Delayed Sleep Phase SyndromePhase 4NCT05463861
Lemborexant in Delayed Sleep Phase Syndrome
A Phase 4 study testing Lemborexant in people with Delayed Sleep Phase Syndrome, run by Stanford University at 2 sites in United States.
Trial summary
The purpose of the study is to evaluate whether Lemborexant is more effective than placebo in shortening sleep onset latency in patients with delayed sleep phase syndrome (both type 1 and type 2). This will be tracked using sleep logs as well as actigraphy. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Delayed Sleep Phase Syndrome
- What is being tested?
- Lemborexant
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 86 participants
- Where
- 2 sitesUnited States
- Study dates
- 1 Feb 2022to 31 May 2027
- Phase
- Phase 4
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 18 years of age or older.
- Diagnosed with delayed sleep phase syndrome (DSPS) meaning that:
- Sleep is delayed by two hours or more beyond what is considered an acceptable or conventional bedtime for the subject (their desired bedtime).
- Subjects not able to fall asleep if trying to sleep before the later bedtime;
- This is interfering with their wishes/having social impact.
- Concomitant medications will be allowed, though dosages will be required to remain fixed throughout participation in the study.
- The participant also needs to be willing and able to comply with all aspects of the protocol.
Who cannot join
- 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).
- 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.
- 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.
- 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.
- Shift workers or subjects working unusual hours.
- Any risk of suicide within 6 months of screening period or throughout the trial (accessed by the Investigator and by the C-SSRS questionnaire).
Show all 13Show fewer
- Transmeridian travel across more than 3 time zones 4 weeks prior to the screening phase.
- Transmeridian travel across more than 2 time zones during this trial (including the screening phase).
- Having a positive drug test or being unwilling to refrain from using illegal drugs or marijuana during this trial.
- 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.
- Impaired liver function (values for enzymes aspartate transaminase (AST) and alanine transaminase (ALT) > 1.5 times the Upper Limit of Normal).
- Known to be human immunodeficiency virus positive.
- 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.
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
United States2 sites, 1 recruiting
- Completed
Stanford Univeristy
Redwood City, California, 94063
- Recruiting
University of California San Francisco
San Francisco, California, 94107
Andrew D Krystal, MD MS, 415-476-7702, andrew.krystal@ucsf.edu
About this study
The purpose of the study is to evaluate whether Lemborexant is more effective than placebo in shortening sleep onset latency in patients with delayed sleep phase syndrome (both type 1 and type 2). This will be tracked using sleep logs as well as actigraphy.
In this 2-year study, we will examine if Lemborexant administered 5-10 mg nightly taken at desired bedtime (at least 2 hours prior to self-reported sleep onset habitual time) can improve the symptoms of Delayed Sleep Phase Syndrome.
Read the detailed description
Delayed sleep phase syndrome (DSPS) is a disorder in which a person's sleep is delayed by two hours or more beyond what is considered an acceptable or conventional bedtime. The delayed sleep then causes difficulty in being able to wake up at the desired time.
In DSPS, bedtime is shifted later than the general population such that individuals have difficulty getting enough sleep to meet their sleep needs before they have to get up for their daytime obligations (work, school, childcare, etc.). As a result, patients experience daytime impairment, including daytime sleepiness and cognitive impairment. DSPS, if maintained in adulthood, is associated with numerous deleterious health effects, although causality is not well established. Two phenotypes of DSPS are recognized depending on the phase of entrainment: one with a late phase and normal phase angle (non-circadian) and other with a late phase and abnormal phase angle (circadian). The differentiation of these two phenotypes is theoretical: a mixed situation may be involved in some cases and the exact pathophysiology of each subtype is still controversial.
In theory, however, separating the sample into these two subtypes is likely important to predict short- and long-term responses to orexin antagonists in DSPS.
Lemborexant is one of the dual orexin receptor antagonists on the US market. The purpose of this study is to examine if lemborexant administered 5 to 10 mg nightly, taken at desired bedtime (at least 2 hours prior to self-reported sleep onset time), can improve the symptoms of Delayed Sleep Phase Syndrome both in the circadian and non-circadian phenotypes. The phenotypes will be recruited in 1:1 proportion.The effect of lemborexant will be analyzed based on the collection of information from actigraphy watches, sleep diaries, and sleep scales. The total participation time involved in this study will be approximately 6 weeks (2 weeks of baseline assessment followed by 2-weeks of treatment/placebo, and 2 weeks post-treatment).
- Conditions
- Delayed Sleep Phase Syndrome
- Being tested
- Lemborexant, Placebo
- Medical subject headings
- Sleep Disorders, Circadian Rhythm
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
LemborexantDrug
Also called dayvigo®
Lemborexant tablet administered orally once daily.
PlaceboDrug
Placebo to match Lemborexant tablet administered orally once daily.
| Study group | Role | What they receive |
|---|---|---|
| Lemborexant | Active comparator | Patients receive Lemborexant 5mg for 7 days and may be dose adjusted to 10mg. Patients continue to take Lemborexant 5mg or 10 mg for an additional 7 days. Receives: Drug: Lemborexant |
| Placebo | Placebo comparator | Patients receive placebo to match Lemborexant for 14 days. Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in actigraphy sleep latency onset
Sleep latency is the time from laying down until falling asleep. Actigraphy data obtained using Axivity- AX6.
Measured: From 2 weeks prior to randomization to 4 weeks post randomization
Secondary outcomes (8)
Change in Epworth Sleepiness Scale (ESS)
This is a scale to evaluate daytime sleepiness. Range from 0 to 24 points (higher scores mean more sleepiness).
Measured: From randomization to 4 weeks post randomization
Change in Karolinska Sleepiness Scale (KSS)
Self-report for daytime sleepiness with 1 being extremely alert and 10 being extremely sleepy, can't keep awake.
Measured: From randomization to 4 weeks post randomization
Change in sleep diary derived sleep onset latency
Sleep latency is the time from laying down until falling asleep as estimated by patient in dairy.
Measured: From 2 weeks prior to randomization to 4 weeks post randomization
Sleep Regularity Index
Sleep Regularity Index is defined as the percentage probability of a person being asleep (or awake) at any two time points 24 hours apart. Actigraphy data obtained using Axivity- AX6.
Measured: From 2 weeks prior to randomization to 4 weeks post randomization
Change in actigraphy derived total sleep time
Actigraphy data obtained using Axivity- AX6.
Measured: From 2 weeks prior to randomization to 4 weeks post randomization
Change in sleep diary derived total sleep time.
Estimated by patient in dairy.
Measured: From 2 weeks prior to randomization to 4 weeks post randomization
Change in mean actigraphy derived wake time
Wake time is total time awake over night after sleep onset. Actigraphy data obtained using Axivity- AX6.
Measured: From 2 weeks prior to randomization to 4 weeks post randomization
Change in mean sleep diary derived wake time
Wake time is total time awake over night after sleep onset as estimated by patient in dairy.
Measured: From 2 weeks prior to randomization to 4 weeks post randomization
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Jul 2022
- Study start1 Feb 2022
- Primary completion31 May 2027 (estimated)
- Study completion31 May 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Delayed Sleep Phase SyndromeStudies of the same condition, open and under way.
- More trials run by Stanford UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 86 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Stanford University
- Sponsor type
- University, hospital or other
- Collaborators
- University of California, San Francisco, Eisai Co., Ltd.
- Responsible party
- Principal investigator, Emmanuel Mignot, Stanford University
- Investigators
- Emmanuel Mignot, MD, PhD, Principal investigator, Stanford UniversityAndrew D Krystal, MD, MS, Principal investigator, University of California, San Francisco
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05463861
- Sponsor's protocol ID
- 59441
- Other IDs
- 23-38738
- Status last verified
- Oct 2026
- First submitted
- 20 Sep 2021
- Last updated
- 26 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 26 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Lemborexant in Delayed Sleep Phase Syndrome
- ClinicalTrials.gov ID
- NCT05463861
- Acronym / sponsor ID
- 59441
- Conditions
- Delayed Sleep Phase Syndrome
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 86 participants (estimated)
- Lead sponsor
- Stanford UniversityUniversity, hospital or other
- Collaborators
- University of California, San Francisco, Eisai Co., Ltd.
- Study start
- 1 Feb 2022 (actual)
- Primary completion
- 31 May 2027 (estimated)
- Study completion
- 31 May 2027 (estimated)
- First posted
- 19 Jul 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of the study is to evaluate whether Lemborexant is more effective than placebo in shortening sleep onset latency in patients with delayed sleep phase syndrome (both type 1 and type 2). This will be tracked using sleep logs as well as actigraphy.
In this 2-year study, we will examine if Lemborexant administered 5-10 mg nightly taken at desired bedtime (at least 2 hours prior to self-reported sleep onset habitual time) can improve the symptoms of Delayed Sleep Phase Syndrome.
Detailed description
Delayed sleep phase syndrome (DSPS) is a disorder in which a person's sleep is delayed by two hours or more beyond what is considered an acceptable or conventional bedtime. The delayed sleep then causes difficulty in being able to wake up at the desired time.
In DSPS, bedtime is shifted later than the general population such that individuals have difficulty getting enough sleep to meet their sleep needs before they have to get up for their daytime obligations (work, school, childcare, etc.). As a result, patients experience daytime impairment, including daytime sleepiness and cognitive impairment. DSPS, if maintained in adulthood, is associated with numerous deleterious health effects, although causality is not well established. Two phenotypes of DSPS are recognized depending on the phase of entrainment: one with a late phase and normal phase angle (non-circadian) and other with a late phase and abnormal phase angle (circadian). The differentiation of these two phenotypes is theoretical: a mixed situation may be involved in some cases and the exact pathophysiology of each subtype is still controversial.
In theory, however, separating the sample into these two subtypes is likely important to predict short- and long-term responses to orexin antagonists in DSPS.
Lemborexant is one of the dual orexin receptor antagonists on the US market. The purpose of this study is to examine if lemborexant administered 5 to 10 mg nightly, taken at desired bedtime (at least 2 hours prior to self-reported sleep onset time), can improve the symptoms of Delayed Sleep Phase Syndrome both in the circadian and non-circadian phenotypes. The phenotypes will be recruited in 1:1 proportion.The effect of lemborexant will be analyzed based on the collection of information from actigraphy watches, sleep diaries, and sleep scales. The total participation time involved in this study will be approximately 6 weeks (2 weeks of baseline assessment followed by 2-weeks of treatment/placebo, and 2 weeks post-treatment).
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Lemborexant | Active comparator | Drug: LemborexantPatients receive Lemborexant 5mg for 7 days and may be dose adjusted to 10mg. Patients continue to take Lemborexant 5mg or 10 mg for an additional 7 days. |
| Placebo | Placebo comparator | Drug: PlaceboPatients receive placebo to match Lemborexant for 14 days. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- 18 years of age or older.
- Diagnosed with delayed sleep phase syndrome (DSPS) meaning that:
- Concomitant medications will be allowed, though dosages will be required to remain fixed throughout participation in the study.
- The participant also needs to be willing and able to comply with all aspects of the protocol.
Key exclusion criteria (13 listed)
- 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).
- 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.
- 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.
- 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.
- Shift workers or subjects working unusual hours.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| LemborexantAlso: dayvigo®Lemborexant tablet administered orally once daily. | Drug | Lemborexant |
| PlaceboPlacebo to match Lemborexant tablet administered orally once daily. | Drug | Placebo |
Primary outcome
Change in actigraphy sleep latency onset
Time frame: From 2 weeks prior to randomization to 4 weeks post randomization
Sleep latency is the time from laying down until falling asleep. Actigraphy data obtained using Axivity- AX6.
8 secondary outcomes
Change in Epworth Sleepiness Scale (ESS)
Time frame: From randomization to 4 weeks post randomization
Change in Karolinska Sleepiness Scale (KSS)
Time frame: From randomization to 4 weeks post randomization
Change in sleep diary derived sleep onset latency
Time frame: From 2 weeks prior to randomization to 4 weeks post randomization
Sleep Regularity Index
Time frame: From 2 weeks prior to randomization to 4 weeks post randomization
Change in actigraphy derived total sleep time
Time frame: From 2 weeks prior to randomization to 4 weeks post randomization
Change in sleep diary derived total sleep time.
Time frame: From 2 weeks prior to randomization to 4 weeks post randomization
Change in mean actigraphy derived wake time
Time frame: From 2 weeks prior to randomization to 4 weeks post randomization
Change in mean sleep diary derived wake time
Time frame: From 2 weeks prior to randomization to 4 weeks post randomization
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 26 Oct 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
University of California San Francisco
San Francisco, United States
Emmanuel Mignot, MD, PhD principal investigator
Stanford University
Andrew D Krystal, MD, MS principal investigator
University of California, San Francisco
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Lemborexant in people with Delayed Sleep Phase Syndrome, run by Stanford University at 2 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 13 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 26 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Each site lists its own contact: choose the nearest one under Trial locations. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in actigraphy sleep latency onset (time frame: From 2 weeks prior to randomization to 4 weeks post randomization). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 26 Oct 2026.