Effectiveness and Optimization of Low-Sodium Oxybate in Participants With Narcolepsy Switching From High-Sodium Oxybate: Interim Data from the Substitution of Equal Grams of Uninterrupted Xyrem to Xywav (SEGUE) Study (P5-13.003)

Abstract

<h3>Objective:</h3> The SEGUE study examines safety, tolerability, effectiveness, and treatment optimization in participants with narcolepsy transitioning from sodium oxybate (SXB) to lower-sodium oxybate (LXB; Xywav^®). <h3>Background:</h3> LXB contains 92% less sodium than SXB and is approved for treating cataplexy or excessive daytime sleepiness (EDS) in patients with narcolepsy (≥7 years of age). <h3>Design/Methods:</h3> Eligible participants in this ongoing, multicenter, open-label study (NCT04794491) are adults with narcolepsy (type 1 or 2) on an SXB stable dose (maximum 9 g/night; no single dose &gt;6 g) and regimen (once, twice, or thrice nightly). After 2 weeks on SXB (baseline period), participants switch to the same LXB dose/regimen (intervention period; 6 weeks). If needed, LXB dose/regimen is titrated to optimize efficacy/tolerability. Assessments include the Patient Global Impression of Change (PGIc), forced preference questionnaire (FPQ), and ease of switching medication scale (EOSMS; all collected at end of treatment/early discontinuation). An interim analysis (first 24 completers) is reported. <h3>Results:</h3> Most participants were White (92%); 54% were female; mean (SD) age was 45.5 (16.20) years. Starting and ending (end of treatment/early discontinuation) median total nightly doses of LXB were both 9.0 g. Most participants took LXB twice nightly (88%). Twenty-two participants completed the transition period; mean (SD) time to optimized dose was 1.4 (1.56) days, and median (range) number of dose/regimen changes was 0.0 (0, 1). At end of treatment/early discontinuation, most reported improvement (very much/much/minimal; 57%) or no change (43%) in narcolepsy symptoms on the PGIc, preferred LXB over SXB on the FPQ (86%), and reported the transition was easy (easy/extremely easy/not difficult at all) on the EOSMS (91%). Most treatment-emergent adverse events reported were mild to moderate. <h3>Conclusions:</h3> Participants switched from SXB to LXB with minimal modifications of dose/regimen and reported the transition was easy. Efficacy of oxybate treatment was maintained or improved, and most participants preferred LXB over SXB. <b>Disclosure:</b> Dr. Leary has received personal compensation for serving as an employee of Jazz Pharmaceuticals. Dr. Leary has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Proper. Dr. Leary has stock in Jazz Pharmaceuticals. Dr. Kirby has received personal compensation for serving as an employee of Jazz Pharmaceuticals, Inc. Dr. Kirby has stock in Jazz Pharmaceuticals, Inc.. Dr. Skowronski has nothing to disclose. Mr. Xu has received personal compensation for serving as an employee of Jazz Pharmaceuticals Inc. Mr. Pfister has received personal compensation for serving as an employee of Jazz Pharmaceuticals. Mr. Pfister has stock in Jazz Pharmaceuticals. Dr. Macfadden has received personal compensation for serving as an employee of Jazz pharma. Dr. Macfadden has stock in Jazz pharma.