New Insights into the Clinical Experience of Patients Transitioning from Xyrem to Xywav to Treat Narcolepsy

Patients who transitioned from Xyrem (sodium oxybate, Jazz Pharmaceuticals, Dublin, Ireland) to Xywav (low-sodium oxybate, Jazz Pharmaceuticals, Dublin, Ireland) to treat narcolepsy experienced minimal dose/regimen modifications, consistent efficacy, and mild-to-moderate treatment emergent adverse events (TEAEs), according to new research presented at the SLEEP 2023 annual meeting of the Associated Professional Sleep Societies (APSS).

The SEGUE phase 4 study (NCT04794491) consisted of a multicenter, open-label, single-arm design with 62 participants aged 18-80 years who had been taking Xyrem for at least 2 months to treat type 1 or type 2 narcolepsy. After a 2-week baseline period, participants transitioned to Xywav for a 6-week intervention period. Researchers assessed treatment efficacy using the Patient Global Impression of Change (PGIc), the Epworth Sleepiness Scale (ESS), a forced reference questionnaire (FPQ), and an Ease of Switching Medication Scale (EOSMS).

A stable regimen on Xywav was achieved after a mean time of 2.5 days, with 89.3% of participants requiring no change in dose. At the end of the intervention period, participants reported similar ESS scores on Xywav vs Xyrem, with a mean change of -0.7. Most patients reported that their condition improved on Xywav vs Xyrem (44.6%) or remained the same (48.2%), per PGIc. In the FPQ, most participants (78.6%) preferred Xywav to Xywav, and 92.9% reported that the transition to Xywav was easy per EOSMS. TEAEs ocurred in 30% of participants and were predominantly mild (18.3%) or moderate (8.3%).

While Xyrem has proven efficacy in improving cataplexy and excessive daytime sleepiness in narcolepsy, it increases intake of sodium, putting patients at risk of cardiovascular morbidity. Xywav, being a low-sodium oxybate, has the potential to improve long-term health outcomes for patients with narcolepsy. The study authors are current or former employees of Jazz Pharmaceuticals.