Late-Breaking Sleep Data: Narcolepsy Drug Efficacy and Weekly Sleep Trends

Data from new studies were presented early on the second day of the Sleep 2026 Annual Meeting, as late-breaking abstracts were presented for those attending the conference. The abstracts covered different aspects of sleep health, with the first focusing on the efficacy of low-sodium oxybate (LXB) in hypersomnia and narcolepsy and the second focusing on how sleep duration can change throughout the week and throughout the year.

LXB Shows Continued Efficacy in Treating Narcolepsy, Hypersomnia

Chad Ruoff, MD, a sleep medicine specialist at Mayo Clinic, presented results from the phase 4 DUET study, which evaluated the effectiveness of LXB in treating sleep and daytime symptoms.¹ The included participants were those with hypersomnia or narcolepsy, as both present with symptoms that can affect sleep at night and daytime functioning due to excessive daytime sleepiness (EDS). EDS can be measured using the Epworth Sleepiness Scale (ESS), whereas the Idiopathic Hypersomnia Severity Scale (IHSS) is used to assess the severity of the symptoms of idiopathic hypersomnia.

Previous studies have shown that LXB, which has been approved by the FDA for use in cataplexy and EDS in patients aged 7 years and older, has shown improvements in EDS in narcolepsy and hypersomnia as well as improvements in symptom severity for patients with hypersomnia based on the IHSS. The abstract aimed to demonstrate the proportion of participants who achieved a clinically important response to treatment with LXB in participants diagnosed with idiopathic hypersomnia or narcolepsy. This was based on established thresholds and normal score ranges of the ESS and IHSS.

Participants could be included in the study if they were aged 18 to 75 years with a primary diagnosis of narcolepsy type 1 (NT1), narcolepsy type 2 (NT2), or idiopathic hypersomnia. Participants also needed an ESS score that was higher than 10 and use of anticataleptic or alerting agents. Individuals with sleep-disordered breathing that was not treated adequately or had a history or presence of an untreated or unstable disorder or condition were excluded from the study.

Participants underwent an overnight PSG at baseline before the intervention period of 4 to 10 weeks, which featured LXB titration for 2 to 8 weeks before a stabilized dose for 2 weeks. They underwent PSG again at the end of treatment. Outcomes that were evaluated in the study included a 2 point or higher decrease in ESS and a 4 point or higher decrease in IHSS. Researchers also looked for normal scores of ESS of 10 or fewer points and fewer than 22 points for IHSS.

There were 40 patients in the idiopathic hypersomnia group and 34 in the narcolepsy group, with most of the participants being female (77.5% and 73.5%, respectively). The patients were primarily White in both groups, and the mean (SD) age was 35.7 (14.2) years in the narcolepsy group and 38.7 (12.3) years in the hypersomnia group.

“What you see here is that of these subjects…[about] 82% had met this threshold of a greater than or equal to 2 reduction in the ESS, and over here you can see about 71% of the subjects achieved a normal score on the ESS, which is pretty impressive for those 34 subjects,” explained Ruoff.

A total of 95.0% of those with hypersomnia also saw at least a 2-point decrease in ESS score, and 70.0% saw a decrease to the normal range. Both of these results occurred regardless of whether the patient took alerting agents or not.

Decreases in IHSS scores also occurred with 94.4% of those with hypersomnia seeing a 4-point decrease and 69.4% achieving a normal range. Limitations to this study were the open-label and single-arm design, which could not establish causality.

Real-World Study Defines Sleep Patterns in Different Seasons, Days

A second poster, presented by Hannah Yang, a research assistant in the Department of Psychiatry and Behavioral Sciences at the University of California San Francisco, focused on how sleep duration and patterns can change throughout the week and be affected by season changes.²

“Though we catalyze solely on internal signals for our sleep wave cycle, we also need to synchronize with external time cues…. This makes sense if you think about how seasonal changes include daylight and temperature. More daylight and warmer temperature mean longer wake duration and shorter sleep duration, and it helps us remind our body to sleep when it is dark and to be awake when it is light,” she explained.

Previous research had shown some consistency with sleep duration going down in the summer and up during the weekends, but this abstract aimed to corroborate those findings in a real-world setting.

The researchers for this study used the Sleeptracker-AI monitor and Fullpower Technologies as under-mattress sleep-monitoring devices to collect data for the study. Data was collected between August 16, 2023, and February 28, 2026. There were 222,748 participants of the study who were a mean age of 48.5 (13.0) years; 46.8% were women. Sleep efficiency percentages, total sleep time (TST), and rapid eye movement (REM) and deep sleep percentages were all assessed.

The mean TST was 403.8 minutes, or less than 7 hours. Peak sleep was found in mid-winter around January 24, and the trough was in early summer around June 23. The peak for REM sleep and deep sleep occurred in late autumn and early winter, correlating to November 3 and December 15, respectively. The lowest recordings for both REM and deep sleep were around the New Year’s holidays, with the lowest for REM sleep coming on December 31 and deep sleep on January 2. Sleep efficiency peaked in spring around May 14, and the lowest was also December 31.

The researchers found that TST was 22.90 minutes longer during the weekends when compared with weekdays. REM sleep peaked on Saturdays, whereas deep sleep peaked midweek. Sleep efficiency also peaked midweek on Thursdays, as lower TST in earlier weekdays could increase sleep efficiency as the week goes on.

“We are experiencing sleep deprivation starting from earlier on in the week, and we enter REM sleep rebound and recovery on the weekend, which kind of allows for that peak on Saturday,” Yang said. “Then we have a peak in midweek for deep sleep with 0.37 percentage points over on weekends. This could be because, despite lower total sleep times during the weekdays, we are prioritizing deep sleep.”

Yang emphasized that further research will need to be done to understand what adjustments would need to be made to address negative health outcomes associated with this change in sleep patterns throughout the week and the year and to collect data from more rural areas. “[Weekly patterns were] quite prominent, so this suggests behavioral routines and social schedules may play a greater role than seasonal changes in shaping sleep patterns in large society,” Yang concluded.

References

1. Ruoff C. Clinical responders to low-sodium oxybate in narcolepsy and idiopathic hypersomnia. Presented at: Sleep 2026 Annual Meeting; June 14-17, 2026; Baltimore, Maryland.
2. Yang H. Seasonal and weekly patterns in sleep duration and architecture in a real-world cohort of 222,748 individuals. Presented at: Sleep 2026 Annual Meeting; June 14-17, 2026; Baltimore, Maryland.