Real-World Data Highlights Reasons for Transitioning From Sodium Oxybate to Lower Sodium Oxybate

Aatif M. Husain, MD

New data from the real-world TENOR study (NCT04803786) showed that a majority of patients with narcolepsy who transitioned from sodium oxybate (SXB; Xyrem; Jazz Pharmaceuticals) to lower sodium oxybate (LXB; Xywav; Jazz Pharmaceuticals) used a gram-for-gram dose conversion, with long-term health cited as the most recurring reason for switching.¹

The analysis, presented at the 2022 SLEEP Annual Meeting, June 4-8, in Charlotte, North Carolina, indicated that 93% of patients previously on sodium oxybate made the switch because of long-term health reasons. Other reasons included physician recommendation (47%), avoidance of cardiovascular issues (39%), avoidance of side effects (31%), to improve control of narcolepsy symptoms (18%), and other (14%).

In June 2020, LXB, previously known as JZP-258, was FDA approved as the first treatment indicated for both cataplexy and excessive daytime sleepiness in people living with narcolepsy in 15 years. The oxybate product contained a unique composition of cations resulting in 92% less sodium, or approximately to 1500 mg/night than SXB, the only approved agent for that indication at the time.²

Led by Aatif M. Husain, MD, division chief of Epilepsy, Sleep, and Neurophysiology at Duke University School of Medicine, the patient-centric, prospective, observational, noninterventional, virtual-format study included 85 participants with confirmed narcolepsy (type 1: n = 45; type 2: n = 40) who transitioned from SXB to LXB within the previous/upcoming 7 days of the trial. Mean time on current SXB regimen was 57.8 months (SD, 52.1) and almost all (96%) patients took their dose twice nightly.¹

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In total, 79% of the cohort was taking at least 1 concomitant medication for their condition at baseline in addition to SXB; of those, 33% were taking 2, and 8% were taking at least 3. After transitioning, 98% (n = 84) of participants took LXB twice nightly, with a mean nightly dose of 7.7 g (SD, 1.5), which were nearly identical to previous total nightly dose of SXB (7.7 g [SD, 1.5]). The dose conversions at baseline were gram-for-gram in 87% of the cohort. Following transition, 56% of patients used LXB doses of at least 7.5 g, 21% using between 6.0 g and 7.5 g, 15% between at least 4.5 g and 6.0 g, and 7% using less than 4.5 g.

In March 2020, when the new drug application for SXB was accepted, Robert Iannone, MD, MSCE, executive vice president of Jazz Pharmaceuticals told NeurologyLive^® that given the significant reduction in sodium with JZP-258, it "will be a better and safer choice for all patients with narcolepsy, and will be more in line with what I would say is very broad accepted guidance around reducing sodium intake that comes from organizations such as the American Heart Association, or even the FDA." Iannone added, "In those guidelines, the ideal total sodium intake for a day is set at 1500 mg, which could be exceeded just based on Xyrem alone. JZP-258 reduces, depending on the dose, the amount of sodium intake by between 1 g and 1.5 g daily."

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REFERENCES
1. Husain A, Leary E, Fuller D, et al. Dosing and reasons for transitioning from sodium oxybate to lower-sodium oxybate in people with narcolepsy: data from the real-world TENOR study. Presented at: SLEEP Annual Meeting; June 4-8, 2022; Charlotte, NC. Abstract 0388
2. Jazz Pharmaceuticals announces US FDA approval of Xywav (calcium, magnesium, potassium, and sodium oxybates) oral solution for cataplexy or excessive daytime sleepiness associated with narcolepsy. News release. Jazz Pharmaceuticals. July 22, 2020. Accessed June 3, 2022. https://investor.jazzpharma.com/news-releases/news-release-details/jazz-pharmaceuticals-announces-us-fda-approval-xywavtm-calcium#:~:text=DUBLIN%20%2C%20July%2022%2C%202020%20%2F,excessive%20daytime%20sleepiness%20(EDS)%20in