Jazz’s Xywav Shows Promise in Improving Heart Health Markers for People with Narcolepsy and Idiopathic Hypersomnia

Rare Daily Staff

Jazz Pharmaceuticals reported new data suggesting its low-sodium sleep medicine Xywav may offer benefits beyond symptom control for people living with narcolepsy and idiopathic hypersomnia, two rare and often debilitating neurologic sleep disorders.

The findings, presented this week at the SLEEP 2026 conference, include real-world and late-stage clinical data pointing to improvements in cardiometabolic risk markers, as well as insights into how the therapy can be tailored to individual patients.

Narcolepsy and idiopathic hypersomnia are chronic conditions marked by overwhelming daytime sleepiness, disrupted nighttime sleep, and, in some cases, sudden muscle weakness known as cataplexy. Both disorders can significantly impair daily functioning and are associated with elevated cardiovascular risk, making long-term management strategies particularly important.

One set of analyses focused on how Xywav is used in practice. Data from the phase 4 DUET study showed that patients reached a stable dose in roughly six weeks on average—42.1 days for idiopathic hypersomnia and 41.8 days for narcolepsy—through gradual adjustments based on effectiveness and tolerability.

Those findings were reinforced by data from more than 13,000 patients enrolled in the drug’s Risk Evaluation and Mitigation Strategy program, which indicated that clinicians are routinely customizing dosing schedules, including once- or twice-nightly regimens, depending on patient needs.

The ability to individualize dosing is particularly relevant in these disorders, where symptom patterns and treatment responses can vary widely from person to person.

A second group of studies examined the potential impact of Xywav’s reduced sodium content. Unlike older oxybate therapies, the drug contains about ninety-two percent less sodium, an important consideration for patients already at higher risk of hypertension and cardiovascular disease.

In the phase 4 XYLO study, patients who switched from high-sodium oxybate to Xywav reported improvements in symptoms linked to fluid and sodium imbalance, including swelling, excessive sweating, and nighttime urination.

A separate retrospective analysis of electronic health records found decreases in lipid markers associated with cardiovascular risk, including non-high-density lipoprotein cholesterol and triglycerides, after patients began treatment. Among those previously treated with high-sodium oxybate, researchers also observed reductions in systolic blood pressure and increases in high-density lipoprotein cholesterol.

Together, these findings suggest that lowering sodium exposure may contribute to broader health benefits over time, although the analyses were not designed to prove cause and effect.

Xywav is approved in the United States for the treatment of cataplexy or excessive daytime sleepiness in patients seven years and older with narcolepsy, and for adults with idiopathic hypersomnia. It remains the only low-sodium oxybate available, and the first therapy approved specifically for idiopathic hypersomnia.

Experts say the new data reflect a growing emphasis on treating these conditions more holistically. In addition to managing sleep-related symptoms, clinicians are increasingly considering long-term risks such as cardiovascular health and the cumulative impact of chronic therapy.

For patients, that shift could translate into more personalized treatment plans that account not only for symptom relief, but also for overall health and quality of life.

As with earlier findings, the company noted that further research will be needed to confirm long-term outcomes and better understand how changes in sodium intake and sleep architecture translate into measurable health benefits.