Results of the first pivotal Phase III trial with pimavanserin in patients with PDP announced

ACADIA Pharmaceuticals Inc. (Nasdaq: ACAD) today announced top-line results from the first pivotal Phase III trial with pimavanserin in patients with Parkinson’s disease psychosis, or PDP. The study did not meet its primary endpoint of antipsychotic efficacy as measured using the Scale for the Assessment of Positive Symptoms, or SAPS. Pimavanserin met the key secondary endpoint of motoric tolerability as measured using the Unified Parkinson’s Disease Rating Scale, or UPDRS. Pimavanserin was safe and well tolerated, with the frequency of adverse events generally similar in the pimavanserin and placebo arms.

The primary endpoint of the study was the mean change in SAPS scores at day 42 compared to baseline for each of the two pimavanserin treatment arms versus placebo. Patients showed marked improvements in the SAPS scores across all study arms. Mean reductions in SAPS scores were 5.9 points in the placebo arm, 5.8 points in the 10 mg pimavanserin arm, and 6.7 points in the 40 mg pimavanserin arm. Statistical significance was not achieved in either pimavanserin arm primarily due to the larger than expected improvement in placebo-treated patients.

“While we obviously are disappointed with the results of this Phase III study, we continue to believe in the potential of pimavanserin based on our clinical experience to date,” said Uli Hacksell, Ph.D., Chief Executive Officer of ACADIA. “We will thoroughly analyze these data along with the data on other secondary and exploratory endpoints over the next month to better understand the outcome of this study. Meanwhile, we are continuing with the second Phase III PDP trial with pimavanserin.”

Trial Design

The Phase III trial was a multi-center, double-blind, placebo-controlled study designed to evaluate the safety and efficacy of pimavanserin in patients with PDP. A total of 298 patients were enrolled in the trial and randomized to one of three study arms, including two different doses of pimavanserin (10 mg or 40 mg) and placebo. Patients received oral doses of either pimavanserin or placebo once daily for six weeks. Patients remained on stable doses of their existing anti-Parkinson’s therapy throughout the study. The primary endpoint was antipsychotic efficacy as measured using the hallucinations and delusions domains of the SAPS. The key secondary endpoint was motoric tolerability as measured using Parts II and III of the UPDRS.