A 12-week open-label, multicenter study evaluating the safety and patient-reported efficacy of sodium oxybate in patients with narcolepsy and cataplexy

Abstract

Objective: This study aimed to evaluate safety and efficacy of sodium oxybate (SXB) titrated to effect.

Methods: SXB-naive patients who had participated in a randomized SXB clinical trial and had not been titrated to adequate clinical effect were initiated on open-label SXB at 4.5 g/night and titrated in 1.5-g increments to 6, 7.5, or 9 g/night or down to 3 g/night, based on individual clinical response. Treatment was 12 weeks; safety was the primary outcome. Efficacy was evaluated using the Narcolepsy Symptom Assessment Questionnaire (NSAQ), a five-point scale ("much improved" to "much worse") that assessed changes from baseline in specific symptoms. Response was defined as "much improved" or "somewhat improved" overall at weeks 6 and 12.

Results: Of 202 patients, 171 (85%) completed treatment; final doses were 3 g (n = 5), 4.5 g (n = 29), 6 g (n = 80), 7.5 g (n = 66), and 9 g (n = 22). Adverse events (AEs) were reported in 114 patients (56%), serious AEs in five (2%). The most common AEs were nausea (10%), headache (7%), and dizziness (5%). Response rate was 92% at week 6 and 90% at week 12; most patients reported improvements in all individual symptoms. Overall, 60% of patients rated their symptoms at 12 weeks as "much improved," and this improvement was dose dependent.

Conclusions: The SXB safety profile was consistent with parent trials. Ninety percent of patients reported improvements as measured by the NSAQ.

Keywords: Attention; Cataplexy; Efficacy; Excessive daytime sleepiness; Narcolepsy; Open-label; Patient-reported outcomes; Safety; Sleep quality; Sodium oxybate.