Sodium Oxybate Treatment of Narcolepsy in Pediatric Patients: Long-term Efficacy and Safety

Objective: To evaluate the long-term efficacy and safety of sodium oxybate (SXB) treatment for narcolepsy in pediatric patients in a placebo-controlled, randomized-withdrawal study with an open-label evaluation.

Methods: On-SXB or SXB-naïve participants, aged 7-16 were eligible. SXB-naïve participants were titrated on SXB, then entered a stable dose period (SD); on-SXB participants entered SD at usual doses. After a double-blind, randomized-withdrawal period (DB), participants entered an open-label evaluation period (OL; total study duration =1 year). Efficacy parameters include change from SD (baseline) in weekly number of cataplexy attacks and Epworth Sleepiness Scale for Children and Adolescents (ESS-CHAD). Treatment-emergent adverse events (TEAEs) were assessed.

Results: As of 2/10/17: 106 enrolled (74 SXB-naïve, 32 on-SXB); 79 completed ≥6 months; 46 completed 1 year. Efficacy on cataplexy and ESS-CHAD was demonstrated during the DB period and was maintained during the OL. Median (Q1, Q3) change in weekly number of cataplexy attacks between the SD and last week in OL was 0.0 (-2.25, 4.17), with little change throughout. Median (Q1, Q3) change from SD in ESS-CHAD score was 0.0 ( 3.0, 3.0) at Week 52. Two serious TEAEs occurred (acute psychosis and suicidal ideation ). The most common TEAEs (>10%) were enuresis, nausea, vomiting, headache, and decreased weight.

Conclusions: SXB demonstrated long-term effectiveness (up to 1-year) for cataplexy and EDS in pediatric patients with narcolepsy. The safety profile was consistent with adult studies, and no new safety concerns were identified.