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MAC Lung DiseasePhase 2/3NCT05327803

Study of Epetraborole in Patients With Treatment-refractory MAC Lung Disease

A Phase 2/3 study testing Epetraborole in people with MAC Lung Disease and Treatment Refractory MAC Lung Disease, run by AN2 Therapeutics, Inc at 91 sites in 4 countries.

Terminated

Stopped early. The study ended before it was planned to and will not resume.

Official record
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Trial summary

This is a pivotal Phase 2/3, double-blind, placebo-controlled study of epetraborole + OBR (Optimized Background Regimen) versus placebo + OBR in patients with treatment-refractory MAC lung disease. Read more about this study

Who is it for?
Ages 18 years and older
What is being tested?
Epetraborole
Type of treatment
Pill or oral medicine
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
177 participants
Where
91 sitesin 4 countries
Study dates
20 May 2022to 18 Dec 2024
Phase
Phase 2/3
Are there results?
Yes, posted in the registrySummary in the doctors' view

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

  • Male or female patients who are 18 years of age or older.
  • Willing and able to provide written informed consent.
  • Patients with a diagnosis of treatment-refractory MAC lung disease consisting of all of the following (a) Microbiological, (b) Clinical, and (c) Radiographic criteria:
  • Microbiological criteria:
  • One Pre-Study MAC-positive respiratory specimen. Documentation of a MAC positive specimen collected per standard of care within 6 months prior to signing the informed consent form (ICF).
  • One Screening MAC-positive expectorated or induced sputum sample.
Show all 19Show fewer
  • Clinical criteria: At least 2 of the following patient-reported clinical symptoms:
  • Cough with sputum production
  • Cough without sputum
  • Chest congestion
  • Hemoptysis
  • Dyspnea
  • Fatigue
  • Night sweats or unusual sweating
  • Radiographic criteria: Non contrast Chest CT scan within 6 months prior to signing the ICF with abnormalities consistent with MAC lung disease.
  • OBR criteria: An OBR is a combination regimen that consists of ≥2 antimycobacterial agents. The patient-specific OBR must be administered for a minimum duration of 6 consecutive months that is either ongoing at the time of Screening or was stopped or paused no more than 12 months before screening. The OBR regimen administered during Screening must be continued after randomization.
  • Patients who are willing to comply with all the study activities and procedures throughout the duration of the study and comply with all planned study visits and study procedures from Screening through the LFU Visit.
  • All patients must agree to use an effective method of birth control.
  • Patients expected to survive with continued antimycobacterial therapy and appropriate supportive care from Screening through the LFU Visit, in the judgment of the Investigator.

Who cannot join

  • Patients with a presence of any suspected or confirmed disease or condition at Screening or the time of randomization that, in the opinion of the Investigator, may confound the assessment of symptom-based clinical response.
  • Patients with active pulmonary malignancy or any malignancy that required or would require chemotherapy or radiation therapy within 1 year prior to randomization through the LFU Visit.
  • Patients with creatinine clearance (CrCl) of ≤30 mL/min, as estimated by the Cockcroft Gault formula, at Screening.
  • Patients with hemoglobin <10.0 g/dL or <6.2 mmol/L at Screening; donation of blood or plasma within 28 days prior to randomization; or symptomatic loss of blood or hemorrhage within 28 days prior to randomization.
  • Patients with severe hemoptysis within 28 days prior to randomization, defined as >100 mL over any 24-hour period or severe or extremely severe hemoptysis.
  • Patients with severe hepatic impairment, as evidenced by alanine aminotransferase (ALT) or aspartate aminotransferase (AST) >3 × upper limit of normal (ULN) or total bilirubin >2 × ULN, or clinical signs of cirrhosis or end-stage hepatic disease.
Show all 13Show fewer
  • Patients who are pregnant or breastfeeding.
  • Patients with a mean QT interval corrected using Fridericia's formula (QTcF) >480 msec based on triplicate 12-lead ECGs at Screening.
  • Patients with an immunodeficiency or an immunocompromised condition and risk for an opportunistic pulmonary infection.
  • Patients with an anticipated start of new non-study antimycobacterial therapy to be administered at any time between Screening and Month 6.
  • Patients who have received any investigational medication during the 30 days or 5 half-lives, whichever is longer, prior to randomization.
  • Patients with any prior exposure to epetraborole.
  • Patients with any condition that, in the opinion of the Investigator, interferes with the ability to safely complete the study or adhere to study requirements, including the patient's inability or unwillingness to comply with all study assessments and visits.

Trial locations and contacts

91 sites in 4 countries.

91 sites in 4 countries

United States49 sites

  • 423078

    Ann Arbor, Michigan, 48109

  • 423027

    Atlanta, Georgia, 30342

  • 423060

    Baltimore, Maryland, 21201

  • 423003

    Baltimore, Maryland, 21231

  • 423075

    Bay Pines, Florida, 33744

  • 423032

    Birmingham, Alabama, 35233

  • 423074

    Boston, Massachusetts, 02114-2696

  • 423061

    Boston, Massachusetts, 02115

  • 423071

    Chapel Hill, North Carolina, 27599

  • 423045

    Charleston, South Carolina, 29414

  • 423001

    Charleston, South Carolina, 29425

  • 423072

    Charlotte, North Carolina, 28204

  • 423012

    Charlottesville, Virginia, 22908

  • 423079

    Cleveland, Ohio, 44195

  • 423018

    DeLand, Florida, 32720

  • 423017

    Durham, North Carolina, 27705

  • 423080

    Edmonds, Washington, 98026

  • 423081

    Fort Worth, Texas, 76104

  • 423076

    Indianapolis, Indiana, 46202

  • 423029

    Iowa City, Iowa, 52242

  • 423065

    Jefferson, Louisiana, 70121

  • 423015

    Kansas City, Kansas, 66205

  • 423034

    Kissimmee, Florida, 34746

  • 423009

    Lebanon, New Hampshire, 03756

  • 423024

    Manhasset, New York, 11030

  • 423011

    Milwaukee, Wisconsin, 53226

  • 423067

    Nashville, Tennessee, 37232

  • 423042

    New Orleans, Louisiana, 70112

  • 423014

    New York, New York, 10017

  • 423013

    New York, New York, 10029

  • 423082

    Oklahoma City, Oklahoma, 73104

  • 423004

    Omaha, Nebraska, 68198

  • 423002

    Philadelphia, Pennsylvania, 19104

  • 423058

    Philadelphia, Pennsylvania, 19107

  • 423007

    Portland, Oregon, 97239

  • 423031

    Rochester, Minnesota, 55902

  • 423070

    Sacramento, California, 95817

  • 423069

    San Francisco, California, 94143

  • 423008

    St Louis, Missouri, 63110

  • 423006

    Stanford, California, 94305

  • 423033

    Tampa, Florida, 33606

  • 423054

    Tampa, Florida, 33612

  • 423047

    Tampa, Florida, 33614

  • 423037

    Tucson, Arizona, 85724

  • 423005

    Tyler, Texas, 75708

  • 423038

    Vero Beach, Florida, 32960

  • 423068

    Washington D.C., District of Columbia, 20037

  • 423063

    Wichita, Kansas, 67211

  • 423039

    Winston-Salem, North Carolina, 27103

Other trials in United States

Japan29 sites

  • 215019

    Aichi, 465-8620

  • 215026

    Aomori, 036-8563

  • 215004

    Fukuoka, 811-3195

  • 215025

    Fukuoka, 814-0180

  • 215016

    Fukuoka, 819-8555

  • 215006

    Gifu, 502-8558

  • 215030

    Hiroshima, 730-0822

  • 215014

    Hokkaido, 070-8644

  • 215028

    Ibaraki, 319-1113

  • 215018

    Ishikawa, 920-8530

  • 215020

    Ishikawa, 920-8650

  • 215017

    Kanagawa, 236-0051

  • 215021

    Kitakyushu, 806-0034

  • 215009

    Kyoto, 610-0113

  • 215013

    Kyoto, 612-8555

  • 215022

    Mie, 514-1101

  • 215023

    Nagano, 382-8577

  • 215002

    Niigata, 951-8510

  • 215029

    Osaka, 560-8552

  • 215008

    Osaka, 591-8555

  • 215012

    Osaka, 591-8555

  • 215001

    Tokyo, 160-8582

  • 215005

    Tokyo, 162-8655

  • 215024

    Tokyo, 180-8610

  • 215003

    Tokyo, 204-8522

  • 215027

    Tokyo

  • 215010

    Wakayama, 646-8558

  • 215007

    Yamaguchi

  • 215011

    Yokohama, 245-8575

Other trials in Japan

Australia7 sites

  • 501007

    Birtinya, Queensland, 4575

  • 501003

    Chermside West, Queensland, 4032

  • 501004

    Clayton, 3168

  • 501005

    Concord, New South Wales, 2139

  • 501001

    Greenslopes, Queensland

  • 501008

    Perth, Western Australia, 6000

  • 501002

    South Brisbane, 4101

Other trials in Australia

South Korea6 sites

  • 219003

    Gwangju, 61469

  • 219005

    Incheon, 21431

  • 219001

    Seongnam-si, 13620

  • 219002

    Seoul, 03080

  • 219007

    Seoul, 05505

  • 219008

    Seoul

Other trials in South Korea

About this study

Official title: A Phase 2/3, Randomized, Double-blind, Placebo-controlled, Multicenter, Prospective Study to Assess the Efficacy, Safety, and Pharmacokinetics of Orally Administered Epetraborole in Patients With Treatment-refractory Mycobacterium Avium Complex Lung Disease

This is a pivotal Phase 2/3, double-blind, placebo-controlled study of epetraborole + OBR (Optimized Background Regimen) versus placebo + OBR in patients with treatment-refractory MAC lung disease. This study will enroll adult patients with treatment-refractory MAC lung disease who meet all eligibility criteria (including clinical, radiographic, and microbiological criteria).

Read the detailed description

In the Phase 2 part of the study, approximately 80 patients will be randomized in a 1:1 ratio (40 patients receiving active epetraborole tablets and 40 patients receiving matching placebo tablets). The Phase 2 part of the study includes a blinded psychometric analysis plan to assess the psychometric properties of a novel PRO instrument. In addition, symptom-based clinical responses will be assessed using blinded data, to inform the measurement of clinical response in the Phase 3 part of the study.

The Phase 3 part of the study will test the superiority of epetraborole + OBR compared to placebo + OBR. In this part of the study, approximately 234 patients are planned to be randomized in a 2:1 ratio (156 patients receiving active epetraborole tablets and 78 patients receiving matching placebo tablets). The current symptom-based clinical response definition (using the novel PRO) in Phase 3 is a placeholder to be verified after Phase 2 analyses based on data through Month 6. In addition, the Sponsor will determine if the sample size for Phase 3 should be adjusted and will verify the Phase 3 epetraborole dosage regimen based on the observed plasma epetraborole exposure.

Phase 3 data analyses will include a review of patient-reported outcomes, microbiological, safety, and PK data collected at multiple time points through Month 6. Patients in Phase 3 will continue double-blinded study drug for 12 months after the first negative MAC culture that defines sputum culture conversion; study drug will be discontinued in patients who remain MAC culture positive despite 6 months of therapy with study drug.

Being tested
Epetraborole, Placebo
Keywords
NTM, Respiratory Infection, antimycobacterial activity, antimycobacterial agent, antimycobacterial therapy, MAC infections, MAC lung disease, MAC lung infection, MAC pulmonary infection, Mycobacteria, mycobacterial disease, mycobacterium, Mycobacterium Avium Complex, Mycobacterium Avium Complex Infections, Mycobacterium avium complex lung disease, Mycobacterium Infections, Nontuberculous, Nontuberculous mycobacteria / mycobacterial / mycobacterium, Non-tuberculous mycobacteria disease, Non-tuberculous mycobacterial (NTM) infections
Medical subject headings
Respiratory Tract Infections, Mycobacterium Infections, Mycobacterium avium-intracellulare Infection, Infections

What participants receive

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

  • EpetraboroleDrug

    Also called AN2-501971

    500 mg taken orally QD

  • PlaceboDrug

    Placebo taken orally QD

Study groups in NCT05327803
Study groupRoleWhat they receive
epetraborole + OBRExperimentalepetraborole + Optimized Background Regimen
Receives: Drug: Epetraborole
placebo + OBRPlacebo comparatorPlacebo + Optimized Background Regimen
Receives: Drug: Placebo

What is being measured

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

  1. Phase 2: Adverse Event Profile of 500 mg Once Daily Dose of Epetraborole

    Percentage of Participants reporting treatment emergent adverse events

    Measured: Baseline to Month 16

  2. Phase 2: Percentage of Participants Achieving Clinical Response

    Detection of within-patient changes in symptoms reported in a novel Patient-Reported Outcome (PRO) instrument at Month 6 (Clinical Response measured as improvement in at least one symptom and no worsening in any others from baseline)

    Measured: Baseline to Month 6

  3. Phase 3: Percentage of Participants Achieving Clinical Response

    Detection of within-patient changes in symptoms reported in a novel Patient-Reported Outcome (PRO) instrument at Month 6 (Clinical Response measured as improvement in at least one symptom and no worsening in any others from baseline)

    Measured: Baseline to Month 6

Secondary outcomes (16)

  1. Phase 2: Percentage of Participants Achieving Culture Conversion

    Sputum conversion will be assessed using culture conversion based on 3 consecutive monthly negative sputum cultures for MAC by Month 6.

    Measured: Baseline to Month 6

  2. Phase 2: Percentage of Participants Achieving Microbiological Improvement

    Microbiological improvement will be assessed at Month 3 and Month 6 using decrease in MAC colony counts of ≥1 category.

    Measured: Baseline to Month 6

  3. Phase 2: Change From Baseline in QOL-B Respiratory Domain PRO

    Mean change from baseline in Quality of Life - Bronchiectasis (QOL-B) respiratory domain score measured monthly through Month 6 (Change from Baseline to Month 6 Reported). QOL-B respiratory domain score is measured on a scale from 0 to 100 (with higher scores indicating better health-related quality of life).

    Measured: Measured at Baseline and months 1, 2, 3, 4, 5, and 6; Change from Baseline to Month 6 Reported

  4. Phase 2: Change From Baseline in NTM Symptoms Module PRO

    Mean change from baseline in NTM Symptoms Module PRO measured monthly through Month 6 (Change from Baseline to Month 6 Reported). NTM Symptoms Module score is measured on a scale from 0 to 100 (with higher scores indicating better function).

    Measured: Measured at Baseline and months 1, 2, 3, 4, 5, and 6; Change from Baseline to Month 6 Reported

  5. Phase 2: Change From Baseline in SGRQ-C PRO

    Mean change from baseline in Saint George's Respiratory Questionnaire for COPD Patients (SGRQ-C) total score measured monthly through Month 6 (Change from Baseline to Month 6 Reported). SGRQ-C total score is measured on a scale from 0 to 100 (with lower scores representing better quality of life).

    Measured: Measured at Baseline and months 1, 2, 3, 4, 5, and 6; Change from Baseline to Month 6 Reported

  6. Phase 2: Concordance Analysis of PRO-based Clinical Response and Microbiological Response

    Concordance between clinical response in a novel Patient-Reported Outcome (PRO) instrument and microbiological response will be assessed at Months 3 and 6. Microbiological response will be assessed using both sputum culture conversion and microbiological improvement.

    Measured: Baseline to Month 6

  7. Phase 2: Maximum Plasma Concentration (Cmax) of Epetraborole

    Cmax is the maximum plasma concentration of epetraborole estimated by population PK model.

    Measured: Day 1 (2-3 hours post-dose) and Day 29 (within 1 hour pre-dose and 2-3 hours post-dose); Day 29 Result Reported

  8. Phase 2: Area Under the Plasma Concentration-Time Curve From Time Point 0 Hours Until 24 Hours [AUC(0-24)] Post Dose

    AUC(0-24) is defined as area under the plasma concentration-time curve of epetraborole from timepoint 0 hours until 24 hours post dose estimated by population PK model.

    Measured: Day 1 (2-3 hours post-dose) and Day 29 (within 1 hour pre-dose and 2-3 hours post-dose); Day 1 Result Reported

  9. Phase 2: Volume of Distribution (Vd) of Epetraborole

    Vd is the apparent volume of distribution of epetraborole estimated by population PK model.

    Measured: Day 1 (2-3 hours post-dose) and Day 29 (within 1 hour pre-dose and 2-3 hours post-dose); Day 29 Result Reported

  10. Phase 3: Percentage of Participants Achieving Culture Conversion

    Sputum conversion will be assessed using culture conversion based on 3 consecutive monthly negative sputum cultures for MAC by Month 6.

    Measured: Baseline to Month 6

  11. Phase 3: Percentage of Participants Achieving Microbiological Improvement

    Microbiological improvement will be assessed at Month 3 and Month 6 using decrease in MAC colony counts of ≥1 category.

    Measured: Baseline to Month 6

  12. Phase 3: Change From Baseline in QOL-B Respiratory Domain PRO

    Mean change from baseline in Quality of Life - Bronchiectasis (QOL-B) respiratory domain score measured monthly through Month 6 (Change from Baseline to Month 6 Reported). QOL-B respiratory domain score is measured on a scale from 0 to 100 (with higher scores indicating better health-related quality of life).

    Measured: Measured at Baseline and months 1, 2, 3, 4, 5, and 6; Change from Baseline to Month 6 Reported

  13. Phase 3: Change From Baseline in NTM Symptoms Module PRO

    Mean change from baseline in NTM Symptoms Module PRO measured monthly through Month 6 (Change from Baseline to Month 6 Reported). NTM Symptoms Module score is measured on a scale from 0 to 100 (with higher scores indicating better function).

    Measured: Measured at Baseline and months 1, 2, 3, 4, 5, and 6; Change from Baseline to Month 6 Reported

  14. Phase 3: Change From Baseline in SGRQ-C PRO

    Mean change from baseline in Saint George's Respiratory Questionnaire for COPD Patients (SGRQ-C) total score measured monthly through Month 6 (Change from Baseline to Month 6 Reported). SGRQ-C total score is measured on a scale from 0 to 100 (with lower scores representing better quality of life).

    Measured: Measured at Baseline and months 1, 2, 3, 4, 5, and 6; Change from Baseline to Month 6 Reported

  15. Phase 3: Concordance Analysis of PRO-based Clinical Response and Microbiological Response

    Concordance between clinical response in a novel Patient-Reported Outcome (PRO) instrument and microbiological response will be assessed at Months 3 and 6. Microbiological response will be assessed using both sputum culture conversion and microbiological improvement

    Measured: Baseline to Month 6

  16. Phase 3: Adverse Event Profile of 500 mg Once Daily Dose of Epetraborole

    Percentage of Participants reporting treatment emergent adverse events.

    Measured: Baseline to Month 16

Timeline

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

  1. First posted14 Apr 2022
  2. Study start20 May 2022
  3. Primary completion18 Dec 2024
  4. Study completion18 Dec 2024

Why it stopped: EBO-301 truncated Phase 3 study (n=97) misses primary endpoint; results unable to confirm clinical efficacy observed in Phase 2 study.

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
Masking
Triple blind
Who is masked
Participant, Care provider, Investigator
Enrolment
177 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05327803
Sponsor's protocol ID
EBO-301
Status last verified
Jun 2026
First submitted
24 Mar 2022
Last updated
10 Jun 2026
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No

Questions about this trial

What is this clinical trial studying?

A Phase 2/3 study testing Epetraborole in people with MAC Lung Disease and Treatment Refractory MAC Lung Disease, run by AN2 Therapeutics, Inc at 91 sites in 4 countries.

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 13 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: stopped early, as of the sponsor's last update on 10 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 91 sites in United States, Japan, Australia, South Korea. 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?

Yes. Results are posted in the registry (first posted 10 Jun 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

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?

Phase 2: Adverse Event Profile of 500 mg Once Daily Dose of Epetraborole (time frame: Baseline to Month 16). The study lists 3 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 NCT05327803.

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 10 Jun 2026.

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