ACADIA Pharmaceuticals Inc. (NASDAQ: ACAD) today announced positive top-line results from its Phase II exploratory study (-019 Study) of pimavanserin in patients with Alzheimer’s disease psychosis (AD Psychosis). As a selective serotonin inverse agonist (SSIA) preferentially targeting 5-HT2A receptors, pimavanserin has a different biological mechanism than other marketed antipsychotics. Pimavanserin has been approved by the United States Food and Drug Administration (FDA) for hallucinations and delusions associated with Parkinson’s disease psychosis and currently is being studied in several other disease states, including AD Psychosis. The FDA has not approved any drug to treat AD Psychosis.
In this Phase II exploratory study, pimavanserin met the primary endpoint showing a statistically significant reduction in psychosis versus placebo as measured by the Neuropsychiatric Inventory-Nursing Home (NPI-NH) Psychosis score at week 6 of dosing (p=0.0451). Pimavanserin was generally well tolerated and the safety profile was consistent with what has been observed in previous studies.
“Alzheimer’s disease patients suffer from a number of debilitating symptoms, of which psychosis carries a poor prognosis and is associated with earlier placement into nursing homes,” said Steve Davis, ACADIA’s President and Chief Executive Officer. “Data from the -019 Study provide solid evidence that pimavanserin can improve psychosis in another major neurological disorder and provide strategic momentum for the further development of pimavanserin to address the needs of AD Psychosis patients.”
About the Phase II -019 Study
The Phase II -019 Study was a double-blind, placebo-controlled exploratory trial designed to evaluate the efficacy and safety of pimavanserin as a treatment for patients with AD Psychosis. A total of 181 patients were enrolled in the study in the United Kingdom and randomized on a one-to-one basis to receive either 34 mg of pimavanserin or placebo once daily. The primary endpoint of the study was antipsychotic efficacy as measured by the mean change in the NPI-NH Psychosis score (combined hallucinations and delusions domains) from baseline to week 6 of dosing. Patients continued dosing through week 12 to gather information on secondary endpoints, including changes in cognition.
Pimavanserin demonstrated efficacy on the primary endpoint of the -019 Study with a 3.76 point improvement in psychosis at week 6 compared to a 1.93 point improvement for placebo, representing a statistically significant treatment improvement in the NPI-NH Psychosis score (p=0.0451). Baseline mean scores for the pimavanserin and placebo treated groups were 9.52 and 10.00, respectively.
Atypical antipsychotics have been associated with a statistically significant worsening of cognitive function in patients with Alzheimer’s disease. In the -019 Study, over the course of 12 weeks of treatment, pimavanserin did not impair cognition as measured by the Mini-Mental State Examination (MMSE) score and was similar to placebo. On the secondary endpoint of mean change in NPI-NH Psychosis score at week 12, pimavanserin maintained the improvement on psychosis observed at the week 6 primary endpoint, but did not statistically separate from placebo.
In the -019 Study, pimavanserin was generally well tolerated and the safety profile was consistent with what has been observed in previous studies. Based on a preliminary analysis of safety data, the most common adverse events reported were falls, urinary tract infection and agitation. The mortality rate was the same in the pimavanserin and placebo treatment groups. The mean age of patients in the study was 86 years.
The data analysis of the Phase II -019 Study is ongoing and ACADIA plans to present data from this study at a future medical conference.
Filed Under: Drug Discovery