Lower Sodium Oxybate May Provide Weight Loss for Adults with Idiopathic Hypersomnia

Yves Dauvilliers, MD, PhD

Lower sodium oxybate (Xywav), an agent approved by the US Food and Drug Administration (FDA) for the treatment of narcolepsy and idiopathic hypersomnia in adults, may additionally provide weight loss benefit among overweight or obese patients.

A new phase 3 study presented at the Associated Professional Sleep Societies (SLEEP) 2022 Annual Meeting this week showed more than one-fourth of patients with idiopathic hypersomnia treated with the Jazz Pharmaceuticals therapy lost ≥5% weight within 16 weeks.

Led by Yves Dauvilliers, MD, PhD, professor of neurology and physiology at University of Montpellier in France, the international team of investigators sought to assess weight change during treatment of lower sodium oxybate in a phase 3 clinical setting.

“Treatment with sodium oxybate has been associated with weight loss in patients with narcolepsy,” they explained. “Lower sodium oxybate contains the same active moiety as sodium oxybate, with 92% less sodium, and is approved in the United States for the treatment of idiopathic hypersomnia in adults.”

Trial participants were aged 18-75 years old with idiopathic hypersomnia. They were either naïve to treatment for the condition or taking an alerting agent, with or without lower sodium oxybate, at baseline. They were stratified by weight status per BMI at baseline.

Investigators initiated lower sodium oxybate treatment through a 10- to 14-week, open-label, optimized treatment and titration period. Following a 2-week stable-dose period on the optimized dose of lower sodium oxybate, patients were randomized 1:1 to either treatment or placebo for another 2-week, double-blind, randomized withdrawal period, then a 24-week open-label extension.

The trial included 154 participants with a mean age of 40.3 years old. Baseline mean weight was 76.9 kg, or approximately 169.5 lbs, and baseline mean body mass index (BMI) was 27.1 kg/m2. Only 2 (1.3%) of participants were underweight per BMI; 62 (40.3%) were normal weight; 52 (33.8%) were overweight; and 38 (24.7%) were obese.

Dauvilliers and colleagues reported that 31 of 108 (28.7%) participants to complete the stable-dose period had a weight loss of ≥5% per bodyweight. Overall, mean change in participant weight at the end of that period was -2.5 kg.

Investigators additionally observed that mean decreases at the end of the stable-dose period were numerically greater among participants with higher baseline BMI; participants with overweight or obese BMI lost a mean 2.8 and 3.2 kg, respectively, while participants with normal BMI lost just a mean 1.8 kg.

“In this phase 3 clinical trial, adults with idiopathic hypersomnia treated with lower sodium oxybate experienced weight loss, including weight loss ≥5% in 28.7% of participants,” investigators concluded. “Mean weight loss was greater in participants with a higher baseline BMI.”

The study, “Weight Changes During Treatment with Lower Sodium Oxybate in a Phase 3 Clinical Study in Patients with Idiopathic Hypersomnia,” was presented at SLEEP 2022.