Early outcome and safety of bedaquiline-containing regimens for treatment of MDR- and XDR-TB in China: a multicentre study

QT Prolongation Associated with Administration of Bedaquiline, a Novel Anti-Tuberculosis Drug

Bedaquiline is a diarylquinoline compound that has recently been introduced and approved for use in the treatment of multidrug-resistant tuberculosis (MDR-TB). Its mechanism of action is inhibition of adenosine triphosphate-synthase. In combination with other antibiotics, bedaquiline-containing regimens administered for 6 months achieve cure rates of roughly 90%, in contrast to the previously used, 24-month-long WHO-recommended regimens for the treatment of MDR-TB. However, since its introduction, concerns have been raised about its effects on QT prolongation and its safety in routine clinical use. We reviewed the published experience regarding bedaquiline use, QT prolongation, and adverse cardiac events when the drug was used alone or in combination. Overall, data are reassuring that bedaquiline use in clinical practice is not associated with an excess of cardiac deaths or other clinically meaningful cardiac events. This review provides reassurance and support for the continued use of bedaquiline in the treatment of MDR-TB.

Identification of fluoroquinolone-resistant Mycobacterium tuberculosis through high-level data fusion of Raman and laser-induced breakdown spectroscopy

Accurate and rapid diagnosis of drug susceptibility of Mycobacterium tuberculosis is crucial for the successful treatment of tuberculosis, a persistent global public health threat. To shorten diagnosis times and enhance accuracy, this study introduces a fusion model combining laser-induced breakdown spectroscopy (LIBS) and Raman spectroscopy. This model offers a rapid and accurate method for diagnosing drug-resistance. LIBS and Raman spectroscopy provide complementary information, enabling accurate identification of drug resistance in tuberculosis. Although individual use of LIBS or Raman spectroscopy achieved approximately 90% accuracy in identifying drug resistance, the fusion model significantly improved identification accuracy to 98.3%. Given the fast measurement capabilities of both techniques, this fusion approach is expected to markedly decrease the time required for diagnosis.

Nine months of bedaquiline, linezolid, levofloxacin, clofazimine, and cycloserine chemotherapy for rifampicin/multidrug-resistant tuberculosis: a multicenter, randomized, open-label non-inferiority trial in China

BACKGROUND

We concurrently developed a prospective study to assess clinical outcomes among patients receiving 9-month bedaquiline (BDQ)-containing regimens, aiming to provide valuable data on the use of this short-course regimen in China.

METHODS

This open-label, randomized, controlled, multicenter, non-inferiority trial was conducted at sixteen hospitals, and enrolled participants aged 18 years and older with pulmonary rifampicin/multidrug tuberculosis. Participants were randomly assigned, in a 1:1 ratio. Individuals within the standard-regimen group received 6 months of BDQ, linezolid, levofloxacin, clofazimine, and cycloserine plus 12 months of levofloxacin, and any three potentially effective drugs from clofazimine, cycloserine pyrazinamide, ethambutol and protionamide, whereas individuals within shorter-regimen group received 9 months of BDQ, linezolid, levofloxacin, clofazimine and cycloserine. The primary outcome was the percentage of participants with a composite unfavorable outcome (treatment failure, death, treatment discontinuation, or loss to follow-up) by the end of the treatment course after randomization in the modified intention-to-treat population. The noninferiority margin was 10%. This trial was registered with www.chictr.org.cn , ChiCTR2000029012.

RESULTS

Between Jan 1, 2020, and Dec 31, 2023, 264 were screened and randomly assigned, 132 of 264 participants were assigned to the standard-regimen group and 132 were assigned to the shorter-regimen. Thirty-three (12.55%) of 264 participants were excluded from the modified intention-to-treat analysis. As a result, 231 participants were included in the modified intention-to-treat analysis (116 in the standard-regimen group and 115 in the shorter-regimen group).In the modified intention-to-treat population, unfavorable outcomes were reported in 19 (16.5%) of 115 participants for whom the outcome was assessable in the shorter-regimen group and 26 (22.4%) of 116 participants in the standard care group (risk difference 5.9 percentage points (97.5% CI - 5.8 to 17.5)). One death was reported in the standard-regimen group. The incidence of QTcF prolongation in the shorter-regimen group (22.6%, 26/115) was similar to the standard-regimen group (24.1%, 28/116).

CONCLUSIONS

The 9-month, all-oral regimen is safe and efficacious for the treatment of pulmonary rifampicin/multidrug-resistant tuberculosis. The high incidence of QTc prolongation associated with the use of BDQ highlights the urgent need of routine electrocardiogram monitoring under treatment with BDQ-containing regimens in the Chinese population.

Clinical outcomes of multidrug-resistant tracheobronchial tuberculosis receiving anti-tuberculosis regimens containing bedaquiline or delamanid

The treatment of multidrug-resistant tracheobronchial tuberculosis poses challenges, and research investigating the efficacy of bedaquiline or delamanid as treatment for this condition is limited. This retrospective cohort study was conducted from 2017 to 2021. The study extracted data of patients with multidrug-resistant tracheobronchial tuberculosis from medical records and followed up on prognoses. Participants were divided into three groups: the bedaquiline, delamanid, and control group. Clinical outcomes and the risk factors associated with early culture conversion were analyzed. This study included 101 patients, with 32, 25, and 44 patients in the bedaquiline, delamanid, and control groups respectively. The differences in the treatment success rates among the three groups did not show statistical significance. Both the bedaquiline and delamanid groups had significantly higher culture conversion rates compared to the control after 2 or 6 months of treatment, with significantly shorter median times to culture conversion (bedaquiline group: 2 weeks, delamanid group: 2 weeks, control group: 12 weeks, P < 0.001). Treatment with bedaquiline or delamanid were identified as independent predictors of culture conversion at 2 months (bedaquiline group: aOR = 13.417, 95% CI 4.067-44.260, delamanid group: aOR = 9.333, 95% CI 2.498-34.878) or 6 months (bedaquiline group: aOR = 13.333, 95% CI 3.379-52.610, delamanid group: aOR = 5.000, 95% CI 1.357-18.426) of treatment through multivariable logistic regression analyses. The delamanid group showed better improvement in lumen stenosis compared to bedaquiline. Regimens containing bedaquiline or delamanid may accelerate the culture conversion during the early treatment phase in multidrug-resistant tracheobronchial tuberculosis, and delamanid appears to have the potential to effectively improve airway stenosis.

Bactericidal and sterilizing activity of sudapyridine-clofazimine-TB47 combined with linezolid or pyrazinamide in a murine model of tuberculosis

As an obligate aerobe, Mycobacterium tuberculosis relies on its branched electron transport chain (ETC) for energy production through oxidative phosphorylation. Regimens targeting ETC exhibit promising potential to enhance bactericidal activity against M. tuberculosis and hold the prospect of shortening treatment duration. Our previous research demonstrated that the bacteriostatic drug candidate TB47 (T) inhibited the growth of M. tuberculosis by targeting the cytochrome bc1 complex and exhibited synergistic activity with clofazimine (C). Here, we found synergistic activities between C and sudapyridine (S), a structural analog of bedaquiline (B). S has shown similar anti-tuberculosis efficacy and may share a mechanism of action with B, which inhibits ATP synthesis and the energy metabolism of bacteria. We evaluated the efficacy of SCT in combination with linezolid (L) or pyrazinamide (Z) using a well-established murine model of tuberculosis. Compared to the BPa(pretomanid)L regimen, SCT and SCTL demonstrated similar bactericidal and sterilizing activities. There was no significant difference in activity between SCT and SCTL. In contrast, SCZ and SCTZ showed much higher activities, with none of the 15 mice experiencing relapse after 2 months of treatment with either SCZ or SCTZ. However, T did not contribute to the activity of the SCZ. Our findings emphasize the efficacy and the potential clinical significance of combination therapy with ETC inhibitors. Additionally, cross-resistance exists not only between S and B but also between S/B and C. This is supported by our findings, as spontaneous S-resistant mutants exhibited mutations in Rv0678, which are associated with cross-resistance to B and C.

Identification of urine biomarkers predictive of prolonged QTc interval in multidrug-resistant tuberculosis patients treated with bedaquiline

The most frequent adverse event associated with bedaquiline (BDQ) is the QTc interval prolongation; however, there was no biomarkers that could be used to predict the occurrence of QTc prolongation in BDQ-treated patients. In this study, we employed the ultra-high performance liquid chromatography-MS/MS (UHPLC-MS/MS) to generate metabolic profiling for the discovery of potential predictive urine biomarkers of QTc prolongation in these patients. Untargeted metabolomic technique was used to concentrate the differential metabolic pathway, and targeted metabolomic technique was subsequently performed to identify predictive biomarkers for QTc prolongation. A total of 45 rifampicin-resistant TB (RR-TB) and multidrug-resistant TB (MDR-TB) patients were enrolled in our study, including 15 RR/MDR-TB patients with QTc interval prolongation (QIP) and 30 RR/MDR-TB patients with QTc interval un-prolongations (QIU). Untargeted technique revealed that the lipid metabolism was the most differential metabolic pathway between two groups. Further targeted technique identified four differential metabolites, including betaine, LPE (18:2), LPE (20:3), and LPE (20:4). The combined analysis of metabolisms revealed that the combined use of LPE (20:3) and LPE (20:4) had the best performance for predicting the occurrence of QTc prolongation in TB patients, yielding a sensitivity of 87.4% and a specificity of 78.5%. In addition, with the progression of BDQ treatment, the LPEs exhibited persistent difference in the BDQ-treated TB patients experiencing QTc interval prolongation. In conclusion, our data demonstrate that the combined use of LPE (20:3) and LPE (20:4) yields promising performance for predicting the occurrence of QTc interval prolongation in BDQ-treated patients.

Efficacy and safety of the all-oral bedaquiline-containing regimen as treatment for pediatric multidrug/rifampicin-resistant tuberculosis: a multicenter, retrospective, cohort study

OBJECTIVE

The study aimed to observe the efficacy and safety of an all-oral bedaquiline (BDQ)-containing regimen for pediatric multidrug/rifampicin-resistant tuberculosis (MDR/RR-TB) through a multicenter, retrospective study in China.

METHODS

In the study, pediatric patients receiving all-oral BDQ-containing regimen (BDQ group) with clinical matched control group were included, the control group received an injection-containing regimen. The treatment outcomes and the incidence of adverse events (AEs) were compared and analyzed.

RESULTS

79 pediatric patients were enrolled, including 37 cases in BDQ group and 42 cases in the control group, the median age was 12 {8-16} and 11 {9-15} in both groups respectively. Favorable treatment outcome and cure rate in BDQ group were significantly higher than those in control group (100%vs 83.3%, p 0.03; 94.6%vs 63.3%, p 0.00). Median time of sputum culture conversion in BDQ group was significantly shorter than that in the control group (4 weeks vs 8 weeks, p 0.00). The incidence of AEs in the BDQ group was significantly less than that in the control group (48.6% vs 71.4%, p 0.03). No AEs leading to treatment discontinuation of BDQ occurred.

CONCLUSIONS

The all-oral BDQ-containing regimens may be effective and safe in the Chinese pediatric population.

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}.

Efficacy and safety of bedaquiline containing regimens in patients of drug-resistant tuberculosis: An updated systematic review and meta-analysis

Background

Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis and leads to serious complications if left untreated. Some strains of Mycobacterium tuberculosis are multi-drug resistant and require treatment with newer drugs. Bedaquiline based treatment regimens have been used in patients who are diagnosed with drug resistant tuberculosis. The aim of this study is to assess the efficacy and safety profile of bedaquiline-based treatment regimens using a systematic review of existing literature and meta-analysis.

Methods

In this study, an electronic search was carried out on PubMed, ScienceDirect, and Cochrane library to find relevant literature from March 2021 onwards. Random-effects model was used to assess pooled treatment success rate and 95 % CIs. p-value of <0.05 was suggestive of publication bias. The review is registered with PROSPERO: CRD42023432748.

Results

A total of 543 articles were retrieved by database searching, out of which 12 new studies met the inclusion criteria. The total number of articles included in the review was 41 including 36 observational studies (having a total of 9,934 patients) and 5 experimental studies (having a total of 468 patients). The pooled treatment success rate was 76.9 % (95 % CI, 72.9-80.4) in the observational studies and 81.7 % (95 % CI, 67.2-90.7) in the experimental studies. Further subgroup analysis was done on the basis of treatment regimens containing bedaquiline only and treatment regimens containing bedaquiline and delamanid. The pooled treatment success rate in the studies consisting of patients who were treated with regimens containing bedaquiline only was 78.4 % (95 % CI, 74.2-82.1) and 73.6 % (95 % CI, 64.6-81.0) in studies consisting of patients who were treated with regimens containing bedaquiline and delamanid. There was no evidence of publication bias.

Conclusions

In patients of drug resistant tuberculosis having highly resistant strains of Mycobacterium tuberculosis undergoing treatment with bedaquiline-based regimen demonstrate high rates of culture conversion and treatment success. Moreover, the safety profile of bedaquiline-based regimens is well-established in all studies.

Molecular mechanisms of resistance and treatment efficacy of clofazimine and bedaquiline against Mycobacterium tuberculosis

Clofazimine (CFZ) and bedaquiline (BDQ) are currently used for the treatment of multidrug-resistant (MDR) Mycobacterium tuberculosis (Mtb) strains. In recent years, adding CFZ and BDQ to tuberculosis (TB) drug regimens against MDR Mtb strains has significantly improved treatment results, but these improvements are threatened by the emergence of MDR and extensively drug-resistant (XDR) Mtb strains. Recently, CFZ and BDQ have attracted much attention for their strong clinical efficacy, although very little is known about the mechanisms of action, drug susceptibility test (DST), resistance mechanisms, cross-resistance, and pharmacokinetics of these two drugs. In this current review, we provide recent updates on the mechanisms of action, DST, associated mutations with individual resistance and cross-resistance, clinical efficacy, and pharmacokinetics of CFZ and BDQ against Mtb strains. Presently, known mechanisms of resistance for CFZ and/or BDQ include mutations within the Rv0678, pepQ, Rv1979c, and atpE genes. The cross-resistance between CFZ and BDQ may reduce available MDR-/XDR-TB treatment options. The use of CFZ and BDQ for treatment in the setting of limited DST could allow further spread of drug resistance. The DST and resistance knowledge are urgently needed where CFZ and BDQ resistance do emerge. Therefore, an in-depth understanding of clinical efficacy, DST, cross-resistance, and pharmacokinetics for CFZ and BDQ against Mtb can provide new ideas for improving treatment outcomes, reducing mortality, preventing drug resistance, and TB transmission. Along with this, it will also help to develop rapid molecular diagnostic tools as well as novel therapeutic drugs for TB.

Efficacy and safety of bedaquiline and delamanid in the treatment of drug-resistant tuberculosis in adults: A systematic review and meta-analysis

Multi and extensively drug-resistant tuberculosis is a grave cause of global public health concern due to its high mortality and limited treatment options. We conducted this systemic review and meta-analysis to evaluate the efficacy and safety of bedaquiline and delamanid, which have been added to the WHO-recommended regimen for treating drug-resistant tuberculosis. Electronic databases were searched from their inception until December 1st, 2021, for eligible studies assessing the efficacy and safety of bedaquiline and delamanid for treating drug-resistant tuberculosis. Binary outcomes were pooled using a DerSimonian-Laird random-effects model and arcsine transformation and reported on a log scale with a 95% confidence interval (CIs). Twenty-one studies were shortlisted in which bedaquiline, delamanid, and a combination of both were administered in 2477, 937, and 169 patients. Pooled culture conversion at 6 months was 0.801 (p < 0.001), 0.849 (p = 0.059) for bedaquiline and delamanid, respectively, and 0.823 (p = 0.017), concomitantly. In the bedaquiline cohort, the pooled proportion of all-cause mortality at 6 months was reported as 0.074 (p < 0.001), 0.031 (p = 0.372) in the delamanid cohort, and 0.172 in the combined cohort. The incidence of adverse events in the bedaquiline cohort ranged from 11.1% to 95.2%, from 13.2% to 86.2% in the delamanid cohort, and 92.5% in a study in the combined cohort. The incidence of QTC prolongation reported in each cohort is as follows: bedaquiline 0.163 (p < 0.001), delamanid 0.344 (p = 0.272) and combined 0.340 (p < 0.001). Our review establishes the efficacy of delamanid, bedaquiline, and their combined use in treating drug-resistant tuberculosis with reasonable rates of culture conversion, low mortality rates, and safety of co-administration, as seen with their effect on the QTc interval.

The emerging threat of fluroquinolone-, bedaquiline-, and linezolid-resistant Mycobacterium tuberculosis in China: Observations on surveillance data

BACKGROUND

Drug-resistant tuberculosis (TB), especially multidrug-resistant tuberculosis (MDR-TB), constitutes a major obstacle to fulfill end TB strategy globally. Although fluoroquinolones (FQs), linezolid (LZD) and bedaquiline (BDQ) were classified as Group A drugs for MDR-TB treatment, our knowledge of the prevalence of TB which were resistant to Group A drugs in China is quite limited.

METHODS

In this study, we conducted a prospective multicenter surveillance study in China to determine the proportion of TB patients that were resistant to Group A drugs. A total of 1877 TB patients were enrolled from 2022 at four TB specialized hospitals. The drug susceptibility of isolated strains was conducted using the MGIT 960 system and the molecular mechanisms conferring drug resistance were investigated by Sanger sequencing.

RESULTS

12.9% of isolates were resistant to levofloxacin (LFX), 13.2% were resistant to moxifloxacin (MOX), 0.2% were resistant to bedaquiline (BDQ), and 0.8% were resistant to linezolid (LZD). Totally, 14.0% and 0.4% were classified as multidrug resistant- (MDR-) and extensively drug resistant- (XDR-) TB. The drug resistance was more common in retreated TB cases compared to new cases. In addition, 70.0% of fluoroquinolone (FQ)-resistant isolates harbored mutations in the gyrA and gyrB gene. By contrast, the common drug-resistant mutations were only found in 50% BDQ-resistant and 20% LZD-resistant isolates.

CONCLUSIONS

Our data demonstrate that approximate half of MDR -TB patients are resistant to fluoroquinolones, with extremely low prevalence of initial BDQ and LZD resistance. Findings from this study provide important implications for the current management of MDR-TB patients.

Bedaquiline Resistance and Molecular Characterization of Rifampicin-Resistant Mycobacterium Tuberculosis Isolates in Zhejiang, China

Purpose

This study aimed to determine the prevalence and molecular characterization of bedaquiline (BDQ) resistance among rifampicin-resistant tuberculosis (RR-TB) isolates collected from Zhejiang, China.

Patients and Methods

A total of 245 RR-TB isolates were collected from 19 municipal TB hospitals in Zhejiang province, China between January and December 2021. Microplate assays were used to determine the minimum inhibitory concentrations (MIC) of BDQ. Whole-genome sequencing (WGS) was performed on isolates with MIC values for BDQ ≥ 0.25 μg/mL.

Results

Five (2.04%) BDQ-resistant strains were isolated from 245 tuberculosis patients. The resistance rate of BDQ was not correlated to the sex, age, treatment history, or occupation of patients. Four BDQ-resistant isolates and three BDQ-sensitive isolates were found to carry Rv0678 mutations, and one BDQ-resistant strain carried both Rv0678 and pepQ mutations. No mutations within the atpE and Rv1979c genes were observed.

Conclusion

BDQ demonstrated strong in vitro antibacterial activity against RR-TB isolates, and the Rv0678 gene was identified as the primary mechanism contributing to BDQ resistance among RR-TB isolates from Zhejiang, China. Furthermore, in addition to the four currently known resistance-associated genes (atpE, Rv0678, Rv1979c, and pepQ), other mechanisms of resistance to BDQ may exist that need further study.

Global treatment outcomes of extensively drug-resistant tuberculosis in adults: A systematic review and meta-analysis

INTRODUCTION

Historically, extensively drug-resistant tuberculosis has been notoriously difficult to treat with devasting outcomes. As we are coming to the end of an era where the 2006 extensively drug-resistant tuberculosis definitions and old treatment regimens are being replaced, we aimed to estimate the proportion of extensively drug-resistant tuberculosis patients globally who achieved successful treatment outcomes.

METHODS

We conducted a systematic review of PubMed/MEDLINE, Scopus, Web of Science, and Embase from January 1, 2005, through April 3, 2023. Included studies reported WHO treatment outcomes, or adaptions hereof, for pre-extensively and/or extensively drug-resistant tuberculosis patients according to the 2006 WHO definition. Eligible studies included cohorts of at least 10 adults (aged>18 years) that were not pregnant. Using a random-effects model, we calculated pooled proportions of treatment outcomes and performed sensitivity and subgroup analyses. PROSPERO registration number: CRD42022340961.

RESULTS

Among 5056 studies reviewed, we identified 94 studies from 26 countries, involving 10,223 extensively drug-resistant tuberculosis patients. The pooled proportion of successful treatment outcomes was 44.2% (95%CI: 38.3-50.3). Sensitivity analyses consistently produced similar estimates. A slight improvement in treatment outcomes was observed after 2013. Furthermore, 25 studies reported outcomes for 3564 individuals with pre-extensively drug-resistant tuberculosis, of which 63.3% achieved successful treatment (95%CI: 43.1-72.5).

CONCLUSION

Globally, the success rate of extensively drug-resistant tuberculosis treatment is 44.2%, far below the WHO's target rate of 75%. These results may serve as a reference for future studies assessing extensively drug-resistant tuberculosis treatment outcomes under the 2021 definition treated with better treatment regimens available. Comprehensive surveillance data of extensively drug-resistant tuberculosis outcomes from the whole world are desirable to monitor treatment progress.

The Efficacy and Safety of Bedaquiline in the Treatment of Pulmonary Tuberculosis Patients: A Systematic Review and Meta-Analysis

BACKGROUND

Bedaquiline (BDQ) has been designated as a Group A drug by the World Health Organization (WHO) for the management of multi-drug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB). This systematic review and meta-analysis aim to evaluate the efficacy and safety of BDQ-containing regimens for the treatment of patients with pulmonary TB.

METHODS

PubMed (MEDLINE), Elton B. Stephens Company (EBSCO) database, the Cochrane Register of Controlled Trials, and the China National Knowledge Infrastructure (CNKI) database were initially searched on 15 June 2022 and again on 20 March 2023. We included randomized controlled trials (RCTs) and non-randomized studies (NRSs) that administered BDQ to TB patients. The outcomes of interest were as follows: (1) efficacy, including the rate of sputum culture conversion at 8 weeks, 24 weeks, and during follow-up, as well as the rates of completion cure, death, treatment failure, and loss at follow-up and at the end of the treatment; and (2) safety, which encompassed the incidences of cardiotoxicity, hepatotoxicity, and grade 3-5 adverse events during the treatment period.

RESULTS

A total of 29 articles were included in this meta-analysis, representing 23,358 individuals. Patients who were treated with BDQ were compared with patients who were not exposed to BDQ. The use of BDQ-containing regimens demonstrated improved rates of sputum conversion in RCTs at 24 weeks (RR = 1.27, 95% CI: 1.10 to 1.46) and during follow-up (RR = 1.33, 95% CI: 1.06 to 1.66). Additionally, BDQ-containing regimens showed increased cure rates (RR = 1.60, 95% CI: 1.13 to 2.26) and decreased failure rates (RR = 0.56, 95% CI: 0.56 to 0.88). In NRSs, BDQ-containing regimens improved the sputum culture conversion rate during follow-up (RR = 1.53, 95% CI: 1.07 to 2.20), increased the rate of cure (RR = 1.86, 95% CI: 1.23 to 2.83), reduced deaths from all causes (RR = 0.68, 95% CI: 0.48 to 0.97), and reduced failure rates (RR = 0.57, 95% CI: 0.46 to 0.71). However, the use of BDQ-containing regimens was associated with increased incidences of cardiotoxicity (RR = 4.54, 95% CI: 1.74 to 11.87) and grade 3-5 adverse events (RR = 1.42, 95% CI: 1.17 to 1.73) in RCTs. NRSs also showed an association between BDQ-containing regimens and cardiotoxicity (RR = 6.00, 95% CI: 1.32 to 27.19). No significant differences were observed between intervention groups and control groups with respect to other outcomes.

CONCLUSIONS

Data from both RCTs and NRSs support the efficacy of BDQ for the treatment of pulmonary tuberculosis. However, the use of BDQ is associated with a higher incidence of cardiotoxicity and serious adverse events. Comparative data on efficacy and safety are limited, and further confirmation is required, due to potential bias and discrepancies in the available studies.

Antibacterial activity of the novel compound Sudapyridine (WX-081) against Mycobacterium abscessus

Objective

This study aimed to investigate sudapyridine (WX-081) antibacterial activity against Mycobacterium abscessus in vitro and its effect on in vivo bacterial growth and host survival using a zebrafish model of M. abscessus infection.

Methods

WX-081 in vitro antibacterial activity was assessed based on growth inhibition of M. abscessus standard strain ATCC19977 and 36 clinical isolates. Maximum tolerated concentrations (MTCs) of WX-081, bedaquiline, and azithromycin and inhibition of M. abscessus growth were assessed in vivo after fluorescently labelled bacilli and drugs were injected into zebrafish. Bacterial counts were analysed using one-way ANOVA and fluorescence intensities of zebrafish tissues were analysed and expressed as the mean ± SE. Moreover, Kaplan-Meier survival analysis was conducted to assess intergroup differences in survival of M. abscessus-infected zebrafish treated with different drug concentrations using a log-rank test, with a p value <0.05 indicating a difference was statistically significant.

Results

Drug sensitivity testing of M. abscessus standard strain ATCC19977 and 36 clinical isolates revealed MICs ranging from 0.12-0.96 µg/mL and MIC50 and MIC90 values of 0.48 µg/mL and 0.96 µg/mL, respectively. Fluorescence intensities of M. abscessus-infected zebrafish tissues was lower after treatment with the WX-081 MTC (62.5 µg/mL) than after treatment with the azithromycin MTC (62.5 µg/mL) and the bedaquiline MTC (15.6 µg/mL). When the concentration of WX-081 increased from 1.95µg/mL to 1/8 MTC(7.81µg/mL), the survival rate of zebrafish at 4-9 dpf decreased from 90.00% to 81.67%.

Conclusion

WX-081 effectively inhibited M. abscessus growth in vitro and in vivo and prolonged survival of M. abscessus-infected zebrafish, thus indicating that WX-081 holds promise as a clinical treatment for M. abscessus infection.

Bedaquiline in Drug-Resistant Tuberculosis: A Mini-Review

Mycobacterium tuberculosis causes a contagious pulmonary disease with a high mortality rate in developing countries. However, the recommendation of DOTS (approved by WHO) was effective in treating tuberculosis, but nowadays, resistance from the first line (MDR-TB) and the second line (XDR-TB) drugs is highly common. Whereas, the resistance is a result of factors like poor patient constancy due to the long duration of therapy and co-infection with HIV. The approval of bedaquiline under an accelerated program for the treatment of MDR-TB has revealed its effectiveness in clinical trials as a therapeutic novel molecule. BDQ selectively inhibits the ATP synthase of bacterium and reduces ATP production. Additionally, the poor pharmacokinetic properties raised provocations in the MDR therapy, but the use of targeted drug delivery can solve the hurdles. While the preclinical and clinical studies included in this review are strongly suggesting the usefulness of BDQ in MDR-TB and XDR-TB, the repurposing of different drug classes in resistant TB is opening new opportunities to manage the disease conditions. In this review, we have summarized the examples of pipeline drugs and repurposed molecules with preclinical formulation developments.

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.

Development and Validation of a Nomogram for Prediction of QT Interval Prolongation in Patients Administered Bedaquiline-Containing Regimens in China: a Modeling Study

Corrected QT duration (QTc) interval prolongation is the most frequent adverse event associated with bedaquiline (BDQ) use. It may affect the safety of antituberculosis therapy, which leads to the consequent demands of needing to monitor during therapy. Our objective was to establish and validate a prediction model for estimating the risk of QTc prolongation after initiation of BDQ-containing regimens to multidrug-resistant tuberculosis (MDR-TB) patients. We constructed an individualized nomogram model based on baseline demographic and clinical characteristics of each patient within a Chinese cohort during BDQ treatment. The generalizability of this model was further validated through use of externally acquired data obtained from Beijing Chest Hospital from 2019 to 2020. Overall, 1,215 and 165 patients were included in training and external validation cohorts, respectively, whereby during anti-TB drug treatment, QTc prolongation was observed in 273 (22.5%) and 29 (17.6%) patients within these respective cohorts, for whom QTc values were >500 ms in 86 (31.5%) and 10 (34.7%) patients, respectively. Next, a total of four Cox proportional hazards models were created and assessed; then, nomograms derived from the models were plotted based on independent predictors of clofazimine, baseline QTc interval, creatinine, extensive drug-resistance (XDR), moxifloxacin, levofloxacin, and sex. Nomogram analysis revealed concordance index values of 0.723 (95% confidence interval [CI], 0.695 to 0.750) for the training cohort and 0.710 (95% CI, 0.627 to 0.821) for the external validation cohort, thus indicating relatively fair agreement between predicted and observed probabilities of QTc prolongation occurrence based on data obtained during 8-week, 16-week, and 24-week anti-TB treatment of both cohorts. Taken together, results obtained using these models demonstrated that coadministration of clofazimine and abnormal baseline QTc interval significantly contributed to QTc prolongation development during MDR-TB patient treatment with a BDQ-containing anti-TB treatment regimen.

The Correlations of Minimal Inhibitory Concentration Values of Anti-TB Drugs with Treatment Outcomes and Clinical Profiles in Patients with Multidrug-Resistant Tuberculosis (MDR-TB) in China

Objective

It is a challenge to obtain satisfactory treatment outcomes for patients with multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB); the study aims to correlate the Minimum Inhibitory Concentration (MIC) value of drugs with the outcome of patients with MDR/RR-TB to obtain an understanding for better regimens and optimal outcomes.

Methods

The patients diagnosed with MDR/RR-TB were retrospectively enrolled from January 1, 2018 to December 31, 2019, recorded clinical characteristics, MIC DST (Drug Susceptibility Test) results, and followed the treatment outcome. The data were analyzed on the correlations of MIC DST values with outcomes and clinical characteristics.

Results

A total of 276 patients with MDR/RR-TB were included, containing 98 cases (35.5%) with newly treated patients and 178 cases (64.5%) with re-treated patients. A total of 220 cases recorded treatment success (79.7%) and 49 cases recorded treatment failure or died. MIC values of isoniazid (H), moxifloxacin (Mfx), and ethionamide (Eto) in newly treated patients were lower than those in retreated patients, and resistance levels of Mfx and H were closely associated with the treatment outcome (P < 0.05) while those of other drugs had no close association with treatment outcome.

Conclusions

MIC values of some anti-TB drugs, such as fluoroquinolones (FQs) and H, can reflect the treatment outcome for patients with MDR/RR-TB, which can contribute to making regimens for better treatment outcomes.

The Characteristics and Patterns of Drug-Resistant Pulmonary Tuberculosis in Eastern India

Background: Drug-resistant tuberculosis is a major public health problem throughout the world and accounts for substantial morbidity and mortality rates in India, too. Early diagnosis is the corner stone of tuberculosis treatment. State-level and cluster-wise variations in drug resistance is a possibility and should be regularly checked in from time to time. Materials and Methods: The present prospective cohort study (January 2019 to May 2022) was conducted in Darbhanga Medical College and Hospital on drug-resistant pulmonary tuberculosis patients. Sputum specimens were collected from designated centers. Rapid molecular drug-resistance testing (genotypic tests) and growth-based drug-susceptibility testing (DST) (phenotypic tests) were performed in the National Tuberculosis Elimination Program certified Laboratory. Results: A total of 268 patients with drug-resistant pulmonary tuberculosis were included in the study group. The treatment outcomes revealed as cured in 100 (37.31%); treatment completed in 43 (16.04%); died in 56 (20.89%); treatment failed in 22 (8.21%); loss of follow up in 34 (12.69%); and transferred out in 13 (4.85%) drug-resistant pulmonary tuberculosis patients. Adverse events were recorded in 199 (74.25%) of the drug-resistant pulmonary tuberculosis patients. Conclusions: Drug-resistant pulmonary tuberculosis patients are a matter of concern and need to be addressed.

Discovery and preclinical profile of sudapyridine (WX-081), a novel anti-tuberculosis agent

Multidrug resistant tuberculosis (MDR-TB) remains a major human health challenge. Bedaquiline was approved in 2012 by the US FDA, and listed by WHO as a treatment for multidrug-resistant tuberculosis (MDR-TB) in 2018. However, the side effects of bedaquiline including the risk of unexplained mortality, QTc prolongation and hepatotoxicity limit its wide clinical use. Based on bedaquiline, we describe herein discovery and development of a novel diarylpyridine series, which led to identification of WX-081 (sudapyridine, 21l). It displayed excellent anti-mycobacterial activity against M. tuberculosis H37Rv in vitro and in vivo and low cytotoxicity; additionally WX-081 had excellent pharmacokinetic parameters in animals, better lung exposure and lower QTc prolongation potential compared to bedaquiline. WX-081 is currently under clinical phase II development (NCT04608955).

Bedaquiline: A Novel Diarylquinoline for Multidrug-Resistant Pulmonary Tuberculosis

A new drug Bedaquiline, a diarylquinoline agent has been approved by the Food and Drug Administration for the treatment of pulmonary multidrug-resistant tuberculosis. It has been given approval for use along with the basic regimen with only conditional access through the National Program for tuberculosis in India. The major problem with existing antitubercular drugs used for the treatment of multi-drug resistant tuberculosis is antimicrobial resistance, less efficacy, and poor side effect profile. Bedaquiline might be a solution to these issues. Bedaquiline is a first of its class drug with a unique and specific mechanism of action. It inhibits mycobacterial adenosine triphosphate (ATP) synthase's proton pump. There are many randomized clinical trials and cohort studies that reported a higher culture conversion rate with bedaquiline treatment as compared to the control group. Many meta-analyses and systematic reviews have reported higher culture conversion rate, higher cure rate, and lower mortality rate in patients with drug-resistant tuberculosis treated with a bedaquiline-containing regimen. Here is a detailed drug profile of bedaquiline to help health care workers treat tuberculosis patients.

Keywords:

High Incidence of Psychiatric Disorders Associated with Cycloserine Treatment of Multidrug-Resistant Tuberculosis Patients: A Cohort Study in Beijing, China

Objective

Cycloserine (CS) is a group B anti-tuberculosis (TB) drug endorsed by the World Health Organization (WHO) for the treatment of drug-resistant (DR)-TB. Despite CS widespread acceptance and known efficacy, the high potential of drug-associated psychiatric disorders is a major concern to multidrug-resistant (MDR)-TB patients. In this study, we investigated CS-associated psychiatric disorders in a cohort of MDR-TB patients in Beijing, China. Our aim was to determine psychiatric disorder prevalence rates and associated risk factors in this population.

Methods

This MDR-TB cohort study was conducted at Beijing Chest Hospital between February 2018 and February 2021. All patients received individualized treatment regimens that included CS at some point during the full treatment course. Patient psychological status was assessed using the Symptom Checklist (SCL-90) questionnaire during the post-treatment follow-up period.

Results

Two hundred and thirty-seven MDR-TB patients were included in the final analysis. Overall, psychiatric disorders were recorded in 22 (9.28%) of the 237 patients in our cohort, with severity grades of 1 or 2 observed for the majority (8.44%) of psychiatric adverse events. As compared to results obtained for control group patients who were ≥40 years of age, patients who were <40 years of age (77.3%, 17/22) were more likely to experience psychiatric disorders [adjusted odds ratio (aOR) = 3.060; 95% CI (1.060–8.828)]. Additionally, patients with body mass index (BMI)s of <18.5 kg/m² [aOR = 3.824; 95% CI (1.502–9.739)] had significantly higher odds of being afflicted with psychiatric disorders as compared with patients with BMIs that were ≥18.5 kg/m².

Conclusion

Our results demonstrated that approximately one-tenth of Chinese MDR-TB patients experienced psychiatric disorders during CS treatment, with the majority of adverse events of moderate severity. In addition, low BMI and age <40 years were identified as independent risk factors for psychiatric disorders in MDR-TB patients receiving CS therapy.

Bedaquiline-containing regimens and multidrug-resistant tuberculosis: a systematic review and meta-analysis

Objective:

Multidrug-resistant tuberculosis (MDR-TB) is a life-threatening infectious disease. Treatment requires multiple antimicrobial agents used for extended periods of time. The present study sought to evaluate the treatment success rate of bedaquiline-based regimens in MDR-TB patients.

Methods:

This was a systematic review and meta-analysis of studies published up to March 15, 2021. The pooled treatment success rates and 95% CIs were assessed with the fixed-effect model or the random-effects model. Values of p < 0.05 were considered significant for publication bias.

Results:

A total of 2,679 articles were retrieved by database searching. Of those, 29 met the inclusion criteria. Of those, 25 were observational studies (including a total of 3,536 patients) and 4 were experimental studies (including a total of 440 patients). The pooled treatment success rate was 74.7% (95% CI, 69.8-79.0) in the observational studies and 86.1% (95% CI, 76.8-92.1; p = 0.00; I² = 75%) in the experimental studies. There was no evidence of publication bias (p > 0.05).

Conclusions:

In patients with MDR-TB receiving bedaquiline, culture conversion and treatment success rates are high even in cases of extensive resistance.

Linezolid for patients with multidrug-resistant tuberculosis/extensively drug-resistant tuberculosis in China

Linezolid has been one of the key anti-tuberculosis agents for the treatment of multidrug-resistant tuberculosis (MDR-TB)/extensively drug-resistant tuberculosis (XDR-TB). It used to be very expensive and was not covered by social insurance from local governments. Nevertheless, a growing number of patients in China received linezolid in their anti- MDR/XDR TB regimens over the past decade. Many scholars in China have reported their experience using linezolid to treat patients with MDR/XDR-TB. In view of this, existing evidence of the efficacy and safety of linezolid and problems faced by Chinese patients with MDR/XDR-TB are summarized here.

Prognostic accuracy of time to sputum culture conversion in predicting cure in extensively drug-resistant tuberculosis patients: a multicentre retrospective observational study

Background

There was a lack of information about prognostic accuracy of time to sputum culture conversion (SCC) in forecasting cure among extensively drug-resistant tuberculosis (XDR-TB) patients. Therefore, this study evaluated the prognostic accuracy of SCC at various time points in forecasting cure among XDR-TB patients.

Methods

This retrospective observational study included 355 eligible pulmonary XDR-TB patients treated at 27 centers in Pakistan between 01-05-2010 and 30-06-2017. The baseline and follow-up information of patients from treatment initiation until the end of treatment were retrieved from electronic nominal recording and reporting system. Time to SCC was analyzed by Kaplan–Meier method, and differences between groups were compared through log-rank test. Predictors of time to SCC and cure were respectively evaluated by multivariate Cox proportional hazards and binary logistic regression analyses. A p-value < 0.05 was considered statistically significant.

Results

A total of 226 (63.6%) and 146 (41.1%) patients respectively achieved SCC and cure. Median time to SCC was significantly shorter in patients who achieved cure, 3 months (95% confidence interval [CI]: 2.47–3.53), than those who did not (median: 10 months, 95% CI: 5.24–14.76) (p-value < 0.001, Log-rank test). Patient’s age > 40 years (hazards ratio [HR] = 0.632, p-value = 0.004), baseline sputum grading of scanty, + 1 (HR = 0.511, p-value = 0.002), + 2, + 3 (HR = 0.523, p-value = 0.001) and use of high dose isoniazid (HR = 0.463, p-value = 0.004) were significantly associated with early SCC. Only SCC at 6 month of treatment had statistically significant association with cure (odds ratio = 15.603, p-value < 0.001). In predicting cure, the sensitivities of SCC at 2, 4 and 6 months were respectively 41.8% (95%CI: 33.7–50.2), 69.9% (95%CI: 61.7–77.2) and 84.9% (95%CI: 78.1–90.3), specificities were respectively, 82.8% (95%CI: 76.9–87.6), 74.6% (95%CI: 68.2–80.4) and 69.4% (95%CI: 62.6–75.5) and prognostic accuracies were respectively 65.9% (95%CI: 60.7–70.8), 72.7% (95%CI: 67.7–77.2) and 75.8% (95%CI: 71.0–80.1).

Conclusion

In forecasting cure, SCC at month 6 of treatment performed better than SCC at 2 and 4 months. However, it would be too long for clinicians to wait for 6 months to decide about the regimen efficacy. Therefore, with somewhat comparable prognostic accuracy to that SCC at 6 month, using SCC at 4 month of treatment as a prognostic marker in predicting cure among XDR-TB patients can decrease the clinicians waiting time to decide about the regimen efficacy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07202-y.

Sudapyridine (WX-081), a Novel Compound against Mycobacterium tuberculosis

Bedaquiline (BDQ) was historically listed by the World Health Organization (WHO) in 2018 as the preferred option for rifampin-resistant tuberculosis (RR-TB) and multidrug-resistant tuberculosis (MDR-TB). However, when there is no other effective regimen, the side effects and weaknesses of BDQ limit its use of MDR-TB. There is a black box warning in the package insert of BDQ to warn patients and health care professionals that this drug may increase the risk of unexplained mortality and QT prolongation, which may lead to abnormal and potentially fatal cardiac rhythm. In addition, the phenomenon of elevated liver enzymes in clinical trials of BDQ is a potential sign of hepatotoxicity. Therefore, it is still a medical need to develop new compounds with better safety profiles, patient compliance, affordability, and the ability to retain the efficacy of BDQ. After extensive lead generation and optimization, a new analog, sudapyridine (WX-081), was selected as a potential new antituberculosis candidate to move into clinical trials. Here, we evaluated WX-081's overall preclinical profile, including efficacy, pharmacokinetics, and toxicology. The in vitro activity of WX-081 against drug-sensitive and drug-resistant tuberculosis was comparable to that of BDQ, and there was comparable efficacy between WX-081 and BDQ in both acute and chronic mouse tuberculosis models using low-dose aerosol infection. Moreover, WX-081 improved pharmacokinetic parameters and, more importantly, had no adverse effects on blood pressure, heart rate, or qualitative ECG parameters from nonclinical toxicology studies. WX-081 is under investigation in a phase 2 study in patients. IMPORTANCE This study is aimed at chemotherapy for multidrug-resistant tuberculosis (MDR-TB), mainly to develop new anti-TB drugs to kill Mycobacterium tuberculosis, a microorganism with strong drug resistance. In this study, the structure of a potent antituberculosis compound, bedaquiline (BDQ), was optimized to generate a new compound, sudapyridine (WX-081). This experiment showed that its efficacy was similar to that of BDQ, its cardiotoxicity was lower, and it had good kinetic characteristics. This compound will certainly achieve significant results in the control and treatment of tuberculosis in the future.

Twenty-four-week interim outcomes of bedaquiline-containing regimens in treatment of adolescents with rifampicin-resistant tuberculosis: A retrospective cohort study in China

AIM

To evaluate the 24-week interim outcomes of bedaquiline-containing regimens in the treatment of adolescents with rifampicin-resistant tuberculosis (RR-TB) in China.

METHODS

Adolescents with RR-TB from two hospitals were included in this retrospective study. All patients received the longer regimen containing bedaquiline. Sputum culture, chest computed tomography, blood tests and electrocardiography were performed regularly, and the outcomes after 24 weeks of treatment were reported.

RESULTS

Four male and six female adolescents aged 11 to 17 years old were included. Among them, four (40.0%), four (40.0%) and two (20.0%) were confirmed to have RR-TB, multidrug-resistant TB and extensively drug-resistant TB, respectively. The most common companion drugs included linezolid (100.0%), cycloserine (90.0%), pyrazinamide (80.0%), moxifloxacin (50.0%) and levofloxacin (40.0%). Culture conversion rates of 80.0%, 100.0% and 100.0% were observed at weeks 2, 4 and 24, respectively. The mean maximum drug concentration of bedaquiline at weeks 2, 12 and 24 was 3.29 ± 0.66, 1.78 ± 0.81 and 1.93 ± 0.74 μg/mL, respectively. Six adverse events including leukopenia (50.0%), Fridericia-corrected QT (QTcF) interval prolongation (16.7%), anaemia (16.7%) and peripheral neuropathy (16.7%) were observed in five (50.0%) patients. No patient discontinued bedaquiline owing to QTcF interval prolongation. Meanwhile, no deaths, reversions or serious adverse events were reported during 24 weeks of treatment.

CONCLUSION

A longer regimen containing bedaquiline was effective and well tolerated in Chinese adolescents with RR-TB. The combination of bedaquiline and linezolid may be a favourable choice for this population.

Prevalence of extensively drug-resistant tuberculosis in a Chinese multidrug-resistant TB cohort after redefinition

OBJECTIVES

Recently, the definition of extensively drug-resistant TB (XDR-TB) has been revised. In this study, we conducted a descriptive and retrospective study to determine the prevalence of XDR-TB in a Chinese multidrug-resistant TB (MDR-TB) cohort.

METHODS

Broth microdilution method was performed to determine in vitro susceptibilities of Mycobacterium tuberculosis (MTB) isolates to (FQs), bedaquiline (BDQ) and linezolid (LZD). The putative drug target genes conferring drug resistance were screened by DNA sequencing.

RESULTS

A total of 425 MDR-TB isolates were included from 13 pilots in China. LZD and BDQ resistance were noted in 30 (7.1%) and 10 (2.4%) isolates. On the basis of latest definitions, 114 (26.8%) were MDR-TB, 282 (66.4%) were pre-XDR-TB, and 29 (6.8%) were XDR-TB. Among 311 FQ-resistant isolates, 265 harbored genetic mutations within QRDRs. The most common mutations were observed at codon 94 of gyrA, accounting for 47.2% of FQ-resistant MTB isolates. Only mutations within the Rv0678 gene were found to confer BDQ resistance in our cohort, conferring 40.0% of BDQ resistance. For LZD resistance, 53.3% of LZD-resistant isolates carried genetic mutations in rplC or 23S rRNA. The most frequent mutation was Cys154Arg in the rplC gene. In addition, we recorded two MDR-TB patients with resistance to both BDQ and LZD, of which one patient experienced continuous positive culture of MTB despite inclusion of efficacious moxifloxacin.

CONCLUSION

Our results demonstrate that the low prevalence of XDR-TB holds great promise for MDR-TB treatment with WHO-endorsed regimens containing BDQ-LZD combination, whereas the high prevalence of FQ-resistance in MDR-TB patients warrants national attention.

Safety, efficacy, and serum concentration monitoring of bedaquiline in Chinese patients with multidrug-resistant tuberculosis

OBJECTIVES

To determine the safety and efficacy of bedaquiline for Chinese patients with multidrug-resistant tuberculosis (MDR-TB) based on serum concentration monitoring and to identify factors associated with QTc prolongation occurring during treatment.

METHODS

Data were collected from 35 patients who received treatment regimens containing bedaquiline for MDR-TB from May 2018 to December 2020. Blood samples were collected, and serum concentrations of bedaquiline were measured using high-performance liquid chromatography-mass spectrometry.

RESULTS

After completing the 24-week bedaquiline treatment course, 80.0% of the patients' sputum cultures turned negative. The median time to sputum culture conversion was 75.5 days (interquartile range 52-126 days). The mean serum concentration of bedaquiline was 0.586 ± 0.288 µg/ml during treatment and 0.205 ± 0.145 µg/ml at 16 weeks after bedaquiline discontinuation. Bedaquiline remained detectable 52 weeks after discontinuation. Combination with clofazimine during bedaquiline treatment significantly increased cardiac QTc prolongation. When QTc prolongation occurred, serum potassium levels decreased by 10.71% from baseline, while serum sodium levels increased by 1.07% from baseline.

CONCLUSIONS

Good treatment outcomes were obtained with bedaquiline treatment in Chinese patients with MDR-TB. Combination with clofazimine increased the risk of QTc prolongation. Serum electrolytes (potassium and sodium) should be measured regularly during treatment of MDR-TB with regimens containing bedaquiline.

Low Rate of Acquired Linezolid Resistance in Multidrug-Resistant Tuberculosis Treated With Bedaquiline-Linezolid Combination

In this retrospective study in China, we aimed to: (1) determine the prevalence of linezolid (LZD) resistance among multidrug-resistant tuberculosis (MDR-TB)-infected patients; (2) monitor for dynamic LZD susceptibility changes during anti-TB treatment; and (3) explore molecular mechanisms conferring LZD resistance. A total of 277 MDR-TB patients receiving bedaquiline (BDQ)-containing regimens in 13 TB specialized hospitals across China were enrolled in the study. LZD and BDQ susceptibility rates were determined using the minimum inhibitory concentration (MIC) method, then DNA sequences of patient isolates were analyzed using Sanger sequencing to detect mutations conferring LZD resistance. Of 277 patients in our cohort, 115 (115/277, 41.5%) with prior LZD exposure yielded 19 (19/277, 6.9%) isolates exhibiting LZD resistance. The LZD resistance rate of LZD-exposed group isolates significantly exceeded the corresponding rate for non-exposed group isolates (P = 0.047). Genetic mutations were observed in 10 (52.6%, 10/19) LZD-resistant isolates, of which a Cys154Arg (36.8%, 7/19) substitution within ribosomal protein L3 was most prevalent. Analysis of sequential positive cultures obtained from 81 LZD-treated patients indicated that cultured organisms obtained from most patients (85.2%, 69/81) retained original LZD MIC values; however, organisms cultured later from two patients exhibited significantly increased MIC values that were attributed to the rplC substitution T460C. Overall, LZD resistance was detected in 6.9% of patients of an MDR-TB cohort in China. Low rate of acquired LZD resistance was noted in MDR-TB treated with BDQ-LZD combination.

Treatment outcomes of patients with multidrug and extensively drug-resistant tuberculosis in Zhejiang, China

Background

The aim of this study was to assess the treatment outcomes of multidrug and extensively drug-resistant tuberculosis (M/XDR-TB) in Zhejiang, China and to evaluate possible risk factors associated with poor outcomes of M/XDR-TB.

Methods

Two-hundred-and-sixty-two patients having M/XDR-TB who received the diagnosis and treatment at nine referral hospitals from 1 January 2016 to 31 December 2016 in Zhejiang, China were included. All patients received second-line regimens recommended by WHO under the DOTS-Plus strategy.

Results

Among the 262 patients, the treatment success rate was 55.34% (n = 145) with 53.44% (n = 140) cured and 1.91% (n = 5) who completed treatment, 62 (23.66%) failed, 27 (10.31%) died, 16 (6.11%) defaulted and 12 (4.58%) transferred out. Forty (64.52%) of the 62 M/XDR-TB patients who failed treatment were due to adverse effects in the first 10 months of treatment. Eighteen patients (6.37%) had XDR-TB. Treatment failure was significantly higher among patients with XDR-TB at 50% than that among patients with non-XDR-TB at 21.72% (P = 0.006). Failure outcomes were associated with a baseline weight less than 50 kg (OR, 8.668; 95% CI 1.679–44.756; P = 0.010), age older than 60 years (OR, 9.053; 95% CI 1.606–51.027; P = 0.013), hemoptysis (OR, 8.928; 95% CI 1.048–76.923; P = 0.045), presence of cavitary diseases (OR, 10.204; 95% CI 2.032–52.631; P = 0.005), or treatment irregularity (OR, 47.619; 95% CI 5.025–500; P = 0.001).

Conclusion

Treatment outcomes for M/XDR-TB under the DOTS-Plus strategy in Zhejiang, China were favorable but still not ideal. Low body weight (< 50 kg), old age (> 60 years), severe symptoms of TB including cavitary disease, hemoptysis and irregular treatment were independent prognostic factors for failure outcomes in patients with M/XDR-TB.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40001-021-00502-0.

Interim Effectiveness and Safety Comparison of Bedaquiline-Containing Regimens for Treatment of Diabetic Versus Non-Diabetic MDR/XDR-TB Patients in China: A Multicenter Retrospective Cohort Study

INTRODUCTION

Diabetes mellitus (DM), a common tuberculosis (TB) comorbidity, is associated with delayed bacillary clearance during anti-TB treatment and unfavorable outcomes. Bedaquiline (BDQ), when used as part of multidrug regimen for multidrug-resistant/extensively drug-resistant tuberculosis (MDR/XDR-TB), has been shown to be effective and safe although treatment outcome and risks for patients with MDR/XDR-TB and DM are unknown. A multicenter retrospective study was conducted to compared the safety and effectiveness of 24-week BDQ-containing anti-TB treatment for patients with MDR/XDR-TB with and without DM.

METHODS

The study of patients with MDR/XDR-TB with or without DM (enrolled February 2018-September 2019, 21 Chinese hospitals) was supervised by the New Drug Introduction and Protection Program (NDIP). Of 640 patients with MDR/XDR-TB receiving BDQ-containing anti-TB treatments, two propensity score-matched groups (107 DM/107 non-DM) were compared for cumulative culture conversion rate, time to culture conversion, adverse events, and corrected QT interval.

RESULTS

Body mass index was higher in patients with DM than patients without DM (23.29 ± 3.9 vs. 20.5 ± 3.6, P < 0.001); lung cavity prevalence (86.9% vs. 72.9%, P = 0.037) was also higher in patients with DM; the non-DM group had higher hepatitis prevalence (29.0% vs. 15.9%, P = 0.022). No significant intergroup differences were found for sputum culture conversion rate at week 8 (80.0% vs. 81.4%, P = 0.884), at week 24 (95.6% vs. 98.2%, P = 0.629), or for median time to sputum culture conversion [56 days (IQR 28-63) vs. 56 days (IQR 28-84) (P = 0.687)]. Favorable post-24-week treatment outcomes were presented by 90.7% and 93.5% in the DM group and non-DM group, respectively, without significant intergroup differences (P = 0.448). The DM adverse event rate exceeded non-DM rate (77.6% vs. 64.5%, P = 0.035).

CONCLUSION

Despite some differences in baseline characteristics, Chinese patients with MDR/XDR-TB with or without DM had similar sputum culture conversion rates and favorable treatment outcomes post-24-week BDQ-containing anti-TB treatment. Low BMI but not DM is risk factor associated with unfavorable outcome of patients with MDR/XDR-TB.

Evaluating bedaquiline as a treatment option for multidrug-resistant tuberculosis

Introduction: Despite efforts to the contrary, tuberculosis remains one of the leading causes of death in the world. The appearance of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of Mycobacterium tuberculosis has increased the need for new therapeutic options against these strains.Areas covered: This review covers the in vitro susceptibility, pharmacokinetics, and pharmacodynamics of bedaquiline, a new drug shown to be active against M. tuberculosis-resistant strains. The authors further review clinical data concerning its use against MDR and XDR strains, discussing recent clinical guidelines from different international societies.Expert opinion: Available data demonstrate the usefulness of bedaquiline against resistant M. tuberculosis. Despite the difficulty in analyzing multidrug therapies, the use of bedaquiline in MDR and XDR tuberculosis increases success rates, allowing shortened treatments and lower drug use than previously recommended regimens. Moreover, the fact that MDR and XDR strains are common in many places creates a need to include this drug in the currently available protocols. It is essential to overcome the substantial barriers that some countries encounter in obtaining bedaquiline, as doing so will make therapeutic regimens including this drug available for all patients.