Effects of Solriamfetol on Driving Performance in Participants With Narcolepsy

Introduction: Solriamfetol, a dopamine/norepinephrine reuptake inhibitor, is approved in the US and EU to improve wakefulness in adults with excessive daytime sleepiness (EDS) associated with narcolepsy (75‒150 mg/day). This study evaluated solriamfetol’s effects on driving performance in participants with narcolepsy.
Methods: In this randomized, double-blind, crossover study (NCT 02806908; EudraCT 2015-003931-36), driving performance during an on-road driving test was assessed at 2 and 6 hours post-dose on day 7 following treatment with solriamfetol (150 mg/day × 3 days, then 300 mg/day × 4 days) or placebo. The primary endpoint was standard deviation of lateral position (SDLP), a measure of “weaving,” at 2 hours post-dose. Wilcoxon signed rank test was used to compare solriamfetol and placebo. 
Results: The study included 24 participants (54% male; mean age, 40 years); 22 were included in analyses of SDLP. At 2 hours post-dose, median SDLP was significantly lower following solriamfetol compared with placebo (19.08 vs 20.46 cm; P=0.0022), indicating better driving performance with solriamfetol. At 2 hours post-dose, 4 participants receiving solriamfetol and 7 receiving placebo failed to complete the driving test. At 6 hours post-dose, median SDLP following solriamfetol was not statistically different from placebo (19.59 vs 19.78 cm; P=0.1245). At 6 hours post-dose, 3 participants receiving solriamfetol and 10 receiving placebo failed to complete the driving test. Common adverse events (≥5%) were headache, decreased appetite, somnolence, sleep disorder, agitation, nausea, and palpitations.
Conclusion: Solriamfetol (300 mg/day) improved SDLP, an important measure of driving performance, at 2 hours after administration in participants with narcolepsy.