BTZ-043 - Multiple Ascending Dose (MAD) to Evaluate Safety, Tolerability and Early Bactericidal Activity (EBA)

August 27, 2026 updated by: Michael Hoelscher

A Prospective Phase Ib/IIa, Active-controlled, Randomized, Open-label Study to Evaluate the Safety, Tolerability, Extended Early Bactericidal Activity and Pharmacokinetics of Multiple Oral Doses of BTZ-043 Tablets in Subjects With Newly Diagnosed, Uncomplicated, Smear-positive, Drug-susceptible Pulmonary Tuberculosis

This is a prospective, open label, two-centre, randomized, controlled, two-stage, phase Ib/IIa study to evaluate the safety, tolerability, PK, drug-drug interaction and bactericidal activity of BTZ-043 administered orally once daily over 14 days to participants with newly diagnosed, uncomplicated, smear-positive, drug-susceptible pulmonary tuberculosis.

The primary objective is to assess the safety and tolerability of BTZ-043 given over 14 days by evaluation of adverse events during treatment and follow-up period in patients with newly diagnosed, uncomplicated, smear-positive, drug-susceptible pulmonary tuberculosis.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

This is a prospective, open label, two-centre, randomized, controlled, two-stage, phase Ib/IIa study to evaluate the safety, tolerability, PK, drug-drug interaction and bactericidal activity of BTZ-043 administered orally once daily over 14 days to participants with newly diagnosed, uncomplicated, smear-positive, drug-susceptible pulmonary tuberculosis:

Stage 1 is an escalating dose design in up to eight cohorts receiving different doses of BTZ-043 to define a safe dose corridor for BTZ-043. The focus of this stage is on adverse events, PK and a food-effect PK-evaluation .

Stage 2 is a parallel group comparison of 4 arms receiving different treatment regimens: three arms to receive BTZ-043 in different doses within the safe corridor defined in stage 1, compared to one arm receiving Rifampicin, Isoniazid, Pyrazinamide, and Ethambutol as a control. This stage is focusing on adverse effects, early bactericidal activity (EBA), PK and an evaluation of PK drug-drug interaction potential.

A total of up to 77 male and female patients, aged ≥ 18 - 64 years, with newly diagnosed, smear positive, drug sensitive pulmonary tuberculosis will be enrolled.

Allocation of patients will be carried out in two stages:

Stage 1: for each cohort 3 patients will be enrolled, treated and followed-up accordingly, starting with cohort 1. In a Trial Steering Committee (TSC) meeting, decision will be made on the dose in the next cohort.

Dose escalation steps to be followed, if no safety concerns arise:

  • Cohort 1: patients to receive 250 mg BTZ-043
  • Cohort 2: patients to receive 500 mg BTZ-043
  • Cohort 3: patients to receive 750 mg BTZ-043
  • Cohort 4: patients to receive 1000 mg BTZ-043
  • Cohort 5: patients to receive 1250 mg BTZ-043
  • Cohort 6: patients to receive 1500 mg BTZ-043
  • Cohort 7: patients to receive 1750 mg BTZ-043
  • Cohort 8: patients to receive 2000 mg BTZ-043

Patients receiving the investigational drug in cohorts 1 - 8 will take BTZ-043 in fasting state for 13 days and after a pre-defined high-fat, high-caloric meal on day 14.

After all patients of a current cohort have completed at least 7 days of dosing, the TSC, composed of the national principal investigator (PI), the trial statistician, the sponsor representative and two independent scientists, will review safety data, including clinical, lab and electrocardiography (ECG) data, to assess whether dose limiting toxicity of BTZ-043, as defined below, has been observed in any participant. Depending on the outcome, the TSC will then decide on dose escalation, or on enrolling more participants to the same or a lower dose in the following cohort, according to dose escalation and stopping rules.

After the end of stage 1, the TSC will decide which of the BTZ-043 doses, which are deemed to not exceed the acceptable toxicity level, are to be moved to stage 2.

Stage 2: after the highest possible dose of the investigational drug, that has proven to be safe within the 1st stage, is identified, all remaining patients will be recruited and randomised to receive one of three different doses of BTZ-043 or to control treatment with Rifafour e-275® at a ratio of 3:3:3:2 favouring the experimental treatment.

Stage 2 is focusing on adverse effects, early bactericidal activity (EBA), PK and an evaluation of PK drug-drug interaction potential.

Allocation of patients:

  • Arm 1: patients to receive BTZ-043 in a higher dose
  • Arm 2: patients to receive BTZ-043 in a medium dose
  • Arm 3: patients to receive BTZ-043 in a lower dose
  • Control Arm 4: patients to receive Rifafour e-275® as control treatment

Participants will take in BTZ-043 in either fasted or fed state, depending on which state has shown to lead to higher exposure during the 1st stage.

Additional measurements in the 2nd stage in BTZ-arms 1 to 3 only:

• Drug-drug interactions will be investigated: patients, who have been randomized to BTZ-043 arms, will additionally be randomized to receive either a probe drug cocktail, with drugs specifically metabolized by certain enzymes, or dolutegravir at a ratio of 2:1. Probe drugs or Dolutegravir (DTG) will be given pre-BTZ on day 0 and on day 14.

After the course of study drugs is completed (on day 14), all patients (in stage 1 and stage 2) will be referred to a government clinic to complete their course of tuberculosis (TB) according to national standards for a total of 6 months of first-line therapy.

Study Type

Interventional

Enrollment (Actual)

78

Phase

  • Phase 2
  • Phase 1

Contacts and Locations

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

Study Locations

      • Cape Town, South Africa, 7530
        • TASK Applied Sciences Clinical Research Centre
      • Cape Town, South Africa, 7700
        • University of Cape Town Lung Institute (UCTLI)

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

Ages Eligible for Study

18 years to 64 years (Adult)

Accepts Healthy Volunteers

No

Description

General inclusion criteria:

  1. Provide written, informed consent prior to all trial-related procedures including HIV testing.
  2. Understand and willing to comply with the study procedures.
  3. Male or female adults, aged 18 up to and including 64 years.
  4. Body weight ≥ 40 kg.
  5. Participants are either unable to conceive/father children AND/OR they will be using two effective methods of contraception, including methods used by the patient's sexual partner(s). At least one to be a barrier method.

    Disease-specific inclusion criteria:

  6. Newly diagnosed, previously untreated, drug-susceptible pulmonary TB
  7. Chest X-ray which is consistent with TB
  8. Ability to produce an adequate volume of sputum (at least 10ml estimated overnight production)
  9. ≥ 1 sputum sample from concentrated sputum positive for acid-fast bacilli on microscopy (at least 1+ on the International Union Against Tuberculosis and Lung Disease/World Health Organization (IUATLD/WHO) scale) from either a spot sputum or overnight sputum sample.

General exclusion criteria:

  1. Poor general condition, where delay in treatment cannot be tolerated or death within three months is likely, as assessed by the investigator.
  2. The patient is pregnant or breast-feeding.

    Disease-specific exclusion criteria:

  3. The patient is infected with HIV.
  4. The patient has a known intolerance to any of the study drugs or concomitant disorders or conditions for which study drugs or standard TB treatment are contraindicated.
  5. Treatment with any other investigational drug within 1 month prior to enrolment or enrolment into other clinical (intervention) trials during participation.
  6. The patient has a history of or current evidence of clinically relevant cardiovascular metabolic, gastrointestinal, neurological, psychiatric or endocrine diseases, malignancy or any other condition, that will influence treatment response, study adherence or survival in the judgement of the investigator, especially:

    1. Clinically significant evidence of severe TB (e.g. miliary TB, TB meningitis, excluding limited lymph node involvement)
    2. Serious lung conditions other than TB or significant respiratory impairment in the discretion of the investigator
    3. Neuropathy, epilepsy or significant psychiatric disorder
    4. Any diabetes mellitus
    5. Cardiovascular disease, such as myocardial infarction, heart failure, coronary heart disease, arrhythmia, tachyarrhythmia, or pulmonary hypertension
    6. Current or history of hypertension (systolic blood pressure >135 mmHg and/or diastolic blood pressure of >85 mmHg) AND/OR ever received antihypertensive treatment)
    7. Long QT syndrome or family history of long QT syndrome or sudden death of unknown or cardiac-related cause
    8. Alcohol or other drug abuse, that is sufficient to significantly compromise the safety or cooperation of the patient, includes substances prohibited by the protocol, or has led to significant organ damage, at the discretion of the investigator

    Laboratory exclusion criteria at screening:

  7. Serum amino aspartate transferase (AST) and/or alanine aminotransferase (ALT) activity >2x the upper limit of normal (ULN)
  8. serum alkaline phosphatase (ALP) or y-glutamyl transferase (GGT) > 2x the ULN
  9. serum total bilirubin level >1.5 times the ULN
  10. estimated creatinine clearance (eCrCl) using the Cockcroft and Gault formula level lower than 60 mls/min
  11. haemoglobin level <8.0 g/dL
  12. platelet count <100,000/mm3
  13. serum potassium below the lower level of normal (LLN) for the laboratory

    ECG-specific exclusion criteria:

  14. corrected QT interval (QTc)F of > 450 milliseconds (ms)
  15. Atrioventricular (AV) block with PR interval > 200 ms
  16. QRS complex > 120 ms
  17. any other changes in the ECG that are clinically relevant as per discretion of the investigator

    Restricted medication:

  18. Treatment with drugs active against Mycobacterium Tuberculosis (MTB) within the last 3 months prior to screening
  19. Requires medication as included in the following drug classes within 2 weeks prior to the first dose of study treatment:

    • medication that prolongs the QTc interval
    • Cytochrome P450 (CYP450) inhibitors or inducers, including grapefruit containing foods / beverages and St. John's Wort
    • Antacids or antipeptic drugs (antacids, H2 blockers, proton pump inhibitors)

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: Sequential Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Stage 1 - Cohort 1 (BTZ 250)
Patients will receive 1 tablet of BTZ-043 orally once daily, containing 250mg BTZ-043 from Day 1 through to Day 14
BTZ-043 (250mg per tablet)
Experimental: Stage 1 - Cohort 2 (BTZ 500)
Patients will receive 2 tablets of BTZ-043 orally once daily, each containing 250mg BTZ-043 (500 mg in total) from Day 1 through to Day 14
BTZ-043 (250mg per tablet)
Experimental: Stage 1 - Cohort 3 (BTZ 750)
Patients will receive 3 tablets of BTZ-043 orally once daily, each containing 250mg BTZ-043 (750 mg in total) from Day 1 through to Day 14
BTZ-043 (250mg per tablet)
Experimental: Stage 1 - Cohort 4 (BTZ 1000)
Patients will receive 4 tablets of BTZ-043 orally once daily, each containing 250mg BTZ-043 (1000 mg in total) from Day 1 through to Day 14
BTZ-043 (250mg per tablet)
Experimental: Stage 1 - Cohort 5 (BTZ 1250)
Patients will receive 5 tablets of BTZ-043 orally once daily, each containing 250mg BTZ-043 (1250 mg in total) from Day 1 through to Day 14
BTZ-043 (250mg per tablet)
Experimental: Stage 1 - Cohort 6 (BTZ 1500)
Patients will receive 6 tablets of BTZ-043 orally once daily, each containing 250mg BTZ-043 (1500 mg in total) from Day 1 through to Day 14
BTZ-043 (250mg per tablet)
Experimental: Stage 1 - Cohort 7 (BTZ 1750)
Patients will receive 7 tablets of BTZ-043 orally once daily, each containing 250mg BTZ-043 (1750 mg in total) from Day 1 through to Day 14
BTZ-043 (250mg per tablet)
Experimental: Stage 1 - Cohort 8 (BTZ 2000)
Patients will receive 8 tablets of BTZ-043 orally once daily, each containing 250mg BTZ-043 (2000 total) from Day 1 through to Day 14
BTZ-043 (250mg per tablet)
Experimental: Stage 2 - Arm 1 (BTZ high)
Patients will receive a higher dose of BTZ-043, that has proven to be safe in stage 1 orally once daily from Day 1 through to Day 14. The dose of BTZ-043 will be determined after review of safety data from stage 1.
BTZ-043 (250mg per tablet)

A probe drug cocktail will be given to randomly selected patients after inclusion on Day 1 and on Day 14 once orally. The probe drug cocktail consists of

  • Caffeine: 1 tablet à 150mg
  • Tolbutamide: 1/4 tablet à 500mg
  • Dextromethorphan: 10 ml syrup à 15mg/5ml
  • Midazolam:2 ml solution à 5mg/5ml
  • Digoxin: 2 tablets à 0.25mg
1 tablet à 50mg Dolutegravir will be given to randomly selected patients after inclusion on Day 1 and on Day 14 once orally.
Other Names:
  • Tivicay®
Experimental: Stage 2 - Arm 2 (BTZ medium)
Patients will receive a medium dose of BTZ-043, that has proven to be safe in stage 1 orally once daily from Day 1 through to Day 14. The dose of BTZ-043 will be determined after review of safety data from stage 1.
BTZ-043 (250mg per tablet)

A probe drug cocktail will be given to randomly selected patients after inclusion on Day 1 and on Day 14 once orally. The probe drug cocktail consists of

  • Caffeine: 1 tablet à 150mg
  • Tolbutamide: 1/4 tablet à 500mg
  • Dextromethorphan: 10 ml syrup à 15mg/5ml
  • Midazolam:2 ml solution à 5mg/5ml
  • Digoxin: 2 tablets à 0.25mg
1 tablet à 50mg Dolutegravir will be given to randomly selected patients after inclusion on Day 1 and on Day 14 once orally.
Other Names:
  • Tivicay®
Experimental: Stage 2 - Arm 3 (BTZ low)
Patients will receive a lower dose of BTZ-043, that has proven to be safe in stage 1 orally once daily from Day 1 through to Day 14. The dose of BTZ-043 will be determined after review of safety data from stage 1.
BTZ-043 (250mg per tablet)

A probe drug cocktail will be given to randomly selected patients after inclusion on Day 1 and on Day 14 once orally. The probe drug cocktail consists of

  • Caffeine: 1 tablet à 150mg
  • Tolbutamide: 1/4 tablet à 500mg
  • Dextromethorphan: 10 ml syrup à 15mg/5ml
  • Midazolam:2 ml solution à 5mg/5ml
  • Digoxin: 2 tablets à 0.25mg
1 tablet à 50mg Dolutegravir will be given to randomly selected patients after inclusion on Day 1 and on Day 14 once orally.
Other Names:
  • Tivicay®
Active Comparator: Stage 2 - Arm 4 (control)

Patients will receive a standard dose of Rifafour e-275® orally once daily according to body weight from Day 1 through to Day 14. Each tablet of Rifafour e-275® contains 150mg rifampicin, 75mg isoniazid, 400mg pyrazinamide and 275mg ethambutol.

The daily doses will be given to fasting patients, in accordance with South African Guidelines for treatment of TB. The total number of tablets will be based on the body weight at screening:

  • participants weighing 38 - 54 kg: 3 tablets
  • participants weighing 55 - 70 kg: 4 tablets
  • participants weighing >70 kg: 5 tablets
Rifafour e-275® (150mg rifampicin, 75mg isoniazid, 400mg pyrazinamide, 275 mg ethambutol per tablet)
Other Names:
  • Isoniazid, Rifampicin, Pyrazinamide, Ethambutol (HRZE)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Safety and Tolerability of BTZ-043
Time Frame: Day 1 to Day 22
Safety and tolerability of BTZ-043 was assessed by evaluation of Adverse Events (AEs) during treatment- and follow-up phase (Clinical observations, Vital signs, Serum chemistry, hematology and coagulation parameters with baseline measurements. Electrocardiography (ECG), including heart rate, PR interval, QRS, QT interval, QTcF; change of QTcF from baseline; morphological abnormalities).
Day 1 to Day 22

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Bactericidal Activity Endpoint - MGIT Time to Positivity (log10 (h))
Time Frame: Day -1 to Day 14. Change from Day -1 to Day 2, Day 2 - Day 14 and Day -1 to Day 14 have been assessed.

Liquid culture is inoculated with overnight sputum of the participants. Upon growth of Mycobacteria, the color of the medium is changing due to changes in pH. This is measured photometric and the time of the change in color is recorded. The more bactera are inoculated, the quicker the change ind color and the time to positivity.

Overnight sputum is collected on Day -1, Day 0, Day 2, Day 3, Day 4, Day 6, Day 8, Day 11 and Day 14 to be able to follow the decrease in bacterial load over time.

Day -1 to Day 14. Change from Day -1 to Day 2, Day 2 - Day 14 and Day -1 to Day 14 have been assessed.
Bactericidal Activity Endpoint - CFU
Time Frame: Day -1 to Day 14. Change from Day -1 to Day 2, Day 2 - Day 14 and Day -1 to Day 14 have been assessed.

Overnight sputum was plated on solid medium. Decrease in log 10 CFU (No. of colony forming untis) over time was assessed.

Overnight sputum is collected on Day -1, Day 0, Day 2, Day 3, Day 4, Day 6, Day 8, Day 11 and Day 14 to be able to follow the decrease in bacterial load over time.

Day -1 to Day 14. Change from Day -1 to Day 2, Day 2 - Day 14 and Day -1 to Day 14 have been assessed.

Collaborators and Investigators

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

Sponsor

Collaborators

Investigators

  • Study Director: Michael Hoelscher, Prof, University Hospital, LMU Munich, Division of Infectious Diseases and Tropical Medicine
  • Principal Investigator: Andreas Diacon, Prof, TASK Applied Science Clinical Research Centre

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

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)

November 15, 2019

Primary Completion (Actual)

March 3, 2022

Study Completion (Actual)

May 31, 2022

Study Registration Dates

First Submitted

July 29, 2019

First Submitted That Met QC Criteria

August 1, 2019

First Posted (Actual)

August 2, 2019

Study Record Updates

Last Update Posted (Actual)

August 31, 2026

Last Update Submitted That Met QC Criteria

August 27, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

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