Long-term safety and maintenance of efficacy of sodium oxybate in the treatment of narcolepsy with cataplexy in pediatric patients

Study objectives: Evaluate long-term efficacy and safety of sodium oxybate (SXB) in children and adolescents (aged 7-16 years) with narcolepsy with cataplexy.

Methods: A double-blind randomized withdrawal study was conducted. Prior to randomization, SXB-naive participants were titrated to an efficacious and tolerable dose of SXB; participants taking SXB entered on their established dose. Following a 2-week stable-dose period and 2-week, double-blind, randomized withdrawal period, participants entered an open-label period (OLP; ≤ 47 weeks). Efficacy measures during the OLP included number of weekly cataplexy attacks, cataplexy-free days, and Epworth Sleepiness Scale for Children and Adolescents (ESS-CHAD). Safety outcomes included treatment-emergent adverse events; assessments of depression, anxiety, and suicidality; and polysomnography.

Results: Of 106 enrolled participants, 95 entered and 85 completed the OLP. In SXB-naive participants and participants previously taking SXB, efficacy of SXB established prior to the double-blind, randomized withdrawal period was maintained throughout the OLP for number of weekly cataplexy attacks (median [quartile 1, quartile 3] change from the stable-dose period to end of the OLP: 0.0 [-2.5, 4.9] and 0.0 [-3.4, 2.6], respectively) and ESS-CHAD scores (0.0 [-3.0, 2.5] and 1.0 [-3.0, 3.0], respectively). The median (quartile 1, quartile 3) number of cataplexy-free days per week was 2.3 (0.0, 6.0) in OLP week 1 and 3.8 (0.5, 5.5) in week 48. Treatment-emergent adverse events (≥ 5%) were enuresis, nausea, vomiting, headache, decreased weight, decreased appetite, nasopharyngitis, upper respiratory tract infection, and dizziness.

Conclusions: SXB demonstrated long-term maintenance of efficacy in pediatric narcolepsy with cataplexy, with a safety profile consistent with that observed in adults.

Clinical trial registration: Registry: ClinicalTrials.gov; Name: A Multicenter Study of the Efficacy and Safety of Xyrem with an Open-Label Pharmacokinetic Evaluation and Safety Extension in Pediatric Subjects with Narcolepsy with Cataplexy; URL: https://clinicaltrials.gov/ct2/show/NCT02221869; Identifier: NCT02221869.

Citation: Lecendreux M, Plazzi G, Dauvilliers Y, et al. Long-term safety and maintenance of efficacy of sodium oxybate in the treatment of narcolepsy with cataplexy in pediatric patients. J Clin Sleep Med. 2022;18(9):2217-2227.