Introduction: Impaired nocturnal sleep and excessive daytime sleepiness are common problems for patients with Parkinson's disease, and patients with Parkinson's disease with sleep dysfunction are 5 times more likely to experience psychotic symptoms. Pimavanserin, a 5-HT2A inverse agonist approved to treat Parkinson's disease psychosis, may improve sleep quality in patients with Parkinson's disease experiencing sleep disturbances.
Methods: Scales for Outcomes in Parkinson's Disease nighttime sleep (SCOPA-NS) and SCOPA-daytime sleepiness (DS) data obtained during 2 double-blind placebo-controlled studies of pimavanserin in persons with Parkinson's disease psychosis were evaluated. Data from the placebo and pimavanserin 34 mg groups in the 2 studies were pooled to provide further information on the effect of pimavanserin 34 mg on sleep. Additional analyses on the pooled study data were performed on participants with significantly impaired nighttime sleep and daytime sleepiness, defined as SCOPA-NS ≥7 and SCOPA-DS ≥5, respectively.
Results: In the pooled analysis, treatment effects, expressed as least squares mean reductions in SCOPA-NS at week 6, were -1.4 for pimavanserin 34 mg and -0.5 for placebo. At week 6, the decrease from baseline in SCOPA-DS for the pimavanserin 34 mg group was -1.7 and -1.2 for the placebo group (P = 0.108). When evaluating participants with impaired nighttime sleep and daytime sleepiness at baseline, the SCOPA-NS score change was -4.4 for the pimavanserin 34 mg group and -2.3 for the placebo group (P = 0.002), whereas the SCOPA-DS change was -2.9 and -1.9 for the pimavanserin 34 mg and placebo groups (P = 0.120), respectively.
Conclusion: The data from the trials suggest that nighttime sleep improved with administration of pimavanserin, a novel 5-HT2A receptor inverse agonist/antagonist.