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Sleep ApneaPhase 2NCT06776432

Safety and Efficacy Study of Sivopixant, Acetazolamide and SASS-001 in Sleep Apnea

A Phase 2 study testing Sivopixant, Acetazolamide and SASS-001 in people with Sleep Apnea, run by Shionogi at 9 sites in United States.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

The primary purpose of this study is to evaluate the effectiveness of sivopixant, acetazolamide and SASS-001 in adults with sleep apnea with a central component. Read more about this study

Who is it for?
Ages 18 to 85 years
Conditions the study is for
Sleep Apnea
What is being tested?
Sivopixant, Acetazolamide and SASS-001
Type of treatment
Pill or oral medicine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
60 participants
Where
9 sitesUnited States
Study dates
2 Apr 2025to 31 Dec 2026
Phase
Phase 2
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 85 years
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • To enroll, subjects need to have a previous diagnosis of at least one or more of the following comorbidities:
  • Stable heart failure with reduced ejection fraction (NYHA class 1-3 inclusive) with or without atrial fibrillation
  • Heart failure with preserved ejection fraction (NYHA class 1-3 inclusive) and hypertension (BP>120/80 mmHg at screening visit despite the treatment with ≥2 antihypertensives) with or without atrial fibrillation
  • Persistent atrial fibrillation (continuous and sustained for more than 7 days, rate controlled with resting HR<100bpm)1 without heart failure
  • History of primary (essential) hypertension with BP at screening visit >130/80 mmHg despite the treatment with >2 antihypertensives
  • Evidence of complex sleep apnea (CPAP-emergent central sleep apnea with documented CAI>5 events/h on CPAP within 1 year from screening)
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  • Standard care for heart failure and atrial fibrillation for at least 3 weeks before the screening visit
  • OSA measures Average ODI4 between 7 and 55 events/h, inclusive, and average SpO2 ≥88% from continuous home pulse oximetry recordings at screening.
  • AHI4 (Hypopneas defined by 4% oxygen desaturation) of >10 to ≤60 events/h
  • At minimum of 25% central or mixed apneas (as proportion of total apneas) with a minimum of 2.5 central or mixed apneas/hour of sleep
  • OR evidence of clear Cheyne-Stokes breathing pattern during the baseline PSG (regardless of central apnea component).
  • OR evidence of OSA with LGn >0.5 at the baseline PSG (regardless of central apnea component) Average SpO2 during sleep ≥88%
  • Weight BMI between 18.5 and 40 kg/m2 for men, or 42 kg/m2 for women, inclusive
  • Male participants If male and sexually active with female partner(s) of childbearing potential, participant must agree, from Study Day 1 through 1 week after the last dose of study drug, to practice the protocol specified contraception. Male participants must refrain from donating sperm for the duration of the study and for 3 months after the last dose of study treatment.
  • Female participants If a woman of childbearing potential (WOCBP), the participant must agree, from Study Day 1 through 1 week after the last dose of study drug, to practice the protocol specified contraception. All WOCBP must have negative result of a serum pregnancy test performed at screening.
  • If female and of non-childbearing potential, the participant must be either postmenopausal or permanently sterile (e.g. bilateral oophorectomy, bilateral salpingectomy or hysterectomy).
  • Informed Consent Participant voluntarily agrees to participate in this study and signs an Institutional Review Board (IRB)-approved informed consent prior to performing any of the Screening Visit procedures.
  • Participant must be able to understand the nature of the study and must have the opportunity to have any questions answered.
  • Patients currently using PAP will be eligible for inclusion in the study if they express willingness to discontinue treatment for a minimum of 7 days before baseline SpO2 assessments, until the study completion.

Who cannot join

  • Sustained SpO2<93% during wakefulness or mean SpO2<88% during sleep, calculated from PSG at screening
  • Dyspnea at rest or patients with heart failure class IV NYHA
  • Blood pressure <90/50 mmHg or >160/100 mmHg at V1.
  • Medical Conditions Recent (<3 months) episode of acute myocardial infarction or acute decompensated heart failure.
  • History of stroke.
  • History of sustained ventricular tachyarrhythmias or other severe arrhythmias without defibrillator implanted.
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  • Heart failure primarily caused by valvular, post-partum cardiomyopathy or active myocarditis
  • History of obesity-hypoventilation syndrome or respiratory disturbance due to opioids.
  • History of bronchiectasis and uncontrolled asthma.
  • History of severe chronic obstructive pulmonary disease (COPD) with a forced expiratory volume in 1 second (FEV1) <50% of predicted (European Respiratory Society criteria)
  • Started treatment with β-blockers <3 months before screening. Patients not taking β-blockers or taking β-blockers for >3 months can be enrolled.
  • Narcolepsy, restless leg syndrome requiring medication, REM sleep behavior disorder.
  • Pronounced anatomical abnormalities of upper airway (adenoid vegetations, grade ≥3 tonsillar hypertrophy, etc.), pronounced micrognathia, or pronounced incomplete development of the lower jaw.
  • History of schizophrenia, schizoaffective disorder or bipolar disorder according to Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5) or International Classification of Disease tenth edition criteria.
  • Medically unexplained positive screen for drugs of abuse (excluding THC/marijuana) or history of substance use disorder as defined in DSM-V within 24 months prior to Screening Visit.
  • A significant illness or infection requiring medical treatment in the past 30 days as determined by investigator.
  • Clinically significant cognitive dysfunction as determined by investigator.
  • Women who are pregnant or nursing.
  • History of kidney stones
  • Prior/Concomitant Therapy Participants with a history of using devices for OSA treatment, including CPAP, oral or nasal devices, or positional devices, may enroll as long as the devices have not been used for at least 1 week before the baseline SpO2 assessments and are not used during participation in the study (through V7). Patients that are non-compliant to CPAP (less than 4hr/night for 5 days/week) can be enrolled, as well as patients who are naïve to PAP and patients who discontinued PAP previously. PAP compliant patients cannot be enrolled.
  • History of chronic oxygen therapy.
  • Concomitant use of medications from the list of disallowed medications.
  • Prior/Concurrent Clinical Study Experience Use of another investigational agent within 30 days or 5 half-lives, whichever is longer, prior to dosing.
  • Diagnostic Assessments Hepatic cirrhosis, hepatictransaminases > 2X the upper limit of normal (ULN), total bilirubin >1.5X ULN (unless confirmed Gilbert syndrome), estimated glomerular filtration rate < 40 ml/min.
  • Participants with reduced sodium and/or potassium blood serum levels.
  • Participants with suprarenal gland failure.
  • Participants with hyperchloremic acidosis.
  • Other Exclusions:
  • Night- or shift-work sleep schedule which causes the major sleep period to be during the day.
  • Employment as a commercial driver or operator of heavy or hazardous equipment.
  • Typically smoking more than 10 cigarettes or 2 cigars per day, or inability to abstain from smoking during overnight PSG visits.
  • Unwilling to use specified contraception.
  • History of regular alcohol consumption of more than 14 standard units per week (males) or more than 7 standard units per week (females), or unwillingness to limit alcohol consumption to no greater than 2 units/day (males), 1 unit per day (females). Alcohol is not to be consumed within 3 hours of bedtime or on PSG nights.
  • Unwilling to agree to limit during the study period caffeinated beverage intake (e.g., coffee, cola, tea) to 400 mg/day or less of caffeine, not to be used within 3 hours of bedtime.
  • Any condition that in the investigator's opinion would present an unreasonable risk to the participant, including recent (<1 year) motor vehicle accident due to drowsy driving, or which would interfere with their participation in the study or confound study interpretation.
  • Participant considered by the investigator, for any reason, an unsuitable candidate to receive sivopixant or acetazolamide or unable or unlikely to understand or comply with the dosing schedule or study evaluations.
  • Allergy to study drugs
  • Note: Other protocol defined Inclusion/Exclusion criteria may apply

Trial locations and contacts

9 sites in 1 country.

9 sites in 1 country

United States9 sites

  • Teradan Clinical Trials

    Brandon, Florida, 33511

  • Intrepid Research, LLC

    Cincinnati, Ohio, 45245

  • John D. Dingell VA Medical Center

    Detroit, Michigan, 48201

  • Huntsville Research Institute LLC

    Huntsville, Texas, 77340

  • Altman Clinical and Translational Research Institute (ACTRI)

    La Jolla, California, 92037

  • PharmaDev Clinical Research Institute, LLC

    Miami, Florida, 33176

  • Infinity Medical Research

    North Dartmouth, Massachusetts, 02747

  • Mayo Clinic

    Rochester, Minnesota, 55905

  • OnSite Clinical Solutions

    Rock Hill, South Carolina, 29732

Other trials in United States

About this study

Official title: A Phase 2A Double-Blind Randomized, Controlled, Dose Escalation, Parallel- Arm, Safety and Efficacy Study of Sivopixant, Acetazolamide and SASS-001 in Sleep Apnea

The primary purpose of this study is to evaluate the effectiveness of sivopixant, acetazolamide and SASS-001 in adults with sleep apnea with a central component.

Conditions
Sleep Apnea
Being tested
Sivopixant, Placebo, Acetazolamide, SASS-001
Keywords
sleep apnea, obstructive sleep apnea, central sleep apnea
Medical subject headings
Sleep Apnea Syndromes, Sleep Apnea, Obstructive, Sleep Apnea, Central

What participants receive

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

  • SivopixantDrug

    Administered as specified in the treatment arm

  • PlaceboDrug

    Administered as specified in the treatment arm.

  • AcetazolamideDrug

    Administered as specified in the treatment arm

  • SASS-001Drug

    Administered as specified in the treatment arm

Study groups in NCT06776432
Study groupRoleWhat they receive
Part A: SivopixantActive comparatorParticipants will receive sivopixant oral tablets once daily at bedtime for 17 days.
Receives: Drug: Sivopixant
PlaceboPlacebo comparatorParticipants will receive placebo to match the study drug during the 17 days of Part A followed by 13 days of Part B.
Receives: Drug: Placebo
Part B I: AcetazolamideActive comparatorAfter completing Part A, participants will receive acetazolamide oral tablets once daily at bedtime for 3 days.
Receives: Drug: Acetazolamide
Part B II: SASS-001Active comparatorAfter completing Part B I, participants will receive SASS-001 oral tablets once daily at bedtime for 10 days.
Receives: Drug: SASS-001

What is being measured

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

  1. Primary Endpoint - Change in apnea-hypopnea index (SASS-001 arm vs baseline at Visit 7 polysomnography). Scale is minimum -60 to max 60. Lower scores mean improvement from baseline.

    Measured: up to 6 weeks

Secondary outcomes (1)

  1. Secondary Endpoint - Change in apnea-hypopnea index (Sivopixant alone vs baseline at Visit 5 polysomnography). Scale is minimum -60 to max 60. Lower scores mean improvement from baseline.

    Measured: up to 6 weeks

Timeline

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

  1. First posted15 Jan 2025
  2. Study start2 Apr 2025
  3. Primary completion31 Dec 2026 (estimated)
  4. Study completion31 Dec 2026 (estimated)

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
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
60 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06776432
Sponsor's protocol ID
SVA-SAS-201
Status last verified
May 2026
First submitted
3 Jan 2025
Last updated
6 May 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Sivopixant, Acetazolamide and SASS-001 in people with Sleep Apnea, run by Shionogi at 9 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 19 inclusion and 38 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: under way, not looking for participants, as of the sponsor's last update on 6 May 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 9 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 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?

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?

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?

Primary Endpoint - Change in apnea-hypopnea index (SASS-001 arm vs baseline at Visit 7 polysomnography). Scale is minimum -60 to max 60. Lower scores mean improvement from baseline. (time frame: up to 6 weeks). 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 NCT06776432.

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 6 May 2026.

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