Endotypic Traits and Obstructive Sleep Apnea Surgery

June 29, 2026 updated by: Eric J. Kezirian, MD, MPH, University of California, Los Angeles
This study will examine factors associated with outcomes after soft palate surgery and medications (acetazolamide, eszopiclone) that may treat other potential causes of obstructive sleep apnea (loop gain, arousal threshold).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

This is a prospective cohort (observational) study of 150 participants with moderate to severe obstructive sleep apnea (OSA) unable to tolerate positive airway pressure who are undergoing drug-induced sleep endoscopy (DISE), including measurement of upper airway closing pressure (Pclose), and tissue-repositioning soft palate surgery. Before and 6 months after surgery, the investigators will measure OSA severity (apnea-hypopnea index) with sleep studies (polysomnograms). Using a recently-validated polysomnography-based signal processing algorithm, the investigators will systematically assess the underlying mechanisms of OSA (traits) and airflow shape (consistent with palate obstruction). The expected 90 participants without resolution of OSA after surgery (surgery failures) will participate in an experimental randomized crossover study of acetazolamide (1 month) and acetazolamide/eszopiclone combination (1 month). Polysomnograms will be performed with each treatment, with algorithm-based determination of traits.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
150

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • California
      • Santa Monica, California, United States, 90401
        • Recruiting
        • UCLA Santa Monica Medical Center
        • Principal Investigator:
          • Eric Kezirian, MD, MPH
        • Contact:
          • Eric Kezirian, MD, MPH
      • Westwood, Los Angeles, California, United States, 90095
        • Not yet recruiting
        • UCLA Westwood
        • Principal Investigator:
          • Eric Kezirian, MD, MPH
        • Contact:
          • Eric Kezirian, MD, MPH

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion criteria are:

  1. age ≥21 years;
  2. moderate to severe OSA (obstructive AHI ≥ 15 events/hour);
  3. central/mixed apnea index <5 events/hour;
  4. intolerance of positive airway pressure (defined as use < 2 hours/night at least 5 nights/week);
  5. intolerance or poor candidate for oral appliance;
  6. participant has provided informed consent for palate surgery as part of their standard of care;
  7. tonsil size 0-2+ (without markedly enlarged tonsils that have high surgical success rates);
  8. DISE without evidence of complete tongue-related obstruction (reflecting poorer results with isolated palate surgery);
  9. medications stable for ≥2 months;
  10. body mass index <35 kg/m2;
  11. absence of uncontrolled nasal obstruction;
  12. no prior pharyngeal surgery other than tonsillectomy;
  13. no neurologic, cardiac or pulmonary disorders;
  14. absence of psychiatric disorder except for treated depression or mild anxiety;
  15. no co-existing sleep disorder, such as narcolepsy, chronic insomnia, or restless legs syndrome;
  16. no use of hypnotics, anxiolytics, stimulants, or sedating antidepressants;
  17. no near-miss or prior motor vehicle crash due to sleepiness in past 12 months; and
  18. <3 caffeinated beverages daily.

Exclusion criteria are:

  1. history of allergic reaction to either of the study drugs;
  2. subjects with prior serious allergic reaction (such as Stevens-Johnson syndrome) to sulfonamides;
  3. subjects with a history of hypersensitivity to either of the two study drugs;
  4. subjects who are on high-dose aspirin therapy due to risk of severe metabolic acidosis;
  5. subjects with severe kidney disease or severe liver disease;
  6. subjects with a history of electrolyte imbalance or adrenal insufficiency (due to risks related to acetazolamide);
  7. subjects on ketoconazole or other strong CYP3A4 inhibitors (these will increase eszopiclone blood levels);
  8. pregnancy; and
  9. alcohol or substance abuse.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Acetazolamide
Treatment with acetazolamide 500 mg nightly for 1 month.
Drug: Acetazolamide 500 MG QHS
Acetazolamide
Experimental: Acetazolamide/Eszopiclone
Treatment with acetazolamide 500 mg and eszopiclone 3 mg nightly for 1 month.
Drug: Acetazolamide 500 MG QHS
Acetazolamide
Drug: Eszopiclone 3 mg QHS
Eszopiclone

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Apnea-hypopnea index
Time Frame: 6 months
apneas plus hypopneas per hour of sleep
6 months

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Pclose
Time Frame: 6 months
upper airway closing pressure, as measured with administration of positive airway pressure therapy and observation of airway dimensions with flexible fiberoptic endoscopy
6 months
Vpassive
Time Frame: 6 months
ventilation at normal ventilatory drive, as measured using software to analyze raw polysomnogram data
6 months
Loop gain
Time Frame: 6 months
ventilatory drive response to a 1 cycle/min reduction in ventilation (ventilatory control), as measured using software to analyze raw polysomnogram data
6 months
Arousal threshold
Time Frame: 6 months
median ventilatory drive immediately preceding scored EEG arousals (propensity to wake up), as measured using software to analyze raw polysomnogram data
6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of California, Los Angeles

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Heart, Lung, and Blood Institute (NHLBI)

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
January 7, 2024

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
August 31, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
August 31, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 8, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 18, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 20, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 1, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 29, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 1.0
  • R01HL160993 (U.S. NIH Grant/Contract)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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