This year’s American Academy of Neurology (AAN) meeting featured results of a randomised, placebo-controlled phase III study evaluating the safety and efficacy of solriamfetol for the treatment of excessive sleepiness (ES) in participants with narcolepsy types 1 and 2 (NT1/2).
Solriamfetol is a selective dopamine and norepinephrine reuptake inhibitor with wake-promoting effects. The study randomised 239 adults with narcolepsy to receive a placebo or 75 mg, 150 mg, or 300 mg solriamfetol. At baseline, participants had to have a mean sleep latency of less than 25 minutes on the Maintenance of Wakefulness Test (MWT), an Epworth Sleepiness Scale (ESS) score of 10 or greater, and minimum nightly sleep time of six hours or more. The double-blind trial included patients with or without cataplexy, although individuals were excluded if they were on medications that could influence cataplexy or ES.
After 12 weeks of treatment, solriamfetol significantly increased MWT sleep latency, leading to a least-squares mean change of 12.3 minutes (min) and 9.8 min in patients receiving the 300 mg and 150 mg doses, respectively. Patients receiving the 75 mg dose reported a mean 4.7 min change from baseline, compared to only a 2.1 min change in the placebo group.
In addition to increased MWT sleep latency, significant least-squares mean changes in ESS score from baseline after 12 weeks were observed for all doses (P<0.05): -6 (300 mg); -5.4 (150 mg); and -3.8 (75 mg). This was compared with -1.6 for the placebo group.
The most common adverse events (AEs; ≥5%) reported were headache, nausea, decreased appetite, nasopharyngitis, dry mouth, and anxiety. One participant in the solriamfetol 150 mg group had two serious AEs, but this was considered unrelated to the drug. Discontinuations due to AEs were more frequent in the solriamfetol 150 mg and 300 mg groups.
As the study authors conclude, solriamfetol improved wakefulness and reduced ES in participants with NT1/2. Furthermore, safety and tolerability were consistent with previous studies of solriamfetol.
Thorpy MJ, et al. Randomized, Placebo-Controlled, Phase 3 Study of the Safety and Efficacy of Solriamfetol (JZP-110) for the Treatment of Excessive Sleepiness (ES) in Participants with Narcolepsy Types 1 and 2 (NT1/2) (CT.003). Neurology. 2018;90(15 Supplement).