Nelotanserin as symptomatic treatment for rapid eye movement sleep behavior disorder: a double-blind randomized study using video analysis in patients with dementia with Lewy bodies or Parkinson's disease dementia

Study objectives: Rapid eye movement sleep behavior disorder (RBD) is frequent in dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD), and poses a risk of injury to patients and their bed partners. We assessed the efficacy of nelotanserin, a selective 5-HT (2A) inverse agonist, for symptomatic treatment of RBD using systematic video analysis. Methods: This was a phase 2 multicenter study in DLB or PDD with video polysomnography (vPSG)confirmed RBD. After a single-blind placebo run-in period, patients meeting eligibility criteria entered a 4-week double-blind treatment period (1:1 ratio with nelotanserin 80 mg/placebo). Whole-night vPSG was conducted during the run-in and at the end of the treatment period. Videos of all rapid eye movement (REM) sleep periods were analysed for RBD behaviors (movements and vocalizations) using the Innsbruck classification system by two of the central reviewers, and a third reviewer adjudicated ambiguous cases. Results: 34 patients (N = 26 DLB, N = 8 PDD; 85.3% men; mean age 71.3 +/- 6.36 years) were included in the analyses. Two (5.9%) patients were excluded due to protocol deviation in treatment compliance. Systematic video analysis demonstrated no difference between nelotanserin and placebo in RBD behaviors. Bland-Altman plot showed high interrater reliability. Conclusions: Despite negative results, this is the first randomized, placebo-controlled study on symptomatic RBD treatment using objective outcome measures based on systematic video analysis. This study provides a new method for outcome research in RBD and proves that movement analysis is a feasible and meaningful outcome for studies evaluating changes in RBD severity. (C) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).