0393 Weight Changes During Treatment With Lower-Sodium Oxybate in a Phase 3 Clinical Study in Patients With Narcolepsy

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 US for treatment of cataplexy or excessive daytime sleepiness in patients ≥7 years of age with narcolepsy and for treatment of adults with idiopathic hypersomnia. This analysis assessed weight changes after 14 weeks of open-label LXB treatment in a phase 3 clinical study in patients with narcolepsy (NCT03030599). Methods Participants 18‒70 years of age with narcolepsy with cataplexy (taking SXB only, SXB+other anticataplectics, or other anticataplectics, or who were anticataplectic-naive at study entry) began LXB treatment in a 12-week, open-label, optimized treatment and titration period, followed by a 2-week stable-dose period (SDP) on LXB. Results Study participants (N=201) had a mean (SD) age of 37.2 (12.2) years. At baseline, mean (SD) weight and body mass index (BMI) were 83.7 (19.2) kg and 28.8 (6.1) kg/m2, respectively; 31.8% of participants (64/201) were normal weight (BMI 18.5 to <25 kg/m2), 31.8% (64/201) were overweight (BMI 25 to <30 kg/m2), and 35.3% (71/201) were obese (BMI ≥30 kg/m2). At the end of SDP, mean (SD) weight and BMI changes in SXB-only (n=45 weight; n=44 BMI), SXB+anticataplectics (n=14), other-anticataplectics (n=23), and anticataplectic-naive (n=65) participants were, respectively, −0.2 (2.5) kg and 0.0 (0.9) kg/m2, −1.0 (1.9) kg and −0.3 (0.6) kg/m2, −2.3 (4.0) kg and −0.8 (1.4) kg/m2, and −2.5 (3.8) kg and −0.9 (1.3) kg/m2. Weight loss ≥5% at the end of SDP occurred in 6.7% of SXB-only, 0.0% of SXB+anticataplectics, 21.7% of other-anticataplectics, and 27.7% of anticataplectic-naive participants. In normal weight, overweight, and obese participants at baseline, mean (SD) decreases in weight at the end of SDP were −1.5 (3.1) kg, −3.3 (3.5) kg, and −2.6 (4.7) kg, respectively (participants who were oxybate-naive at study entry), and −0.1 (1.8) kg, −1.0 (2.4) kg, and 0.2 (2.8) kg, respectively (participants taking SXB at study entry). Conclusion In this study, adults with narcolepsy who were oxybate-naive at study entry experienced greater weight loss during LXB treatment compared with adults previously taking SXB. Support (If Any) Jazz Pharmaceuticals.