Evaluating Lemborexant for Delayed Sleep Phase Syndrome

Lemborexant in Delayed Sleep Phase Syndrome

PHASE4 · Stanford University · NCT05463861

This study is testing if a medication called Lemborexant can help people with Delayed Sleep Phase Syndrome fall asleep faster and improve their overall sleep quality.

Quick facts

PhasePHASE4
Study typeInterventional
Enrollment60 (estimated)
Ages18 Years and up
SexAll
SponsorStanford University (other)
Locations1 site (Redwood City, California)
Trial IDNCT05463861 on ClinicalTrials.gov

What this trial studies

This study aims to assess the effectiveness of Lemborexant in reducing sleep onset latency in patients diagnosed with Delayed Sleep Phase Syndrome (DSPS). Participants will receive either Lemborexant or a placebo nightly for two years, with their sleep patterns monitored through sleep logs and actigraphy. The study will differentiate between two phenotypes of DSPS to better understand treatment responses. The goal is to determine if Lemborexant can improve sleep quality and daytime functioning for individuals affected by this condition.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 and older diagnosed with Delayed Sleep Phase Syndrome who experience significant sleep delays impacting their daily life.

Not a fit: Patients with clinically significant depression, anxiety disorders, or other sleep disorders may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly improve sleep onset and overall quality of life for patients with Delayed Sleep Phase Syndrome.

How similar studies have performed: Previous studies on orexin antagonists have shown promise in treating sleep disorders, suggesting potential success for this approach.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. 18 years of age or older.
2. Diagnosed with delayed sleep phase syndrome (DSPS) meaning that:

   1. Sleep is delayed by two hours or more beyond what is considered an acceptable or conventional bedtime for the subject (their desired bedtime).
   2. Subjects not able to fall asleep if trying to sleep before the later bedtime;
   3. This is interfering with their wishes/having social impact.
3. Concomitant medications will be allowed, though dosages will be required to remain fixed throughout participation in the study.
4. The participant also needs to be willing and able to comply with all aspects of the protocol.

Exclusion Criteria:

1. Clinically significant depression (PHQ-9 score of 10 or more), anxiety disorder (GAD-7 score of 10 or more), substance use disorder, any other sleep disorder (assessed by the Alliance Sleep Questionnaire- ASQ), or any medical disorder/therapy that could interfere with the trial (this will be verified through interview and analysis of the ASQ).
2. Use of medications with significant effects on sleep-wake function (insomnia therapies, stimulants)- unless they are discontinued at least 5 half-lives prior to study participation. Non-sedative antidepressants or SSRI will be allowed if at a stable dose in the absence of concomitant severe depression or severe anxiety.
3. Use of CYP3A inhibitors and CYP3A inducers, at least 1 week (or five half-lives, whichever is longer) prior to the first day of the baseline phase.
4. Pregnancy (verified by urine pregnancy test on visits 1, 2, and 3) or plan to become pregnant in the next 3 months or currently breastfeeding.
5. Shift workers or subjects working unusual hours.
6. Any risk of suicide within 6 months of screening period or throughout the trial (accessed by the Investigator and by the C-SSRS questionnaire).
7. Transmeridian travel across more than 3 time zones 4 weeks prior to the screening phase.
8. Transmeridian travel across more than 2 time zones during this trial (including the screening phase).
9. Having a positive drug test or being unwilling to refrain from using illegal drugs or marijuana during this trial.
10. Any clinically abnormal symptom or organ impairment found by medical history at Screening or Baseline and physical examinations, vital signs, ECG findings, or laboratory test results that require medical treatment.
11. Impaired liver function (values for enzymes aspartate transaminase (AST) and alanine transaminase (ALT) \> 1.5 times the Upper Limit of Normal).
12. Known to be human immunodeficiency virus positive.
13. Has a QT interval corrected using Fridericia's formula interval (QTcF interval) \>450 ms demonstrated on repeated ECGs (repeated only if initial ECG showed corrected QT interval (QTc) \>450 ms) at Screening or Baseline.

Where this trial is running

Redwood City, California

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Delayed Sleep Phase Syndrome

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.