ACADIA Pharmaceuticals Inc. is a biopharmaceutical company. The Company is focused on the development and commercialization of medicines for central nervous system disorders. The Company's lead drug candidate, NUPLAZID (pimavanserin), is under development for the treatment of Parkinson's disease psychosis (PDP). NUPLAZID is a selective serotonin inverse agonist (SSIA), targeting 5-HT2A receptors. The Company's Pimavanserin is a chemical entity, which has completed Phase III development, and is indicated for the treatment of Parkinson's disease psychosis. NUPLAZID (pimavanserin) is a selective serotonin inverse agonist preferentially targeting the 5-HT2A receptor, a key serotonin receptor that plays a role in psychosis. Through this mechanism, NUPLAZID has demonstrated efficacy in Parkinson's disease psychosis in its Phase III pivotal trial and avoids the side effects of existing antipsychotics.