Treatment outcomes 24 months after initiating short, all-oral bedaquiline-containing or injectable-containing rifampicin-resistant tuberculosis treatment regimens in South Africa: a retrospective cohort study.

BACKGROUND: There is a need for short and safe all-oral treatment of rifampicin-resistant tuberculosis. We compared outcomes up to 24 months after treatment initiation for patients with rifampicin-resistant tuberculosis in South Africa treated with a short, all-oral bedaquiline-containing regimen (bedaquiline group), or a short, injectable-containing regimen (injectable group). METHODS: Patients with rifampicin-resistant tuberculosis, aged 18 years or older, eligible for a short regimen starting treatment between Jan 1 and Dec 31, 2017, with a bedaquiline-containing or WHO recommended injectable-containing treatment regimen of 9-12 months, registered in the drug-resistant tuberculosis database (EDRWeb), and with known age, sex, HIV status, and national identification number were eligible for study inclusion; patients receiving linezolid, carbapenems, terizidone or cycloserine, delamanid, or para-aminosalicylic acid were excluded. Bedaquiline was given at a dose of 400 mg once daily for two weeks followed by 200 mg three times a week for 22 weeks. To compare regimens, patients were exactly matched on HIV and ART status, previous tuberculosis treatment history, and baseline acid-fast bacilli smear and culture result, while propensity score matched on age, sex, province of treatment, and isoniazid-susceptibility status. We did binomial linear regression to estimate adjusted risk differences (aRD) and 95% CIs for 24-month outcomes, which included: treatment success (ie, cure or treatment completion without evidence of recurrence) versus all other outcomes, survival versus death, disease free survival versus survival with treatment failure or recurrence, and loss to follow-up versus all other outcomes. FINDINGS: Overall, 1387 (14%) of 10152 patients with rifampicin-resistant tuberculosis treated during 2017 met inclusion criteria; 688 in the bedaquiline group and 699 in the injectable group. Four patients (1%) had treatment failure or recurrence, 44 (6%) were lost to follow-up, and 162 (24%) died in the bedaquiline group, compared with 17 (2%), 87 (12%), and 199 (28%), respectively, in the injectable group. In adjusted analyses, treatment success was 14% (95% CI 8-20) higher in the bedaquiline group than in the injectable group (70% vs 57%); loss to follow-up was 4% (1-8) lower in the bedaquiline group (6% vs 12%); and disease-free survival was 2% (0-5) higher in the bedaquiline group (99% vs 97%). The bedaquiline group had 8% (4-11) lower risk of mortality during treatment (17·0% vs 22·4%), but there was no difference in mortality post-treatment. INTERPRETATION: Patients in the bedaquiline group experienced significantly higher rates of treatment success at 24 months. This finding supports the use of short bedaquiline-containing regimens in eligible patients. FUNDING: WHO Global TB Programme. TRANSLATION: For the French translation of the abstract see Supplementary Materials section.

Assessment of epidemiological and genetic characteristics and clinical outcomes of resistance to bedaquiline in patients treated for rifampicin-resistant tuberculosis: a cross-sectional and longitudinal study.

BACKGROUND: Bedaquiline improves outcomes of patients with rifampicin-resistant and multidrug-resistant (MDR) tuberculosis; however, emerging resistance threatens this success. We did a cross-sectional and longitudinal analysis evaluating the epidemiology, genetic basis, and treatment outcomes associated with bedaquiline resistance, using data from South Africa (2015-19). METHODS: Patients with drug-resistant tuberculosis starting bedaquiline-based treatment had surveillance samples submitted at baseline, month 2, and month 6, along with demographic information. Culture-positive baseline and post-baseline isolates had phenotypic resistance determined. Eligible patients were aged 12 years or older with a positive culture sample at baseline or, if the sample was invalid or negative, a sample within 30 days of the baseline sample submitted for bedaquiline drug susceptibility testing. For the longitudinal study, the first surveillance sample had to be phenotypically susceptible to bedaquiline for inclusion. Whole-genome sequencing was done on bedaquiline-resistant isolates and a subset of bedaquiline-susceptible isolates. The National Institute for Communicable Diseases tuberculosis reference laboratory, and national tuberculosis surveillance databases were matched to the Electronic Drug-Resistant Tuberculosis Register. We assessed baseline resistance prevalence, mutations, transmission, cumulative resistance incidence, and odds ratios (ORs) associating risk factors for resistance with patient outcomes. FINDINGS: Between Jan 1, 2015, and July 31, 2019, 8041 patients had surveillance samples submitted, of whom 2023 were included in the cross-sectional analysis and 695 in the longitudinal analysis. Baseline bedaquiline resistance prevalence was 3·8% (76 of 2023 patients; 95% CI 2·9-4·6), and it was associated with previous exposure to bedaquiline or clofazimine (OR 7·1, 95% CI 2·3-21·9) and with rifampicin-resistant or MDR tuberculosis with additional resistance to either fluoroquinolones or injectable drugs (pre-extensively-drug resistant [XDR] tuberculosis: 4·2, 1·7-10·5) or to both (XDR tuberculosis: 4·8, 2·0-11·7). Rv0678 mutations were the sole genetic basis of phenotypic resistance. Baseline resistance could be attributed to previous bedaquiline or clofazimine exposure in four (5·3%) of 76 patients and to primary transmission in six (7·9%). Odds of successful treatment outcomes were lower in patients with baseline bedaquiline resistance (0·5, 0·3-1). Resistance during treatment developed in 16 (2·3%) of 695 patients, at a median of 90 days (IQR 62-195), with 12 of these 16 having pre-XDR or XDR. INTERPRETATION: Bedaquiline resistance was associated with poorer treatment outcomes. Rapid assessment of bedaquiline resistance, especially when patients were previously exposed to bedaquiline or clofazimine, should be prioritised at baseline or if patients remain culture-positive after 2 months of treatment. Preventing resistance by use of novel combination therapies, current treatment optimisation, and patient support is essential. FUNDING: National Institute for Communicable Diseases of South Africa.

Sputum culture and drug sensitivity testing outcome among X-pert Mycobacterium tuberculosis/rifampicin-positive, rifampicin-resistant sputum: A retrospective study - Not all rifampicin resistance is multi-drug resistant.

OBJECTIVE: Rifampicin-resistant (RR) tuberculosis (TB) on X-pert Mycobacterium tuberculosis/rifampicin (MTB/Rif) is assumed to be a surrogate for multi-drug resistant (MDR) TB. Following an RR result, a second specimen was taken for confirmatory culture and drug-susceptibility testing (DST). This study compared the initial diagnostic X-pert MTB/RIF result with the confirmatory DST in a high human immunodeficiency virus (HIV) seroprevalence setting. DESIGN: Records analysing demographics, HIV serostatus, prior TB treatments, and DST results were retrospectively reviewed. RESULTS: Of 604 patients with X-pert MTB/RIF RR, 374 (61.9%) had DST and were included. The mean age was 36.9 years and 82% were HIV infected. Following DST, MDR was confirmed in 49% and Rif mono-resistant (RMR) TB in 36%. Amongst RMR TB, 84% were HIV-infected, and amongst those with CD4 < 50 versus those 50-350 cells/mm3 RMR TB was noted in 51% versus 33%, respectively (P = 0.012). Primary DR was diagnosed in 43% (61% MDR and 33% RMR). CONCLUSION: Rifampicin resistance detected on a diagnostic X-pert MTB/Rif assay did not always predict MDR. Rifampicin mono-resistance is emerging amongst those with HIV co-infection and low CD4 counts (<50 cells/mm3). Research is needed to reduce the number of drugs and treatment durations for RMR TB.

High treatment success rate for multidrug-resistant and extensively drug-resistant tuberculosis using a bedaquiline-containing treatment regimen.

South African patients with rifampicin-resistant tuberculosis (TB) and resistance to fluoroquinolones and/or injectable drugs (extensively drug-resistant (XDR) and preXDR-TB) were granted access to bedaquiline through a clinical access programme with strict inclusion and exclusion criteria.PreXDR-TB and XDR-TB patients were treated with 24 weeks of bedaquiline within an optimised, individualised background regimen that could include levofloxacin, linezolid and clofazimine as needed. 200 patients were enrolled: 87 (43.9%) had XDR-TB, 99 (49.3%) were female and the median age was 34 years (interquartile range (IQR) 27-42). 134 (67.0%) were living with HIV; the median CD4+ count was 281 cells·µL-1 (IQR 130-467) and all were on antiretroviral therapy.16 out of 200 patients (8.0%) did not complete 6 months of bedaquiline: eight were lost to follow-up, six died, one stopped owing to side effects and one was diagnosed with drug-sensitive TB. 146 out of 200 patients (73.0%) had favourable outcomes: 139 (69.5%) were cured and seven (3.5%) completed treatment. 25 patients (12.5%) died, 20 (10.0%) were lost from treatment and nine (4.5%) had treatment failure. 22 adverse events were attributed to bedaquiline, including a QT interval corrected using the Fridericia formula (QTcF) >500 ms (n=5), QTcF increase >50 ms from baseline (n=11) and paroxysmal atrial flutter (n=1).Bedaquiline added to an optimised background regimen was associated with a high rate of successful treatment outcomes for this preXDR-TB and XDR-TB cohort.

Effect of bedaquiline on mortality in South African patients with drug-resistant tuberculosis: a retrospective cohort study.

BACKGROUND: Addition of bedaquiline to treatment for multidrug-resistant tuberculosis was associated with an increased risk of death in a phase 2b clinical trial, resulting in caution from WHO. Following a compassionate access programme and local regulatory approval, the South African National Tuberculosis Programme began widespread use of bedaquiline in March, 2015, especially among patients with extensively drug resistant tuberculosis for whom no other effective treatment options were available. We aimed to compare mortality in patients on standard regimens with that of patients on regimens including bedaquiline. METHODS: In this retrospective cohort study, we analysed patient data from the South African rifampicin-resistant tuberculosis case register (EDRweb), and identified additional mortality using the national vital statistics register. We excluded patients who started treatment before July 1, 2014, or after March 31, 2016; patients younger than 15 years or older than 75 years; patients without documented rifampicin resistance, and patients with pre-extensively drug-resistant tuberculosis (multidrug-resistant tuberculosis with further resistance to a second-line injectable or fluoroquinolone). We compared all-cause mortality between patients who received bedaquiline in treatment regimens and those who did not. Patients who did not receive bedaquiline had kanamycin or capreomycin and moxifloxacin as core medicines in their regimen. We estimated hazard ratios for mortality separately for multidrug-resistant or rifampicin-resistant tuberculosis and extensively drug-resistant tuberculosis and adjusted using propensity score quintile strata for the potential confounders of sex, age, HIV and antiretroviral therapy status, history of prior tuberculosis, valid identification number, and year and province of treatment. FINDINGS: 24 014 tuberculosis cases were registered in the EDRweb between July 1, 2014, and March 31, 2016. Of these, 19 617 patients initiated treatment and met our analysis eligibility criteria. A bedaquiline-containing regimen was given to 743 (4·0%) of 18 542 patients with multidrug-resistant or rifampicin-resistant tuberculosis and 273 (25·4%) of 1075 patients with extensively drug-resistant tuberculosis. Among 1016 patients who received bedaquiline, 128 deaths (12·6%) were reported, and there were 4612 deaths (24·8%) among 18 601 patients on the standard regimens. Bedaquiline was associated with a reduction in the risk of all-cause mortality for patients with multidrug-resistant or rifampicin-resistant tuberculosis (hazard ratio [HR] 0·35, 95% CI 0·28-0·46) and extensively drug-resistant tuberculosis (0·26, 0·18-0·38) compared with standard regimens. INTERPRETATION: Our retrospective cohort analysis of routinely reported data in the context of high HIV and extensively drug-resistant tuberculosis prevalence showed that bedaquiline-based treatment regimens were associated with a large reduction in mortality in patients with drug-resistant tuberculosis, compared with the standard regimen. FUNDING: None.