Obstructive Sleep ApneaPhase 1/2RemmOSANCT05589792
Acetazolamide on REM OSA
A Phase 1/2 study testing Acetazolamide in people with Obstructive Sleep Apnea, run by Brigham and Women's Hospital at 1 site in United States.
Trial summary
OSA is a highly prevalent disorder that has major consequences for cardiovascular health, neurocognitive function, risk of traffic accidents, daytime sleepiness and quality of life. Read more about this study
- Who is it for?
- Ages 21 to 75 years
- Conditions the study is for
- Obstructive Sleep Apnea
- What is being tested?
- Acetazolamide
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 11 participants
- Where
- 1 siteUnited States
- Study dates
- 30 Jan 2023to 31 Dec 2025
- Phase
- Phase 1/2
- 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 21 to 75 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Diagnosed REM OSA (per baseline screening: REM AHI/nREM AHI≥2) [31-33]
- REM duration>10 minutes
- Not using CPAP (>1 week).
Who cannot join
- Any uncontrolled medical condition
- Current use of the medications under investigation
- Use of medications expected to stimulate or depress respiration (including opioids, barbiturates, doxapram, almitrine, theophylline, 4-hydroxybutanoic acid).
- Conditions likely to affect obstructive sleep apnea physiology: neuromuscular disease or other major neurological disorder, heart failure (also below), or any other unstable major medical condition.
- Respiratory disorders other than sleep disordered breathing:
- chronic hypoventilation/hypoxemia (awake SaO2 < 92% by oximetry) due to chronic obstructive pulmonary disease or other respiratory conditions.
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- Other sleep disorders: periodic limb movements (periodic limb movement arousal index > 10/hr), narcolepsy, or parasomnias.
- Contraindications for acetazolamide, including:
- Hyperchloremic acidosis
- Hypokalemia
- Hyponatremia
- Adrenal insufficiency
- Impaired kidney function
- Hypersensitivity to acetazolamide or other sulfonamides.
- Marked liver disease or impairment of liver function, including cirrhosis.
- Contraindications to the use of lidocaine 4%/oxymetazoline HCT.
- Claustrophobia
- Pregnancy or nursing
Trial locations and contacts
1 site in 1 country.
United States1 site
Brigham and Women's Hospital
Boston, Massachusetts, 02115
About this study
Official title: The Effect of Acetazolamide on the Severity of REM Obstructive Sleep Apnea
OSA is a highly prevalent disorder that has major consequences for cardiovascular health, neurocognitive function, risk of traffic accidents, daytime sleepiness and quality of life. In particular, REM sleep is accompanied by more frequent and longer obstructive events, that yield more profound hypoxemia than during non-REM (nREM). Exaggerated OSA severity in REM is the consequence of ventilatory drive dips, particularly during phasic eye movements. Unfortunately, the leading treatment for REM and nREM OSA, CPAP-which acts to pneumatically splint the pharynx open-is intolerable for many patients. Treatment outcomes for REM OSA are burdened by further incomplete CPAP adherence later in the night, which commonly leaves REM periods undertreated. In this protocol, the investigators will test the effect of Acetazolamide on REM OSA and on ventilatory parameters such as genioglossus muscle activity and ventilatory drive.
Read the detailed description
After a baseline home sleep test that will assess the presence of OSA and REM OSA, two overnight, in-lab sleep studies will be performed: a drug night and a placebo night. The patient will breath spontaneously (without CPAP) for both nights. On the study nights, subjects will present to the laboratory in the evening and be instrumented with a full polysomnigraphy for monitoring sleep, physiological variables (endotypes), and respiratory events. Participants will also be instrumented with EMG wires and introesophageal catheter for the recording of genioglossus muscle activity and respiratory drive, respectively. A history and physical examination will be performed on each night prior to beginning the study, as will a urine pregnancy test in premenopausal women. Acetazolamide 500 mg will be taken for 2 days (including the day of the study), after a day in which it will be administered at half dose, before bedtime. Subjects will sleep at least 50% of the night in the supine position. At least four hours of sleep with high quality signal acquisition will be required for a study to be judged adequate. Subjective sleep quality will be assessed in the morning. After the first overnight study is completed, there will be a four day washout period prior to crossing over to the other treatment
- Conditions
- Obstructive Sleep Apnea
- Being tested
- Placebo oral capsule, Acetazolamide
- 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.
Placebo oral capsuleDrug
Placebo before sleep for 3 nights before the study (inclusive)
AcetazolamideDrug
Acetazolamide 250 mg 3 nights before the study at bedtime, Acetazolamide 500 mg for 2 nights before the study (inclusive) at bedtime.
| Study group | Role | What they receive |
|---|---|---|
| Placebo | Placebo comparator | Placebo capsule before bedtime for 3 nights before the studies (inclusive) Receives: Drug: Placebo oral capsule |
| Acetazolamide | Active comparator | Acetazolamide 250 mg before bedtime 3 nights before the study, Acetazolamide 500 mg before bedtime for 2 nights before the study (inclusive) Receives: Drug: Acetazolamide |
What is being measured
The primary outcome is the main question the study is designed to answer.
Apnea hypopnea index
Number of events/hour of sleep
Measured: 1 night
Hypoxic burden
The total area under the respiratory event-related desaturation curve, measured as in %min/hr
Measured: 1 night
Ventilatory drive in REM and NREM
Ventilatory drive will be calculated using diaphragm EMG (as percent of eupneic ventilatory drive)
Measured: 1 night
Genioglossus activity in REM and NREM
Genioglossus activity will be calculated using EMG wires under the tongue (as percent of eupneic activity or maximal activity)
Measured: 1 night
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Oct 2022
- Study start30 Jan 2023
- Primary completion1 Dec 2025
- Study completion31 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Obstructive Sleep ApneaStudies of the same condition, open and under way.
- More trials run by Brigham and Women's HospitalThe 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 1/2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 11 participants (actual)
Sponsor and investigators
- Lead sponsor
- Brigham and Women's Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Ludovico Messineo, Brigham and Women's Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05589792
- Sponsor's protocol ID
- 2022p002458
- Acronym
- RemmOSA
- Status last verified
- Jan 2026
- First submitted
- 18 Oct 2022
- Last updated
- 20 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Messineo L, Kim M, Azarbarzin A, Vena D, Preuss M, Esmaeili N, Aishah A, Lawrence NV, Gilbertson DC, White DP, Wellman A, Sands SA. Acetazolamide to prevent ventilatory drive withdrawal in REM sleep apnoea: a randomised controlled trial. Thorax. 2026 Mar 4:thorax-2025-223922. doi: 10.1136/thorax-2025-223922. Online ahead of print.
PubMed 41781273
Study at a glance
From the registry record, last updated by the sponsor on 20 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Acetazolamide on the Severity of REM Obstructive Sleep Apnea
- ClinicalTrials.gov ID
- NCT05589792
- Acronym / sponsor ID
- RemmOSA / 2022p002458
- Conditions
- Obstructive Sleep Apnea
- Phase
- Phase 1/2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 11 participants (actual)
- Lead sponsor
- Brigham and Women's HospitalUniversity, hospital or other
- Study start
- 30 Jan 2023 (actual)
- Primary completion
- 1 Dec 2025 (actual)
- Study completion
- 31 Dec 2025 (actual)
- First posted
- 21 Oct 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.
OSA is a highly prevalent disorder that has major consequences for cardiovascular health, neurocognitive function, risk of traffic accidents, daytime sleepiness and quality of life. In particular, REM sleep is accompanied by more frequent and longer obstructive events, that yield more profound hypoxemia than during non-REM (nREM). Exaggerated OSA severity in REM is the consequence of ventilatory drive dips, particularly during phasic eye movements. Unfortunately, the leading treatment for REM and nREM OSA, CPAP-which acts to pneumatically splint the pharynx open-is intolerable for many patients. Treatment outcomes for REM OSA are burdened by further incomplete CPAP adherence later in the night, which commonly leaves REM periods undertreated. In this protocol, the investigators will test the effect of Acetazolamide on REM OSA and on ventilatory parameters such as genioglossus muscle activity and ventilatory drive.
Detailed description
After a baseline home sleep test that will assess the presence of OSA and REM OSA, two overnight, in-lab sleep studies will be performed: a drug night and a placebo night. The patient will breath spontaneously (without CPAP) for both nights. On the study nights, subjects will present to the laboratory in the evening and be instrumented with a full polysomnigraphy for monitoring sleep, physiological variables (endotypes), and respiratory events. Participants will also be instrumented with EMG wires and introesophageal catheter for the recording of genioglossus muscle activity and respiratory drive, respectively. A history and physical examination will be performed on each night prior to beginning the study, as will a urine pregnancy test in premenopausal women. Acetazolamide 500 mg will be taken for 2 days (including the day of the study), after a day in which it will be administered at half dose, before bedtime. Subjects will sleep at least 50% of the night in the supine position. At least four hours of sleep with high quality signal acquisition will be required for a study to be judged adequate. Subjective sleep quality will be assessed in the morning. After the first overnight study is completed, there will be a four day washout period prior to crossing over to the other treatment
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Placebo | Placebo comparator | Drug: Placebo oral capsulePlacebo capsule before bedtime for 3 nights before the studies (inclusive) |
| Acetazolamide | Active comparator | Drug: AcetazolamideAcetazolamide 250 mg before bedtime 3 nights before the study, Acetazolamide 500 mg before bedtime for 2 nights before the study (inclusive) |
Who may qualify
- Ages
- 21 to 75 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Diagnosed REM OSA (per baseline screening: REM AHI/nREM AHI≥2) [31-33]
- REM duration>10 minutes
- Not using CPAP (>1 week).
Key exclusion criteria (18 listed)
- Any uncontrolled medical condition
- Current use of the medications under investigation
- Use of medications expected to stimulate or depress respiration (including opioids, barbiturates, doxapram, almitrine, theophylline, 4-hydroxybutanoic acid).
- Conditions likely to affect obstructive sleep apnea physiology: neuromuscular disease or other major neurological disorder, heart failure (also below), or any other unstable major medical condition.
- Respiratory disorders other than sleep disordered breathing:
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 |
|---|---|---|
| Placebo oral capsulePlacebo before sleep for 3 nights before the study (inclusive) | Drug | Placebo |
| AcetazolamideAcetazolamide 250 mg 3 nights before the study at bedtime, Acetazolamide 500 mg for 2 nights before the study (inclusive) at bedtime. | Drug | Acetazolamide |
Primary outcome
Apnea hypopnea index
Time frame: 1 night
Number of events/hour of sleep
Hypoxic burden
Time frame: 1 night
The total area under the respiratory event-related desaturation curve, measured as in %min/hr
Ventilatory drive in REM and NREM
Time frame: 1 night
Ventilatory drive will be calculated using diaphragm EMG (as percent of eupneic ventilatory drive)
Genioglossus activity in REM and NREM
Time frame: 1 night
Genioglossus activity will be calculated using EMG wires under the tongue (as percent of eupneic activity or maximal activity)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Jan 2026.
- Derived from this study: PubMed 41781273Messineo L, Kim M, Azarbarzin A, Vena D, Preuss M, Esmaeili N, Aishah A, Lawrence NV, Gilbertson DC, White DP, Wellman A, Sands SA. Acetazolamide to prevent ventilatory drive withdrawal in REM sleep apnoea: a randomised controlled trial. Thorax. 2026 Mar 4:thorax-2025-223922. doi: 10.1136/thorax-2025-223922. Online ahead of print.
- 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. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1/2 study testing Acetazolamide in people with Obstructive Sleep Apnea, run by Brigham and Women's Hospital at 1 site 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 3 inclusion and 18 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 20 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site 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 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
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?
Apnea hypopnea index (time frame: 1 night). 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?
On the ClinicalTrials.gov record for NCT05589792, which also lists 1 linked publication.
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 20 Jan 2026.