0767 Long-term Safety Of Sodium Oxybate In Pediatric Narcolepsy With Cataplexy: Open-label Continuation Post 1-year of Treatment

Abstract

Introduction: In a placebo-controlled, randomised withdrawal study with subsequent open-label investigation for up to 1 year, sodium oxybate (SXB) demonstrated efficacy and safety in the treatment of paediatric narcolepsy with cataplexy. In a further continuation period for up to 2 years, safety of SXB and effects on growth were assessed. Materials and methods: Participants who completed Part 1 (up to 52 weeks on study) could transition or re-enrol into the open-label continuation (Part 2) for up to an additional 2 years. Part 2 evaluations included body mass index (BMI), weight, height, treatment-emergent adverse events (TEAEs), and vital signs. Age- and sex-based percentiles for height, weight, and BMI at each assessment were determined using standardised growth charts (Centers for Disease Control, 2000). Results: Of participants in Part 2 (n=44), 35 completed and 9 discontinued (4 withdrew consent, 2 lost to follow-up, 3 due to AEs). Mean (SD) age at first SXB dose in Part 2 was 13.1 (2.2) years; 29.5% were 7-11 years, 70.5% were 12-17 years; 68.2% were male; and 65.9%, 27.3%, 2.3%, and 4.5% were white, black or African American, Asian, and other race, respectively. In Part 1, mean baseline BMI percentile was elevated relative to age-matched population means. In Part 1, there were initial decreases from baseline in median BMI percentile values (median change from Part 1 baseline to end of Part 1: BMI percentile, −7.8; weight percentile, −5.9; height percentile, −1.8), which stabilised in Part 2 (median change from Part 2 baseline to Part 2, month 12: BMI percentile, +0.6; weight percentile, +0.2; height percentile, −3.75; median change in absolute height, +3.1 cm). TEAEs with onset in Part 2 were reported in 21/44 (47.7%) participants; the most frequent were upper respiratory tract infection (9.1%), nasopharyngitis (6.8%), headache (4.5%), somnambulism (4.5%), and vomiting (4.5%). There were 2 serious TEAEs in Part 2 (colon cancer [n=1] and hallucination [n=1]), neither related to treatment. Three participants discontinued due to AEs in Part 2: one due to anger, anxiety, and depression (treatment related), one due to colon cancer (not treatment related), and one due to asthma (not treatment related). Mean vital signs generally remained within normal range throughout the study, with increases in mean blood pressure observed in Part 2. Conclusions: Although the population changed over time, median growth parameters were relatively unchanged throughout the ≤2-year continuation period. Overall safety findings were consistent with those previously reported. Acknowledgements: Jazz Pharmaceuticals.