This is a multi-centre, open label, multi-arm, randomised, controlled, phase II-III trial; evaluating short treatment regimens containing bedaquiline and pretomanid in combination with existing and re-purposed anti-TB drugs for the treatment of biologically confirmed pulmonary multidrug-resistant TB (MDR-TB).
The study will be divided into two stages, with a seamless transition between the stages, meaning recruitment into an arm will only stop after a decision has been taken following stage 1 primary end point data analysis. All recruited patients will be followed up to 108 weeks post randomisation unless they die or withdraw consent. The local standard of care (SOC) MDR-TB regimen will be used as the internal control for both safety and efficacy.
The first stage corresponds to a Phase II trial of safety and preliminary efficacy in patients with MDR-TB. Patients will be recruited into 3 parallel B and Pa containing regimen arms plus a SOC control. The main objective of Stage 1 is to select drug regimens for evaluation in Stage 2 based on 8 week safety and efficacy endpoints. All stage 1 patients will be hospitalised for 8 weeks for intensive cardiological evaluations to establish the QT-specific liability of the regimens.
Investigational arms that do not meet predefined safety and efficacy criteria (percentage culture conversion >40%; percentage discontinuation and death <45%) will not be considered for further evaluation. The regimens that do not meet these pre-defined safety and/or efficacy criteria will be eligible to be evaluated for long term safety, tolerability and efficacy in Stage 2.
If less than two investigational arms are available for stage two assessment, the SAC will make recommendations on whether new arms should be introduced in the study. If more than two arms are available for the Stage 2 assessment, two regimens will be chosen. The SAC will make recommendations on which two arms to take forward to the trial steering committee.
The second stage corresponds to a phase III trial. Patients in this stage will be recruited into 2 arms chosen from stage 1 plus the SOC. The regimens will primarily be evaluated for safety and efficacy in comparison with the SOC arm at 72 weeks post randomisation. The primary efficacy outcome will be a composite endpoint of the percentage of unfavourable outcomes. The secondary outcomes will include safety outcomes and in particular the percentage of Grade 3 or 4 AEs and SAEs in the investigational regimens compared with the SOC.