High-dose rifamycins in the treatment of TB: a systematic review and meta-analysis

BackgroundThere is growing interest in using high-dose rifamycin (HDR) regimens in TB treatment, but the safety and efficacy of HDR regimens remain uncertain. We performed a systematic review and meta-analysis comparing HDR to standard-dose rifamycin (SDR) regimens.MethodsWe searched MEDLINE, Embase, CENTRAL, Cochrane Database of Systematic Reviews and clinicaltrials.gov for prospective studies comparing daily therapy with HDRs to SDRs. Rifamycins included rifampicin, rifapentine and rifabutin. Our primary outcome was the rate of severe adverse events (SAEs), with secondary outcomes of death, all adverse events, SAE by organ and efficacy outcomes of 2-month culture conversion and relapse. This study was prospectively registered in the International Prospective Register of Systematic Reviews (CRD42020142519).ResultsWe identified 9057 articles and included 13 studies with 6168 participants contributing 7930 person-years (PY) of follow-up (HDR: 3535 participants, 4387 PY; SDR: 2633 participants, 3543 PY). We found no significant difference in the pooled incidence rate ratio (IRR) of SAE between HDR and SDR (IRR 1.00, 95% CI 0.82 to 1.23, I2=41%). There was no significant difference when analysis was limited to SAE possibly, probably or likely medication-related (IRR 1.07, 95% CI 0.82 to 1.41, I2=0%); studies with low risk of bias (IRR 0.98, 95% CI 0.79 to 1.20, I2=44%); or studies using rifampicin (IRR 1.00, 95% CI 0. 0.75–1.32, I2=38%). No significant differences were noted in pooled outcomes of death, 2-month culture conversion and relapse.ConclusionsHDRs were not associated with a significant difference in SAEs, 2-month culture conversion or death. Further studies are required to identify specific groups who may benefit from HDR.

Xpert MTB/RIF use is associated with earlier treatment initiation and culture conversion among patients with sputum smear-negative multidrug-resistant tuberculosis

Background While rapid molecular diagnostic tests for tuberculosis (TB) have decreased detection time of M. tuberculosis and drug resistance, whether their use improves clinical care and outcomes is uncertain. To address these knowledge gaps, we evaluated whether use of the Xpert MTB/RIF assay impacts treatment and clinical outcome metrics among patients treated for sputum smear-negative multidrug-resistant (MDR)-TB. Methods A retrospective cohort of adult patients initiating treatment for sputum smear-negative MDR-TB at the National Center for Tuberculosis and Lung Diseases in Tbilisi, Georgia from 2011-2016. The Xpert MTB/RIF was introduced in Georgia in 2010 and implemented into programmatic use in 2014. Exposure was availability of an Xpert result at time of diagnosis. Time to second-line treatment initiation, sputum culture conversion, and end-of-treatment outcomes were determined from. Time to event was compared using a Cox proportional hazards model. Results Among 151 patients treated for sputum smear-negative MDR-TB (96% culture positive), the Xpert was utilized in the clinical management of 78 (52%) patients and not used in 73 (48%). An adjusted analysis controlling for potential confounders found that patients in the Xpert group had shorter median time to second-line treatment (13 vs. 56 days, adjusted hazard ratio [aHR]10.21, p<0.0001) and culture conversion (61 vs. 93 days, aHR 1.93, p<0.001). There was no difference in treatment outcomes. Conclusions Use of the Xpert in the management of sputum smear-negative MDR-TB decreases time to second-line therapy and sputum culture conversion, providing evidence of its clinical impact and supporting its programmatic utility.

Drug exposure and susceptibility of second-line drugs correlate with treatment response in patients with multidrug resistant tuberculosis: a multi-centre prospective cohort study in China

BackgroundUnderstanding the impact of drug exposure and susceptibility on treatment response of multidrug-resistant tuberculosis (MDR-TB) will help to optimize treatment. This study aimed to investigate the association between drug exposure, susceptibility and response to MDR-TB treatment.MethodsDrug exposure and susceptibility for second-line drugs were measured for patients with MDR-TB. Multivariate analysis was applied to investigate the impact of drug exposure and susceptibility on sputum culture conversion and treatment outcome. Probability of target attainment was evaluated. Random Forest and classification and regression tree (CART) analysis was used to identify key predictors and their clinical targets among patients on WHO-recommended regimens.ResultsDrug exposure and corresponding susceptibility were available for 197 patients with MDR-TB. Target attainment was highly variable ranging from 0% for ethambutol to 97% for linezolid, while patients with fluoroquinolones above targets had higher probability of two-month culture conversion (56.3% versus 28.6%, OR 2.91, 95% CI 1.42–5.94) and favourable outcome (88.8% versus 68.8%, OR 2.89, 95% CI 1.16–7.17). Higher exposure values of fluoroquinolones, linezolid and pyrazinamide were associated with earlier sputum culture conversion. CART analysis selected moxifloxacin AUC/MIC of 231 and linezolid AUC/MIC of 287 as best predictors for six-month culture conversion in patients receiving identical Group A-based regimen. These association were confirmed in multivariate analysis.ConclusionsOur findings indicated that target attainment of TB drugs is associated with response to treatment. The CART-derived thresholds may serve as targets for early dose adjustment in a future randomized controlled study to improve the MDR-TB treatment outcome.

Factors Associated with Acid Fast Bacilli and Sputum Culture Conversion in Patients with Multidrug-Resistant Tuberculosis in Surabaya

Introduction: Indonesia is a high incidence country of multidrug-resistant tuberculosis. There are approximately 11,000 MDR TB cases, 2.8% of them are new cases and 16% of them are relapse cases. Although guidelines for MDR-TB are frequently designed, medication freely provided, and centers for treatment duly expanded, studies on time to sputum culture conversion have been very limited in Indonesia. Therefore the aim of the study is to identify risk factors that effect on sputum and culture conversion.Methods: Data on short-term regimen for MDR TB in Dr. Soetomo General Hospital from January 1st – December 31st, 2018 were collected with a total sampling approach, and fulfill the inclusion and exclusion. Data were analyzed by computer software IBM SPSS Statistic 24 for windows. Results: Male is more likely to have delayed sputum conversion and culture conversion but no statistical difference is observed (p>0.05). Smoking history is more likely to have delayed sputum and culture conversion but only in sputum smear test shows a significant difference (p≤ 0.05). Alcohol consumption has delay effect on sputum and culture conversion but there is statistically difference in only culture conversion (p<0.05). The high baseline smear test also affects delay the sputum and culture conversion but only in sputum smear reveals a significant effect (p<0.05).Conclusion: In this present study, we identified sex, smoking history, high bacillary loads as significant factors on sputum conversion. In addition, we revealed that alcohol-consumption history is a significant factor affecting on culture conversion.

In Vitro Activity and Clinical Outcomes of Clofazimine for Nontuberculous Mycobacteria Pulmonary Disease

Limited data are available regarding the in vitro activity of clofazimine against nontuberculous mycobacteria (NTM) or on outcomes of clofazimine-containing regimens in NTM-pulmonary disease (PD). Therefore, we evaluated the in vitro activity of clofazimine and the clinical outcomes of clofazimine-containing regimens. We evaluated clofazimine in vitro activity for 303 NTM isolates from NTM-PD patients. Fifty-seven clarithromycin-resistant and 35 amikacin-resistant isolates were also analyzed. Culture conversion after a 12-month treatment regimen containing clofazimine was evaluated in 58 NTM-PD patients, including 20 patients with drug-resistant isolates. Most of the 303 isolates (238/303) had minimum inhibitory concentrations (MICs) ≤0.25 µg/mL for clofazimine (57/63 Mycobacterium avium, 53/57 M. intracellulare, 49/52 M. kansasii, 22/64 M. abscessus, and 57/67 M. massiliense). For the 57 clarithromycin-resistant and 35 amikacin-resistant isolates, most had MICs ≤0.25 µg/mL (47/57 and 32/35, respectively). Among the 38 NTM-PD patients without resistance to clarithromycin or amikacin, 47% achieved culture conversion (8/27 M. abscessus, 9/9 M. massiliense, 0/1 M. avium, and 1/1 M. intracellulare). The conversion rate was higher in the MIC ≤0.25 µg/mL group than in the MIC = 0.5 µg/mL group (13/18 vs. 5/20, p = 0.004), and an MIC ≤0.25 µg/mL remained a significant factor in multivariable analysis. Culture conversion was achieved in 20% of 20 patients with clarithromycin- or amikacin-resistant isolates. However, a clofazimine MIC ≤0.25 µg/mL was not significant for culture conversion in the 58 NTM-PD patients, regardless of the drug resistance pattern. Clofazimine was effective in vitro against NTM species. Some patients on clofazimine-containing regimens achieved culture conversion.

Treatment success using novel and adapted treatment regimens in registered DR-TB children in Dushanbe, Tajikistan, 2013-2019

Introduction: Approximately 3% of all pediatric TB cases develop MDR-TB, with only 3–4% of such children receiving MDR-TB treatment. In Tajikistan, children as a proportion of all DR-TB in the country increased from 4.3 to 7.5% during 2013-2018. Despite limited evidence on the use of new anti-TB drugs in children, WHO has updated its guidelines for DR-TB treatment for children, and Tajikistan did so in 2013 and 2017. Novel and adapted regimens included individual regimens for RR/MDR, XDR (with and without Bedaquiline and Delamanid) and short treatment regimens with and without injectables. It is important to document the outcomes of the treatment regimens. Therefore, the aim of this study was to describe characteristics of children receiving different treatment regimens for DR-TB, the culture conversion and treatment outcomes. Methodology: Cohort study of children enrolled in DR-TB treatment by the National Tuberculosis Program in Dushanbe, Tajikistan, January 2013 to July 2019. Results: The study included 60 DR-TB children. The male to female ratio was 1:2 and mean age 13.6 years. Median time to culture conversion was 66 days [IQR:31-103; Range:2-232]. In children with treatment outcomes (N = 58), 93% had favorable outcomes. There were four children (7%) with unfavorable treatment outcomes, all of whom were female 15-17 years, on standard (RR/MDR) treatment during 2013-2015. Favorable outcomes by DR-TB type were 91%, 90%, and 100% in RR/MDR, PreXDR, and XDR-TB patients, respectively. Conclusions: All children enrolled after the introduction of modified guidelines for novel and adapted regimens for DR-TB showed positive TB treatment outcomes.

9-12 months short treatment for patients with MDR-TB increases treatment success in Kyrgyzstan

Introduction: MDR/RR-TB is a growing problem in Kyrgyzstan. In 2005, the country introduced standard or individualized treatment for 20-24 months. Because of poor treatment outcomes, in 2017 a short treatment with strict eligibility criteria was introduced. The aim of this study was to compare characteristics and treatment outcomes of MDR/RR-TB patients receiving short (9-12 months) treatment in 2017 with those receiving standard or individualized (20-24 months) treatment in 2016/2017. Methodology: A comparative cohort study using routine programmatic data. Characteristics, sputum culture conversion and treatment outcomes were compared between those on short treatment with those on standard/individualized treatment using the chi-square test, crude and adjusted risk ratios (RR and aRR). Results: The study included 274, 82 and 132 patients on standard, individualized and short treatment, respectively. There were more females, fewer migrants/homeless and unemployed and more new TB patients on short treatment compared with the other two groups. A favorable outcome (cure and treatment completed) was significantly higher in short treatment patients (83%) compared with those on standard (50%) or individualized (59%) treatment (p < 0.001). There was higher 1-month sputum culture conversion with short treatment (35%) compared with the other two groups (19% and 24%, p < 0.05). Short treatment (aRR 1.6, 1.4-1.8), female gender (aRR 1.2, 1.1-1.4), not being homeless (aRR 12.9, 4.5-17.3) and having new TB (aRR 1.3, 1.0-1.5) were independently associated with a favorable outcome. Conclusions: The treatment success was higher in selected MDR-TB patients given short treatment in Kyrgyzstan: this regimen should be scaled-up to all MDR-TB patients.