Weight changes during treatment with low-sodium oxybate in two phase 3 clinical studies in participants with...

Low-sodium oxybate (LXB) is approved in the United States for treating cataplexy or excessive daytime sleepiness in patients aged ≥7 years with narcolepsy and idiopathic hypersomnia in adults. This post hoc analysis evaluated LXB effects on weight in patients with narcolepsy or idiopathic hypersomnia from two phase 3 studies.

Adults with narcolepsy with cataplexy or idiopathic hypersomnia began LXB treatment during open-label titration (10-14 weeks), followed by 2-week stable-dose periods (SDP).

Safety populations comprised 201 participants with narcolepsy (75 previously taking sodium oxybate) and 148 with idiopathic hypersomnia (oxybate-naive at study entry); most were overweight or obese at baseline (narcolepsy, 67 %; idiopathic hypersomnia, 60 %). Least-squares (LS) mean (95 % CI) weight changes at end of SDP were -1.0 (-2.2, 0.1), -3.5 (-4.7, -2.3), and -2.3 (-3.4, -1.1) kg in oxybate-naive participants with narcolepsy and normal weight, overweight, and obese, respectively, and 0.0 (-1.6, 1.6), -0.7 (-2.2, 0.8), and 0.3 (-1.1, 1.7) kg in participants with narcolepsy previously taking oxybate and normal weight, overweight, and obese, respectively. In oxybate-naive participants with idiopathic hypersomnia, LS mean (95 % CI) changes at end of SDP were -2.2 (-3.5, -0.8), -2.6 (-4.1, -1.2), and -3.4 (-4.9, -1.8) kg in normal weight, overweight, and obese participants, respectively. Weight loss ≥5 % at end of SDP occurred in 26 % of oxybate-naive participants with narcolepsy, 5 % of those with narcolepsy previously taking oxybate, and 30 % with idiopathic hypersomnia.

Open-label LXB was associated with modest weight loss in participants with narcolepsy with cataplexy or idiopathic hypersomnia.