Patients With Narcolepsy Able to Switch Medications Easily, Maintain Effectiveness

Switching from high-sodium oxybate (SXB) to lower-sodium oxybate (LXB) with minimal amounts of modifications was reported to be easy by patients with narcolepsy, according to a poster presented at the SLEEP 2023 meeting. A separate poster also found that LXB left more patients feeling refreshed after sleep at the end of the study compared with SXB, although their sleep quality was generally unchanged.

LXB contains 92% less sodium than its counterpart SXB, making it a preferred treatment according to the FDA due to lower chronic sodium exposure; the treatment is approved for treating cataplexy and excessive daytime sleepiness in narcolepsy and for idiopathic hypersomnia. The posters on the 2 medications evaluated the safety and efficacy of switching from SXB to LXB and its perceived effectiveness according to patients.

The first poster¹ evaluated the transition from SXB to LXB. Adults with narcolepsy type 1 or type 2 who were on a stable dose and regimen of SXB were eligible for this study. Stable doses were defined as a maximum of 9 g/night, with no single dose of greater than 6 g and with the patient receiving the dosage once, twice, or 3 times per night. Patients stayed on their SXB medication for 2 weeks as a baseline period before switching to the same dose and regimen of LXB for 6 weeks.

The dosage of LXB could be measured for efficacy and tolerability. The patient Global Impression of Change (PGIc), a forced preference questionnaire (FPQ), an ease of switching medication scale (EOSMS), and the Epworth Sleepiness Scale (ESS) were all used to evaluate the switch, with data collected at the end of treatment or at early discontinuation.

There were 60 participants in this trial, with 62% female participants and 88% identifying as White; the mean (SD) age was 43.9 (15.33) years. The starting and ending median total nightly doses for LXB were 8.5 g and 9.0 g, respectively. LXB was taken twice nightly by the majority of participants (93%). The mean (SD) time to a stable dose was 2.5 (4.82) days in the 56 participants who completed the transition period; the median (range) number of changes was 0.0 (0-1).

As measured by the PGIc, most participants reported improvement by the end of treatment or early discontinuation (45%) or no change at all (48%). The FPQ revealed that 79% preferred LXB over SXB, and the EOSMS revealed that 93% said that the transition was easy or not difficult at all. The mean (SD) change in ESS from baseline was –0.7 (2.31).

The researchers concluded that the patients with narcolepsy who switched from SXB to LXB reported that the transition was easy, with effectiveness being maintained and patients preferring the LXB.

The latter point was emphasized in another poster² that evaluated the sleep quality of patients with narcolepsy who were switching from SXB to LXB. Transition Experience of persons with Narcolepsy taking Oxybate in the Real-World (TENOR) was an observational study that evaluated adults in the United States who were diagnosed with narcolepsy and were transitioning from SXB to LXB within the previous or upcoming 7 days.

Weekly and daily questionnaires provided the longitudinal data that were collected during the transition and 21 weeks after. Sleep diaries where participants rated their quality of sleep and how refreshed they felt on waking were also kept. Sleep latency, wake after sleep onset (WASO), time in bed (TIB), and total sleep time (TST) were all recorded.

There were 85 participants included who had a mean (SD) age of 40.3 (13.0) years, were mostly female participants (73%), and were primarily White (87%). There were 45 participants with type 1 narcolepsy and 40 participants with type 2 narcolepsy. Most of the participants took SXB twice per night before their transition (96%) and LXB twice per night after transition (98%).

A total of 54% of participants rated their sleep quality as “good” or “very good” at baseline and at the end of study; 29% at baseline and 42% at the end of the study reported feeling “well-rested” or “very well-rested.” The mean (SD) sleep latency decreased by 10.5 (16.2) minutes, the mean WASO decreased by 14.8 (56.6) minutes, the mean TIB increased by 7.6 (67.7) minutes, and the mean TST increased by 33.0 (93.8) minutes.

This study did not have a nontransitioning arm as a control group, which could have affected the results of the study. However, the researchers concluded that, although the sleep quality was generally unchanged, more participants reported feeling refreshed at the end of the study when they were on LXB compared with baseline.

The 2 posters combined present convincing data that patients on SXB generally find the transition to LXB both easy and effective in treating their narcolepsy, which encourages the usage of LXB overall.

References

1. Leary E, Pfister C, Fuller D, Macfadden W. Effectiveness and optimization of lower-sodium oxybate in participants with narcolepsy switching from sodium oxybate (SEGUE). Presented at: SLEEP 2023; June 3-June 7, 2023; Indianapolis, IN. Abstract 0591.
2. Husain A, Zee P, Leary E, et al. Patient-reported sleep quality in people with narcolepsy transitioning from sodium oxybate to lower-sodium oxybate. Presented at: SLEEP 2023; June 3-June 7, 2023; Indianapolis, IN. Abstract 0598.