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Obstructive Sleep ApneaPhase 2/3REPOSANCT06146101

RePOSA-Revealing the Efficacy of IHL-42X Use in Patients With OSA

A Phase 2/3 study testing IHL-42X Low Dose, IHL-42X High Dose and IHL-42X (Optimal Dose) in people with Obstructive Sleep Apnea, run by Incannex Healthcare Ltd at 20 sites in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

The goal of this randomised, double-blind phase II/III clinical trial is to determine the safety and efficacy of IHL-42X in subjects with obstructive sleep apnoea who are intolerant, non-compliant, or naïve to positive airway pressure. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Obstructive Sleep Apnea
What is being tested?
IHL-42X Low Dose, IHL-42X High Dose and IHL-42X (Optimal Dose)
Type of treatment
Pill or oral medicine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
121 participants
Where
20 sitesUnited States
Study dates
2 May 2024to 27 Jul 2025
Phase
Phase 2/3
Are there results?
None posted in the registry

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

  • Aged ≥18 years of age
  • Screening polysomnography (PSG) findings confirmed on central over-read:
  • AHI ≥15
  • ≤ 25% central or mixed apneas/hypopneas
  • no Cheyne-Stokes respiration
  • total sleep time ≥ 2 hours
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  • Intolerant, non-compliant, or naïve to PAP (Note: No more than 25% of the study population will consist of PAP-naïve patients). Patients will be identified as intolerant, non-compliant, or naïve to PAP devices by the following criteria:
  • Patients are regarded as PAP-non-compliant if they do not use PAP for ≥ 4 hours for at least 21 nights during consecutive 30-day period based on data collected from the PAP device (eg, SD storage cards) and/or a cloud-based repository of PAP device data.
  • Patients are regarded as PAP-intolerant if they are former PAP users, ie, a PAP device that they have not used for >30 days or who do not have access to PAP device
  • Patients are regarded as PAP-naïve if they have no prior experience with PAP. Patients who have undergone a split-study, ie, a study of PAP during PSG, are not considered PAP- naïve and should be categorised according to a through b above. (Note: PAP-naïve patients will have the benefits and risks of PAP explained at screening, including that PAP is standard of care for OSA. These patients also have the option to withdraw from the study at any time if he/she elects to be treated with PAP or other alternative therapy such as an oral appliance or surgery)
  • Must agree not to take any form of cannabis or cannabinoid, or any other illicit or recreational drug with the exception of the investigational product (IP) while participating in this study.
  • A female patient of childbearing potential must agree to use 2 approved methods of contraception. Approved methods of contraception include the following:
  • Intra-uterine device in place for at least 3 months prior to Day 1 through to 10 days following the last dose of the study drug
  • Barrier method (condom or diaphragm) for at least 3 months prior to Day 1 through to 10 days after the last dose of the study drug
  • Stable hormonal contraceptive which includes oral, intravaginal, intrauterine, transdermal, injectable, or implantable methods of hormonal contraception for at least 3 months prior to Day 1.
  • A female will not be considered of childbearing potential if:
  • 12 months of spontaneous amenorrhea or 6 months of spontaneous amenorrhea with serum FSH levels > 40 mIU/ml
  • undergone bilateral tubal ligation, hysterectomy, or bilateral oophorectomy at least 6 months prior to Day 1
  • A male patient must agree to use at least 1 approved method of contraception (or as required by local regulations) while engaging in sexual activity from study Day -1 through End-of-Study (EOS) follow-up and/or up to 10 days following the last administration of the study drug. Male patients must not donate sperm during this same period. Approved methods of contraception include the following:
  • Barrier method (condom) for at least 14 days prior to Day 1 through to 10 days after the final dose of the study drug
  • Surgical sterilisation (vasectomy) at least 6 months prior to Day 1
  • Voluntarily written consent to participate in the study and be willing and able to participate in all scheduled visits, treatment plans, tests, and other study procedures according to the protocol

Who cannot join

  • Body mass index >45 kg/m2
  • PAP-compliant, defined by the use of PAP for ≥ 4 hours for at least 21 nights during the consecutive 30-day period
  • Current use of oral appliances (eg, mandibular advancement device, tongue retaining device, or mouth guard)
  • Maxillomandibular advancement, upper airway, or bariatric surgery within the last 6 months prior to first administration of the study drug; or patients who are considering surgical treatment
  • Use of benzodiazepines, sedative-hypnotics, or stimulants (ATC N06B, N05C, N05BA, N03AE, and N01AF categories) to treat insomnia, OSA, other sleep disorders
  • Pierre Robin, Treacher Collins, or other craniofacial malformation syndrome, or grade ≥3 tonsillar hypertrophy
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  • Chronic neuromuscular disorders such as motor neuron disease, muscular dystrophy, or myopathy
  • Known allergic reaction to cannabis products with previous use
  • Known allergic reaction to sesame oil
  • Known allergic reaction to acetazolamide
  • Pregnant or breast-feeding
  • Current illicit drug abuse (within the last 6 months prior to screening) ; "abuse" has some subsets that are objective and some that require investigator judgement; questions should be discussed with the medical monitor or with the sponsor
  • An objective subset includes consumption of substances that are "illicit", i.e. not legal per local laws
  • Investigator judgement is expected for legally marketed products ingested for other than the approved indication(s)
  • Severe depression, defined as a score of ≥30 on the Major Depression Inventory questionnaire
  • Severe anxiety, defined as score of >15 on the General Anxiety Disorder-7 questionnaire
  • Any of the following co-morbid conditions (Note: clarification on co-morbidities and inclusion/exclusion criteria may be discussed with the medical monitor and/or sponsor):
  • severe psychiatric disorder that might be aggravated or exacerbated by dronabinol's potential to cause anxiety/nervousness, depersonalization, hallucination, etc;
  • cardiac dysfunction and/or its treatment that might augment dronabinol's potential to cause tachycardia or vasodilation;
  • marked hepatic dysfunction as defined by elevated ALT or AST >3 times the upper limit of normal, that would reduce dronabinol metabolism; one retest per subject is permitted at the discretion of the investigator; the subject may continue in RePOSA if BOTH repeat transaminase levels are within the reference range;
  • current or history of encephalopathy or cirrhosis Child-Pugh category B or C (see Appendix 7) since acetazolamide can increase blood ammonia levels precipitating a bout of hepatic encephalopathy;
  • marked renal dysfunction, including eGFR <60 mL/min/1.73m2, as determined using the National Kidney Foundation calculator
  • hypokalaemia (low blood potassium), hyponatremia (low blood sodium), hyperchloraemic acidosis, and/or adrenal insufficiency that might be aggravated or exacerbated by acetazolamide's activity as a carbonic anhydrase inhibitor
  • Other ongoing condition(s) that the investigator considers may be clinically significant with regards to the patient's safe participation in this study or may confound this study's findings; any consideration should be discussed with the medical monitor or with the sponsor
  • Participation in any other interventional studies involving investigational or marketed products within 30 days or 5.5 half-lives, whichever is longer, of the IP prior to screening. Patients in Phase II may enter screening (with a different identifier) for Phase III after 30 days from the last administration of the study drug in Phase II.

Trial locations and contacts

20 sites in 1 country.

20 sites in 1 country

United States20 sites

  • Velocity Clinical Research - Anderson

    Anderson, South Carolina, 29621

  • NeuroTrials Research, Inc.

    Atlanta, Georgia, 30328

  • FutureSearch Trials

    Austin, Texas, 78731

  • Exalt Clinical Research

    Chula Vista, California, 91910

  • CTI Clinical Trial and Consulting Services

    Cincinnati, Ohio, 45212

  • Intrepid Research

    Cincinnati, Ohio, 45245-4501

  • FutureSearch Trials of Dallas, LP

    Dallas, Texas, 75231-3442

  • Centennial Medical Group

    Elkridge, Maryland, 21075-6434

  • Velocity Clinical Research - Greenville

    Greenville, South Carolina, 29615

  • Henderson Clinical Trials,LLC

    Henderson, Nevada, 89052-5016

  • Advanced Respiratory and Sleep Medicine, PLLC

    Huntersville, North Carolina, 28078

  • Clinical Neuroscience Solutions, Inc. (CNS Healthcare of Jacksonville)

    Jacksonville, Florida, 32256

  • CenExel CNS- Los Alamitos

    Long Beach, California, 90806

  • Tandem Clinical Research, LLC

    Marrero, Louisiana, 70072

  • Clinical Neuroscience Solutions, Inc. (CNS Healthcare of Memphis)

    Memphis, Tennessee, 38119

  • Clinical Neuroscience Solutions, Inc. (CNS Healthcare of Orlando)

    Orlando, Florida, 32806

  • Meridian Clinical Research, LLC

    Rockville, Maryland, 20854

  • Pacific Clinical Research Medical Group

    Upland, California, 91786-4985

  • Teradan Clinical Trials

    Valrico, Florida, 33596-8262

  • Palm Beach Research Center

    West Palm Beach, Florida, 33409-3401

Other trials in United States

About this study

Official title: A Phase II/III, Randomised, Double-Blind Clinical Trial to Determine the Safety and Efficacy of IHL-42X in Subjects With Obstructive Sleep Apnoea Who Are Intolerant, Non-Compliant, or Naïve to Positive Airway Pressure

The goal of this randomised, double-blind phase II/III clinical trial is to determine the safety and efficacy of IHL-42X in subjects with obstructive sleep apnoea who are intolerant, non-compliant, or naïve to positive airway pressure.

Phase II study will be a 4-week dose-finding study comparing two dose strengths of IHL-42X to placebo. The optimal dose strength will be selected based on comparing the safety and efficacy of the two IHL-42X dose strengths to placebo over a 4-week treatment period. The three treatment groups are; IHL-42X Low dose (2.5mg dronabinol, 125mg acetazolamide), IHL-42X High dose (5mg dronabinol, 250mg acetazolamide) and Placebo. Each treatment group will enrol approximately 40 patients per treatment arm, for a total of approximately 120 patients.

Read more

The safety and efficacy results of the Phase II study will be used to select the dose strength of IHL-42X and corresponding doses of dronabinol and acetazolamide in Phase III.

Phase III study will use the optimal dose strength of IHL-42X identified in Phase II and will be compared to the component active pharmaceutical ingredients at equivalent dose strengths to those found in the IHL-42X optimal dose strength and placebo over 52 weeks. The four treatment groups are; IHL-42X (optimal dose from Phase II), Acetazolamide (equivalent dose strength to that in the IHL-42X optimal dose strength), Dronabinol (equivalent dose strength to that in the IHL-42X optimal dose strength) and placebo. The treatment groups will enrol approximately 165 patients in IHL-42X, approximately 55 patients in dronabinol, approximately 55 in acetazolamide, and approximately 165 in placebo, for a total of approximately 440 patients.

Being tested
IHL-42X Low Dose, IHL-42X High Dose, Placebo, IHL-42X (Optimal Dose), Dronabinol
Medical subject headings
Sleep Apnea, Obstructive

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • IHL-42X Low DoseDrug

    Also called Phase 2 Investigational Product - IHL-42X Low dose

    Softgel capsule

  • IHL-42X High DoseDrug

    Also called Phase 2 Investigational Product - IHL-42X High dose

    Softgel capsule

  • PlaceboDrug

    Also called Phase 2 Placebo

    Softgel capsule

  • IHL-42X (Optimal Dose)Drug

    Also called Phase 3 Investigational Product - IHL-42X

    Softgel capsule

  • DronabinolDrug

    Also called Phase 3 Comparator - Reference Listed Drug/Dronabinol

    Softgel capsule

  • AcetazolamideDrug

    Also called Phase 3 Comparator - Reference Listed Drug/Acetazolamide

    Softgel capsule

  • PlaceboDrug

    Also called Phase 3 Placebo

    Softgel capsule

Study groups in NCT06146101
Study groupRoleWhat they receive
Phase 2 Investigational Product - IHL-42X Low doseExperimentalIHL-42X (2.5 mg dronabinol + 125 mg acetazolamide), one capsule self-administered once daily every night approximately 1 hour prior to bed for 4 weeks.
Receives: Drug: IHL-42X Low Dose
Phase 2 Investigational Product - IHL-42X High doseExperimentalIHL-42X (5 mg dronabinol + 250 mg acetazolamide), one capsule self-administered once daily every night approximately 1 hour prior to bed for 4 weeks.
Receives: Drug: IHL-42X High Dose
Phase 2 PlaceboPlacebo comparatorOne capsule self-administered once daily every night approximately 1 hour prior to bed for 4 weeks.
Receives: Drug: Placebo
Phase 3 Investigational Product - IHL-42XExperimentalIHL-42X (dose will be identified based on the safety and efficacy results in Phase II), one capsule self-administered once daily every night approximately 1 hour prior to bed for 52 weeks.
Receives: Drug: IHL-42X (Optimal Dose)
Phase 3 Comparator - Reference Listed Drug/DronabinolActive comparatorOne capsule of dronabinol (equivalent dose strength to that in the IHL-42X optimal dose strength) self-administered once daily every night approximately 1 hour prior to bed for 3 months then IHL-42X (optimal dose) one capsule self-administered once daily every night approximately 1 hour prior to bed for the remaining 9 months.
Receives: Drug: Dronabinol
Phase 3 Comparator - Reference Listed Drug/AcetazolamideActive comparatorOne capsule of acetazolamide (equivalent dose strength to that in the IHL-42X optimal dose strength) self-administered once daily every night approximately 1 hour prior to bed for 3 months then IHL-42X (optimal dose) one capsule self-administered once daily every night approximately 1 hour prior to bed for the remaining 9 months.
Receives: Drug: Acetazolamide
Phase 3 PlaceboPlacebo comparatorOne capsule self-administered once daily every night approximately 1 hour prior to bed for 52 weeks.
Receives: Drug: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Change in apnea-hypopnea index (AHI)

    Phase 2 - Assess the change in AHI compared to baseline

    Measured: 4 weeks

  2. Change in apnea-hypopnea index (AHI)

    Phase 3 - Assess the change in AHI compared to baseline

    Measured: 52 weeks

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted24 Nov 2023
  2. Study start2 May 2024
  3. Primary completion20 May 2025
  4. Study completion27 Jul 2025

Resources

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 2/3
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Model description
Phase 2 (3 arms) 1. IHL-42X low dose (2.5mg dronabinol, 125mg acetazolamide) 2. IHL-42X high dose (5mg dronabinol, 250mg acetazolamide) 3. Placebo Phase 3 (4 Arms) 1. IHL-42X (Optimal dose from phase 2) 2. Dronabinol (equivalent dose strength to that in the IHL-42X optimal dose strength) 3. Acetazolamide (equivalent dose strength to that in the IHL-42X optimal dose strength) 4. Placebo
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
121 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06146101
Sponsor's protocol ID
IHL42XOSAP2/3
Other IDs
U1111-1302-4915
Acronym
REPOSA
Status last verified
Jul 2026
First submitted
17 Nov 2023
Last updated
27 Jul 2026
Results posted
No
FDA-regulated drug
Yes
FDA-regulated device
No

Questions about this trial

What is this clinical trial studying?

A Phase 2/3 study testing IHL-42X Low Dose, IHL-42X High Dose and IHL-42X (Optimal Dose) in people with Obstructive Sleep Apnea, run by Incannex Healthcare Ltd at 20 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 22 inclusion and 25 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: finished, as of the sponsor's last update on 27 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 20 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 combined phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

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?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change in apnea-hypopnea index (AHI) (time frame: 4 weeks). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT06146101.

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 27 Jul 2026.

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