A phase 2 double-blind study of solriamfetol in excessive daytime sleepiness (EDS) in patients with Parkinson’s disease (PD) showed dose-dependent improvement in sleep latency. These results were published in Movement Disorders.
Patients (N = 66) with PD and EDS were recruited at 33 locations in the United States between 2017 and 2018. The randomization was done in a ratio of 3: 3: 1 in order to receive a treatment with sequence A, B or C. Treatments comprised 4 1 weeks with placebo, 75, 150, 300 mg solriamfetol (A); 75, 150, 300 mg solriamfetol, placebo (B); or 4 weeks placebo (C). The participants were examined for safety, tolerability and effectiveness. This study was carried out by Jazz Pharmaceuticals.
Treatment-related side effects were reported by 58.9%. Common events were nausea (10.7%), dizziness (7.1%), dry mouth (7.1%), headache (7.1%), anxiety (5.4%), constipation (5.4%) , and dyspepsia (5.4%). A single patient experienced a serious adverse event during the 300 mg dose phase and 3 discontinued use due to a non-serious adverse event.
On the Epworth Sleepiness Scale (ESS), mean least squares difference from baseline was -0.03 (P = 0.9546) for the 75 mg dose, -0.25 (P = 0.7104) for the 150 mg dose and -0.93 (P = .1276) for the 300 mg dose.
The mean sleep latency of the wakefulness test (MWT) had a dose-dependent improvement of 5.05 (95% CI, 1.24–8.57; P = 0.0098) minutes for the 300 mg dose compared to placebo.
No significant effects on the motor or non-motor symptoms of PD were observed.
This study was too weak and statistical tests could not be performed between the subgroups. In addition, the MWT instrument has not been validated for use in the PD population.
No new adverse events or safety concerns related to therapy with solriamfetol were identified in this phase 2 study. No evidence of worsening Parkinson’s symptoms has been reported. Solriamfetol may improve sleep latency in patients with PD, but there was limited evidence that EDS was improved.
Disclosure: Several authors stated links to the pharmaceutical industry. For a full list of details, see the original article.
Videnovic A, Amara AW, Comella C, et al. Solriamfetol for excessive daytime sleepiness in Parkinson’s disease: phase 2 proof-of-concept study. Movement disorder. Published online June 30, 2021. doi: 10.1002 / mds.28702