ACADIA Announces Pimavanserin Meets Primary and Key Secondary Endpoints in Pivotal Phase III Parkinson’s Disease Psychosis Trial
Pimavanserin Demonstrates Highly Significant Antipsychotic Efficacy and Maintenance of Motor Control in Parkinson’s Patients
Significant Improvements Also Observed in All Secondary and Exploratory Measures
Conference Call and Webcast to Be Held Today,
“These data represent an unprecedented advance for Parkinson’s patients
who suffer from the psychosis frequently associated with this disease,”
The primary endpoint of the trial was antipsychotic efficacy as measured using the SAPS-PD, a 9-item scale adapted from the hallucinations and delusions domains of the Scale for the Assessment of Positive Symptoms, by comparing the mean change from baseline to day 43 for pimavanserin versus placebo. SAPS-PD assessments were performed by blinded, independent centralized raters. The pimavanserin arm demonstrated a robust 5.79 point improvement in psychosis at day 43 compared to a 2.73 point improvement for placebo, representing a highly significant and clinically meaningful treatment difference of 3.06 points on SAPS-PD (p=0.001).
|Baseline Mean||Mean Change at Day 43|
Note: mixed model repeated measures (MMRM) method was applied in the primary analysis of the intent-to-treat (ITT) population. The significance test was based on least-square mean change from baseline for each arm using a 2-sided beta = 0.05.
Key Secondary Endpoint
The key secondary endpoint of the trial evaluated motoric tolerability and functional outcome using Parts II and III of the UPDRS. The objective of this secondary endpoint was to demonstrate that pimavanserin could achieve its antipsychotic effects without worsening motor function as compared to placebo in PDP patients. A pre-specified, non-inferiority analysis was used to compare the mean change from baseline to day 43 for pimavanserin versus placebo using a two-sided 95 percent confidence interval (CI) for the treatment difference. Motoric improvements were seen in both the pimavanserin and placebo arms and the CI associated with the treatment difference did not exceed a pre-specified margin of 5 points for clinically relevant change, confirming that pimavanserin met this key secondary endpoint and did not worsen motor function in PDP patients.
Secondary and Exploratory Efficacy Measures
The secondary efficacy measure in the trial was an assessment of clinical global improvement by the investigator using the CGI-I scale. Pimavanserin demonstrated a highly significant improvement on this measure (p=0.001), further supporting its antipsychotic efficacy.
In addition, other clinical benefits of pimavanserin were observed in exploratory efficacy measures of sleep and caregiver burden. Sleep was assessed using the SCOPA-sleep scale, which was designed to enable the investigator to evaluate nighttime sleep and daytime wakefulness in Parkinson’s patients. Pimavanserin demonstrated significant improvements on both nighttime sleep (p=0.045) and daytime wakefulness (p=0.012) on SCOPA.
Caregiver burden was assessed using the Caregiver Burden Scale. This scale was completed by the caregiver to provide a quantitative assessment of burden associated with the patient’s functional/behavioral impairments, the circumstances of at-home care, as well as the caregiver’s health, social life and interpersonal relations. Pimavanserin demonstrated a highly significant improvement on the Caregiver Burden Scale (p=0.002).
Safety and Tolerability Profile
Consistent with previous studies, pimavanserin was safe and well tolerated in this trial. Based on a preliminary analysis of safety data, the most common adverse events were urinary tract infection (11.7% PBO vs. 13.5% PIM) and falls (8.5% PBO vs. 10.6% PIM). Adverse events were generally characterized as mild to moderate in nature. The only serious adverse events that occurred in more than one patient were urinary tract infection (1-PBO vs. 3-PIM) and psychotic disorder (0-PBO vs. 2-PIM). Ninety percent of the patients who completed the clinical phase of this trial elected to roll over into the ongoing open-label safety extension study. Patients were only eligible to participate in the extension study if the treating investigator also deemed them to be likely to benefit from continued treatment with pimavanserin.
“We are excited with the results of this study which demonstrate that pimavanserin has the potential to offer PDP patients a new treatment option that, for the first time, can achieve the desired clinical profile by providing an effective, safe and well tolerated antipsychotic therapy,” said Uli Hacksell, Ph.D., Chief Executive Officer of ACADIA. “We remain committed to advancing pimavanserin to registration as a first-in-class treatment for this large unmet medical need. These results also suggest that pimavanserin may have the ideal clinical profile to address a broader range of neuropsychiatric disorders that are underserved by currently marketed antipsychotics.”
“These significant and consistent top-line results are a strong
validation of the optimized study design used in this trial,” said
About the Trial Design
The pivotal Phase III trial, referred to as the -020 Study, was a multi-center, double-blind, placebo-controlled study designed to evaluate the efficacy, tolerability and safety of pimavanserin as a treatment for patients with PDP. A total of 199 patients were enrolled in the study and randomized on a one-to-one basis to receive either 40 mg of pimavanserin or placebo once-daily for six weeks, following a two-week screening period including brief psycho-social therapy. Patients also received stable doses of their existing anti-Parkinson’s therapy throughout the study. The primary endpoint of the -020 Study was antipsychotic efficacy as measured using the “SAPS–PD” scale, which consists of nine items from the hallucinations and delusions domains of the Scale for the Assessment of Positive Symptoms, or SAPS. These nine items have been shown to be particularly relevant to the expression of psychotic symptoms in patients with Parkinson’s disease and to have high inter-rater reliability for assessment of severity. Motoric tolerability was a key secondary endpoint in the study and was measured using Parts II and III of the Unified Parkinson’s Disease Rating Scale, or UPDRS.
Conference Call and Webcast Information
ACADIA will host a conference call and webcast with slides today,
Pimavanserin is ACADIA’s proprietary small molecule that acts selectively as an antagonist/inverse agonist on serotonin 5-HT2A receptors and is in Phase III development as a potential first-in-class treatment for Parkinson’s disease psychosis. Pimavanserin can be taken orally as a tablet once-a-day. ACADIA discovered pimavanserin and holds worldwide rights to this new chemical entity.
About Parkinson’s Disease Psychosis
According to the National Parkinson’s Foundation, about one million
ACADIA is a biopharmaceutical company focused on innovative treatments
that address unmet medical needs in neurological and related central
nervous system disorders. ACADIA has a pipeline of product candidates
led by pimavanserin, which is in Phase III development as a potential
first-in-class treatment for Parkinson's disease psychosis. ACADIA also
has clinical-stage programs for chronic pain and glaucoma in
Statements in this press release that are not strictly historical in
nature are forward-looking statements. These statements include but are
not limited to statements related to the progress and timing of ACADIA’s
drug discovery and development programs, either alone or with a partner,
including the commencement or progress of clinical trials and the
results of clinical trials, and the clinical benefits to be derived from
ACADIA’s product candidates, in each case including pimavanserin. In
particular, forward-looking statements include statements regarding the
potential implications of the results of the -020 study; the potential
for selective, non-dopaminergic-based therapy, such as pimavanserin, to
transform the treatment landscape for patients with PDP; the potential
of pimavanserin as a first-in-class, effective, safe and well tolerated
antipsychotic therapy and treatment for PDP; and the possibility that
pimavanserin may have a clinical profile suitable to address a broader
range of neuropsychiatric disorders that are underserved by currently
marketed antipsychotics. These statements are only predictions based on
current information and expectations and involve a number of risks and
uncertainties. Actual events or results may differ materially from those
projected in any of such statements due to various factors, including
the risks and uncertainties inherent in drug discovery, development,
regulatory review and commercialization, and in collaborations with
others, and the fact that past results of clinical trials may not be
indicative of future trial results. For a discussion of these and other
factors, please refer to ACADIA’s annual report on Form 10-K for the
year ended December 31, 2011 as well as ACADIA’s subsequent filings with
ACADIA Pharmaceuticals Inc.
Uli Hacksell, Ph.D., Chief Executive Officer
Thomas H. Aasen, Executive Vice President,
Chief Financial Officer and Chief Business Officer
(212) 845-4271 or (858) 717-2310