ACADIA Pharmaceuticals Reports Promising Effects of Pimavanserin in Preclinical Model of Alzheimer’s Disease Psychosis

SAN DIEGO—(BUSINESS WIRE)—Jul. 9, 2012—ACADIA Pharmaceuticals Inc. (NASDAQ: ACAD), a biopharmaceutical companyfocused on innovative treatments that address unmet medical needs inneurological and related central nervous system disorders, todayannounced results of preclinical studies, which suggest thatpimavanserin, ACADIA’s proprietary product candidate currently in PhaseIII development for Parkinson’s disease psychosis, also may havetherapeutic benefits in the treatment of Alzheimer’s disease psychosis(ADP). Results of these studies were published in the scientificjournal, Behavioural Pharmacology (Price et al., “Pimavanserin, a5-HT_2A Receptor Inverse Agonist, Reverses Psychosis-likeBehaviors in a Rodent Model of Alzheimer’s Disease,” July 2012 e-pub).

ACADIA scientists reported results of experiments using mice that hadreceived intracerebroventricular (ICV) infusion of an amyloid β peptidefragment and developed Alzheimer’s disease-like pathology. These animalsdeveloped psychosis-like behaviors with enhanced responses to thepsychostimulants DOI and amphetamine as well as disrupted prepulseinhibition. Treatment with pimavanserin prevented DOI-induced responses,reversed the augmented responses to amphetamine, and normalized prepulseinhibition in animals with amyloid pathology. These findings suggestthat 5-HT_2A antagonists/inverse agonists, suchas pimavanserin, may be effective in the treatment of patients with ADP.

“ADP represents a major unmet medical need with no proven safe andeffective therapy,” said Uli Hacksell, Ph.D., ACADIA’s Chief ExecutiveOfficer. “Physicians often resort to off-label use of antipsychoticmedications in patients with ADP despite their association withincreased mortality and potential worsening of cognitive disturbances.These new findings suggest that pimavanserin may be ideally suited toaddress the need for a new ADP treatment that is safe, effective andwell tolerated.”

About Alzheimer’s Disease Psychosis

Alzheimer’s disease is a neurodegenerative disorder characterized byprogressive deterioration in cognitive functioning, memoryabnormalities, and a host of behavioral and neuropsychiatric symptoms.According to the Alzheimer’s Association, 5.4 million people in theUnited States are living with Alzheimer’s disease. An estimated 25 to 50percent of Alzheimer’s patients may develop Alzheimer’s diseasepsychosis (ADP), which commonly consists of disturbing visualhallucinations and delusions. ADP is associated with greater cognitiveimpairment, more rapid disease progression, lower quality of life,greater caregiver burden, and earlier institutionalization. Currently,there is no therapy approved to treat ADP in the United States.

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 and holds worldwiderights to pimavanserin.

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 four product candidates in clinicaldevelopment led by pimavanserin, which is in Phase III development as apotential first-in-class treatment for Parkinson's disease psychosis.ACADIA’s other clinical-stage products include collaborative programsfor chronic pain and glaucoma with Allergan, Inc. and a collaborativeprogram for schizophrenia with Meiji Seika Pharma Co., Ltd. In addition,ACADIA has preclinical programs directed at Parkinson’s disease andother neurological disorders. All of ACADIA’s product candidates aresmall molecules that emanate from discoveries made using its proprietarydrug discovery platform. 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 of ACADIA’s drugdiscovery and development programs, either alone or with a partner, andthe benefits to be derived from ACADIA’s product candidates, includingin each case pimavanserin. These statements are only predictions basedon current information and expectations and involve a number of risksand uncertainties. Actual events or results may differ materially fromthose projected in any of such statements due to various factors,including the risks and uncertainties inherent in drug discovery,development and commercialization, and 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, 2011 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.

Source: ACADIA Pharmaceuticals Inc.

ACADIA Pharmaceuticals Inc.
Uli Hacksell, Ph.D., ChiefExecutive Officer
(858) 558-2871