News Release Details

SAN DIEGO--(BUSINESS WIRE)--April 24, 2007--ACADIA Pharmaceuticals Inc. (Nasdaq:ACAD), a biopharmaceutical company utilizing innovative technology to fuel drug discovery and clinical development of novel treatments for central nervous system disorders, today announced that the United States Adopted Names (USAN) Council has approved the nonproprietary name "pimavanserin tartrate" for ACADIA's drug candidate ACP-103.

The USAN Council serves health professionals in the United States by selecting simple, informative, and unique nonproprietary names for drugs by establishing logical nomenclature classifications based on pharmacological and/or chemical relationships to ensure that drug information is communicated accurately and unambiguously. The USAN Council aims for global standardization and unification of drug nomenclature by working closely with the International Nonproprietary Name Programme of the World Health Organization and various national nomenclature groups.

About Pimavanserin

Pimavanserin tartrate (previously referred to as ACP-103) is a novel, potent and selective 5-HT2A inverse agonist that ACADIA discovered and is developing as a co-therapy for schizophrenia and as a treatment for Parkinson's disease psychosis and sleep maintenance insomnia. In March 2007, ACADIA announced positive top-line results from its Phase II schizophrenia co-therapy trial, which demonstrated a number of important advantages of co-therapy combining pimavanserin and low-dose risperidone compared to a standard dose of risperidone, including enhanced efficacy, a faster onset of antipsychotic action, and an improved side-effect profile. In addition, ACADIA is preparing to initiate the first of two planned pivotal trials in its Phase III program with pimavanserin for the treatment of Parkinson's disease psychosis during the first half of 2007.

About ACADIA Pharmaceuticals

ACADIA is a biopharmaceutical company utilizing innovative technology to fuel drug discovery and clinical development of novel treatments for central nervous system disorders. ACADIA currently has five clinical programs as well as a portfolio of preclinical and discovery assets directed at large unmet medical needs, including schizophrenia, Parkinson's disease psychosis, sleep maintenance insomnia, and neuropathic pain. All of the drug candidates in ACADIA's product pipeline emanate from discoveries made using its proprietary drug discovery platform. ACADIA's corporate headquarters is located in San Diego, California and it maintains research and development operations in both San Diego and Malmo, Sweden.

Forward-Looking Statements

Statements in this press release that are not strictly historical in nature are forward-looking statements. These statements include but are not limited to statements related to benefits to be derived from ACADIA's drug development programs, including the potential advantages of the use of pimavanserin as a co-therapy for schizophrenia and as a treatment for Parkinson's disease psychosis and sleep maintenance insomnia. These statements are only predictions based on current information and expectations and involve a number of risks and uncertainties. Actual events or results may differ materially from those projected in any of such statements due to various factors, including the risks and uncertainties inherent in clinical trials and drug development and commercialization, including the uncertainty of whether results in testing of pimavanserin to date will be predictive of results in later stages of development. For a discussion of these and other factors, please refer to ACADIA's annual report on Form 10-K for the year ended December 31, 2006 as well as other subsequent filings with the Securities and Exchange Commission. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date hereof. This caution is made under the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. All forward-looking statements are qualified in their entirety by this cautionary statement and ACADIA undertakes no obligation to revise or update this press release to reflect events or circumstances after the date hereof.

CONTACT: ACADIA Pharmaceuticals Inc.
Lisa Barthelemy, Director, Investor Relations
Thomas H. Aasen, Vice President and Chief Financial Officer
858-558-2871

SOURCE: ACADIA Pharmaceuticals Inc.