InsomniaPhase 3NCT06655883
A Study of Suvorexant (MK-4305) for the Treatment of Insomnia Disorder in Participants With Opioid Use Disorder (MK-4305-098)
A Phase 3 study testing Suvorexant in people with Insomnia, run by Merck Sharp & Dohme LLC at 13 sites in United States.
Trial summary
People with opioid use disorder (OUD) can have trouble falling or staying asleep. Researchers want to know if suvorexant will help people with OUD fall asleep and stay asleep. The goal of this study is to learn about the safety of suvorexant and how well people tolerate it. Read more about this study
- Who is it for?
- Ages 18 to 70 years
- Conditions the study is for
- Insomnia
- What is being tested?
- Suvorexant
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 300 participants
- Where
- 13 sitesUnited States
- Study dates
- 9 Oct 2025to 24 Jun 2027
- Phase
- Phase 3
- 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 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- The main inclusion criteria include but are not limited to the following:
- Has a primary diagnosis of OUD according to Diagnostic and Statistical Manual of Mental Disorder, 5th Edition (DSM-5), and confirmed through the Mini International Neuropsychiatric Interview (MINI).
- Is on a verified, stable dose of medications for opioid use disorder (MOUD) treatment.
- Meets DSM-5 criteria for the diagnosis of Insomnia Disorder
- Has a regular bedtime between 8 PM (20:00) and 1 AM (01:00) and is willing to maintain it for the duration of the study.
- Has not used opioids for a period of at least 4 weeks before entering the study.
Who cannot join
- The main exclusion criteria include but are not limited to the following:
- Has current uncontrolled major co-morbid psychiatric illness including major depressive disorder, bipolar disorder, schizophrenia, or any psychiatric condition with psychotic features.
- Has current diagnosis or history within 5 years of any of the following: narcolepsy, sleep paralysis, severe periodic limb movement disorder, restless leg syndrome, cataplexy, circadian rhythm sleep disorder, parasomnia including nightmare disorder, sleep terror disorder, sleepwalking disorder, rapid eye movement (REM) behavior disorder, significant degree of sleep-related breathing disorder, excessive daytime sleepiness (EDS), or primary hypersomnia.
- Is at imminent risk of self-harm.
- Has a known history of stroke that may confound the diagnosis of insomnia.
- Has a clinically significant movement disorder such as akinesia.
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- Has a history of hepatitis or live disease.
- Has habitual use of central nervous system (CNS)-depressants or stimulants that may be responsible for the participant's disturbed sleep.
- Has a history of malignancy, ≤3 years prior to start of study, with the exception of nonmelanoma skin cancer, prostate cancer or localized carcinoma in situ of the cervix.
- Has a history of hypersensitivity to more than 3 chemical classes of drugs, including prescription and over-the-counter medications.
- Has donated blood products or had phlebotomy within 8 weeks prior to start of study.
- Has a history of transmeridian travel within 2 weeks prior to start of study.
Trial locations and contacts
13 sites in 1 country. Contact the study team or a site near you to ask about taking part.
13 sites in 1 country
United States13 sites, 13 recruiting
- Recruiting
Johns Hopkins University ( Site 1001)
Baltimore, Maryland, 21224
Study Coordinator, 443-216-9237
- Recruiting
Bradenton Research Center ( Site 2021)
Bradenton, Florida, 34205
Study Coordinator, 941-708-0005
- Recruiting
Medical University of South Carolina ( Site 1005)
Charleston, South Carolina, 29403
Study Coordinator, 843-792-4636
- Recruiting
Adams Clinical Dallas ( Site 2007)
DeSoto, Texas, 75115
Study Coordinator, 972-283-6286
- Recruiting
Cenexel CNS ( Site 2012)
Garden Grove, California, 92845
Study Coordinator, 866-787-4257
- Recruiting
Memorial Hermann Village ( Site 2001)
Houston, Texas, 77043
Study Coordinator, 281-369-5765
- Recruiting
Hassman Research Institute Marlton Site ( Site 2005)
Marlton, New Jersey, 08053
Study Coordinator, 856-261-6420
- Recruiting
Yale University School of Medicine ( Site 1003)
New Haven, Connecticut, 06520
Study Coordinator, 203-785-3627
- Recruiting
The Rivus Wellness & Research Institute ( Site 2014)
Oklahoma City, Oklahoma, 73112
Study Coordinator, 405-607-2233
- Recruiting
Penn Medicine University of Pennsylvania Health System- Center for Studies of Addiction ( Site 1006)
Philadelphia, Pennsylvania, 19104
Study Coordinator, 215-222-3200
- Recruiting
Butler Hospital ( Site 1002)
Providence, Rhode Island, 02906
Study Coordinator, 401-455-6440
- Recruiting
VCU Institute for Drug and Alcohol Studies ( Site 1004)
Richmond, Virginia, 23219
Study Coordinator, 804-827-3784
- Recruiting
CenExel iResearch, LLC ( Site 2010)
Savannah, Georgia, 31405
Study Coordinator, 912-744-0800
About this study
Official title: A Phase 3, Multicenter, Randomized, Double-blind, Placebo-controlled Study to Evaluate the Efficacy and Safety of Suvorexant for the Treatment of Insomnia in Participants With Opioid Use Disorder
People with opioid use disorder (OUD) can have trouble falling or staying asleep. Researchers want to know if suvorexant will help people with OUD fall asleep and stay asleep. The goal of this study is to learn about the safety of suvorexant and how well people tolerate it. Researchers also want to learn if suvorexant helps people sleep longer compared to people who take placebo. A placebo looks like the study medicine but has no actual study medicine in it.
- Conditions
- Insomnia
- Being tested
- Suvorexant, Placebo
- Medical subject headings
- Sleep Initiation and Maintenance Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
SuvorexantDrug
Also called MK-4305
Oral Tablet
PlaceboDrug
Oral Tablet
| Study group | Role | What they receive |
|---|---|---|
| Suvorexant | Experimental | Participants receive 10 mg of suvorexant for the first three nights, increased to 20 mg of suvorexant nightly thereafter at the investigator's discretion, for up to approximately 8 weeks. Receives: Drug: Suvorexant |
| Placebo | Placebo comparator | Participants receive suvorexant-matching placebo for up to approximately 8 weeks. Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change from Baseline in Total Sleep Time at Week 8
Total sleep time will be measured in a sleep laboratory by polysomnography at the participant's habitual bedtime. Change from baseline in total sleep time at Week 8 will be reported.
Measured: Baseline and Week 8
Number of Participants Who Experience One or More Adverse Events (AEs)
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Measured: Up to approximately 10 weeks
Number of Participants Who Experience One or More Serious Adverse Events (SAEs)
An SAE is any untoward medical occurrence that at any dose results in death, is life threatening, requires or prolongs inpatient hospitalization, results in persistent or significant disability or incapacity, is a congenital anomaly or birth defect or is another important medical event deemed such by medical or scientific judgement.
Measured: Up to approximately 10 weeks
Number of Participants Who Discontinue Study Treatment Due to an AE
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Measured: Up to approximately 8 weeks
Secondary outcomes (7)
Change from Baseline in Wakefulness after Persistent Sleep Onset at Week 8
Wakefulness after persistent sleep onset will be measured in a sleep laboratory by polysomnography at the participant's habitual bedtime. Change from baseline in wakefulness after persistent sleep onset at Week 8 will be reported.
Measured: Baseline and Week 8
Number of Participants Who are Positive for Substance Abuse at Day 1
A positive assessment for substance abuse at Day 1 is defined as either a positive urine drug test for opioids and other nonmedical substances including fentanyl, cocaine, amphetamines, benzodiazepines, and cannabis OR a positive response on the Substance Use History (SUH) Since Last Assessment questionnaire. The Substance Use History Questionnaire (SUH) has been developed specifically for this study. This is a self-reported questionnaire used to obtain a variety of quantitative estimates of cannabis, alcohol, and other nonmedical substance use. The SUH Since Last Assessment Questionnaire will be used to assess nonmedical substance and alcohol use since the previous study visit.
Measured: Day 1
Number of Participants Who are Positive for Substance Abuse at Day 4
A positive assessment for substance abuse at Day 4 is defined as either a positive urine drug test for opioids and other nonmedical substances including fentanyl, cocaine, amphetamines, benzodiazepines, and cannabis OR a positive response on the Substance Use History (SUH) Since Last Assessment questionnaire. The Substance Use History Questionnaire (SUH) has been developed specifically for this study. This is a self-reported questionnaire used to obtain a variety of quantitative estimates of cannabis, alcohol, and other nonmedical substance use. The SUH Since Last Assessment Questionnaire will be used to assess nonmedical substance and alcohol use since the previous study visit.
Measured: Day 4
Number of Participants Who are Positive for Substance Abuse at Week 2
A positive assessment for substance abuse at Week 2 is defined as either a positive urine drug test for opioids and other nonmedical substances including fentanyl, cocaine, amphetamines, benzodiazepines, and cannabis OR a positive response on the Substance Use History (SUH) Since Last Assessment questionnaire. The Substance Use History Questionnaire (SUH) has been developed specifically for this study. This is a self-reported questionnaire used to obtain a variety of quantitative estimates of cannabis, alcohol, and other nonmedical substance use. The SUH Since Last Assessment Questionnaire will be used to assess nonmedical substance and alcohol use since the previous study visit.
Measured: Week 2
Number of Participants Who are Positive for Substance Abuse at Week 4
A positive assessment for substance abuse at Week 4 is defined as either a positive urine drug test for opioids and other nonmedical substances including fentanyl, cocaine, amphetamines, benzodiazepines, and cannabis OR a positive response on the Substance Use History (SUH) Since Last Assessment questionnaire. The Substance Use History Questionnaire (SUH) has been developed specifically for this study. This is a self-reported questionnaire used to obtain a variety of quantitative estimates of cannabis, alcohol, and other nonmedical substance use. The SUH Since Last Assessment Questionnaire will be used to assess nonmedical substance and alcohol use since the previous study visit.
Measured: Week 4
Number of Participants Who are Positive for Substance Abuse at Week 8
A positive assessment for substance abuse at Week 8 is defined as either a positive urine drug test for opioids and other nonmedical substances including fentanyl, cocaine, amphetamines, benzodiazepines, and cannabis OR a positive response on the Substance Use History (SUH) Since Last Assessment questionnaire. The Substance Use History Questionnaire (SUH) has been developed specifically for this study. This is a self-reported questionnaire used to obtain a variety of quantitative estimates of cannabis, alcohol, and other nonmedical substance use. The SUH Since Last Assessment Questionnaire will be used to assess nonmedical substance and alcohol use since the previous study visit.
Measured: Week 8
Number of Participants with Positive Urine Drug Screen
A positive urine drug screen is defined as urine drug test positive for opioids and other nonmedical substances including fentanyl, cocaine, amphetamines, benzodiazepines, and cannabis
Measured: Day 1, Day 4, Week 2, Week 4, Week 8
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted24 Oct 2024
- Study start9 Oct 2025
- Primary completion24 Jun 2027 (estimated)
- Study completion24 Jun 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for InsomniaStudies of the same condition, open and under way.
- More trials run by Merck Sharp & Dohme LLCThe 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 3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 300 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Merck Sharp & Dohme LLC
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Medical Director, Study director, Merck Sharp & Dohme LLC
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06655883
- Sponsor's protocol ID
- 4305-098
- Other IDs
- MK-4305-098
- Status last verified
- Sep 2026
- First submitted
- 22 Oct 2024
- Last updated
- 21 Sep 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf
Study at a glance
From the registry record, last updated by the sponsor on 21 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 3, Multicenter, Randomized, Double-blind, Placebo-controlled Study to Evaluate the Efficacy and Safety of Suvorexant for the Treatment of Insomnia in Participants With Opioid Use Disorder
- ClinicalTrials.gov ID
- NCT06655883
- Acronym / sponsor ID
- 4305-098
- Conditions
- Insomnia
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 300 participants (estimated)
- Lead sponsor
- Merck Sharp & Dohme LLCIndustry (pharma, biotech, devices)
- Study start
- 9 Oct 2025 (actual)
- Primary completion
- 24 Jun 2027 (estimated)
- Study completion
- 24 Jun 2027 (estimated)
- First posted
- 24 Oct 2024 (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.
People with opioid use disorder (OUD) can have trouble falling or staying asleep. Researchers want to know if suvorexant will help people with OUD fall asleep and stay asleep. The goal of this study is to learn about the safety of suvorexant and how well people tolerate it. Researchers also want to learn if suvorexant helps people sleep longer compared to people who take placebo. A placebo looks like the study medicine but has no actual study medicine in it.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Suvorexant | Experimental | Drug: SuvorexantParticipants receive 10 mg of suvorexant for the first three nights, increased to 20 mg of suvorexant nightly thereafter at the investigator's discretion, for up to approximately 8 weeks. |
| Placebo | Placebo comparator | Drug: PlaceboParticipants receive suvorexant-matching placebo for up to approximately 8 weeks. |
Who may qualify
- Ages
- 18 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Has a primary diagnosis of OUD according to Diagnostic and Statistical Manual of Mental Disorder, 5th Edition (DSM-5), and confirmed through the Mini International Neuropsychiatric Interview (MINI).
- Is on a verified, stable dose of medications for opioid use disorder (MOUD) treatment.
- Meets DSM-5 criteria for the diagnosis of Insomnia Disorder
- Has a regular bedtime between 8 PM (20:00) and 1 AM (01:00) and is willing to maintain it for the duration of the study.
- Has not used opioids for a period of at least 4 weeks before entering the study.
Key exclusion criteria (12 listed)
- Has current uncontrolled major co-morbid psychiatric illness including major depressive disorder, bipolar disorder, schizophrenia, or any psychiatric condition with psychotic features.
- Has current diagnosis or history within 5 years of any of the following: narcolepsy, sleep paralysis, severe periodic limb movement disorder, restless leg syndrome, cataplexy, circadian rhythm sleep disorder, parasomnia including nightmare disorder, sleep terror disorder, sleepwalking disorder, rapid eye movement (REM) behavior disorder, significant degree of sleep-related breathing disorder, excessive daytime sleepiness (EDS), or primary hypersomnia.
- Is at imminent risk of self-harm.
- Has a known history of stroke that may confound the diagnosis of insomnia.
- Has a clinically significant movement disorder such as akinesia.
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 |
|---|---|---|
| SuvorexantAlso: MK-4305Oral Tablet | Drug | Suvorexant |
| PlaceboOral Tablet | Drug | Placebo |
Primary outcome
Change from Baseline in Total Sleep Time at Week 8
Time frame: Baseline and Week 8
Total sleep time will be measured in a sleep laboratory by polysomnography at the participant's habitual bedtime. Change from baseline in total sleep time at Week 8 will be reported.
Number of Participants Who Experience One or More Adverse Events (AEs)
Time frame: Up to approximately 10 weeks
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
Number of Participants Who Experience One or More Serious Adverse Events (SAEs)
Time frame: Up to approximately 10 weeks
An SAE is any untoward medical occurrence that at any dose results in death, is life threatening, requires or prolongs inpatient hospitalization, results in persistent or significant disability or incapacity, is a congenital anomaly or birth defect or is another important medical event deemed such by medical or scientific judgement.
Number of Participants Who Discontinue Study Treatment Due to an AE
Time frame: Up to approximately 8 weeks
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention.
7 secondary outcomes
Change from Baseline in Wakefulness after Persistent Sleep Onset at Week 8
Time frame: Baseline and Week 8
Number of Participants Who are Positive for Substance Abuse at Day 1
Time frame: Day 1
Number of Participants Who are Positive for Substance Abuse at Day 4
Time frame: Day 4
Number of Participants Who are Positive for Substance Abuse at Week 2
Time frame: Week 2
Number of Participants Who are Positive for Substance Abuse at Week 4
Time frame: Week 4
Number of Participants Who are Positive for Substance Abuse at Week 8
Time frame: Week 8
Number of Participants with Positive Urine Drug Screen
Time frame: Day 1, Day 4, Week 2, Week 4, Week 8
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 21 Sep 2026.
- Merck Clinical Trials InformationLink provided by the sponsor.
- Individual participant dataSharing planned: Yes. https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf
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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.
Medical Director study director
Merck Sharp & Dohme LLC
13 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Suvorexant in people with Insomnia, run by Merck Sharp & Dohme LLC at 13 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 6 inclusion and 12 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 21 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 13 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 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
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?
Contact Toll Free Number (1-888-577-8839, Trialsites@msd.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change from Baseline in Total Sleep Time at Week 8 (time frame: Baseline and Week 8). The study lists 4 primary outcomes in all. 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 21 Sep 2026.