A Phase 3 Trial Assessing Safety and Efficacy of B-Pa-L in Participants With DR-TB

A Phase 3 Open-label Trial Assessing the Safety and Efficacy of Bedaquiline Plus PA-824 Plus Linezolid in Participants With Pulmonary Infection of Either XDR-TB or Treatment Intolerant / Non-responsive MDR-TB.

The purpose of this study is to evaluate the efficacy, safety, tolerability and pharmacokinetics of bedaquiline plus PA-824 plus linezolid after 6 months of treatment (option for 9 months for participants who remain culture positive at month 4) in participants with either pulmonary extensively drug resistant tuberculosis (XDR-TB), treatment intolerant or non-responsive multi-drug resistant tuberculosis (MDR-TB).

Study Overview

• Status: Completed
• Conditions: Pulmonary Tuberculosis
• Intervention / Treatment: Drug: Linezolid; Drug: Bedaquiline; Drug: PA-824

Detailed Description

Up to 200 male and female participants aged 14 and over with confirmed sputum positive for M.tb. in culture pulmonary XDR-TB, or with pulmonary MDR-TB with a documented intolerability or non-response to the best treatment available for 6 months or more will be enrolled.

All participants will have up to a maximum of 9 days for screening, receive 6 months of treatment, and have followup visits performed 1 and 2 months after treatment completion and every 3 months after study treatment completion for 24 months. If a participant is culture positive or revert to being culture positive between Month 4 and Month 6 visits and their clinical condition suggests they may have ongoing TB infection, they may have treatment extended to 9 months (with 24 months of Follow Up) or be withdrawn from the study.

Participants who withdraw after <14 days of IMP should attend an Early Withdrawal visit. Participants who withdraw after >15 days of IMP should return for an Early Withdrawal visit and follow-up visits at 3, 6 and 24 months after their last dose of IMP to check for survival, SAEs and resolution of TB symptoms.

• Study Type: Interventional
• Enrollment (Actual): 109
• Phase: Phase 3

Contacts and Locations

Study Locations

• South Africa
  • Cape Town
    • Ysterplaat, Cape Town, South Africa, 7405
      • Task Applied Science - Brooklyn Chest Hospital
  • Durban
    • Sydenham, Durban, South Africa, 4001
      • King DinuZulu Hospital Complex
  • Johannesburg
    • Sandringham, Johannesburg, South Africa, 2131
      • Sizwe Tropical Disease Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 14 years and older (Child, Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Key Inclusion Criteria

1. Provide written, informed consent prior to all trial-related procedures (if under 18, include consent of legal guardian).
2. Body weight of ≥35 kg (in light clothing and no shoes).
3. Male or female, aged 14 years or above.

4. Subjects with one of the following pulmonary TB conditions (WHO definitions prior to 2021):

   a. Extensively Drug Resistant Tuberculosis (XDR-TB) with

   i. documented culture positive (for M.tb.) results within 3 months prior to screening or M.tb. confirmed in sputum based on molecular test within 3 months prior to or at screening;

   ii. documented resistance to isoniazid, rifamycins, a fluoroquinolone and an injectable historically at any time or at screening;

   b. Multi-Drug Resistant Tuberculosis (MDR-TB) documented by culture positive results (for M.tb.) within 3 months prior to or at screening with documented non-response to treatment with the best available regimen for 6 months or more prior to enrolment who in the opinion of the Investigator have been adherent to treatment and will be adherent to study regimen;

   c. MDR-TB documented by culture positive (for M.tb.) results within 3 months prior to or at screening who are unable to continue second line drug regimen due to a documented intolerance to:

   i. PAS, ethionamide, aminoglycosides or fluoroquinolones;

   ii. Current treatment not listed above that renders subject eligible for the study in the Investigator's opinion.

6. Chest X-Ray picture (taken within a year prior to screening) consistent with pulmonary TB in the opinion of the Investigator.

Key Exclusion Criteria

1. Karnofsky score < 50 within 30 days prior to entry.
2. Body Mass index (BMI) < 17 kg/m²
3. History of allergy or known hypersensitivity to any of the trial Investigational Medicinal Products or related substances.
4. HIV infected Subjects having a CD4+ count ≤ 50 cells/μL
5. Having participated in other clinical studies with dosing of investigational agents within 8 weeks prior to trial start or currently enrolled in an investigational study that includes treatment with medicinal agents. Subjects who are participating in observational studies or who are in a follow up period of a trial that included drug therapy may be considered for inclusion.
6. Significant cardiac arrhythmia requiring medication.

7. Subjects with the following at Screening:

   1. QTcF interval on ECG >500 msec.
   2. History of additional risk factors for Torsade de Pointes, (e.g., heart failure, hypokalemia, family history of Long QT Syndrome);
   3. Clinically significant ventricular arrhythmias;
   4. Subjects with other cardiac abnormalities that may place them at risk of arrhythmias must be discussed with the sponsor medical monitor before enrolment. Such abnormalities include: Evidence of ventricular pre-excitation (e.g., Wolff Parkinson White syndrome); Electrocardiographic evidence of complete or clinically significant incomplete left bundle branch block or right bundle branch block; Evidence of second or third degree heart block; Intraventricular conduction delay with QRS duration more than 120 msec.
8. Females who have a positive pregnancy test at Screening or already known to be pregnant, breastfeeding, or planning to conceive a child during the study or within 6 months of cessation of treatment. Males planning to conceive a child during the study or within 6 months of cessation of treatment.
9. A peripheral neuropathy of Grade 3 or 4, according to DMID (Appendix 2). Or, subjects with a Grade 1 or 2 neuropathy which is likely to progress/worsen over the course of the study, in the opinion of the Investigator.
10. Concomitant use of Monoamine Oxidase Inhibitors (MAOIs) or prior use within 2 weeks of treatment assignment.

11. Subjects with the following toxicities at Screening as defined by the enhanced Division of Microbiology and Infectious Disease (DMID) adult toxicity table (November 2007):

    a. serum potassium less than the lower limit of normal for the laboratory; b. Hemoglobin level grade 2 or greater (< 8.0 g/dL); c. Platelets grade 2 or greater(<75,000/mm3); d. Absolute neutrophil count (ANC) < 1000/ mm3; e. Aspartate aminotransferase (AST) > 3 x ULN g. Total bilirubin > or = to 2xULN h. Direct bilirubin > ULN i. Serum creatinine level greater than 2 times upper limit of normal j. Albumin <32 g/L

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Bedaquiline + PA-824 + Linezolid; bedaquiline 400 mg once daily for 2 weeks then 200mg 3 times per week plus PA-824 200mg once daily plus linezolid 1200mg once daily. A reduction in the dose of linezolid (to either 600 mg qd or 300 mg qd), or temporary cessation of linezolid (due to a linezolid-specific toxicity), or of the full regimen per Investigator discretion was allowed for suspected drug related toxicity. Re-introduction of the regimen could be considered post a cessation not greater than 35 consecutive days. If participants had toxicity events related to linezolid prohibiting further treatment with that drug, they could remain on the bedaquiline and pretomanid study IMP if they received the initial total of 1200 mg daily dose of linezolid for at least the first 4 consecutive weeks of treatment and they were smear negative, or with trace/scanty results and judged to be clinically improving by the Investigator.

Drug: Linezolid; Scored 600mg tablets; Other Names: L; Lin; Drug: Bedaquiline; 100mg tablets; Other Names: B; TMC-207; Drug: PA-824; 200mg tablets; Other Names: Pa; pretomanid

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of Treatment Failure (Unfavorable Outcome), Defined as Bacteriologic Failure or Relapse or Clinical Failure (Derived) Through Follow-up Until 6 Months After the End of Treatment.	Bacteriologic failure: During the treatment period, failure to attain culture conversion to negative. Bacteriologic relapse: During the follow-up period, failure to maintain culture conversion to negative status in culture, with culture conversion to positive status with a Mycobacterium tuberculosis (M.tb.) strain that is genetically identical to the infecting strain at baseline. Clinical failure: A change from protocol-specified tuberculosis (TB) treatment due to treatment failure, retreatment for TB during follow up, or TB-related death. Note: Culture conversion requires at least 2 consecutive culture negative/positive samples at least 7 days apart. Participants who are documented at a visit as unable to produce sputum and who are clinically considered to be responding well to treatment will be considered to be culture negative at that visit.	6 Months post End of Treatment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of Treatment Failure (Unfavorable Outcome), Defined as Bacteriologic Failure or Relapse or Clinical Failure (Derived) Through Follow-up Until 24 Months After the End of Treatment.	Bacteriologic failure: During the treatment period, failure to attain culture conversion to negative. Bacteriologic relapse: During the follow-up period, failure to maintain culture conversion to negative status in culture, with culture conversion to positive status with a Mycobacterium tuberculosis (M.tb.) strain that is genetically identical to the infecting strain at baseline. Clinical failure: A change from protocol-specified TB treatment due to treatment failure, retreatment for TB during follow up, or TB-related death. Note: Culture conversion requires at least 2 consecutive culture negative/positive samples at least 7 days apart. Participants who are documented at a visit as unable to produce sputum and who are clinically considered to be responding well to treatment will be considered to be culture negative at that visit.	24 Months post End of Treatment
Time to Sputum Culture Conversion to Negative Status Through the Treatment Period	Median time (in weeks) to culture negative status (first of 2 negative cultures without an intervening positive culture), MITT analysis.	Day 1 through End of Treatment, approximately 6 to 9 months of treatment
Proportion of Participants With Sputum Culture Conversion to Negative Status	Proportion of participants with sputum culture conversion to negative status for those positive at baseline at 4, 6, 8, 12, 16, and End of Treatment (26 or 39 weeks)	Week 4, 6, 8, 12, 16, 26, 39
Number of Treatment Emergent Adverse Events (TEAEs)	Treatment-emergent adverse events (TEAEs): adverse events which started or worsened on or after the first trial drug administration up to and including 14 days after the last trial drug administration. Grade I, II, III, IV TEAEs: DMID grade is indicated as Grade 1 (mild), Grade 2 (moderate), Grade 3 (severe) and Grade 4 (potentially life-threatening). TEAEs of special interest based on Section 7.3 of the protocol. Liver-related adverse events: any adverse event with a High Level Group Term of HEPATIC AND BILIARY NEOPLASMS BENIGN, HEPATIC AND HEPATOBILIARY DISORDERS, HEPATOBILIARY DISORDERS CONGENITAL, HEPATOBILIARY NEOPLASMS MALIGNANT AND UNSPECIFIED, HEPATOBILIARY INVESTIGATIONS or HEPATOBILIARY THERAPEUTIC PROCEDURES.	Day 1 to 14 days post-End of Treatment
Incidence of Treatment Emergent Adverse Events (TEAEs) of Special Interest	Treatment-emergent adverse events (TEAEs): Defined as adverse events which started or worsened on or after the first trial drug administration up to and including 14 days after the last trial drug administration. TEAEs of special interest: Identified by prespecified SMQ codes as confirmed by TB Alliance. Section 7.3 of the protocol specified the "Monitoring and Safety for Specific Toxicities" and are presented here as TEAEs of special interest. These specific toxicities of interest were based on nonclinical toxicology findings of concern for any of the 3 trial drugs, or from identified toxicities based on the IBs for pretomanid and bedaquiline, on the product label for linezolid and literature reports of linezolid long-term toxicity.	Day 1 to 14 days post-End of Treatment
Incidence of Nervous System Disorders - Peripheral Neuropathy Events Grouped	Treatment-emergent adverse events (TEAEs): Defined as adverse events which started or worsened on or after the first trial drug administration up to and including 14 days after the last trial drug administration. #: Indicates TEAEs of special interest. TEAEs of special interest: Identified by pre-specified SMQ codes as confirmed by TB Alliance. Adverse events in System Organ Class "NERVOUS SYSTEM DISORDERS" are presented into the table. Preferred term "PERIPHERAL NEUROPATHY" was a grouping of terms "PERIPHERAL SENSORY NEUROPATHY", "NEUROPATHY PERIPHERAL", "PARAESTHESIA", "HYPOAESTHESIA", "PERIPHERAL MOTOR NEUROPATHY", "BURNING SENSATION", "HYPOREFLEXIA" and "PERIPHERAL SENSORIMOTOR NEUROPATHY".	Day 1 to 14 days post-End of Treatment

Collaborators and Investigators

• Sponsor: Global Alliance for TB Drug Development
• Investigators: Principal Investigator: Francesca Conradie, MD, CHRU Themba Lethu Clinic - Helen Joseph Hospital; Principal Investigator: Morounfolu Olugbosi, MD, Global Alliance for TB Drug Development

Publications and helpful links

General Publications

• Imperial MZ, Nedelman JR, Conradie F, Savic RM. Proposed Linezolid Dosing Strategies to Minimize Adverse Events for Treatment of Extensively Drug-Resistant Tuberculosis. Clin Infect Dis. 2022 May 30;74(10):1736-1747. doi: 10.1093/cid/ciab699.
• Conradie F, Diacon AH, Ngubane N, Howell P, Everitt D, Crook AM, Mendel CM, Egizi E, Moreira J, Timm J, McHugh TD, Wills GH, Bateson A, Hunt R, Van Niekerk C, Li M, Olugbosi M, Spigelman M; Nix-TB Trial Team. Treatment of Highly Drug-Resistant Pulmonary Tuberculosis. N Engl J Med. 2020 Mar 5;382(10):893-902. doi: 10.1056/NEJMoa1901814.
• Solans BP, Imperial MZ, Olugbosi M, Savic RM. Analysis of Dynamic Efficacy Endpoints of the Nix-TB Trial. Clin Infect Dis. 2023 Jun 8;76(11):1903-1910. doi: 10.1093/cid/ciad051.

Helpful Links

• TB Alliance Website

Study record dates

Study Major Dates

• Study Start: March 1, 2015
• Primary Completion (Actual): January 14, 2019
• Study Completion (Actual): August 3, 2020

Study Registration Dates

• First Submitted: January 6, 2015
• First Submitted That Met QC Criteria: January 6, 2015
• First Posted (Estimated): January 7, 2015

Study Record Updates

• Last Update Posted (Estimated): September 8, 2025
• Last Update Submitted That Met QC Criteria: August 18, 2025
• Last Verified: August 1, 2025

More Information

Terms related to this study

• Keywords: Tuberculosis; TB; MDR-TB; PA-824; Linezolid; Pretomanid; XDR-TB; Bedaquiline; Multi-drug resistant; Extensively drug resistant; TMC-207; NiX-TB
• Additional Relevant MeSH Terms: Respiratory Tract Infections; Infections; Respiratory Tract Diseases; Lung Diseases; Gram-Positive Bacterial Infections; Bacterial Infections; Bacterial Infections and Mycoses; Actinomycetales Infections; Mycobacterium Infections; Tuberculosis; Tuberculosis, Pulmonary; Tuberculosis, Multidrug-Resistant; Extensively Drug-Resistant Tuberculosis; Organic Chemicals; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Azoles; Acids, Acyclic; Carboxylic Acids; Amides; Acetamides; Acetates; Oxazolidinones; Oxazoles; Linezolid; bedaquiline; pretomanid
• Other Study ID Numbers: Nix-TB-(B-L-Pa)