0591 Effectiveness and Optimization of Lower-Sodium Oxybate in Participants With Narcolepsy Switching From Sodium Oxybate (SEGUE)

Abstract

Abstract Introduction Lower-sodium oxybate (LXB, Xywav®) contains 92% less sodium than higher-sodium oxybate (SXB, Xyrem®) and is approved for treating cataplexy or excessive daytime sleepiness in patients with narcolepsy (≥7 years of age) and idiopathic hypersomnia in adults. The SEGUE study examines the safety, tolerability, effectiveness, and treatment optimization in participants with narcolepsy transitioning from SXB to LXB. Methods Eligible participants in this multicenter, open-label study were adults with narcolepsy type 1 or 2 who were on a stable dose (maximum 9 g/night; no single dose >6 g) and regimen (once, twice, or thrice nightly) of SXB. After 2 weeks on a stable SXB dose/regimen (baseline period), participants switched to the same dose/regimen of LXB (intervention period; 6 weeks). If needed, LXB dose/regimen was titrated to optimize efficacy/tolerability. Assessments included the Patient Global Impression of Change (PGIc), a forced preference questionnaire (FPQ), an ease of switching medication scale (EOSMS), and the Epworth Sleepiness Scale (ESS); all collected at end of treatment or early discontinuation. Results Of 60 participants who entered the intervention period, a majority were female (62%) and White (88%); mean (SD) age was 43.9 (15.33) years. Starting and ending (end of treatment or early discontinuation) median total nightly doses of LXB were 8.5 g and 9.0 g, respectively. In terms of regimen, most took LXB twice nightly (93% at both time points). Fifty-six participants completed the transition period; mean (SD) time to stable dose was 2.5 (4.82) days, and median (range) number of changes in dose/regimen was 0.0 (0, 1). At end of treatment or early discontinuation, most participants reported improvement (very much/much/minimal; 45%) or no change (48%) in narcolepsy symptoms on the PGIc, preferred LXB over SXB on the FPQ (79%), and reported the transition to LXB was easy, extremely easy, or not difficult at all on the EOSMS (93%). Mean (SD) change from baseline on the ESS (n=55) was −0.7 (2.31). Conclusion Most participants with narcolepsy switched from SXB to LXB with minimal modifications of dose/regimen and reported the transition process was easy. Effectiveness of oxybate treatment (ESS) was maintained after transition, and most preferred LXB over SXB. Support (if any) Jazz Pharmaceuticals.