0387 Weight Changes During Treatment With Lower-Sodium Oxybate in a Phase 3 Clinical Study in Patients With Idiopathic Hypersomnia

Abstract

Abstract Introduction Treatment with sodium oxybate (SXB) has been associated with weight loss in patients with narcolepsy. Lower-sodium oxybate (LXB) contains the same active moiety as SXB, with 92% less sodium, and is approved in the United States for the treatment of idiopathic hypersomnia in adults. This analysis assessed weight changes during LXB treatment in a phase 3 clinical study (NCT03533114). Methods Participants 18–75 years of age with idiopathic hypersomnia (treatment naive or taking an alerting agent [with or without SXB] at study entry) began LXB treatment in a 10- to 14-week, open-label, optimized treatment and titration period. After a 2-week stable-dose period (SDP) on their optimized dose of LXB, participants were randomized (1:1) to LXB or placebo for a 2-week, double-blind, randomized withdrawal period, followed by a 24-week open-label extension (OLE). Results Study participants (N=154) had a mean (SD) age of 40.3 (13.7) years; baseline mean (SD) weight was 76.9 (18.6) kg, and baseline mean (SD) body mass index (BMI) was 27.1 (5.9) kg/m2. At baseline, 1.3% (2/154) of participants were underweight (BMI <18.5 kg/m2), 40.3% (62/154) of participants had a normal weight (BMI 18.5 to <25 kg/m2), 33.8% (52/154) were overweight (BMI 25 to <30 kg/m2), and 24.7% (38/154) were obese (BMI ≥30 kg/m2). At the end of the SDP, 28.7% (31/108) of participants had weight loss ≥5%. Mean (SD) change in weight at the end of the SDP (n=108) was −2.5 (4.1) kg. Mean (SD) decreases in weight at the end of SDP were numerically greater in participants with higher baseline BMI (normal baseline BMI, −1.8 [3.0] kg; overweight baseline BMI, −2.8 [3.1] kg; obese baseline BMI, −3.2 [5.9] kg). Conclusion In this phase 3 clinical trial, adults with idiopathic hypersomnia treated with LXB experienced weight loss, including weight loss ≥5% in 28.7% of participants. Mean weight loss was greater in participants with a higher baseline BMI. Support (If Any) Jazz Pharmaceuticals.