Among adults with idiopathic hypersomnia treated with lower-sodium oxybate (LXB), weight loss equal to or greater than 5% is common in more than 25% of patients, according to study results presented at Sleep 2022, held from June 4 to 8, 2022, in Charlotte, North Carolina.

Weight loss for patients with narcolepsy has been linked with sodium oxybate (SXB) treatment. LXB, already approved for adults in the US for idiopathic hypersomnia, contains 92% less sodium than SXB. Researchers sought to investigate weight changes associated with LBX.

To accomplish this, they conducted a prospective, open-label, phase 3 clinical study ( Identifier: NCT03533114) that included 154 participants (40.3±13.7 years of age; range 18-75 years; baseline weight 76.9±18.6 kg; baseline body mass index [BMI] 27.1±5.9 kg/m2) with idiopathic hypersomnia. Among the 154 participants at baseline, 2 (1.3%) were underweight (BMI < 18.5 kg/m2); 62 (40.3%) were average weight (BMI 18.5-<25); 52 (33.8%) were overweight (BMI 25-<30); 38 (24.7%) were obese (BMI ≥30).

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All participants received an optimized dose of LXB for a 2-week stable-dose period (SDP) before being randomized to placebo or LXB for a 2-week double-blind withdrawal period which preceded a 24-week open-label extension.

Following the SDP (n reduced to 108), mean weight decreased -2.5±4.1 kg. Following the SDP, mean weight decreases were numerically higher among participants whose baseline BMI was higher (average BMI: -1.8±3.0 kg; overweight BMI: -2.8±3.1 kg; obese BMI: -3.2±5.9 kg).

Researchers concluded that, “adults with idiopathic hypersomnia treated with LXB experienced weight loss, including weight loss (equal to or greater than) 5% in 28.7% of participants.” Those participants with higher baseline BMI also experienced higher mean weight loss

Disclosure: This research was supported by Jazz Pharmaceuticals. Please see the original reference for a full list of disclosures. 


Dauvilliers Y, Chandler P, Hickey L, Chen A, Steininger T, Foldvary-Schaefer N. Weight changes during treatment with lower-sodium oxybate in a phase 3 clinical study in patients with idiopathic hypersomnia. Presented at Sleep 2022; June 4-8, 2022; Charlotte, North Carolina. Abstract 387.