Standardised shorter regimens versus individualised longer regimens for rifampin- or multidrug-resistant tuberculosis

Effectiveness, cost, and safety of four regimens recommended by WHO for RR/MDR-TB treatment: a cohort study in Eastern China

BACKGROUND

To compare the effectiveness, cost, and safety of four regimens recommended by the World Health Organization (WHO) for rifampicin resistance/multidrug-resistance tuberculosis (RR/MDR-TB) Treatment in Eastern China.

METHODS

We performed a cohort study among patients with RR/MDR between 2020 and 2022 in Jiangsu Province. The treatment success rate, cost, and drug adverse reaction rate were compared.

RESULTS

Between 2020 and 2022, 253 RR/MDR-TB patients were enrolled in the study. 37 (14.62%), 76 (30.04%), 74 (29.25%), and 66 (26.09%) patients had the short-term regimens, the new long-term oral regimens, the new long-term injectable regimens, and the traditional long-term regimens, respectively. The treatment success rate was the highest among patients treated with the short-term regimen (75.68%) and was the lowest among patients treated with the traditional long-term regimens (60.61%). The estimated mean cost per favorable outcome was 142.61 thousand Chinese Yuan (CNY), and the short-term regimens showed the lowest cost in the four regimes (88.51 thousand CNY vs. 174.24 thousand CNY, 144.00 thousand CNY, and 134.98 thousand CNY). Incremental cost-effectiveness ratios of the short-term regimens, the new long-term oral regimen, and the new long-term injectable regimens were -3083.04, 6040.09, and 819.68 CNY compared to the traditional long-term regimens.

CONCLUSIONS

For RR/MDR-TB patients in China who meet the criteria for short-term regimens, the short-term regimens were proven to be the most cost-effective of the four regimens recommended by WHO. For RR/MDR-TB patients in China who don't meet the criteria for short-term regimens, the new long-term injectable regimens are more cost-effective than the remaining two regimens.

Treatment outcomes of standardized injectable shorter regimen for multi-drugs resistant tuberculosis in Ethiopia: a retrospective cohort study

BACKGROUND

The injectable shorter multi-drug resistant tuberculosis (MDR-TB) regimen, has been reported to be less costly and more effective in the treatment of MDR-TB compared to the longer regimen. Ethiopia introduced the injectable shorter regimen (SR) in April 2018 following official recommendation by the World Health Organization (WHO) in 2016. While the WHO recommendation was based on evidence coming from extensive programmatic studies in some Asian and African countries, there is paucity of information on patient outcomes in the Ethiopian context. Thus, we aimed to assess the treatment outcomes and identify factors associated with the outcomes of MDR-TB patients on injectable SR.

METHODS

A multi-center facility-based retrospective cohort study was conducted in Ethiopia on 245 MDR-TB patients who were treated between April 2018 and March 2020. Data were collected from patients' medical records and analyzed using SPSS version 25. Descriptive statistics was used to summarize the results while inferential analysis was employed to investigate predictors of treatment outcomes and survival status.

RESULTS

A total of 245 patients were included in the study, with 129 (52.7%) of them being female. Median age of the patients was 27 (IQR: 21-33). The overall treatment success rate was 87.8%, with 156 (63.7%) cured and 59 (24.1%) patients who completed treatment. The unfavorable outcomes accounted for 12.2%, with 16 (6.5%) treatment failure, 8 (3.3%) death and 6 (2.4%) lost to follow up. Majority of the unfavorable outcomes occurred during the early phase of therapy, with median time to event of 1.8 months (95% CI: 0.99-2.69). The use of khat (a green leafy shrub abused for its stimulant like effect) and being diagnosed with MDR-TB than rifampicin resistant only, were identified as independent factors associated with unfavorable outcomes.

CONCLUSION

The injectable SR for MDR-TB was found to have positive treatment outcomes in the context of programmatic management in Ethiopia.

Treatment of Multidrug-resistant or Rifampicin-resistant Tuberculosis With an All-oral 9-month Regimen Containing Linezolid or Ethionamide in South Africa: A Retrospective Cohort Study

BACKGROUND

In 2019, the South African tuberculosis program replaced ethionamide with linezolid as part of an all-oral 9-month regimen. We evaluated treatment outcomes for patients assigned to regimens including linezolid in 2019 and ethionamide in 2017.

METHODS

This retrospective cohort study included patients treated for multidrug-resistant/rifampicin-resistant tuberculosis throughout South Africa between 1 January and 31 December 2017 and 1 January to 31 December 2019. The cohort treated with a 9-month regimen containing ethionamide for four months, was compared with a cohort treated with a 9-month regimen containing linezolid for 2 months. The regimens were otherwise identical. Inverse probability weighting of propensity scores was used to adjust for potential confounding. A log-binomial regression model was used to estimate adjusted relative risk (aRR) comparing 24-month outcomes between cohorts including treatment success, death, loss to follow up, and treatment failure. Adverse event data were available for the linezolid cohort.

FINDINGS

In total, 817 patients were included in the cohort receiving ethionamide and 4244 in the cohort receiving linezolid. No evidence for a difference was observed between linezolid and ethionamide regimens for treatment success (aRR = 0.96, 95% confidence interval [CI] .91-1.01), death (aRR = 1.01, 95% CI .87-1.17) or treatment failure (aRR = 0.87, 95% CI .44-1.75). Loss to follow-up was more common in the linezolid group, although estimates were imprecise (aRR = 1.22, 95% CI .99-1.50).

CONCLUSIONS

No significant differences in treatment success and survival were observed with substitution of linezolid for ethionamide as a part of an all-oral 9-month regimen. Linezolid is an acceptable alternative to ethionamide in this shorter regimen for treatment of multidrug-resistant/rifampicin-resistant tuberculosis.

Impact and cost-effectiveness of the 6-month BPaLM regimen for rifampicin-resistant tuberculosis in Moldova: A mathematical modeling analysis

BACKGROUND

Emerging evidence suggests that shortened, simplified treatment regimens for rifampicin-resistant tuberculosis (RR-TB) can achieve comparable end-of-treatment (EOT) outcomes to longer regimens. We compared a 6-month regimen containing bedaquiline, pretomanid, linezolid, and moxifloxacin (BPaLM) to a standard of care strategy using a 9- or 18-month regimen depending on whether fluoroquinolone resistance (FQ-R) was detected on drug susceptibility testing (DST).

METHODS AND FINDINGS

The primary objective was to determine whether 6 months of BPaLM is a cost-effective treatment strategy for RR-TB. We used genomic and demographic data to parameterize a mathematical model estimating long-term health outcomes measured in quality-adjusted life years (QALYs) and lifetime costs in 2022 USD ($) for each treatment strategy for patients 15 years and older diagnosed with pulmonary RR-TB in Moldova, a country with a high burden of TB drug resistance. For each individual, we simulated the natural history of TB and associated treatment outcomes, as well as the process of acquiring resistance to each of 12 anti-TB drugs. Compared to the standard of care, 6 months of BPaLM was cost-effective. This strategy was estimated to reduce lifetime costs by $3,366 (95% UI: [1,465, 5,742] p < 0.001) per individual, with a nonsignificant change in QALYs (-0.06; 95% UI: [-0.49, 0.03] p = 0.790). For those stopping moxifloxacin under the BPaLM regimen, continuing with BPaL plus clofazimine (BPaLC) provided more QALYs at lower cost than continuing with BPaL alone. Strategies based on 6 months of BPaLM had at least a 93% chance of being cost-effective, so long as BPaLC was continued in the event of stopping moxifloxacin. BPaLM for 6 months also reduced the average time spent with TB resistant to amikacin, bedaquiline, clofazimine, cycloserine, moxifloxacin, and pyrazinamide, while it increased the average time spent with TB resistant to delamanid and pretomanid. Sensitivity analyses showed 6 months of BPaLM to be cost-effective across a broad range of values for the relative effectiveness of BPaLM, and the proportion of the cohort with FQ-R. Compared to the standard of care, 6 months of BPaLM would be expected to save Moldova's national TB program budget $7.1 million (95% UI: [1.3 million, 15.4 million] p = 0.002) over the 5-year period from implementation. Our analysis did not account for all possible interactions between specific drugs with regard to treatment outcomes, resistance acquisition, or the consequences of specific types of severe adverse events, nor did we model how the intervention may affect TB transmission dynamics.

CONCLUSIONS

Compared to standard of care, longer regimens, the implementation of the 6-month BPaLM regimen could improve the cost-effectiveness of care for individuals diagnosed with RR-TB, particularly in settings with a high burden of drug-resistant TB. Further research may be warranted to explore the impact and cost-effectiveness of shorter RR-TB regimens across settings with varied drug-resistant TB burdens and national income levels.

A pragmatic randomized controlled trial to evaluate the efficacy and safety of an oral short-course regimen including bedaquiline for the treatment of patients with multidrug-resistant tuberculosis in China: study protocol for PROSPECT

INTRODUCTION

The lack of safe, effective, and simple short-course regimens (SCRs) for multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB) treatment has significantly impeded TB control efforts in China.

METHODS

This phase 4, randomized, open-label, controlled, non-inferiority trial aims to assess the efficacy and safety of a 9-month all-oral SCR containing bedaquiline (BDQ) versus an all-oral SCR without BDQ for adult MDR-TB patients (18-65 years) in China. The trial design mainly mirrors that of the "Evaluation of a Standardized Treatment Regimen of Anti-Tuberculosis Drugs for Patients with MDR-TB" (STREAM) stage 2 study, while also incorporating programmatic data from South Africa and the 2019 consensus recommendations of Chinese MDR/RR-TB treatment experts. Experimental arm participants will receive a modified STREAM regimen C that replaces three group C drugs, ethambutol (EMB), pyrazinamide (PZA), and prothionamide (PTO), with two group B drugs, linezolid (LZD) and cycloserine (CS), while omitting high-dose isoniazid (INH) for confirmed INH-resistant cases. BDQ duration will be extended from 6 to 9 months for participants with Mycobacterium tuberculosis-positive sputum cultures at week 16. The control arm will receive a modified STREAM regimen B without high-dose INH and injectable kanamycin (KM) that incorporates experimental arm LZD and CS dosages, treatment durations, and administration methods. LZD (600 mg) will be given daily for ≥ 24 weeks as guided by observed benefits and harm. The primary outcome measures the proportion of participants with favorable treatment outcomes at treatment completion (week 40), while the same measurement taken at 48 weeks post-treatment completion is the secondary outcome. Assuming an α = 0.025 significance level (one-sided test), 80% power, 15% non-inferiority margin, and 10% lost to follow-up rate, each arm requires 106 participants (212 total) to demonstrate non-inferiority.

DISCUSSION

PROSPECT aims to assess the safety and efficacy of a BDQ-containing SCR MDR-TB treatment at seventeen sites across China, while also providing high-quality data to guide SCRs administration under the direction of the China National Tuberculosis Program for MDR-TB. Additionally, PROSPECT will explore the potential benefits of extending the administration of the 9-month BDQ-containing SCR for participants without sputum conversion by week 16.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05306223. Prospectively registered on 16 March 2022 at https://clinicaltrials.gov/ct2/show/NCT05306223?term=NCT05306223&draw=1&rank=1 {2}.

The efficacy and safety of high-dose isoniazid-containing therapy for multidrug-resistant tuberculosis: a systematic review and meta-analysis

Objectives: Accumulating evidence are available on the efficacy of high-dose isoniazid (INH) for multidrug-resistant tuberculosis (MDR-TB) treatment. We aimed to perform a systematic review and meta-analysis to compare clinical efficacy and safety outcomes of high-dose INH- containing therapy against other regimes. Methods: We searched the following databases PubMed, Embase, Scopus, Web of Science, CINAHL, the Cochrane Library, and ClinicalTrials.gov. We considered and included any studies comparing treatment success, treatment unsuccess, or adverse events in patients with MDR-TB treated with high-dose INH (>300 mg/day or >5 mg/kg/day). Results: Of a total of 3,749 citations screened, 19 studies were included, accounting for 5,103 subjects, the risk of bias was low in all studies. The pooled treatment success, death, and adverse events of high-dose INH-containing therapy was 76.5% (95% CI: 70.9%-81.8%; I2: 92.03%), 7.1% (95% CI: 5.3%-9.1%; I2: 73.75%), and 61.1% (95% CI: 43.0%-77.8%; I2: 98.23%), respectively. The high-dose INH administration is associated with significantly higher treatment success (RR: 1.13, 95% CI: 1.04-1.22; p < 0.01) and a lower risk of death (RR: 0.45, 95% CI: 0.32-0.63; p < 0.01). However, in terms of other outcomes (such as adverse events, and culture conversion rate), no difference was observed between high-dose INH and other treatment options (all p > 0.05). In addition, no publication bias was observed. Conclusion: In MDR-TB patients, high-dose INH administration is associated with a favorable outcome and acceptable adverse-event profile. Systematic review registration: identifier CRD42023438080.

A Comprehensive Review on Long vs. Short Regimens in Multidrug-Resistant Tuberculosis (MDR-TB) Under Programmatic Management of Drug-Resistant Tuberculosis (PMDT)

This comprehensive review delves into the intricate landscape of multidrug-resistant tuberculosis (MDR-TB) treatment within the programmatic management of drug-resistant tuberculosis (PMDT) framework. MDR-TB poses a substantial global health threat, necessitating targeted approaches for effective management. The analysis explores the historical evolution, efficacy, safety profiles, and implementation challenges associated with long and short regimens. The findings underscore the importance of individualized clinical practices, considering patient-specific factors, and the need for ongoing monitoring within PMDT programs. Recommendations advocate for integrating advanced diagnostics, continuous surveillance, and training for healthcare professionals. The review concludes with a nuanced outlook on long versus short regimens, emphasizing a balanced approach and the imperative role of collaborative efforts in shaping the future of MDR-TB treatment. This synthesis contributes to the ongoing discourse, providing valuable insights for healthcare practitioners, policymakers, and researchers working toward optimizing outcomes for individuals afflicted with MDR-TB.

Finding and treating both tuberculosis disease and latent infection during population-wide active case finding for tuberculosis elimination

In recognition of the high rates of undetected tuberculosis in the community, the World Health Organization (WHO) encourages targeted active case finding (ACF) among "high-risk" populations. While this strategy has led to increased case detection in these populations, the epidemic impact of these interventions has not been demonstrated. Historical data suggest that population-wide (untargeted) ACF can interrupt transmission in high-incidence settings, but implementation remains lacking, despite recent advances in screening tools. The reservoir of latent infection-affecting up to a quarter of the global population -complicates elimination efforts by acting as a pool from which future tuberculosis cases may emerge, even after all active cases have been treated. A holistic case finding strategy that addresses both active disease and latent infection is likely to be the optimal approach for rapidly achieving sustainable progress toward TB elimination in a durable way, but safety and cost effectiveness have not been demonstrated. Sensitive, symptom-agnostic community screening, combined with effective tuberculosis treatment and prevention, should eliminate all infectious cases in the community, whilst identifying and treating people with latent infection will also eliminate tomorrow's tuberculosis cases. If real strides toward global tuberculosis elimination are to be made, bold strategies are required using the best available tools and a long horizon for cost-benefit assessment.

Real-world experience of adverse reactions-necessitated rifampicin-sparing treatment for drug-susceptible pulmonary tuberculosis

Rifampicin is an important agent for tuberculosis treatment; however, it is often discontinued because of adverse reactions. The treatment regimen then can be administered as that for rifampicin-resistant tuberculosis, which can be toxic. We retrospectively reviewed 114 patients with drug-susceptible pulmonary tuberculosis who discontinued rifampicin due to adverse reactions during an 18 year period at a tertiary referral center, of which 92 (80.7%) exhibited favorable response. Hepatotoxicity was the leading cause of intolerance. Patients with a favorable response were younger and less likely to have comorbidities. The majority of patients were administered four medications during the intensive phase and three to four during the consolidative phase. For those with a favorable response, the median duration of treatment was 10.2 months and the most common intensive regimen was a combination of isoniazid, ethambutol, pyrazinamide, and fluoroquinolone (25%). The most common consolidation regimen was a combination of isoniazid, ethambutol, and fluoroquinolone (22.8%). Among the patients with a favorable response, two (2.2%) experienced recurrence after a follow-up of 3.4 (interquartile range 1.8-6.8) years. For patients with drug-susceptible pulmonary tuberculosis who do not tolerate rifampicin owing to its toxicity, a shorter regimen may be a useful alternative.

Prospective study on outcome of MDR-TB using the shorter regimen during COVID-19 pandemic

Background

According to Indian TB report 2020, 66,225 MDR/RR-TB cases were detected in India, 56,569 (85%) were put on treatment, and 40,397 (75%) were initiated on shorter drug regimens at the time of diagnosis. In the absence of an effective vaccine, there is an urgent need for new treatment regimens, drugs, and diagnostics to slow the evolution of drug resistance and limit transmission of resistant variants, as well as to ameliorate the treatment outcome of patients infected with MDR/XDR M. tuberculosis strains.

Aim

To evaluate the efficacy of a shorter drug regimen in MDR-PTB and estimate the adverse effects of drugs used in the regimen.

Methods

This is an institution-based prospective study which included 135 confirmed MDR-PTB patients. Patients with extra-pulmonary MDR-TB and use of SLI for more than one month were excluded.

Results

The success rate using a shorter regimen was 65.2% which is respectable, given the COVID-19 pandemic considered during the study period. Minor adverse events such as nausea (39.3%) and vomiting (34.8%) were reported. Rare adverse effects such as hearing loss (8.9%) and hypothyroidism (0.2%) were also seen in the study population.

Conclusion

Overall treatment success was similar when compared to other studies done previously. A shorter drug regimen was associated with minor adverse effects such as gastrointestinal adverse effects such as vomiting and hearing loss observed in elderly patients. Baseline unknown drug resistance and lower BMI were associated with unsuccessful outcomes. Measures should be taken to improve nutrition. Our results argue the need for improving baseline DST at peripheral areas in order to effectively evaluate resistance to other drugs, especially in settings with high levels of first and second-line drug resistance.

Long-term treatment outcomes in patients with multidrug-resistant tuberculosis

OBJECTIVES

To describe long-term treatment outcomes in patients with multi-drug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB) and validate established outcome definitions for MDR/RR-TB treatment.

METHODS

Among patients with MDR/RR-TB admitted to a German MDR/RR-TB referral centre from 1 September 2002 to 29 February 2020, we compared long-term treatment outcomes derived from individual patient follow-up with treatment outcomes defined by WHO-2013, WHO-2021 and the Tuberculosis Network European Trials Group-2016.

RESULTS

In a total of 163 patients (mean age, 35 years; standard deviation, 13 years; 14/163 [8.6%] living with HIV; 109/163 [66.9%] men, 149/163 [91.4%] migrating to Germany within 5 years), the treatment of culture-confirmed MDR/RR-TB was initiated. Additional drug resistance to a fluoroquinolone or a second-line injectable agent was present in 15 of the 163 (9.2%) Mycobacterium tuberculosis strains; resistance against both the drug classes was present in 29 of the 163 (17.8%) strains. The median duration of MDR/RR-TB treatment was 20 months (interquartile range, 19.3-21.6 months), with a medium of five active drugs included. The median follow-up time was 4 years (47.7 months; interquartile range, 21.7-65.8 months). Among the 163 patients, cure was achieved in 25 (15.3%), 82 (50.3%) and 95 (58.3%) patients according to the outcome definitions of WHO-2013, WHO-2021, and the Tuberculosis Network European Trials Group-2016, respectively. The lost to follow-up rate was 17 of 163 (10.4%). Death was more likely in patients living with HIV (hazard ratio, 4.28; 95% confidence interval, 1.26-12.86) and older patients (hazard ratio, 1.08; 95% confidence interval, 1.05-1.12; increment of 1 year). Overall, 101/163 (62.0%) patients experienced long-term, relapse-free cure; of those, 101/122 (82.8%) patients with a known status (not lost to-follow-up or transferred out) at follow-up.

CONCLUSION

Under optimal management conditions leveraging individualized treatment regimens, long-term, relapse-free cure from MDR/RR-TB is substantially higher than cure rates defined by current treatment outcome definitions.

The Changing Paradigm of Drug-Resistant Tuberculosis Treatment: Successes, Pitfalls, and Future Perspectives

Drug-resistant tuberculosis (DR-TB) remains a global crisis due to the increasing incidence of drug-resistant forms of the disease, gaps in detection and prevention, models of care, and limited treatment options. The DR-TB treatment landscape has evolved over the last 10 years. Recent developments include the remarkable activity demonstrated by the newly approved anti-TB drugs bedaquiline and pretomanid against Mycobacterium tuberculosis. Hence, treatment of DR-TB has drastically evolved with the introduction of the short-course regimen for multidrug-resistant TB (MDR-TB), transitioning to injection-free regimens and the approval of the 6-month short regimens for rifampin-resistant TB and MDR-TB. Moreover, numerous clinical trials are under way with the aim to reduce pill burden and shorten the DR-TB treatment duration. While there have been apparent successes in the field, some challenges remain. These include the ongoing inclusion of high-dose isoniazid in DR-TB regimens despite a lack of evidence for its efficacy and the inclusion of ethambutol and pyrazinamide in the standard short regimen despite known high levels of background resistance to both drugs. Furthermore, antimicrobial heteroresistance, extensive cavitary disease and intracavitary gradients, the emergence of bedaquiline resistance, and the lack of biomarkers to monitor DR-TB treatment response remain serious challenges to the sustained successes. In this review, we outline the impact of the new drugs and regimens on patient treatment outcomes, explore evidence underpinning current practices on regimen selection and duration, reflect on the disappointments and pitfalls in the field, and highlight key areas that require continued efforts toward improving treatment approaches and rapid biomarkers for monitoring treatment response.

Treatment outcomes for multidrug- and rifampicin-resistant tuberculosis in Central and West Africa: a systematic review and meta-analysis

OBJECTIVES

We aimed to investigate published data on treatment outcomes of multidrug-resistant (MDR)/rifampicin-resistant tuberculosis (TB) in Central and West Africa because these, to the best of our knowledge, are sparsely available.

METHODS

Systematic review and meta-analysis.

RESULTS

A total of 14 studies were included, representing 4268 individuals in 14 of the 26 countries. Using a random-effects model meta-analysis, we observed a pooled success rate of 80.8% (95% confidence interval [CI] 56.0-93.3) for the Central African subgroup and 69.2% (95% CI 56.3-79.7) for the West African subgroup (P = 0.0522). The overall treatment success for all studies was 74.6% (95% CI 65.0-82.2). We found high heterogeneity among included studies (I² = 96.1%). The estimated proportion of successfully treated individuals with MDR/rifampicin-resistant TB was considerably higher than the global estimate provided by the World Health Organization (59%), reaching the 2015 World Health Organization target of at least 75% treatment success for MDR-TB.

CONCLUSION

The use of shorter treatment regimens and the standardized treatment conditions, including directly observed therapy in these studies, could have contributed to a high treatment success. Yet, the available literature was not fully representative of the regions, possibly highlighting the sparse resources in many of these countries. The review was registered at PROSPERO (https://www.crd.york.ac.uk/prospero/) (CRD42022353163).

Comparative effectiveness of individualized longer and standardized shorter regimens in the treatment of multidrug resistant tuberculosis in a high burden country

Objective: To compare the effectiveness of second line injectables containing shorter (duration 9–12 months) and longer treatment regimens (LTR, duration ≥ 20 months) among multidrug-resistant tuberculosis (MDR-TB) patients with no documented resistance and history of treatment with any second-line anti-TB drug (SLD) for ≥ 1 month.

Methods: This was an observational cohort study of MDR-TB patients treated at eight PMDT units in Pakistan. Patients’ data from baseline until treatment outcomes were collected from Electronic Nominal Recording and Reporting System. The treatment outcomes of “cured” and “treatment completed” were grouped together as successful, whereas “death,” “treatment failure,” and “lost to follow-up” were collectively grouped as unsuccessful outcomes. Time to sputum culture conversion (SCC) was analyzed using the Kaplan–Meier method and the differences between groups were compared through the log-rank test. Multivariate Cox proportional hazards and binary logistic regression analyses were used to find predictors of time to SCC and unsuccessful treatment outcomes. A p-value < 0.05 was considered statistically significant.

Results: A total 701 eligible MDR-TB patients [313 treated with shorter treatment regimen (STR) and 388 treated with LTR at eight centres in Pakistan were evaluated]. Time to achieve SCC was significantly shorter in STR group [mean: 2.03 months, 95% confidence interval (CI):1.79–2.26] than in LTR group (mean: 2.69 months, 95% CI: 2.35–3.03) (p-value<0.001, Log-rank test). Treatment success was higher in STR (83.7%) than in LTR (73.2%) group (p-value <0.001) due to high cure (79.9% vs. 70.9%, p-value = 0.006) and low death (9.9% vs. 18.3%, p-value = 0.002) rates with STR. Treatment with STR emerged the only predictor of early SCC [adjusted Hazards ratio (aHR) = 0.815, p-value = 0.014], whereas, patient’s age of 41–60 (OR = 2.62, p-value<0.001) and >60 years (OR = 5.84, p-value<0.001), baseline body weight of 31–60 (OR = 0.36, p-value = 0.001) and >60 kg (OR = 0.23, p-value <0.001), and treatment with LTR (OR = 1.88, p-value = 0.001) had statistically significant association with unsuccessful treatment outcomes.

Conclusion: STR exhibited superior anti-microbial activity against MDR-TB. When compared LTR, treatment with STR resulted in significantly early SCC, high cure, and lower death rates among MDR-TB patients who had no documented resistance and history of treatment with any SLD ≥ 1 month.

Costs of Tuberculosis at 3 Treatment Centers, Canada, 2010-2016

We estimated costs of managing different forms of tuberculosis (TB) across Canada by conducting a retrospective chart review and cost assessment of patients treated for TB infection, drug-susceptible TB (DS TB), isoniazid-resistant TB, or multidrug-resistant TB (MDR TB) at 3 treatment centers. We included 90 patients each with TB infection and DS TB, 71 with isoniazid-resistant TB, and 62 with MDR TB. Median per-patient costs for TB infection (in 2020 Canadian dollars) were $804 (interquartile range [IQR] $587-$1,205), for DS TB $12,148 (IQR $4,388-$24,842), for isoniazid-resistant TB $19,319 (IQR $7,117-$41,318), and for MDR TB $119,014 (IQR $80,642-$164,015). Compared with costs for managing DS TB, costs were 11.1 (95% CI 9.1-14.3) times lower for TB infection, 1.7 (95% CI 1.3-2.1) times higher for isoniazid-resistant TB, and 8.1 (95% CI 6.1-10.6) times higher for MDR TB. Broadened TB infection treatment could avert high costs associated with managing TB disease.

Failure or relapse predictors for the STREAM Stage 1 short regimen for RR-TB

BACKGROUND: STREAM (Standardised Treatment Regimens of Anti-tuberculosis drugs for Multidrug-Resistant Tuberculosis) Stage 1 demonstrated non-inferior efficacy of a short regimen for rifampicin-resistant TB (RR-TB) compared to a long regimen as recommended by the WHO. The present paper analyses factors associated with a definite or probable failure or relapse (FoR) event in participants receiving the Short regimen.METHODS: This analysis is restricted to 253 participants allocated to the Short regimen and is based on the protocol-defined modified intention to treat (mITT) population. Multivariable Cox regression models were built using backwards elimination with an exit probability of P = 0.157, equivalent to the Akaike Information Criterion, to identify factors independently associated with a definite or probable FoR event.RESULTS: Four baseline factors were identified as being significantly associated with the risk of definite or probable FoR (male sex, a heavily positive baseline smear grade, HIV co-infection and the presence of costophrenic obliteration). There was evidence of association of culture positivity at Week 8 and FoR in a second model and Week 16 smear positivity, presence of diabetes and of smoking in a third model.CONCLUSION: The factors associated with FoR outcomes identified in this analysis should be considered when determining the optimal shortened treatment regimen.

Social and health factors associated with adverse treatment outcomes among people with multidrug-resistant tuberculosis in Sierra Leone: a national, retrospective cohort study

BACKGROUND

Multidrug-resistant tuberculosis (MDR-TB) is a global health emergency. We aimed to evaluate treatment outcomes among people with MDR-TB in Sierra Leone and investigate social and health factors associated with adverse treatment outcomes.

METHODS

This national, retrospective cohort study recruited all people notified with MDR-TB to the Sierra Leone National TB Programme, admitted to Lakka hospital (Lakka, Western Area Rural District, Freetown, Sierra Leone) between April, 2017, and September, 2019. Participants were followed up to May, 2021. People who were eligible but had no social or health data available, or were subsequently found to have been misdiagnosed, were excluded from participation. MDR-TB treatment was with the 2017 WHO-recommended short (9-11 month) or long (18-24 month) aminoglycoside-containing regimens. Multivariable logistic regression models examined associations of programmatic social and health data with WHO-defined adverse treatment outcomes (death, treatment failure, loss to follow-up).

FINDINGS

Of 370 notified MDR-TB cases, 365 (99%) were eligible for study participation (five participants were excluded due to lack of social or health data or misdiagnosis). Treatment was started by 341 (93%) of 365 participants (317 received the short regimen, 24 received the long regimen, and 24 received no treatment). Median age was 35 years (IQR 26-45), 263 (72%) of 365 were male and 102 (28%) were female, 71 (19%) were HIV-positive, and 127 (35%) were severely underweight (body-mass index <16·5 kg/m²). Overall, 267 (73%) of 365 participants had treatment success, 95 (26%) had an adverse outcome, and three (1%) were still on treatment in May, 2021. Age 45-64 years (adjusted odds ratio [aOR] 2·4, 95% CI 1·2-5·0), severe underweight (aOR 4·2, 1·9-9·3), untreated HIV (aOR 10, 2·6-40·0), chronic lung disease (aOR 2·0, 1·0-4·2), previously unsuccessful drug-sensitive tuberculosis retreatment (aOR 4·3, 1·0-19), and a long regimen (aOR 6·5, 2·3-18·0) were associated with adverse outcomes. A sensitivity analysis showed that prothionamide resistance (aOR 3·1, 95% CI 1·5-10·0) and aminoglycoside-related complete deafness (aOR 6·6, 1·3-35) were independently associated with adverse outcomes.

INTERPRETATION

MDR-TB treatment success in Sierra Leone approached WHO targets and the short regimen was associated with higher success. The social and health factors associated with adverse outcomes in this study suggest a role for integrated tuberculosis, HIV, and non-communicable disease services alongside nutritional and socioeconomic support for people with MDR-TB and emphasise the urgent need to scale up coverage of all-oral aminoglycoside-sparing regimens.

FUNDING

Wellcome Trust, Joint Global Health Trials.

Factors associated with treatment outcome of MDR/RR-TB patients treated with shorter injectable based regimen in West Java Indonesia

Background and aims

Multi drug or rifampicin resistant tuberculosis (MDR/RR-TB) is a major burden to TB prevention and eradication globally. Since 2016, WHO guidelines have included options for treating MDR/RR-TB with a standard regimen of 9 to 11 months duration (the ’shorter regimen’) rather than an individual regimen of at least 20 months. This regimen has been introduced in Indonesia since September 2017. Therefore, we aimed to determine the success rate and factors associated with the treatment outcome of shorter injectable based regimen in West Java province, Indonesia.

Methods

This was a retrospective cohort study of MDR/RR-TB patients aged over 18 years old who received the shorter injectable based regimen between September 2017 and December 2020. We defined successful outcomes as the combined proportion of patients who were cured or had complete treatment. While, unsuccessful outcomes were defined as the combined proportion of patients who died from any causes, failure, and loss to follow-up (LTFU).

Results

A total of 315 patients were included in this study. The success rate was 64.5%. Multivariate analysis showed male gender (aRR = 1.18, 95% CI 1.04 to 1.34) increased the chance of successful outcome, while malnutrition (aRR = 0.78, 95% CI 0.68 to 0.89), history of previous TB treatment (aRR = 0.80%CI 0.68 to 0.94), and time of culture conversion >2 months (aRR = 0.72 (95% CI 0.59 to 0.87) decreased the chance of successful outcome.

Conclusion

History of previous TB treatment, time of culture conversion >2 months, and malnutrition were independent factors that decrease the chance for success rate, while male gender increase the likelihood for success rate of patients treated by the shorter injectable based regimen.

Coverage and effectiveness of conditional cash transfer for people with drug resistant tuberculosis in Zimbabwe: A mixed methods study

The End TB strategy recommends social protection to mitigate socio-economic impacts of tuberculosis. Zimbabwe started implementing a conditional cash transfer (CCT) programme for people on drug resistant tuberculosis (DR-TB) treatment in 2013. We aimed to determine the proportion of people receiving CCT and effectiveness of CCT in improving treatment outcomes, explore their experiences with registering for CCT and understand the impact of CCT from the perspective of beneficiaries. Data from 2014-2021 were extracted from TB registers and CCT payment records within the National TB Programme. Sixteen in-depth interviews were conducted with people who were completing treatment or had completed treatment within two months. Poisson regression, adjusted for province, year of treatment, age and sex was used to investigate associations between receiving CCT and successful treatment outcomes among people who were in DR-TB care for ≥3 months after treatment initiation. Qualitative data were analyzed using thematic analysis. A total of 481 people were included in the quantitative study. Of these, 53% (254/481) received CCT at some point during treatment. People who exited DR-TB care within three months were 73% less likely to receive CCT than those who did not (prevalence ratio (PR) = 0.27 [95%CI: 0.18-0.41]). Among those who were alive and in care three months after treatment initiation, CCT recipients were 32% more likely to have successful outcomes than those who did not (adjusted PR = 1.32, [95%CI: 1.00-1.75]). Qualitative results revealed lack of knowledge about availability of CCT among people with DR-TB and missed opportunities by healthcare providers to provide information about availability of CCT. Delays and inconsistencies in disbursements of CCT were frequent themes. CCT were associated with successful treatment outcomes. Improvements in coverage, timeliness and predictability of disbursements are recommended.

Efficacy of integrating short-course chemotherapy with Chinese herbs to treat multi-drug resistant pulmonary tuberculosis in China: a study protocol

Background

Tuberculosis (TB) caused Mycobacterium tuberculosis (M.tb) is one of infectious disease that lead a large number of morbidity and mortality all over the world. Although no reliable evidence has been found, it is considered that combining chemotherapeutic drugs with Chinese herbs can significantly improves the cure rate and the clinical therapeutic effect.

Methods

Multi-drug resistant pulmonary tuberculosis (MDR-PTB, n = 258) patients with Qi-yin deficiency syndrome will be randomly assigned into a treatment group (n = 172) or control/placebo group (n = 86). The treatment group will receive the chemotherapeutic drugs combined with Chinese herbs granules (1 + 3 granules), while the control group will receive the chemotherapeutic drugs combined with Chinese herbs placebo (1 + 3 placebo granules). In addition, MDR-PTB (n = 312) patients with Yin deficiency lung heat syndrome will be randomly assigned to a treatment (n = 208) or control/placebo (n = 104) group. The treatment group will receive the chemotherapeutic regimen combined with Chinese herbs granules (2 + 4 granules), while the control group will receive the chemotherapeutic drugs and Chinese herbs placebo (2 + 4 placebo granules). The primary outcome is cure rate, the secondary outcomes included time to sputum culture conversion, lesion absorption rate and cavity closure rate. BACTEC™ MGIT™ automated mycobacterial detection system will be used to evaluate the M.tb infection and drug resistance. Chi-square test and Cox regression will be conducted with SAS 9.4 Statistical software to analyze the data.

Discussion

The treatment cycle for MDR-PTB using standardized modern medicine could cause lengthy substantial side effects. Chinese herbs have been used for many years to treat MDR-PTB, but are without high-quality evidence. Hence, it is unknown whether Chinese herbs enhances the clinical therapeutic effect of synthetic drugs for treating MDR-PTB. Therefore, this study will be conducted to evaluate the clinical therapeutic effect of combining Chinese herbs and chemotherapeutic drugs to treat MDR-PTB cases. It will assist in screening new therapeutic drugs and establishing treatment plan that aims to improve the clinical therapeutic effect for MDR-PTB patients.

Trial registration

This trial was registered at ClinicalTrials.gov (ChiCTR1900027720) on 24 November 2019 (prospective registered).

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40249-021-00913-5.

Evaluating newly approved drugs for multidrug-resistant tuberculosis (endTB): study protocol for an adaptive, multi-country randomized controlled trial

BACKGROUND

Treatment of multidrug- and rifampin-resistant tuberculosis (MDR/RR-TB) is expensive, labour-intensive, and associated with substantial adverse events and poor outcomes. While most MDR/RR-TB patients do not receive treatment, many who do are treated for 18 months or more. A shorter all-oral regimen is currently recommended for only a sub-set of MDR/RR-TB. Its use is only conditionally recommended because of very low-quality evidence underpinning the recommendation. Novel combinations of newer and repurposed drugs bring hope in the fight against MDR/RR-TB, but their use has not been optimized in all-oral, shorter regimens. This has greatly limited their impact on the burden of disease. There is, therefore, dire need for high-quality evidence on the performance of new, shortened, injectable-sparing regimens for MDR-TB which can be adapted to individual patients and different settings.

METHODS

endTB is a phase III, pragmatic, multi-country, adaptive, randomized, controlled, parallel, open-label clinical trial evaluating the efficacy and safety of shorter treatment regimens containing new drugs for patients with fluoroquinolone-susceptible, rifampin-resistant tuberculosis. Study participants are randomized to either the control arm, based on the current standard of care for MDR/RR-TB, or to one of five 39-week multi-drug regimens containing newly approved and repurposed drugs. Study participation in all arms lasts at least 73 and up to 104 weeks post-randomization. Randomization is response-adapted using interim Bayesian analysis of efficacy endpoints. The primary objective is to assess whether the efficacy of experimental regimens at 73 weeks is non-inferior to that of the control. A sample size of 750 patients across 6 arms affords at least 80% power to detect the non-inferiority of at least 1 (and up to 3) experimental regimens, with a one-sided alpha of 0.025 and a non-inferiority margin of 12%, against the control in both modified intention-to-treat and per protocol populations.

DISCUSSION

The lack of a safe and effective regimen that can be used in all patients is a major obstacle to delivering appropriate treatment to all patients with active MDR/RR-TB. Identifying multiple shorter, safe, and effective regimens has the potential to greatly reduce the burden of this deadly disease worldwide.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT02754765. Registered on 28 April 2016; the record was last updated for study protocol version 3.3, on 27 August 2019.

Risk factors for poor engagement in drug-resistant TB care in South Africa: a systematic review

BACKGROUND

Metrics of poor patient engagement, including missed appointments, treatment interruption, sub-optimal medication adherence, and loss to follow-up, have been linked to poor clinical multidrug-resistant TB (MDR-TB) outcomes. Understanding the risk factors for poor patient engagement is necessary to improve outcomes and control TB. This review synthesizes the risk factors for poor patient engagement in MDR-TB treatment across South Africa.

DESIGN

A systematic review of five databases (PubMed, Embase, CINAHL, Cochrane, and Web of Science) was conducted, covering articles published between 2010 and 2020. Articles were included if they provided information about risk factors associated with poor engagement among adults (⩾15 years) in treatment for MDR-TB in South Africa. Reviews, editorials, abstracts, and case studies were excluded.

RESULTS

Six studies met the inclusion criteria. Male sex and younger age were the most consistently identified risk factors for poor engagement; however, there was a lack of consistency in the choice of covariates, measurement of the variables, analytic methods, and significant factors associated with poor engagement between studies. Alcohol use, substance use, living with HIV, pulmonary TB site, and ethnicity were all identified as risk factors in at least one included study, while formal housing and steady employment were found to be protective.

CONCLUSION

The available literature offers little cohesive data to address poor patient engagement in this population. Further research needs to focus on identifying and addressing risk factors for poor patient engagement. This is particularly salient within the context of newer all-oral and short-course MDR-TB treatment regimens.

Prediction of anti-tuberculosis treatment duration based on a 22-gene transcriptomic model

BACKGROUND

The World Health Organization recommends standardised treatment durations for patients with tuberculosis (TB). We identified and validated a host-RNA signature as a biomarker for individualised therapy durations for patients with drug-susceptible (DS)- and multidrug-resistant (MDR)-TB.

METHODS

Adult patients with pulmonary TB were prospectively enrolled into five independent cohorts in Germany and Romania. Clinical and microbiological data and whole blood for RNA transcriptomic analysis were collected at pre-defined time points throughout therapy. Treatment outcomes were ascertained by TBnet criteria (6-month culture status/1-year follow-up). A whole-blood RNA therapy-end model was developed in a multistep process involving a machine-learning algorithm to identify hypothetical individual end-of-treatment time points.

RESULTS

50 patients with DS-TB and 30 patients with MDR-TB were recruited in the German identification cohorts (DS-GIC and MDR-GIC, respectively); 28 patients with DS-TB and 32 patients with MDR-TB in the German validation cohorts (DS-GVC and MDR-GVC, respectively); and 52 patients with MDR-TB in the Romanian validation cohort (MDR-RVC). A 22-gene RNA model (TB22) that defined cure-associated end-of-therapy time points was derived from the DS- and MDR-GIC data. The TB22 model was superior to other published signatures to accurately predict clinical outcomes for patients in the DS-GVC (area under the curve 0.94, 95% CI 0.9-0.98) and suggests that cure may be achieved with shorter treatment durations for TB patients in the MDR-GIC (mean reduction 218.0 days, 34.2%; p<0.001), the MDR-GVC (mean reduction 211.0 days, 32.9%; p<0.001) and the MDR-RVC (mean reduction of 161.0 days, 23.4%; p=0.001).

CONCLUSION

Biomarker-guided management may substantially shorten the duration of therapy for many patients with MDR-TB.

Antimicrobial compounds were isolated from the secondary metabolites of Gordonia, a resident of intestinal tract of Periplaneta americana

Gordonia sp. are members of the actinomycete family, their contribution to the environment improvement and environmental protection by their biological degradation ability, but there are few studies on the antimicrobial activity of their secondary metabolites. Our team isolated and purified an actinomycete WA 4-31 from the intestinal tract of Periplaneta americana, firstly identified the strain WA 4-31 by the morphological characteristics and the phylogenetic analyses, and found it was completely homologous to the strain of Gordonia terrae from the Indian desert. Meanwhile, actinomycin D (1), actinomycin X2 (2), mojavensin A (3) and cyclic (leucine-leucne) dipeptide (4) were obtained from the EtOAc extract from the broth of WA 4-31. Compounds 1–4 showed anti-fungus activities against Candida albicans, Aspergillus niger, A. fumigatus and Trichophyton rubrum, also anti-MRSA and inhibited Escherichia coli in different degree. Interestingly, we found when 3 was mixed with 4 with ratio of 1:1, the activity of the mixture on anti-Candida albicans was better than the single. Besides, compounds 1–3 had varying degrees of antiproliferative activities on CNE-2 and HepG-2 cell lines. These indicated that Gordonia rare actinomycete from the intestinal tract of Periplaneta americana possessed a potential as a source of active secondary metabolites.

Novel treatments in multidrug-resistant tuberculosis

The management of multidrug-resistant tuberculosis (TB) is associated with low treatment success, high mortality and failure rates. New drugs and novel short-therapeutic regimens have only recently helped overcome these obstacles. We carried out a narrative literature review aimed at summarizing the scientific evidence on the recent therapeutic advances in the field of drug-resistant TB. Experimental and observational studies on novel (i.e. bedaquiline, delamanid, pretomanid) drugs and novel regimens and the main pharmacological characteristics of the newest compounds are described. We also highlight the main scientific evidence on therapeutic strategies complementary to standard chemotherapy (i.e. new approaches to drug delivery, host-directed therapy, surgery, new collapse therapy, rehabilitation, and palliative care).

Evidence-based Definition for Extensively Drug-resistant Tuberculosis

RATIONALE

Until 2020, extensively drug-resistant tuberculosis (XDR-TB) was defined as resistance to rifampicin and isoniazid (multidrug-resistant tuberculosis, MDR-TB), any fluoroquinolone (FQ) and any second-line injectable drug (SLID). In 2019 the World Health Organization issued new recommendations for managing patients with drug-resistant tuberculosis, substantially limiting the role of SLID in MDR-TB treatment and thus putting that XDR-TB definition into question.

OBJECTIVE

To propose an up-to-date definition for XDR-TB.

METHODS

We used a large dataset to assess treatment outcomes for MDR-TB patients exposed to any type of longer regimen. We included patients with bacteriologically confirmed MDR-TB and known FQ and SLID resistance results. We did logistic regression to estimate adjusted odds ratios (aORs) for unfavourable treatment outcome (failure, relapse, death, loss-to-follow-up) by resistance pattern (FQ, SLID) and Group A drug use (moxifloxacin/levofloxacin, linezolid, bedaquiline).

MEASUREMENTS AND MAIN RESULTS

We included 11,666 patients with MDR-TB; 4653 (39.9%) had an unfavourable treatment outcome. Resistance to FQs increased the odds of an unfavourable treatment outcome (aOR 1.91; 95% confidence interval [95%CI] 1.63-2.23). Administration of bedaquiline and/or linezolid improved treatment outcomes regardless of resistance to FQ and/or SLID. Among XDR-TB patients, compared to persons receiving no Group A drug, aORs for unfavourable outcome were 0.37 (95%CI 0.20-0.69) with linezolid only, 0.40 (95%CI 0.21-0.77) with bedaquiline only, and 0.21 (95%CI 0.12-0.38) with both.

CONCLUSIONS

Our study supports a new definition of XDR-TB as MDR plus additional resistance to FQ plus bedaquiline and/or linezolid, and helps assess the adequacy of this definition for surveillance and treatment choice.NOTE: This article has been updated on July 16, 2021. When it was initially posted on June 9, 2021, the name of one of the coauthors, Dr. Christian Lienhardt, was inadvertently omitted. This version includes Dr. Lienhardt's affilations and contributions; the affiliations have therefore been renumbered.

World Health Organization recommendations on the treatment of drug-resistant tuberculosis, 2020 update

Antimicrobial resistance is a major public health problem globally. Likewise, forms of tuberculosis (TB) resistant to first- and second-line TB medicines present a major challenge for patients, healthcare workers and healthcare services. In November 2019, the World Health Organization (WHO) convened an independent international expert panel to review new evidence on the treatment of multidrug- (MDR) and rifampicin-resistant (RR) TB, using the Grading of Recommendations Assessment, Development and Evaluation approach.Updated WHO guidelines emerging from this review, published in June 2020, recommend a shorter treatment regimen for patients with MDR/RR-TB not resistant to fluoroquinolones (of 9-11 months), with the inclusion of bedaquiline instead of an injectable agent, making the regimen all oral. For patients with MDR-TB and additional fluoroquinolone resistance, a regimen composed of bedaquiline, pretomanid and linezolid may be used under operational research conditions (6-9 months). Depending on the drug-resistance profile, extent of TB disease or disease severity, a longer (18-20 months) all-oral, individualised treatment regimen may be used. In addition, the review of new data in 2019 allowed the WHO to conclude that there are no major safety concerns on the use of bedaquiline for >6 months' duration, the use of delamanid and bedaquiline together and the use of bedaquiline during pregnancy, although formal recommendations were not made on these topics.The 2020 revision has highlighted the ongoing need for high-quality evidence and has reiterated the need for clinical trials and other research studies to contribute to the development of evidence-based policy.

Effectiveness and Safety of a Shorter Treatment Regimen in a Setting with a High Burden of Multidrug-Resistant Tuberculosis

Treatment of drug-resistant tuberculosis is lengthy, insufficiently effective, and toxic. Since 2016, the World Health Organization has recommended shorter treatment regimens (STR). We assessed effectiveness and predictors of drug adverse events (DAE) among patients treated with STR. There were 95 consecutive rifampicin-resistant patients enrolled in STR in Tashkent between June 2018 and September 2019. Of these, 66.3% were successfully treated, 17.9% suffered failed treatment, 7.4% died, 5.3% were lost to follow-up and 3.2% were not evaluated. No recurrence was identified in 54 patients after 12 months of successful treatment completion. There were 47 reported DAE: the incidence rate was 6.15 DAE per 100 person-months-of-treatment. Any DAE was reported in 38 (40%) patients and grade 3/4 DAE were recorded in 21 (22.1%) patients. Median time to DAE was 101 (interquartile range 64-139) days. The most frequently encountered DAE were gastro-intestinal disorders, followed by hepatotoxicity and ototoxicity. The most commonly offending drug inducing DAE was protionamide. The dose was temporarily interrupted in 55.3% of DAE, reduced in 8.5% of DAE and permanently withdrawn in another 8.5% of DAE. HIV status was the only predictor associated with increased hazard of DAE. In Uzbekistan STR showed moderate effectiveness and safety, although treatment failure was high.

Accelerating development of new shorter TB treatment regimens in anticipation of a resurgence of multi-drug resistant TB due to the COVID-19 pandemic

The WHO 2020 global TB Report estimates that in 2019 there were an estimated 500,000 cases of multi-drug resistant TB (MDR-TB) of which only 186,772 MDR-TB cases were diagnosed, and positive treatment outcomes were achieved in 57% of them. These data highlight the need for accelerating and improving MDR-TB screening, diagnostic, treatment and patient follow-up services. The last decade has seen three new TB drugs being licensed; bedaquiline, delamanid and pretomanid, and combinations these new, existing and repurposed drugs are leading to improved cure rates. The all oral six month WHO regimen for MDR-TB is more tolerable, has higher treatment success rates and lower mortality. However, the unprecedented ongoing COVID-19 pandemic is having major direct and indirect negative impacts on health services overall, including national TB programs and TB services. This adds further to longstanding challenges for tackling MDR-TB such as cost, rollout of diagnostics and drugs, and implementation of latest WHO guidelines for MDR-TB. In light of COVID-19 disruption of TB services, it is anticipated the numbers of MDR-TB cases will rise in 2021 and 2022 and will affect treatment outcomes further. Investing more in development of new TB drugs and shorter MDR-TB treatment regimens is required in anticipation of emerging drug resistance to new TB drug regimens. There is an urgent need for protecting current investments in TB services, sustaining gains being made in TB control and accelerating roll out of TB diagnostic and treatment services.

Clinical characteristics and treatment outcomes of patients with MDR tuberculosis in Dar Es Salaam region, Tanzania

Background

In Tanzania more than 28% of all multi-drug resistant tuberculosis (MDR-TB) cases occur in Dar es Salaam. However, information about management and clinical outcomes of patients with MDR-TB in the region is scarce, and hence the need for this study.

Methods

A 5-year retrospective cohort study was conducted in six centres in Dar es Salaam. Descriptive statistics were used to summarize social demographics and clinical characteristics. Associations between occurrence of adverse events, regimen change and cure were determined using the Chi-square test whereas factors associated with mortality were determined using the Log-ranking test and Cox regression model.

Results

Three-hundred patient files were found and reviewed. The majority were male 199 (66.3%), aged 25-44 years [176 (58.7%)] and 89 (30.1%) were HIV co-infected. 186 (62%) completed their treatment, 68 (22.0%) were on treatment and 9 (3.3%) were lost to follow-up. The majority, 152 (51.0%) were managed using long MDR-TB regimens. The overall mortality rate was 5.7 per 1000 MDR-TB patients. A higher mortality rate was associated with being ≥45 years [adjusted hazard ratio (AHR): 10.82, 95% CI: 1.14-102.74, P = 0.038), female (AHR: 5.92, 95% CI: 1.75-20.08, P = 0.004), on a short anti-TB regimen (AHR: 4.34, 95% CI: 1.41-13.35, P = 0.010), HIV co-infected [crude hazard ratio (CHR): 2.56, 95% CI: 1.01-6.50, P = 0.048), on concomitant long-term medication use (CHR: 2.99, 95% CI: 1.17-7.64, P = 0.022) and having other co-morbidities (CHR: 3.45, 95% CI: 1.32-9.02, P = 0.011).

Conclusions

MDR-TB mortality was associated with short anti-TB regimens, sex, age, concomitant long-term medication use and HIV coinfection. In this population, use of long and individualized regimens is recommended.

Principles of chemotherapy for tuberculosis in national tuberculosis programmes of low- and middle-income countries

National tuberculosis programmes (NTPs) should aim for achieving a very high proportion of cure of all tuberculosis (TB) cases. Ineffective chemotherapy of TB that keeps a substantial proportion of patients alive without cure may amplify resistance during treatment and promote transmission of TB. In 2017, the World Health Organization (WHO) recommended that in patients who require TB retreatment, the retreatment regimen that comprised 8 months of isoniazid, rifampicin and ethambutol supplemented by streptomycin for the initial 2 months, and pyrazinamide for the initial 3 months (2SHRZE/HRZE/5HRE) should no longer be prescribed and drug susceptibility testing (DST) should be conducted to inform the choice of treatment regimen. While GeneXpert MTB/RIF assay may detect rifampicin resistance, it does not detect isoniazid resistance. A 6-month regimen consisting of rifampicin, isoniazid, pyrazinamide and ethambutol may be used for the treatment of previously treated cases in whom rifampicin resistance has been excluded but DST of isoniazid is not available. WHO recommended to treat isoniazid-resistant, rifampicin-susceptible TB (Hr-TB) with rifampicin, ethambutol, pyrazinamide and levofloxacin for a duration of 6 months. In several low- and middle-income countries, the majority of Hr-TB cases are detected after the initiation of treatment with first-line regimens. If patients have an unsatisfactory response to first-line treatment with persistent positive sputum, modification of regimens needs to be done very carefully. Adding a fluoroquinolone in cases with undetected rifampicin resistance runs the risk of acquired fluoroquinolone resistance. Recently, WHO advises NTPs to phase out the injectable-containing short regimen for multidrug-resistant and rifampicin-resistant TB (MDR-/RR-TB) and recommends that the preferred treatment option is a shorter, all-oral, bedaquiline-containing regimen. WHO emphasizes that access to rapid DST, especially for ruling out fluoroquinolone resistance, is required before starting the bedaquiline-containing shorter regimen. The problem is that access to rapid DST for ruling out fluoroquinolone resistance is limited in low- and middle-income countries. The use of WHO-recommended bedaquiline-containing regimens in the treatment of MDR-/RR-TB patients with undetected resistance to fluoroquinolones runs a high risk of acquired bedaquiline resistance, especially in settings with a high prevalence of fluoroquinolone resistance. It is crucial to mitigate the risks of both primary and acquired resistance of rifampicin, fluoroquinolone and bedaquiline by rational design of regimens and effective management of TB patients.

Investigation of the efficacy of the short regimen for rifampicin-resistant TB from the STREAM trial

BACKGROUND

The STREAM trial demonstrated that a 9-11-month "short" regimen had non-inferior efficacy and comparable safety to a 20+ month "long" regimen for the treatment of rifampicin-resistant tuberculosis. Imbalance in the components of the composite primary outcome merited further investigation.

METHODS

Firstly, the STREAM primary outcomes were mapped to alternatives in current use, including WHO programmatic outcome definitions and other recently proposed modifications for programmatic or research purposes. Secondly, the outcomes were re-classified according to the likelihood that it was a Failure or Relapse (FoR) event on a 5-point Likert scale: Definite, Probable, Possible, Unlikely, and Highly Unlikely. Sensitivity analyses were employed to explore the impact of informative censoring. The protocol-defined modified intention-to-treat (MITT) analysis population was used for all analyses.

RESULTS

Cure on the short regimen ranged from 75.1 to 84.2% across five alternative outcomes. However, between-regimens results did not exceed 1.3% in favor of the long regimen (95% CI upper bound 10.1%), similar to the primary efficacy results from the trial. Considering only Definite or Probable FoR events, there was weak evidence of a higher risk of FoR in the short regimen, HR 2.19 (95%CI 0.90, 5.35), p = 0.076; considering only Definite FoR events, the evidence was stronger, HR 3.53 (95%CI 1.05, 11.87), p = 0.030. Cumulative number of grade 3-4 AEs was the strongest predictor of censoring. Considering a larger effect of informative censoring attenuated treatment differences, although 95% CI were very wide.

CONCLUSION

Five alternative outcome definitions gave similar overall results. The risk of failure or relapse (FoR) may be higher in the short regimen than in the long regimen, highlighting the importance of how loss to follow-up and other censoring is accounted for in analyses. The outcome of time to FoR should be considered as a primary outcome for future drug-sensitive and drug-resistant TB treatment trials, provided sensitivity analyses exploring the impact of departures from independent censoring are also included.

Understanding the gaps in DR-TB care cascade in Nigeria: A sequential mixed-method study

Background

Despite the availability of free drug-resistant tuberculosis (DR-TB) care in Nigeria since 2011, the country continues to tackle low case notification and treatment rates. In 2018, 11% of an estimated 21,000 cases were diagnosed and 9% placed on treatment. These low rates are nevertheless a marked improvement from 2015 when only 3.4% were diagnosed and 2.3% placed on treatment of an estimated 29,000 cases. This study describes the Nigerian DR-TB care cascade from 2013 to 2017 and considers factors influencing gaps in care.

Methods

Our study utilized a mixed-method design. For the quantitative component, we utilized the national diagnosis and treatment databases, as well as the World Health Organization’s estimates for prevalence to construct a 5-year care cascade: numbers of patients at each level of DR-TB care, including incident cases, individuals who accessed testing, were diagnosed, initiated treated and completed treatment in Nigeria between 2013 and 2017. Using retrospective data for patients diagnosed in 2015, we performed the Fisher’s exact test to determine the association between patient (age and gender) and provider/patient (region- north or south) variables, permitting a closer look at the gaps in care revealed across the 5 years. Barriers to care were explored using framework thematic analysis of 57 qualitative interviews and focus group discussions with patients, including 5 cases not initiated on treatment from the 2015 cohort, treatment supporters, community members, healthcare workers and program managers in 2017.

Results

A 5-year analysis of cascade of care data shows significant, but inadequate, increases in overall numbers of cases accessing care. On average, between 2013 and 2017, 80% of estimated cases did not access testing; 75% of those who tested were not diagnosed; 36% of those diagnosed were not initiated on treatment and 23% of these did not finish treatment. In 2015, children and patients in Northern Nigeria had odds of 0.3 [95% CI 0.1–0.7] and 0.4 [0.3–0.5] of completing treatment once diagnosed; while males were shown to have a 1.34 [95% CI 1.0–1.7] times greater chance of completing treatment after diagnosis. The main themes from qualitative data identified barriers to care along the care cascade at individual, family and community, as well as health systems levels. At the individual level, a lack of awareness of the true cause of disease and the availability of ‘free’ care was a recurring theme. Family interference was found to be a particular challenge for children and women. At the health system level, low index of suspicion, lack of rapid diagnostic tools and human resource shortages appeared to limit patients’ access.

Conclusions

Any gains in diagnostic technology and shorter regimens are lost with inadequate access to DR-TB services. The biggest losses in the Nigerian cascade happen before treatment initiation. There is a need for urgent action on identified gaps in the DR-TB cascade in order to improve care continuity at multiple stages, improve health service delivery and facilitate TB control in Nigeria.

Translating drug resistant tuberculosis treatment guidelines to reality in war-torn Kandahar, Afghanistan: A retrospective cohort study

INTRODUCTION

Afghanistan is affected by one of the world's longest protracted armed conflicts, frequent natural disasters, disease outbreaks and large population movements and it suffers from a high burden of tuberculosis (TB), including rifampicin-resistant TB (RR-TB). The study shows Médecins Sans Frontières' experiences with care for patients with RR-TB in Kandahar Province. We describe the uptake of RR-TB treatment, how World Health Organisation criteria for the choice between the short and an individualized regimen were implemented, and treatment outcomes.

METHODS

This is a retrospective cohort analysis of routinely collected data from RR-TB patients enrolled in care from 2016 until 2019. Descriptive analysis was performed to present characteristics of patients and treatment outcomes. Multivariable Cox analysis was performed to identify risk factors for having an unfavourable treatment outcome.

RESULTS

Out of 146 enrolled RR-TB patients, 112 (76.7%) started treatment: 41 (36.6%) and 71 (63.4%) with the short and individualized treatment regimen, respectively. Of 82 with results for fluoroquinolone susceptibility, 39 (47.6%) had fluoroquinolone-resistant TB. Seven patients with initially fluoroquinolone-resistant TB and three pregnant women started the short regimen and 18 patients eligible for the short regimen started the injectable-free individualized regimen. Overall, six-month smear and culture conversion were 98.7% and 97.1%, respectively; treatment success was 70.1%. Known initial fluoroquinolone resistance (aHR 3.77, 95%CI:1.53-9.27) but not choice of regimen predicted having an unfavourable outcome.

CONCLUSION

Even though criteria for the choice of treatment regimen were not applied strictly, we have achieved acceptable outcomes in this cohort. To expand RR-TB care, treatment regimens should fit provision at primary health care level and take patient preferences into account.

How To Optimally Combine Genotypic and Phenotypic Drug Susceptibility Testing Methods for Pyrazinamide

False-susceptible phenotypic drug-susceptibility testing (DST) results for pyrazinamide due to mutations with MICs close to the critical concentration (CC) confound the classification of pncA resistance mutations, leading to an underestimate of the specificity of genotypic DST. This could be minimized by basing treatment decisions on well-understood mutations and by adopting an area of technical uncertainty for phenotypic DST rather than only testing the CC, as is current practice for the Mycobacterium tuberculosis complex.

Better programmatic outcome with the shorter regimen for the treatment of multidrug-resistant tuberculosis (MDR-TB) in Guinea: A retrospective cohort study

Setting

Since August 2016, after the Ebola outbreak, the Guinean National Tuberculosis Programme and Damien Foundation implemented the shorter treatment regimen (STR) for multidrug-resistant tuberculosis (MDR-TB) in the three MDR-TB sites of Conakry. Previously, the longer regimen was used to treat MDR-TB.

Objectives

In a post-Ebola context, with a weakened health system, we describe the MDR-TB treatment uptake, patients characteristics, treatment outcomes and estimate the effect of using the longer versus STR on having a programmatically adverse outcome.

Design

This is a retrospective cohort study in RR-TB patients treated with either the longer regimen or STR.

Results

In Conakry, in 2016 and 2017, 131 and 219 patients were diagnosed with rifampicin-resistant tuberculosis (RR-TB); and 108 and 163 started treatment, respectively. Of 271 patients who started treatment, 75 were treated with the longer regimen and 196 with the STR. Patients characteristics were similar regardless of the regimen except that the median age was higher among those treated with a longer regimen (30 years (IQR:24–38) versus 26 years (IQR:21–39) for the STR. Patients treated with a STR were more likely to obtain a programmatically favorable outcome (74.0% vs 58.7%, p = 0.01) as lost to follow up was higher among those treated with a longer regimen (20.0% vs 8.2%, p = 0.006). Patients on a longer regimen were more than 2 times more likely (aOR: 2.5; 95%CI:1.3,4.7) to have a programmatically adverse outcome as well as being 45 years or older (aOR: 2.8; 95%CI:1.3,6.2), HIV positive (aOR:3.3; 95%CI:1.6,6.6) and attendance at a clinic without NGO support (aOR:3.0; 95%:1.6,5.7).

Conclusion

In Guinea, patients treated with the STR were more likely to have a successful outcome than those treated with the longer MDR-TB treatment regimen. Lost to follow-up was higher in patients on the longer regimen. However, STR treatment outcomes were less good than those reported in the region.

Treatment of Drug-Resistant Tuberculosis: Current Status

Drug-resistant tuberculosis (DR-TB) has been an area of growing concern and posing threat to human health worldwide. The treatment has been defined for all types of DR-TB with or without newer anti-TB drugs. multi-DR-TB (MDR-TB) patients have now choice of two types of regimen, shorter and longer regimens. Shorter regimen for treatment of subset of MDR-TB patients who have not been previously treated with second line drugs and in whom resistance to fluoroquinolones and second-line injectable agents has been excluded is given for 9 to 11 months. A longer regimen of at least five effective anti-TB drugs (ATDs) during the intensive phase is recommended, including pyrazinamide and four core second-line ATDs. Intensive phase, including injectables, should be given for at least 8 months. The total duration of treatment is at least 20 months, which can be prolonged up to 24 months depending on the response of the patient. World Health Organization (WHO) has recently revised the grouping of ATD for use in DR-TB patients in 2018 into three groups based on individual patient data meta-analysis depending on their individual efficacy, risk of relapse, treatment failure, and death. Recently, an all oral longer regimen comprising bedaquiline, pretomanid, and linezolid (BPal regime) for 6 to 9 months for extensive-DR-TB (XDR-TB) patients and those MDR-TB patients who cannot tolerate or do not respond to conventional MDR-TB regimen. These new developments will be a step forward toward establishing universal regimen to treat all types of DR-TB. This article has summarized the current evidence from literature search to date, including prevalence of DR-TB, types of regimen used and the advancement in the regimens for effective treatment of DR-TB patients.

Course of Adverse Events during Short Treatment Regimen in Patients with Rifampicin-Resistant Tuberculosis in Burundi

The introduction of the nine-month short-treatment regimen (STR) has drastically improved outcomes of rifampicin-resistant tuberculosis (RR-TB) treatment. Adverse events (AE) commonly occur, including injectable-induced hearing loss. In Burundi we retrospectively assessed the frequency of adverse events and treatment modifications in all patients who initiated the STR between 2013–2017. Among 225 included patients, 93% were successfully treated without relapse, 5% died, 1% was lost-to-follow-up, 0.4% had treatment failure and 0.4% relapsed after completion. AE were reported in 53%, with grade 3 or 4 AE in 4% of patients. AE occurred after a median of two months. Hepatotoxicity (31%), gastro-intestinal toxicity (22%) and ototoxicity (10%) were most commonly reported. One patient suffered severe hearing loss. Following AE, 7% of patients had a dose reduction and 1% a drug interruption. Kanamycin-induced ototoxicity led to 94% of modifications. All 18 patients with a modified regimen were cured relapse-free. In this exhaustive national RR-TB cohort, RR-TB was treated successfully with the STR. Adverse events were infrequent. To replace the present STR, all-oral regimens should be at least as effective and also less toxic. During and after transition, monitoring, management, and documentation of AE will remain essential.

Shortened tuberculosis treatment regimens: what is new?

Given the global burden of tuberculosis, shortened treatment regimens with existing or repurposed drugs are needed to contribute to tuberculosis control. The long duration of treatment of drug-susceptible tuberculosis (DS-TB) is associated with nonadherence and loss to follow up, and the treatment success rate of multidrug-resistant tuberculosis (MDR-TB) is low (approximately 50%) with longer regimens. In this review article, we report recent advances and ongoing clinical trials aimed at shortening regimens for DS-TB and MDR-TB. We discuss the role of high-dose rifampin, as well as that of clofazimine and linezolid in regimens for DS-TB. There are at least 5 ongoing clinical trials and 17 observational studies and clinical trials evaluating shorter regimens for DS-TB and MDR-TB, respectively. We also report the results of observational studies and clinical trials evaluating a standardized nine-month moxifloxacin-based regimen for MDR-TB. Further studies, especially randomized clinical trials, are needed to evaluate regimens including newer drugs, drugs proven to be or highly likely to be efficacious, and all-oral drugs in an effort to eliminate the need for injectable drugs.

Outcomes of a nine-month regimen for rifampicin-resistant tuberculosis up to 24 months after treatment completion in nine African countries

BACKGROUND

Treatment outcomes of the shorter regimen for rifampicin-resistant tuberculosis are not completely established. We report on these outcomes two years after treatment completion among patients enrolled in an observational cohort study in nine African countries.

METHODS

1,006 patients treated with the nine-month regimen were followed every six months with sputum cultures up to 24 months after treatment completion. The risk of any unfavourable outcome, of failure and relapse, and of death during and after treatment was analysed according to patient's characteristics and initial drug susceptibility by Cox proportional hazard models.

FINDINGS

Respectively 67.8% and 57.2% patients had >=1 culture result six months and 12 months after treatment completion. Fourteen relapses were diagnosed. The probability of relapse-free success was 79.3% (95% confidence interval [CI] 76.6-82.0%) overall, 80.9% (95% CI 78.0-84.0%) among HIV-negative and 72.5% (95% CI 66.5-78.9%) among HIV-infected patients. Initial fluoroquinolone (adjusted hazard ratio [aHR] 6.7 [95% CI 3.4-13.1]) and isoniazid resistance (aHR 9.4 [95% CI 1.3-68.0]) were significantly associated with increased risk of failure/relapse and of any unfavourable outcome.

INTERPRETATION

The close to 80% relapse-free success indicates the good outcome of the regimen in low-and middle-income settings. Results confirm the lesser effectiveness of the regimen in patients with initial resistance to fluoroquinolones and support the use of high-dose isoniazid, but do not support exclusion of patients for resistance to drugs other than fluoroquinolones.

FUNDING

Expertise-France and Agence Française de Développement.