Solriamfetol improves daily fatigue symptoms in adults with myalgic encephalomyelitis/chronic fatigue syndrome after eight weeks of treatment

Background: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a long-term illness with no treatment options that address the disease directly. Solriamfetol is a selective dual norepinephrine-dopamine reuptake inhibitor that promotes wakefulness in obstructive sleep apnea and narcolepsy.Aims: This study evaluated the efficacy and safety of solriamfetol for fatigue symptoms in adults with ME/CFS with 8 weeks of treatment.Methods: This was a phase 4, double-blind, randomized, placebo-controlled trial of solriamfetol in adults with ME/CFS. Eligible participants were randomly assigned to receive 75mg (titrated to 150mg as needed) solriamfetol or placebo. Participants completed a battery of assessments at weekly visits. The primary outcome was Fatigue Symptom Inventory (FSI) scores, and the secondary outcome measure was Behavioral Rating Inventory of Executive Function for Adults (BRIEF-A), at weeks 6 and 8. T-tests assessed the differences in mean change from baseline between solriamfetol and placebo. Adverse events were monitored throughout the study.Results: At week 8 (p = .039), but not week 6 (p = .270), solriamfetol improved FSI severity compared to placebo. On the BRIEF-A global executive composite, solriamfetol improved more than placebo at week 8 (p = .012), driven by improved metacognition index (p = .004), but not behavioral regulation index (p = .574). Solriamfetol was well tolerated, with most common AEs being sleep loss and headaches.Conclusions: Solriamfetol demonstrated good safety and efficacy in improving fatigue and executive functioning in patients with ME/CFS. As a dual norepinephrine-dopamine reuptake inhibitor and wakefulness-promotion, solriamfetol has the potential to improve fatigue symptoms of ME/CFS.