ACADIA Pharmaceuticals Inc. (NASDAQ: ACAD), a biopharmaceutical company focused on innovative treatments that address unmet medical needs in neurological and related central nervous system disorders, today announced results of preclinical studies, which suggest that pimavanserin, ACADIA’s proprietary product candidate currently in Phase III development for Parkinson’s disease psychosis, also may have therapeutic benefits in the treatment of Alzheimer’s disease psychosis (ADP). Results of these studies were published in the scientific journal, Behavioural Pharmacology (Price et al., “Pimavanserin, a 5-HT 2A Receptor Inverse Agonist, Reverses Psychosis-like Behaviors in a Rodent Model of Alzheimer’s Disease,” July 2012 e-pub). ACADIA scientists reported results of experiments using mice that had received intracerebroventricular (ICV) infusion of an amyloid β peptide fragment and developed Alzheimer’s disease-like pathology. These animals developed psychosis-like behaviors with enhanced responses to the psychostimulants DOI and amphetamine as well as disrupted prepulse inhibition. Treatment with pimavanserin prevented DOI-induced responses, reversed the augmented responses to amphetamine, and normalized prepulse inhibition in animals with amyloid pathology. These findings suggest that 5-HT 2A antagonists/inverse agonists, such as pimavanserin, may be effective in the treatment of patients with ADP. “ADP represents a major unmet medical need with no proven safe and effective therapy,” said Uli Hacksell, Ph.D., ACADIA’s Chief Executive Officer. “Physicians often resort to off-label use of antipsychotic medications in patients with ADP despite their association with increased mortality and potential worsening of cognitive disturbances. These new findings suggest that pimavanserin may be ideally suited to address the need for a new ADP treatment that is safe, effective and well tolerated.” About Alzheimer’s Disease Psychosis Alzheimer’s disease is a neurodegenerative disorder characterized by progressive deterioration in cognitive functioning, memory abnormalities, and a host of behavioral and neuropsychiatric symptoms. According to the Alzheimer’s Association, 5.4 million people in the United States are living with Alzheimer’s disease. An estimated 25 to 50 percent of Alzheimer’s patients may develop Alzheimer’s disease psychosis (ADP), which commonly consists of disturbing visual hallucinations and delusions. ADP is associated with greater cognitive impairment, 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.