The sponsor reported in May 2008 that it "initiated the second Phase III pivotal trial in its program with pimavanserin as a treatment for Parkinson's disease psychosis (PDP) in March 2008. ACADIA also is continuing to enroll patients in the first Phase III pivotal trial in this program, which was initiated in June 2007. Each of these Phase III trials is a double-blind, placebo-controlled study designed to evaluate the safety and efficacy of pimavanserin in approximately 240 patients with PDP.

* ACADIA is currently conducting an open-label safety extension study pursuant to which eligible patients who have completed either of the Phase III pivotal trials have the opportunity to enroll if, in the opinion of the physician, the patient may benefit from continued treatment with pimavanserin. ACADIA also is continuing to conduct an open-label extension study in connection with its earlier Phase II PDP trial." (press release 5/5/08)

In Aug 2008 ACADIA announced it would reduce its workforce by 50%. "The company will focus on developing a portfolio of its four most advanced product candidates, ACADIA's top priority is to advance its Phase III program with pimavanserin for Parkinson's disease psychosis, or PDP, toward registration. A key objective in this program is the successful and timely execution of the first Phase III pivotal trial. This trial remains on track and ACADIA anticipates reporting top-line results during the third quarter of 2009. ACADIA is also continuing to enroll patients in its second Phase III pivotal trial for PDP. " (press release)

In May 2009, ACADIA and Biovail Corporation, announced the completion of enrollment in the first pivotal Phase III clinical trial of pimavanserin in patients with Parkinson's disease psychosis (PDP). Top-line results from this trial are expected to be announced by the end of the third quarter of 2009" (press release)

In Septemeber 2009, "Acadia announced that the phase III 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." (company press release)

The phase III trials will continue. In October 2009, the sponsors announced "that they’re not giving up on pimavanserin. They plan to use data from the failed trial, along with data from an ongoing late-stage trial, to aid in the design of a new late-stage trial. Biovail will cover the cost of the new trial, which is planned for the first half of 2010. Acadia plans to cut expenses this month to fund operations through the first half of 2011. " (MedTech Sentinel http://www.onemedplace.com/blog/archives/3259 )