. “With its highly selective mechanism of action,pimavanserin may provide a new approach to the adjunctive treatment ofpatients with major depressive disorder and may represent an opportunityto improve clinical outcomes in these patients.”

“We are committed to the development of pimavanserin in additional CNSdisorders that are underserved by currently available therapies andrepresent a significant unmet medical need. Inadequate response tocurrent antidepressants is one such condition,” said Serge Stankovic,M.D., M.S.P.H., ACADIA’s Executive Vice President, Head of Research andDevelopment. “We are gratified to be able to leverage the vast knowledgeand expertise of our colleagues at MGH and conduct this study incollaboration with the MGH Clinical Trials Network & Institute.”

About CLARITY

CLARITY is a Phase II, 10-week, randomized, double-blind,placebo-controlled, multi-center study designed to examine the efficacyand safety of adjunctive use of pimavanserin in patients with majordepressive disorder who have an inadequate response to standardantidepressant therapy with either a selective serotonin reuptakeinhibitor (SSRI) or a serotonin norepinephrine reuptake inhibitor(SNRI). Approximately 188 patients will be randomized to receive either34 mg of pimavanserin or placebo, orally, once daily, in addition totheir ongoing antidepressant for 10 weeks. The primary endpoint of thestudy is the change from baseline on the Hamilton Depression RatingScale (HAM-D) total score.

About Major Depressive Disorder (MDD)

According to the National Institute of Mental Health, MDD affectsapproximately 16 million adults in the United States and is the leadingcause of disability for ages 15-44. MDD is a condition characterized bydepressive symptoms, such as a depressed mood or a loss of interest orpleasure in daily activities for more than two weeks, as well asimpaired social, occupational or other important functioning. Themajority of people who suffer from MDD do not respond to initialantidepressant therapy.

About Pimavanserin

Pimavanserin is a selective serotonin inverse agonist (SSIA)preferentially targeting 5-HT_2A receptors. These receptorsare thought to play an important role in depression. Pimavanserin isbeing evaluated in an extensive clinical development program by ACADIAacross multiple indications. Pimavanserin (34 mg) was approved for thetreatment of hallucinations and delusions associated with Parkinson’sdisease psychosis by the U.S. Food and Drug Administration in April 2016under the trade name NUPLAZID^®. NUPLAZID is not approved forthe adjunctive treatment of patients with major depressive disorder.

About ACADIA Pharmaceuticals

ACADIA is a biopharmaceutical company focused on the development andcommercialization of innovative medicines to address unmet medical needsin central nervous system disorders. 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 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, the expected design and scopeof ACADIA’s clinical trials, the benefits to be derived from NUPLAZID(pimavanserin) and ACADIA’s product candidates, including whetherpimavanserin can effectively be used to adjunctively treat MDD, providea new approach to the adjunctive treatment of patients with MDD orrepresent an opportunity to improve clinical outcomes for patients withMDD, and ACADIA’s future development efforts in CNS disorders that areunderserved by currently available therapies and represent a significantunmet medical need. These statements are only predictions based oncurrent information 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,approval and commercialization, and in collaborations with others, andthe fact that past results of clinical trials may not be indicative offuture trial results. For a discussion of these and other factors,please refer to ACADIA’s annual report on Form 10-K for the year endedDecember 31, 2015 as well as ACADIA’s subsequent filings with theSecurities and Exchange Commission. You are cautioned not to place unduereliance on these forward-looking statements, which speak only as of thedate hereof. This caution is made under the safe harbor provisions ofthe Private Securities Litigation Reform Act of 1995. Allforward-looking statements are qualified in their entirety by thiscautionary statement and ACADIA undertakes no obligation to revise orupdate this press release to reflect events or circumstances after thedate 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 NUPLAZID and 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)increase NUPLAZID concentrations. Reduce the NUPLAZID dose by one-half.Strong CYP3A4 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.

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