Bedaquiline and delamanid result in low rates of unfavourable outcomes among TB patients in Eswatini

Drug recommendation for optimization on treatment outcome for MDR/RR-TB based on a multi-center, large scale, retrospective cohort study in China

OBJECTIVE

With the change in drug-resistant pattern, MDR/RR-TB was faced with underlying changes in regimens. A multi-center, large-scale, retrospective study performed aims to provide a recommendation of drug selection on optimization of outcome for the patients.

METHOD

The study was conducted in six TB-specialized hospitals in China. Patients were included from 2018-2021 and followed up throughout the treatment. Using a multivarariable and propensity score-matched logistic regression analysis, we evaluated associations between outcomes and drug use, as well as clinical characteritics.

RESULTS

Of 3112 patients, 74.29% had treatment sucess, 14.52% lost to follow-up, 9.67% failure, and 1.51% died. Treatment success was positively associated with Bedaquiline(Bdq), Linezolid(Lzd), and Cycloserin(Cs). Capreomycin(Cm) increased the risk of unfavorable outcomes. other drugs such as Amikacin(Amk) and clofazimine had no significant effect on outcomes. If isolates were susceptible to fluoroquinolones(FQs), FQs could decrease the risk of unfavorable outcomes.

CONCLUSIONS

The recommendation order for the treatment of MDR/RR-TB is Bdq, Lzd, and Cs. FQs were decreased in use intensity. Injection drugs, whether Amk or Cm, are not recommended.

Favorable outcome of individual regimens containing bedaquiline and delamanid in drug-resistant tuberculosis: A systematic review

Background

Drug-resistant tuberculosis (DR-TB) is a public health concern that is difficult to treat, requiring long and complex treatment with highly effective drugs. Bedaquiline and/or delamanid have already shown promising outcomes in patients with DR-TB, increasing the rate of culture conversion and lowering TB-related mortality.

Methods

We comprehensively searched and evaluated the effectiveness of individual regimens containing bedaquiline and delamanid on culture conversion and treatment success. We assessed for quality either observational or experimental studies.

Results

We identified 14 studies that met the inclusion criteria using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses flowchart with 12 observational and 2 experimental studies. Of 1691 DR-TB patients enrolled in the included studies, 1407 of them concomitantly received regimens containing bedaquiline and delamanid. Overall multidrug resistant (MDR), preextensively drug resistant (XDR), and XDR-TB were seen in 21.4%, 44.1%, and 34.5%, respectively. Of 14 studies, 8 of them reported favorable outcomes including sputum culture conversion and cure rate at the end of treatment, meanwhile 6 studies only reported sputum culture conversion. Sputum culture conversion at the end of the 6^th month was 63.6%-94.7% for observational studies, and 87.6%-95.0% for experimental studies. The favorable outcome at the end of treatment was 67.5%-91.4%. With high pre-XDR and XDR cases among DR-TB patients with limited treatment options, regimens containing bedaquiline and delamanid provide successful treatment.

Conclusion

In DR-TB patients receiving regimens containing bedaquiline and delamanid, favorable outcomes were high including sputum conversion and cure rate.

Drug resistant TB - latest developments in epidemiology, diagnostics and management

AIM

The aim of this review is to inform the reader on the latest developments in epidemiology, diagnostics and management.

EPIDEMIOLOGY

Drug-resistant Tuberculosis (DR-TB) continues to be a current global health threat, and is defined by higher morbidity and mortality, sequelae, higher cost and complexity. The WHO classifies drug-resistant TB into 5 categories: isoniazid-resistant TB, rifampicin resistant (RR)-TB and MDR-TB, (TB resistant to isoniazid and rifampicin), pre-extensively drug-resistant TB (pre-XDR-TB) which is MDR-TB with resistance to a fluoroquinolone and finally XDR-TB that is TB resistant to rifampicin, plus any fluoroquinolone, plus at least one further priority A drug (bedaquiline or linezolid). Of 500,000 estimated new cases of RR-TB in 2020, only 157 903 cases are notified. Only about a third of cases are detected and treated annually.

DIAGNOSTICS

Recently newer rapid diagnostic methods like the GeneXpert, whole genome sequencing and Myc-TB offer solutions for rapid detection of resistance.

TREATMENT

The availability of new TB drugs and shorter treatment regimens have been recommended for the management of DR-TB.

CONCLUSION

Despite advances in diagnostics and treatments we still have to find and treat two thirds of the drug resistant cases that go undetected and therefore go untreated each year. Control of TB and elimination will only occur if cases are detected, diagnosed and treated promptly.

9 months of delamanid, linezolid, levofloxacin, and pyrazinamide versus conventional therapy for treatment of fluoroquinolone-sensitive multidrug-resistant tuberculosis (MDR-END): a multicentre, randomised, open-label phase 2/3 non-inferiority trial in South Korea

BACKGROUND

With the introduction of new anti-tuberculosis drugs, all-oral regimens with shorter treatment durations for multidrug-resistant tuberculosis have been anticipated. We aimed to investigate whether a new all-oral regimen was non-inferior to the conventional regimen including second-line anti-tuberculosis drugs for 20-24 months in the treatment of fluoroquinolone-sensitive multidrug-resistant tuberculosis.

METHODS

In this multicentre, randomised, open-label phase 2/3 non-inferiority trial, we enrolled men and women aged 19-85 years with multidrug-resistant tuberculosis confirmed by phenotypic or genotypic drug susceptibility tests or rifampicin-resistant tuberculosis by genotypic tests at 12 participating hospitals throughout South Korea. Participants with fluoroquinolone-resistant multidrug-resistant tuberculosis were excluded. Participants were randomly assigned (1:1) to two groups using a block randomisation, stratified by the presence of diabetes and cavitation on baseline chest radiographs. The investigational group received delamanid, linezolid, levofloxacin, and pyrazinamide for 9 months, and the control group received a conventional 20-24-month regimen, according to the 2014 WHO guidelines. The primary outcome was the treatment success rate at 24 months after treatment initiation in the modified intention-to-treat population and the per-protocol population. Participants who were "cured" and "treatment completed" were defined as treatment success following the 2014 WHO guidelines. Non-inferiority was confirmed if the lower limit of a 97·5% one-sided CI of the difference between the groups was greater than -10%. Safety data were collected for 24 months in participants who received a predefined regimen at least once. This study is registered with ClinicalTrials.gov, NCT02619994.

FINDINGS

Between March 4, 2016, and Sept 14, 2019, 214 participants were enrolled, 168 (78·5%) of whom were included in the modified intention-to-treat population. At 24 months after treatment initiation, 60 (70·6%) of 85 participants in the control group had treatment success, as did 54 (75·0%) of 72 participants in the shorter-regimen group (between-group difference 4·4% [97·5% one-sided CI -9·5% to ∞]), satisfying the predefined non-inferiority margin. No difference in safety outcomes was identified between the control group and the shorter-regimen group.

INTERPRETATION

9-month treatment with oral delamanid, linezolid, levofloxacin, and pyrazinamide could represent a new treatment option for participants with fluoroquinolone-sensitive multidrug-resistant tuberculosis.

FUNDING

Korea Disease Control and Prevention Agency, South Korea.

Bedaquiline and Linezolid improve anti-TB treatment outcome in drug-resistant TB patients with HIV: A systematic review and meta-analysis

OBJECTIVES

We aimed to assess the effect of second-line anti-TB treatment and determine which drugs can achieve the greatest clinical benefit for DR-TB-HIV patients by comparing multiple chemotherapy regimens, to provide a basis for evidence-based practice.

METHODS

We searched three electronic databases (PubMed, Web of Science and Cochrane) for related English studies published since 2010. A random-effect model was used to estimate the pooled result for the treatment outcomes. Subgroup analysis based on possible factors, such as ART, baseline CD4 T-cell count, treatment regimens, and profiles of drug resistance, was also conducted to assess factors for favorable outcome. Outcomes were treatment success and mortality.

RESULTS

38 studies, 40 cohorts with 9279 patients were included. The pooled treatment success, mortality, treatment failure, and default rates were 57.5 % (95 % CI 53.1-61.9), 21 % (95 % CI 17.8-24.6), 4.8 % (95 % CI 3.5-6.5), and 10.7 % (95 % CI 8.7-13.1), respectively, in patients with DR-TB and HIV co-infection. Subgroup analysis showed that BDQ and LZD based regimen, and ≥ 2 Group A drugs were associated with a higher treatment success rate. Besides, higher CD4 T-cell count at baseline was also correlated with higher treatment success rate, too.

CONCLUSIONS

Suboptimal anti-TB outcomes underlining the need to expand the application of effective drugs and better regimen in high HIV setting. BDQ and LZD based all-oral regimen and early ART could contribute to higher treatment success, particularly among XDR-TB-HIV patients. Given that all included studies were observational, our findings emphasize the need for high-quality studies to further investigate the optimal treatment regimen for DR-TB-HIV.

Effectiveness of the Novel Anti-TB Bedaquiline against Drug-Resistant TB in Africa: A Systematic Review of the Literature

Background: In 2018, an estimated 10.0 million people contracted tuberculosis (TB), and 1.5 million died from it, including 1.25 million HIV-negative persons and 251,000 HIV-associated TB fatalities. Drug-resistant tuberculosis (DR-TB) is an important contributor to global TB mortality. Multi-drug-resistant TB (MDR-TB) is defined as TB resistant to at least isoniazid (INH) and rifampin (RMP), which are recommended by the WHO as essential drugs for treatment. Objective: To investigate the effectiveness of bedaquiline addition to the treatment of drug-resistant TB infections on the African continent. Methodology: The search engine databases Medline, PubMed, Google Scholar, and Embase were used to obtain published data pertaining to DR-TB between 2012 and 2021 in Africa. Included studies had to document clinical characteristics at treatment initiation and outcomes at the end of treatment (i.e., success, failure, recurrence, loss to follow-up, and death). The included studies were used to conduct a meta-analysis. All data analysis and visualization were performed using the R programming environment. The log risk ratios and sample variances were calculated for DR-TB patients treated with BBQ monotherapy vs. BDQ and other drug therapy. To quantify heterogeneity among the included studies, random effect sizes were calculated. Results: A total of 16 studies in Africa from Mozambique (N = 1 study), Eswatini (N = 1 study), Democratic Republic of the Congo (N = 1 study), South Africa (N = 12 studies), and a multicenter study undertaken across Africa (N = 1 study) were included. In total, 22,368 individuals participated in the research studies. Among the patients, (55.2%; 12,350/22,368) were male while 9723/22,368 (44%) were female. Overall, (9%; 2033/22,368) of patients received BDQ monotherapy, while (88%; 19,630/22,368) patients received bedaquiline combined with other antibiotics. In total, (42%; 9465/22,368) of the patients were successfully treated. About (39%; 8653/22,368) of participants finished their therapy, meanwhile (5%; 1166/22,368) did not finish their therapy, while people (0.4%; 99/22,368) were lost to follow up. A total of (42%; 9265/22,368) patients died. Conclusion: Very few studies on bedaquiline usage in DR-TB in Africa have been published to date. Bedaquiline has been shown to enhance DR-TB results in clinical studies and programmatic settings. Hence, the World Health Organization (WHO) has recommended that it be included in DR-TB regimens. However, in the current study limited improvement to DR-TB treatment results were observed using BDQ on the continent. Better in-country monitoring and reporting, as well as multi-country collaborative cohort studies of DR-TB, can expand the knowledge of bedaquiline usage and clinical impact, as well as the risks and benefits throughout the continent.

Unraveling the possible inhibitors for Chorismate synthase to combat tuberculosis using in silico approach

Tuberculosis antibiotic resistance is a huge concern to the global population. The goal of this study was to find new and effective compounds to treat multidrug-resistant tuberculosis by targeting Chorismate synthase (CS), a crucial enzyme for Mycobacterium tuberculosis survival (MbT). The potential of a library of compounds as selective anti - tuberculosis drugs was investigated. Docking was first conducted using MoE to determine the effectiveness of the compounds. Molecular docking studies followed by MD simulation studies (total of 500 ns) in combination with free energy calculations grade the ligands in terms of their binding affinities. In the ligand bound state of the CS, MD simulations revealed a change from stretched to bended motional shift in loop L19. The RMSF analysis also revealed this flexibility, which was confirmed by visual inspection of L19 at various time intervals during the experiment. It appears that ZF1(-25.43Kcal/mol) and ZF2 (-22.04Kcal/mol) form hbonds and have a high binding energy in the active region of protein. Residues wise distribution of binding energy reveals that Arg144, Trp4, Thr6, and L19 amino acid residues are engaged in binding of CS with inhibitors. In summary, the findings suggest that compounds ZF1 and ZF2 may be more effective and selective anti-TB agents than currently available drugs. Also the role of L19, mediated by αH9 and αH5 in the retention of ligand inside the active pocket, through the formation of lid was also revealed. This knowledge will aid in the discovery of drugs that are potent CS inhibitors. More experimental research and a better understanding of the structure-activity relationship could aid in the development of possible candidates with better CS inhibition.Communicated by Ramaswamy H. Sarma.

The pipeline of new molecules and regimens against drug-resistant tuberculosis

The clinical development and regulatory approval of bedaquiline, delamanid and pretomanid over the last decade brought about significant progress in the management of drug-resistant tuberculosis, providing all-oral regimens with favorable safety profiles. The Nix-TB and ZeNix trials of a bedaquiline - pretomanid - linezolid regimen demonstrated for the first time that certain forms of drug-resistant tuberculosis can be cured in the majority of patients within 6 months. Ongoing Phase 3 studies containing these drugs may further advance optimized regimen compositions. Investigational drugs in clinical development that target clinically validated mechanisms, such as second generation oxazolidinones (sutezolid, delpazolid, TBI-223) and diarylquinolines (TBAJ-876 and TBAJ-587) promise improved potency and/or safety compared to the first-in-class drugs. Compounds with novel targets involved in diverse bacterial functions such as cell wall synthesis (DrpE1, MmpL3), electron transport, DNA synthesis (GyrB), cholesterol metabolism and transcriptional regulation of ethionamide bioactivation pathways have advanced to early clinical studies with the potential to enhance antibacterial activity when added to new or established anti-TB drug regimens. Clinical validation of preclinical in vitro and animal model predictions of new anti-TB regimens may further improve the translational value of these models to identify optimal anti-TB therapies.

Outcomes of multidrug-resistant tuberculosis treated with bedaquiline or delamanid

BACKGROUND

Since September 1, 2016, bedaquiline and delamanid have been administered for treatment of patients with multidrug-resistant/rifampicin-resistant tuberculosis after the official approval in South Korea. This study aimed to assess and compare the final treatment outcomes of patients who received bedaquiline with those of patients who received delamanid.

METHODS

This is a nationwide cohort study of patients with multidrug-resistant/rifampicin-resistant tuberculosis in whom bedaquiline or delamanid was administered from September 1, 2016, to February 28, 2018, after receiving the official approval in South Korea. Patients were classified into the bedaquiline and delamanid group according to the first used drug. We evaluated and compared the final treatment outcomes between the groups.

RESULTS

During the study period, 284 patients with multidrug-resistant/rifampicin-resistant tuberculosis were approved to use bedaquiline or delamanid and 260 were included in the final analysis; 119 (45.8%) and 141 patients (54.2%) were classified into bedaquiline and delamanid groups, respectively. Among them, 30 patients (11.5%) exhibited additional resistance to second-line injectable drugs, 94 patients (36.2%) had additional resistance to fluoroquinolones, and 37 patients (14.2%) had resistance to both drugs. The overall treatment success rate was 79.2%. Initiation of bedaquiline rather than delamanid was not associated with treatment success (adjusted odds ratio = 0.671, 95% confidence interval = 0.350-1.285). Frequencies of adverse events were not significantly different between the two groups.

CONCLUSIONS

Initial choice of bedaquiline or delamanid did not make any significant difference in the final treatment outcome or the frequencies of adverse events among patients with multidrug-resistant/rifampicin-resistant tuberculosis.

Outcome of treatment of MDR-TB or drug-resistant patients treated with bedaquiline and delamanid: Results from a large global cohort

The World Health Organization (WHO) recommends countries introduce new anti-TB drugs in the treatment of multidrug-resistant tuberculosis. The aim of the study is to prospectively evaluate the effectiveness of bedaquiline (and/or delamanid)- containing regimens in a large cohort of consecutive TB patients treated globally. This observational, prospective study is based on data collected and provided by Global Tuberculosis Network (GTN) centres and analysed twice a year. All consecutive patients (including children/adolescents) treated with bedaquiline and/or delamanid were enrolled, and managed according to WHO and national guidelines. Overall, 52 centres from 29 countries/regions in all continents reported 883 patients as of January 31st 2021, 24/29 countries/regions providing data on 100% of their consecutive patients (10-80% in the remaining 5 countries). The drug-resistance pattern of the patients was severe (>30% with extensively drug-resistant -TB; median number of resistant drugs 5 (3-7) in the overall cohort and 6 (4-8) among patients with a final outcome). For the patients with a final outcome (477/883, 54.0%) the median (IQR) number of months of anti-TB treatment was 18 (13-23) (in days 553 (385-678)). The proportion of patients achieving sputum smear and culture conversion ranged from 93.4% and 92.8% respectively (whole cohort) to 89.3% and 88.8% respectively (patients with a final outcome), a median (IQR) time to sputum smear and culture conversion of 58 (30-90) days for the whole cohort and 60 (30-100) for patients with a final outcome and, respectively, of 55 (30-90) and 60 (30-90) days for culture conversion. Of 383 patients treated with bedaquiline but not delamanid, 284 (74.2%) achieved treatment success, while 25 (6.5%) died, 11 (2.9%) failed and 63 (16.5%) were lost to follow-up.

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.