ACADIA Pharmaceuticals to Present Phase 2 CLARITY Results for Pimavanserin as an Adjunctive Treatment in Major Depressive Disorder at the 2019 American Psychiatric Association Annual Meeting

SAN DIEGO—(BUSINESS WIRE)—May 18, 2019—ACADIA Pharmaceuticals Inc. (Nasdaq: ACAD), a biopharmaceutical companyfocused on the development and commercialization of innovative medicinesto address unmet medical needs in central nervous system disorders,today announced it will present data from its Phase 2 CLARITY study,which evaluated the efficacy, safety, and tolerability of pimavanserinas an adjunctive treatment for major depressive disorder (MDD) at the2019 American Psychiatric Association Annual Meeting in San Francisco,May 18 – 22, 2019.

Poster Presentation
Poster:#P8-049
Date/Time: Tuesday, May 21, 2:00 p.m. – 4:00 p.m. PacificTime
Title: CLARITY: A Phase 2 Double-blind, Placebo-controlledStudy to Evaluate the Efficacy and Safety of Adjunctive Pimavanserin inMajor Depressive Disorder

The Phase 2 CLARITY study was a 10-week, randomized, double-blind,placebo-controlled, multi-center, two-stage sequential parallelcomparison design study that evaluated the efficacy, safety, andtolerability of pimavanserin (34 mg once daily). Pimavanserin wasadministered as an adjunctive treatment in patients with MDD who had aninadequate response to a stable dose of standard antidepressant therapywith either a selective serotonin reuptake inhibitor (SSRI) or aserotonin norepinephrine reuptake inhibitor (SNRI). The study randomized207 patients across 27 clinical research centers in the U.S. and wasconducted in collaboration with the Massachusetts General Hospital (MGH)Clinical Trials Network and Institute.

“There is a significant need for new therapies for the majority ofpatients suffering from major depressive disorder who do not respond toinitial antidepressant therapy,” said Professor Maurizio Fava, M.D.,Executive Vice Chair, Department of Psychiatry, MGH, Director of theDivision of Clinical Research of the MGH Research Institute, andAssociate Dean for Clinical & Translational Research, Harvard MedicalSchool. “The results observed in the Phase 2 CLARITY study combined witha favorable tolerability profile provides evidence that adjunctivetreatment with pimavanserin may provide meaningful benefit to those MDDpatients who have an inadequate response to either a SSRI or a SNRItherapy.”

In the trial, pimavanserin met the overall primary endpoint of theweighted average results of Stage 1 and Stage 2 by significantlyreducing the 17-item Hamilton Depression Rating Scale total scorecompared to placebo (p=0.039). On the key secondary endpoint,pimavanserin demonstrated statistically significant reductions comparedto placebo in the Sheehan Disability Scale score (p=0.004). Positiveresults were also observed for seven other secondary endpoints,including improvement in daytime sleepiness as measured by theKarolinska Sleepiness Scale and improvement in sexual function asmeasured by the Massachusetts General Hospital Sexual Functioning Index.

“In this Phase 2 study of pimavanserin as an adjunctive treatment forMDD, we found patients treated with pimavanserin experienced significantreduction in their depression symptoms in addition to improvement indaytime sleepiness and sexual function when compared to placebo,” saidSerge Stankovic, M.D., M.S.P.H., ACADIA’s President. “These results areencouraging for patients with MDD who may experience challenges withtheir current treatment options. We look forward to further evaluatingpimavanserin as an adjunctive treatment in our ongoing Phase 3 CLARITYprogram.”

On April 25, ACADIAannounced it had initiated its Phase 3 CLARITY program forpimavanserin as an adjunctive treatment for MDD. The CLARITY-2 studywill be based in the U.S. and has already initiated enrollment and theCLARITY-3 study will be based outside the U.S. and will initiateenrollment in the upcoming months. Both studies are six-week,parallel-designed, randomized, double-blind, placebo-controlled,multi-center studies designed to evaluate the efficacy and safety ofpimavanserin as adjunctive treatment in patients with MDD who have aninadequate response to standard antidepressant therapy with either aSSRI or a SNRI.

About Major Depressive Disorder
According to the NationalInstitute of Mental Health, MDD affects approximately 16 million adultsin the U.S.¹, with approximately 2.5 million adults treatedwith adjunctive therapy.^2,3 MDD is a condition characterizedby depressive 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 adequately toinitial antidepressant therapy.⁴

About Pimavanserin
Pimavanserin is a selective serotonininverse agonist and antagonist preferentially targeting 5-HT_2Areceptors. These receptors are thought to play an important role indepression, psychosis, and other neuropsychiatric disorders. ACADIA isevaluating pimavanserin in an extensive clinical development programacross multiple indications with significant unmet need includingdementia-related psychosis, schizophrenia inadequate response,schizophrenia-negative symptoms, and MDD. Pimavanserin was approved forthe treatment of hallucinations and delusions associated withParkinson’s disease psychosis by the U.S. Food and Drug Administrationin April 2016 under the trade name NUPLAZID^®. NUPLAZID is notapproved for the adjunctive treatment of patients with MDD.

About ACADIA Pharmaceuticals
ACADIA is abiopharmaceutical company focused on the development andcommercialization of innovative medicines to address unmet medical needsin central nervous system disorders. ACADIA has developed andcommercialized the first and only medicine approved for the treatment ofhallucinations and delusions associated with Parkinson’s diseasepsychosis. ACADIA also has ongoing clinical development efforts inadditional areas with significant unmet need, including dementia-relatedpsychosis, schizophrenia inadequate response, schizophrenia-negativesymptoms, major depressive disorder, and Rett syndrome. This pressrelease and further information about ACADIA can be found at: www.acadia-pharm.com.

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 potential benefits of pimavanserin as adjunctivetreatment for MDD or other central nervous system disorders as well asthe potential results of clinical trials of pimavanserin in otherindications. 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 development, approval andcommercialization, and the fact that past results of clinical trials maynot be indicative of future trial results. For a discussion of these andother factors, please refer to ACADIA’s annual report on Form 10-K forthe year ended December 31, 2018 as well as ACADIA’s subsequent filingswith the Securities and Exchange Commission. You are cautioned not toplace undue reliance on these forward-looking statements, which speakonly as of the date hereof. This caution is made under the safe harborprovisions of the 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)

WARNING: INCREASED MORTALITY IN ELDERLY PATIENTS WITHDEMENTIA-RELATED PSYCHOSIS

• Elderly patients with dementia-related psychosis treated withantipsychotic drugs are at an increased risk of death.
• NUPLAZID is not approved for the treatment of patients withdementia-related psychosis unrelated to the hallucinations anddelusions associated with Parkinson’s disease psychosis.

• Contraindication: NUPLAZID is contraindicated in patients witha history of a hypersensitivity reaction to pimavanserin or any of itscomponents. Rash, urticaria, and reactions consistent with angioedema(e.g., tongue swelling, circumoral edema, throat tightness, anddyspnea) have been reported.
• QT Interval Prolongation: NUPLAZID prolongs the QT interval.
  • The use of NUPLAZID should be avoided in patients with known QTprolongation or in combination with other drugs known to prolongQT interval including Class 1A antiarrhythmics or Class 3antiarrhythmics, certain antipsychotic medications, and certainantibiotics.
  • NUPLAZID should also be avoided in patients with a history ofcardiac arrhythmias, as well as other circumstances that mayincrease the risk of the occurrence of torsade de pointes and/orsudden death, including symptomatic bradycardia, hypokalemia orhypomagnesemia, and presence of congenital prolongation of the QTinterval.

• Adverse Reactions: The most common adverse reactions (≥2% forNUPLAZID and greater than placebo) were peripheral edema (7% vs 2%),nausea (7% vs 4%), confusional state (6% vs 3%), hallucination (5% vs3%), constipation (4% vs 3%), and gait disturbance (2% vs <1%).
• Drug Interactions:
  • Coadministration with strong CYP3A4 inhibitors (e.g.,ketoconazole) increases NUPLAZID exposure. Reduce NUPLAZID dose to10 mg taken orally as one tablet once daily.
  • Coadministration with strong or moderate CYP3A4 inducers reducesNUPLAZID exposure. Avoid concomitant use of strong or moderateCYP3A4 inducers with NUPLAZID.

Indication: NUPLAZID is indicated for the treatment ofhallucinations and delusions associated with Parkinson’s diseasepsychosis.

Dosage and Administration: Recommended dose: 34 mg capsule takenorally once daily, without titration.

NUPLAZID is available as 34 mg capsules and 10 mg tablets.

Please see the full PrescribingInformation including Boxed WARNING for NUPLAZID.

References
¹National Institute of Mental Health.(2017). Major Depression. Retrieved from http://www.nimh.nih.gov/health/statistics/major-depression.shtml.

²IMS NSP, NPA, NDTI MAT-24 month data through Aug-2017.

³PLOS One, Characterization of Treatment Resistant DepressionEpisodes in a Cohort of Patients from a US Commercial ClaimsDatabase, Oct 2013, Vol 8, Issue 10.

⁴Rush AJ, et al. (2007) Am J. Psychiatry 163:11, pp.1905-1917 (STAR*D Study).

Source: ACADIA Pharmaceuticals Inc.

Investor Contact:

ACADIA Pharmaceuticals Inc.
MarkJohnson, CFA
(858) 261-2771
ir@acadia-pharm.com

Media Contact:

ACADIA Pharmaceuticals Inc.
MaurissaMessier
(858) 768-6068
media@acadia-pharm.com