Author response: Pimavanserin: A novel therapeutic option for Parkinson disease psychosis

We appreciate the comments from Lawler et al. on our recent review of pimavanserin for the treatment of Parkinson disease psychosis (PDP) and agree that PDP can lead to major negative effects on patients and caregivers. Indeed, we stated PDP is “associated with functional decline, greater caregiver burden, and risk of nursing home placement, as well as increased morbidity and mortality.”1 We, however, did not suggest that low dose quetiapine be tried prior to pimavanserin. Rather, we reported pimavanserin meets Level B recommendation criteria—a level “higher than that for quetiapine.” Nevertheless, available evidence does not support that pimavanserin should always be first-line and started at symptom onset for every patient. As we reported, Food and Drug Administration approval was largely based on a single, 6-week randomized placebo-controlled trial in which an improvement of 37% on a newly adapted psychosis scale for PDP (compared to 14% for placebo) was observed.2 As such, additional trials and open-label extension studies are needed to provide a more complete safety profile and information about long-term efficacy. In addition, important first steps at symptom onset continue to be ruling out secondary causes of psychosis and assessing for medications that may be contributing to symptoms