LOS ANGELES—Sodium oxybate reduces cataplexy and excessive sleepiness in children with narcolepsy type 1, according to a study described at the 70th Annual Meeting of the American Academy of Neurology. The treatment’s safety profile in this population is similar to that in adults.
Although symptoms of narcolepsy often begin during childhood or adolescence, few studies have evaluated treatments for narcolepsy in pediatric patients. Sodium oxybate is approved for the treatment of cataplexy and excessive daytime sleepiness in adults with narcolepsy, but it had not previously been studied in a large pediatric narcolepsy trial. Chad Ruoff, MD, Clinical Assistant Professor of Psychiatry and Behavioral Sciences at the Stanford Center for Sleep Sciences and Medicine in California, and colleagues conducted a double-blind, placebo-controlled, randomized-withdrawal study to evaluate the efficacy and safety of sodium oxybate in pediatric patients with narcolepsy type 1.
A Randomized-Withdrawal Study
Eligible participants were children and adolescents between ages 7 and 16 who had been diagnosed with narcolepsy type 1 and had cataplexy. Patients who were on stable doses of sodium oxybate and patients who were sodium-oxybate-naïve were included. Patients with evidence of sleep-disordered breathing were excluded.
Sodium-oxybate-naïve participants were titrated to a stable dose. After a stable-dose period, all participants began a two-week, double-blind, placebo-controlled withdrawal period. The investigators randomized participants in equal groups to continue sodium oxybate or to be switched to placebo. At the end of the double-blind period, all participants received open-label sodium oxybate treatment. Efficacy assessments compared measurements during or at the end of the double-blind period with those taken the last two weeks of the stable-dose period. The study’s primary end point was change in weekly number of cataplexy attacks.
Study Was Terminated Early
Dr. Ruoff and colleagues randomized 63 participants. Approximately 41% of the population was between ages 7 and 11, 44% was female, and 38% was receiving sodium oxybate at baseline. A preplanned interim analysis of 35 participants indicated that sodium oxybate was effective, based on the primary end point result. The double-blind, randomized-withdrawal period thus was terminated early.
For the total group of 63 randomized participants, weekly cataplexy attacks were significantly increased in the placebo group (median, 12.7/week), compared with the sodium-oxybate-treated group (median, 0.3/week). Cataplexy severity, assessed using the Clinical Global Impression of Change (CGI-C), was worse in the placebo group than in the sodium-oxybate group. For 65% of participants in the placebo group, cataplexy was rated “much worse” or “very much worse,” compared with 17% of the sodium-oxybate group. Excessive sleepiness, assessed using the Epworth Sleepiness Scale for Children and Adolescents, also was worse in the placebo group (median increase, 3.0 points) than in the sodium-oxybate group (no change). In addition, the CGI-C for narcolepsy overall was worse in the placebo group.
Treatment-emergent adverse events occurring in more than 10% of the overall sample were enuresis, nausea, vomiting, headache, and decreased weight. These adverse events had been reported in previous trials of sodium oxybate in adults with narcolepsy.
The study was sponsored by Jazz Pharmaceuticals.