Idiopathic Hypersomnia Treatment: Low-Sodium Oxybate Shows Long-Term Safety

The long-term safety profile of low-sodium oxybate as an idiopathic hypersomnia treatment is similar to the short-term profile, according to study results presented at the SLEEP 2024 Annual Meeting, held in Houston, Texas, from June 1-5, 2024.

The United States Food and Drug Administration (FDA) approved low-sodium oxybate for the treatment of the sleep disorder among adults.

Researchers conducted a post-hoc analysis of a phase 3, double-blind, placebo-controlled, randomized withdrawal study (ClinicalTrials.gov Identifier: NCT03533114) to investigate the long-term safety profile of low-sodium oxybate in patients with idiopathic hypersomnia.

Patients (N=148) with idiopathic hypersomnia who were naïve to low-sodium oxybate and received open-label titration of low-sodium oxybate for 10 to 14 weeks, followed by stable dosing for 2 weeks, blinded randomized withdrawal for 2 weeks, open-label extension for 24 weeks, and a 2-week safety follow-up were included in this analysis. The study population comprised patients who were treatment-naïve (n=66) or had been exposed to alerting agents (n=82).

The primary outcomes were the onset and duration of treatment-emergent adverse events (TEAEs) affecting 5% or more of the participants. The duration of TEAEs was defined as the time from the start of an adverse event to its resolution.

In general, most TEAEs occurred in the first 5 weeks of the study and were mild or moderate in severity. In the treatment-naïve and alerting agent-experienced cohorts, 3.7% or fewer participants discontinued treatment due to TEAEs.

Among the treatment-naïve group, the most common TEAEs were nausea (19.7%), headache (18.2%), dizziness (16.7%), anxiety (10.6%), and decreased appetite (10.6%). These events had durations ranging between 3.0 days for headache to 15.0 days for decreased appetite.

The most common TEAEs among patients who had previously used alerting agents were nausea (25.6%), headache (18.3%), vomiting (17.1%), anxiety (12.2%), insomnia (11.0%), and tremor (11.0%). These TEAEs lasted from between 1.5 days for vomiting to 11.0 days for tremor.

Serious TEAEs were reported by 2.7%. No serious events were related with the study drug or led to discontinuation.

This study may have been limited by the imbalanced cohorts.

“In this study of LXB [low-sodium oxybate] in participants with idiopathic hypersomnia, the common TEAEs (≥5% of participants) were consistent with the known safety profile of oxybate, peaked early (generally within 5 weeks), and were mild to moderate in severity, in both treatment-naive participants and participants taking alerting agents,” the researchers concluded.

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