The Evaluation of a Standard Treatment Regimen of Anti-tuberculosis Drugs for Patients With MDR-TB

The STREAM study is an international, multi-centre, parallel-group, open-label, randomised, controlled trial in patients with multi-drug resistant tuberculosis (MDR-TB) including patients with rifampicin-resistant and isoniazid-sensitive TB.

Background and Rationale:

In 2011, World Health Organisation (WHO) guidelines for the treatment for MDR-TB recommended an intensive phase of treatment based on at least four drugs known to be effective and given for a minimum of 20 months; this is referred to as the WHO 2011 long regimen. Outcomes with this approach are generally poor. In the most recent WHO TB surveillance report only 50% of MDR-TB patients were successfully treated and a recent meta-analysis reported on average 62% successful outcome and a mortality of 11%.

In 2010, Van Deun et al (2010) reported excellent long-term outcomes in a cohort of over 200 patients in Bangladesh with MDR-TB who were treated with a regimen given for only nine to 11 months. Such a regimen, if successful, would represent a considerable advance over current practice. Evaluation of this regimen is the objective of Stage 1 of STREAM.

In 2016, following review of the available data, the WHO MDR TB treatment guidelines were modified to recommend a 9-12 month shortened regimen under specific conditions similar to Regimen B used in STREAM Stage 1 (referred to as the WHO 2016 short regimen).

Bedaquiline is a novel diarylquinoline antibiotic with bactericidal activity. In a phase II trial of patients with MDR-TB time to culture conversion was significantly less in patients receiving bedaquiline compared to those receiving an optimised background regimen only (Diacon et al (2012). In December 2012 the US Food and Drug Administration (FDA) approved bedaquiline as part of the treatment regimen for MDR-TB when other agents are unavailable. Stage 2 of STREAM was designed to investigate ways in which Regimen B could be improved either by removing the second-line injectable, which is associated with severe drug toxicity, or by shortening the regimen to 6 months.

Treatments that are evaluated within the STREAM trial include:

Regimen A The locally-used MDR-TB regimen in accordance with 2011 WHO MDR-TB treatment guidelines.

Regimen B is based on the regimen described by Van Deun 2010. At the start of STREAM this consisted of clofazimine, ethambutol, moxifloxacin, and pyrazinamide given for 40 weeks, supplemented by isoniazid, kanamycin, and prothionamide in the first 16 weeks (intensive phase). ); this combination is referred to as Regimen Bmox. With Version 8.0 of the protocol Regimen B is modified by replacement of moxifloxacin with levofloxacin (referred to as Regimen Blev). Regimen B without specification of which fluoroquinolone is in the regimen refers to either (Bmox or Blev).