First case of extensively drug-resistant tuberculosis treated with both delamanid and bedaquiline

Impact of Prior Tuberculosis Treatment With New/Companion Drugs on Clinical Outcomes in Patients Receiving Concomitant Bedaquiline and Delamanid for Multidrug- and Rifampicin-Resistant Tuberculosis

BACKGROUND

There are scarce data on the clinical outcomes of persons retreated with new/companion anti-tuberculosis (TB) drugs for multidrug- and rifampicin-resistant tuberculosis (MDR/RR-TB). We sought to evaluate the efficacy and safety of bedaquiline and delamanid containing regimens among patients with and without prior exposure to the new/companion drugs (bedaquiline, delamanid, linezolid, clofazimine, and fluoroquinolones).

METHODS

We conducted a retrospective cohort study among patients with pulmonary MDR/RR-TB in Georgia who received bedaquiline and delamanid combination as a part of a salvage regimen from November 2017 to December 2020 in a programmatic setting.

RESULTS

Among 106 persons with a median age of 39.5 years, 44 (41.5%) were previously treated with new/companion TB drugs. Patients with prior exposure to new/companion drugs had higher rates of baseline resistance compared to those without exposure to new/companion TB drugs (bedaquiline 15.2% vs 1.8%, linezolid 22.2% vs 16.7%). Sputum culture conversion rates among patients exposed and not exposed to new/companion drugs were 65.9% vs 98.0%, respectively (P < .001). Among patients with and without prior new/companion TB drug use, favorable outcome rates were 41.0% and 82.3%, respectively (P < .001). Treatment adherence in 32 (30.2%) patients was ≤80%. Five of 21 patients (23.8%) who had a baseline and repeat susceptibility test had acquired bedaquiline resistance. QTC/F prolongation (>500 ms) was rare (2.8%).

CONCLUSIONS

Prior exposure to new/companion TB drugs was associated with poor clinical outcomes and acquired drug resistance. Tailoring the TB regimen to each patient's drug susceptibility test results and burden of disease and enhancing adherence support may improve outcomes.

Hydrazone-Tethered 5-(Pyridin-4-yl)-4H-1,2,4-triazole-3-thiol Hybrids: Synthesis, Characterisation, in silico ADME Studies, and in vitro Antimycobacterial Evaluation and Cytotoxicity

Compounds containing arylpyrrole-, 1,2,4-triazole- and hydrazone structural frameworks have been widely studied and demonstrated to exhibit a wide range of pharmacological properties. Herein, an exploratory series of new 1,2,4-triazole derivatives designed by amalgamation of arylpyrrole and 1,2,4-triazole structural units via a hydrazone linkage is reported. The synthesised compounds were tested in vitro for their potential activity against Mycobacterium tuberculosis (MTB) H₃₇ Rv strain. The most promising compound 13 - the derivative without the benzene ring appended to the pyrrole unit displayed acceptable activity (MIC₉₀ =3.99 μM) against MTB H₃₇ Rv, while other compounds from the series exhibited modest to weak antimycobacterial activity with MIC₉₀ values in the range between 7.0 and >125 μM. Furthermore, in silico results, predicated using the SwissADME web tool, show that the prepared compounds display desirable ADME profile with parameters within acceptable range.

Biocultural perspectives of infectious diseases and demographic evolution: Tuberculosis and its comorbidities through history

Anthropologists recognize the importance of conceptualizing health in the context of the mutually evolving nature of biology and culture through the biocultural approach, but biocultural anthropological perspectives of infectious diseases and their impacts on humans (and vice versa) through time are relatively underrepresented. Tuberculosis (TB) has been a constant companion of humans for thousands of years and has heavily influenced population health in almost every phase of cultural and demographic evolution. TB in human populations has been dramatically influenced by behavior, demographic and epidemiological shifts, and other comorbidities through history. This paper critically discusses TB and some of its major comorbidities through history within a biocultural framework to show how transitions in human demography and culture affected the disease-scape of TB. In doing so, I address the potential synthesis of biocultural and epidemiological transition theory to better comprehend the mutual evolution of infectious diseases and humans.

Safety, Tolerability, and Pharmacokinetics of Telacebec (Q203), a New Antituberculosis Agent, in Healthy Subjects

Telacebec (Q203) is a potent drug candidate under clinical development for the treatment of drug-naïve and drug-resistant tuberculosis. The first-in-human randomized, placebo-controlled, double-blind, dose-escalation Phase 1A trial (Q203-TB-PI-US001) was conducted to evaluate the safety, tolerability, and pharmacokinetics of telacebec. A total of 56 normal, healthy, male and female subjects (42 active and 14 placebo) were enrolled in the study. The doses of telacebec were 10 mg (Cohort 1), 30 mg (Cohort 2), 50 mg (Cohort 3), 100 mg (Cohort 4), 200 mg (Cohort 5), 400 mg (Cohort 6), and 800 mg (Cohort 7) in a fasted state. Subjects participating in Cohort 4 were also enrolled in Cohort 8 to investigate the food effect on the pharmacokinetics of telacebec after a high-fat meal. In all subjects dosed with telacebec (10 - 800 mg), telacebec was well tolerated and did not lead to any significant or serious adverse events. Following a single oral administration of telacebec (10 - 800 mg), telacebec plasma concentration reached the maximal plasma concentration (C_max) in average 2.0 - 3.5 h and showed multi-exponential decline thereafter. The area under the plasma concentration vs. time curve (AUC) was approximately dose-proportional. A significant increase in plasma concentrations was observed in the fed condition compared with the fasted condition with the geometric mean ratio of 3.93 for C_max. Moderate delay in T_max (4.5 h) was also observed in the fed condition. These results, combined with the demonstrated activity against drug-sensitive and multidrug-resistant Mycobacterium tuberculosis, support further investigation of telacebec for the treatment of tuberculosis.

Delamanid Resistance: Update and Clinical Management

Delamanid, a-first-in-class bicyclic nitroimidazole, was recently approved for multidrug-resistant tuberculosis treatment. Pitted against the hope for improving treatment outcomes is the threat of the rapid resistance emergence. This review provides information on the mechanisms of action, resistance emergence, and drug susceptibility testing (DST) for delamanid. Delamanid resistance has already been reported in both in vitro experiments and clinical settings. Although mutations conferring delamanid resistance have been identified in fbiA, fbiB, fbiC, ddn, and fgd1 genes of Mycobacterium tuberculosis, knowledge about the molecular resistance mechanisms is limited, and there remains no standardized DST method. The rapid acquisition of delamanid resistance emphasizes the need for optimal use of new drugs, the need for drug resistance surveillance, and a comprehensive understanding of drug resistance mechanisms. Further studies are necessary to investigate genetic and phenotypic changes that determine clinically relevant delamanid resistance to help develop a rapid delamanid DST.

Bedaquiline: Current status and future perspectives

The development of drug-resistant tuberculosis (TB) is a major threat worldwide. Based on World Health Organization (WHO) reports, it is estimated that more than 500 000 new cases of drug-resistant TB occur annually. In addition, there are alarming reports of increasing multidrug-resistant TB (MDR-TB) and the emergence of extensively drug-resistant TB (XDR-TB) from different countries of the world. Therefore, new options for TB therapy are required. Bedaquiline (BDQ), a novel anti-TB drug, has significant minimum inhibitory concentrations (MICs) both against drug-susceptible and drug-resistant TB. Moreover, BDQ was recently approved for therapy of MDR-TB. The current narrative review summarises the available data on BDQ resistance, describes its antimicrobial properties, and provides new perspectives on clinical use of this novel anti-TB agent.

Promising Lead Compounds in the Development of Potential Clinical Drug Candidate for Drug-Resistant Tuberculosis

According to WHO report, globally about 10 million active tuberculosis cases, resulting in about 1.6 million deaths, further aggravated by drug-resistant tuberculosis and/or comorbidities with HIV and diabetes are present. Incomplete therapeutic regimen, meager dosing, and the capability of the latent and/or active state tubercular bacilli to abide and do survive against contemporary first-line and second line antitubercular drugs escalate the prevalence of drug-resistant tuberculosis. As a better understanding of tuberculosis, microanatomy has discovered an extended range of new promising antitubercular targets and diagnostic biomarkers. However, there are still no new approved antitubercular drugs of routine therapy for several decades, except for bedaquiline, delamanid, and pretomanid approved tentatively. Despite this, innovative methods are also urgently needed to find potential new antitubercular drug candidates, which potentially decimate both latent state and active state mycobacterium tuberculosis. To explore and identify the most potential antitubercular drug candidate among various reported compounds, we focused to highlight the promising lead derivatives of isoniazid, coumarin, griselimycin, and the antimicrobial peptides. The aim of the present review is to fascinate significant lead compounds in the development of potential clinical drug candidates that might be more precise and effective against drug-resistant tuberculosis, the world research looking for a long time.

Compassionate use of delamanid in adults and children for drug-resistant tuberculosis: 5-year update

BACKGROUND

Although delamanid has been approved for the treatment of multidrug-resistant TB (MDR-TB) in numerous regions, in areas where it is not yet registered it can be accessed as part of salvage therapy (in particular for those patients with limited treatment options) via the Otsuka compassionate use programme. Here we present the analysis of interim treatment outcomes by 24 weeks of more than 200 MDR-TB patients globally who received delamanid under this programme.

METHODS

We evaluated treatment efficacy with respect to culture negativity at 24 weeks, as well as the safety profile of delamanid, in an MDR-TB patient cohort treated under compassionate use between 2014 and 2019.

RESULTS

Among patients who received delamanid as part of a multidrug regimen, 123 (61%) out of 202 had extensively drug-resistant TB (XDR-TB), 66 (33%) out of 202 had HIV co-infection and 34 (17%) out of 202 were children aged between 6 and 17 years. Of those patients who were culture positive at delamanid treatment initiation and who completed 24 weeks of delamanid treatment in combination with other anti-tuberculosis (TB) drugs, culture negativity was achieved in 116 (79%) out of 147 cases. The corresponding rates of culture negativity for patients with XDR-TB and HIV co-infection, as well as the paediatric subgroup were 69 (77%) out of 90, 44 (92%) out of 48 and 20 (80%) out of 25, respectively. QT interval prolongation was the most frequently observed serious adverse event and was reported in 8% of patients receiving delamanid. Overall, treatment safety outcomes did not reveal any new or unidentified risks.

CONCLUSIONS

The use of delamanid combined with other active drugs has the potential to achieve high rates of culture negativity in difficult-to-treat drug-resistant TB cases, with a favourable safety profile.

Anti-tubercular profile of new selenium-menadione conjugates against Mycobacterium tuberculosis H37Rv (ATCC 27294) strain and multidrug-resistant clinical isolates

Tuberculosis (TB) is one of the most fatal diseases and is responsible for the infection of millions of people around the world. Most recently, scientific frontiers have been engaged to develop new drugs that can overcome drug-resistant TB. Following this direction, using a designed scaffold based on the combination of two separate pharmacophoric groups, a series of menadione-derived selenoesters was developed with good yields. All products were evaluated for their in vitro activity against Mycobacterium tuberculosis H37Rv and attractive results were observed, especially for the compounds 8a, 8c and 8f (MICs 2.1, 8.0 and 8.1 μM, respectively). In addition, 8a, 8c and 8f demonstrated potent in vitro activity against multidrug-resistant clinical isolates (CDCT-16 and CDCT-27) with promising MIC values ranging from 0.8 to 3.1 μM. Importantly, compounds 8a and 8c were found to be non-toxic against the Vero cell line. The SI value of 8a (>23.8) was found to be comparable to that of isoniazid (>22.7), which suggests the possibility of carrying out advanced studies on this derivative. Therefore, these menadione-derived selenoesters obtained as hybrid compounds represent promising new anti-tubercular agents to overcome TB multidrug resistance.

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New menadione-derived selenoesters were synthesized.

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The compounds demonstrated excellent activity against M. tuberculosis H37Rv.

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8a, 8c and 8f showed potent activity against multidrug resistant clinical isolates.

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Compounds 8a and 8c were found to be non-toxic.

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These organoselenium compounds represent promising new anti-tubercular agents.

Current advances in the clinical development of anti-tubercular agents

Tuberculosis (TB) is a communicable airborne infectious disease caused by the Mycobacterium tuberculosis (MTB) that primarily affects the lungs, and can disseminate to other parts of the body. MTB is one of the most dangerous pathogens, killing about 1.4 million people annually worldwide. Although the standard treatment of TB is comprised of four anti-TB drugs, the emergence of multidrug-resistant (MDR) and extensive drug-resistant (XDR) strains in the recent past and associated side effects have affected the tailor-made regimens. Notably, existing therapies approved by the World Health Organisation (WHO) can only treat less than 50% of drug-resistant TB. Therefore, an expeditious pace in the TB research is highly needed in search of effective, affordable, least toxic novel drugs with shorter regimens to reach the goals viz. 2020 milestones End TB strategy set by the WHO. Currently, twenty-three drug-like molecules are under investigation in different stages of clinical trials. These newer agents are expected to be effective against the resistant strains. This article summarizes the properties, merits, demerits, and the probability of their success as novel potential therapeutic agents.

Bedaquiline and delamanid for drug-resistant tuberculosis: a clinician's perspective

Drug-resistant tuberculosis (TB) represents a substantial threat to the global efforts to control this disease. After decades of stagnation, the treatment of drug-resistant TB is undergoing major changes: two drugs with a new mechanism of action, bedaquiline and delamanid, have been approved by stringent regulatory authorities and are recommended by the WHO. This narrative review summarizes the evidence, originating from both observational studies and clinical trials, which is available to support the use of these drugs, with a focus on special populations. Areas of uncertainty, including the use of the two drugs together or for prolonged duration, are discussed. Ongoing clinical trials are aiming to optimize the use of bedaquiline and delamanid to shorten the treatment of drug-resistant TB.

Pneumonia caused by Mycobacterium tuberculosis

Tuberculosis (TB) is one of the top ten leading causes of death worldwide. The causative agent of TB is Mycobacterium tuberculosis. Acute tuberculous pneumonia (TP) is an acute form of pulmonary TB. However, acute TP and non-tuberculous community-acquired pneumonia can be easily confused, resulting in deterioration of TP due to delayed treatment. Therefore, rapid and accurate diagnosis of acute TP is crucial in order to stop the transmission of TB. Moreover, development of new diagnostic tools (technologies and approaches), and flexible application of different therapy schemes will help to reduce the incidence of TP and promote the goal of ending the TB epidemic.

Treatment of Drug-Resistant Tuberculosis. An Official ATS/CDC/ERS/IDSA Clinical Practice Guideline

Background: The American Thoracic Society, U.S. Centers for Disease Control and Prevention, European Respiratory Society, and Infectious Diseases Society of America jointly sponsored this new practice guideline on the treatment of drug-resistant tuberculosis (DR-TB). The document includes recommendations on the treatment of multidrug-resistant TB (MDR-TB) as well as isoniazid-resistant but rifampin-susceptible TB.Methods: Published systematic reviews, meta-analyses, and a new individual patient data meta-analysis from 12,030 patients, in 50 studies, across 25 countries with confirmed pulmonary rifampin-resistant TB were used for this guideline. Meta-analytic approaches included propensity score matching to reduce confounding. Each recommendation was discussed by an expert committee, screened for conflicts of interest, according to the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology.Results: Twenty-one Population, Intervention, Comparator, and Outcomes questions were addressed, generating 25 GRADE-based recommendations. Certainty in the evidence was judged to be very low, because the data came from observational studies with significant loss to follow-up and imbalance in background regimens between comparator groups. Good practices in the management of MDR-TB are described. On the basis of the evidence review, a clinical strategy tool for building a treatment regimen for MDR-TB is also provided.Conclusions: New recommendations are made for the choice and number of drugs in a regimen, the duration of intensive and continuation phases, and the role of injectable drugs for MDR-TB. On the basis of these recommendations, an effective all-oral regimen for MDR-TB can be assembled. Recommendations are also provided on the role of surgery in treatment of MDR-TB and for treatment of contacts exposed to MDR-TB and treatment of isoniazid-resistant TB.

Bedaquiline in multidrug-resistant tuberculosis treatment: Safety and efficacy in a Korean subpopulation

BACKGROUND

The final treatment outcomes of Korean multidrug-resistant tuberculosis (MDR-TB) patients treated with bedaquiline in the C209 trial have not yet been reported. Therefore, a subgroup analysis of the Korean population from the C209 trial was performed, and the results were compared with those of the overall C209 study population.

METHODS

In the C209 trial, MDR-TB patients were treated with bedaquiline for 24 weeks in combination with background anti-TB drugs, and were followed-up until week 120 after bedaquiline treatment initiation.

RESULTS

With the exception of drug susceptibility patterns, the baseline clinical characteristics of both groups were similar. The proportions of pre-extensively drug-resistant TB to extensively drug-resistant TB (pre-XDR-TB/XDR-TB) were 61.9 and 35.2% in the Korean and the overall C209 populations, respectively. Aminoglycosides, later-generation fluoroquinolones, cycloserine, and linezolid were the most common concomitant drugs used during bedaquiline treatment. The culture conversion rates of both groups were similar at week 24 (end of bedaquiline treatment; 80.0% vs. 79.5%) and 120 (75.0% vs. 72.2%). Additionally, the frequency and type of adverse events during treatment were similar in both groups, and 1 patient (5.0%) died due to a cause unrelated to bedaquiline treatment.

CONCLUSIONS

Bedaquiline showed similar efficacy and safety in Korean patients with MDR-TB, despite their advanced drug-resistance profiles, possibly due to other concomitant drugs such as linezolid.

Regulatory T Cells Subvert Mycobacterial Containment in Patients Failing Extensively Drug-Resistant Tuberculosis Treatment

RATIONALE

The advent of extensively drug-resistant (XDR) tuberculosis (TB) and totally drug-resistant TB, with limited or no treatment options, has facilitated renewed interest in host-directed immunotherapy, particularly for therapeutically destitute patients. However, the selection and utility of such approaches depend on understanding the host immune response in XDR-TB, which hitherto remains unexplored.

OBJECTIVES

To determine the host immunological profile in patients with XDR-TB, compared with drug-sensitive TB (DS-TB), using peripheral blood and explanted lung tissue.

METHODS

Blood and explanted lung tissue were obtained from patients with XDR-TB (n = 31), DS-TB (n = 20), and presumed latent TB infection (n = 20). T-cell phenotype (T-helper cell type 1 [Th1]/Th2/Th17/regulatory T cells [Tregs]) was evaluated in all patient groups, and Treg function assessed in XDR-TB nonresponders by coculturing PPD-preprimed effector T cells with H37Rv-infected monocyte-derived macrophages, with or without autologous Tregs. Mycobacterial containment was evaluated by counting colony-forming units.

MEASUREMENTS AND MAIN RESULTS

Patients failing XDR-TB treatment had an altered immunophenotype characterized by a substantial increase in the frequency (median; interquartile range) of CD4⁺CD25⁺FoxP3⁺ Tregs (11.5%; 5.9-15.2%) compared with DS-TB (3.4%; 1.6-5.73%; P < 0.001) and presumed latent TB infection (1.8%; 1.2-2.3%; P < 0.001), which was unrelated to disease duration. Tregs isolated from patients with XDR-TB suppressed T-cell proliferation (up to 90%) and subverted containment of H37Rv-infected monocyte-derived macrophages (by 30%; P = 0.03) by impairing effector T-cell function through a mechanism independent of direct cell-to-cell contact, IL-10, TGF (transforming growth factor)-β, and CTLA-4 (cytotoxic T-lymphocyte-associated protein 4).

CONCLUSIONS

Collectively, these data suggest that Tregs may be contributing to immune dysfunction, and bacterial persistence, in patients with XDR-TB. The relevant cellular pathways may serve as potential targets for immunotherapeutic intervention.

Targeted therapy in chronic diseases using nanomaterial-based drug delivery vehicles

The application of nanomedicines is increasing rapidly with the promise of targeted and efficient drug delivery. Nanomedicines address the shortcomings of conventional therapy, as evidenced by several preclinical and clinical investigations indicating site-specific drug delivery, reduced side effects, and better treatment outcome. The development of suitable and biocompatible drug delivery vehicles is a prerequisite that has been successfully achieved by using simple and functionalized liposomes, nanoparticles, hydrogels, micelles, dendrimers, and mesoporous particles. A variety of drug delivery vehicles have been established for the targeted and controlled delivery of therapeutic agents in a wide range of chronic diseases, such as diabetes, cancer, atherosclerosis, myocardial ischemia, asthma, pulmonary tuberculosis, Parkinson's disease, and Alzheimer's disease. After successful outcomes in preclinical and clinical trials, many of these drugs have been marketed for human use, such as Abraxane®, Caelyx®, Mepact®, Myocet®, Emend®, and Rapamune®. Apart from drugs/compounds, novel therapeutic agents, such as peptides, nucleic acids (DNA and RNA), and genes have also shown potential to be used as nanomedicines for the treatment of several chronic ailments. However, a large number of extensive clinical trials are still needed to ensure the short-term and long-term effects of nanomedicines in humans. This review discusses the advantages of various drug delivery vehicles for better understanding of their utility in terms of current medical needs. Furthermore, the application of a wide range of nanomedicines is also described in the context of major chronic diseases.

Telemedicine in Resource-Limited Settings to Optimize Care for Multidrug-Resistant Tuberculosis

The emergence and spread of multidrug-resistant tuberculosis (MDR-TB) poses a major threat to the global targets for TB control. In recent years, an evolving science and evidence base for MDR-TB has led to much needed changes in international guidelines promoting the use of newer TB drugs and regimens for MDR-TB, however, there remains a significant implementation gap. Due to the complexity of treating MDR-TB, management of cases is often supported by an expert multidisciplinary team, or clinical expert group. This service is often centralized, and may be delivered through a telemedicine platform. We have implemented a Web-based "store-and-forward" telemedicine service to optimize MDR-TB patient care in Daru, a remote and resource limited setting in Papua New Guinea (PNG). From April 2016 to February 2019, 237 cases were discussed using the service. This encompassed diagnostic (presumptive) and treatment cases, and more recently, support to the scale up of preventative therapy for latent TB infection. There were 75 cases in which the use of Bedaquiline was discussed or mentioned, with a high frequency of discussions occurring in the initial period (26 cases in the first 12 months), which has appeared to decrease as clinicians gained familiarity with use of the drug (15 cases in the last 12 months). This service has supported high quality clinical care and fostered collaboration between clinicians and technical experts in a shared learning environment.

Multi and extensively drug-resistant pulmonary tuberculosis: advances in diagnosis and management

PURPOSE OF REVIEW

Multidrug-resistant (MDR) tuberculosis (TB) and extensively drug-resistant (XDR)-TB epidemics are key obstacles towards TB control and elimination.

RECENT FINDINGS

Diagnosis of MDR/XDR-TB is difficult and requires several weeks. New diagnostic tools are being tested and proposed allowing for shorter time to diagnosis and reduced delays in starting an adequate treatment regimen. MDR/XDR-TB treatment strategies are currently on an evolving stage. New shortened treatments based on the recommended 'Bangladesh regimen' or on the newer anti-TB drugs, delamanid and bedaquiline may represent part of the future scenario. In addition, more information on safety and efficacy of delamanid and bedaquiline has been published, allowing to better position these drugs. Recent information on treatment regimens for the paediatric age, with or without delamanid or bedaquiline, has become available. This is of great help in designing safer and more efficacious regimens for the treatment of MDR/XDR-TB in children and adolescents.

SUMMARY

The accessibility, sustainability and scale-up of new diagnostic technologies are lagging behind and more efforts are needed. In addition, we need high-quality information on safety and efficacy of various combinations of drugs to obtain the best possible regimens to treat the largest possible proportion of patients.

Bedaquiline and delamanid in the treatment of multidrug-resistant tuberculosis: Promising but challenging

Improving treatment outcomes in multidrug‐resistant tuberculosis (MDR‐TB) is partly hampered by inadequate effective antitubercular agents. Development of bedaquiline and delamanid has potentially changed the treatment landscape for MDR‐TB. This review provides an update on the progress of these novel antitubercular agents. We review published studies aimed at evaluating clinical efficacy and effectiveness of bedaquiline and delamanid. Five prospective clinical studies and seven retrospective studies on bedaquiline showed that patients treated with a bedaquiline‐containing regimen had a high culture conversion rate ranging from 65 to 100% and a satisfactory treatment outcome. The combined use with linezolid might add to the effectiveness of bedaquiline. Controversies about bedaquiline resistance are discussed. Three clinical trials have reported outcomes on delamanid and showed that introducing delamanid to a background regimen improved culture conversion rate at 2 months from 29.6% to more than 40%. A higher favorable treatment rate was also observed among patients who received delamanid for more than 6 months, but about a quarter of patients defaulted in the control group. Seven retrospective studies were summarized and found a treatment benefit as well. More reliable evidence from randomized clinical trials reporting on the treatment outcomes is needed urgently to support a strong recommendation for the use of delamanid. Advances in the combined use of bedaquiline and delamanid are also reviewed, and the combination may be well tolerated but requires electrocardiograph monitoring.

Tuberculosis Status and Coinfection of Pulmonary Fungal Infections in Patients Referred to Reference Laboratory of Health Centers Ghaemshahr City during 2007-2017

BACKGROUND

Pulmonary tuberculosis is one of the most important health concerns. Pulmonary fungal infections have clinical and radiological characteristics similar to tuberculosis which may be easily misdiagnosed as tuberculosis. This study aimed to evaluate tuberculosis (TB) status and coinfection of TB with pulmonary fungal infections in patients referred to reference laboratory of health centers Ghaemshahr city during 2007-2017.

METHODS

This cross-sectional study was conducted during eleven years, between 2007-2017, on 3577 patients with suspected TB referred to health centers of Ghaemshahr City. For isolation, sputum smear preparation and Ziehl-Neelson staining in companying with microscopy direct observation and KOH 10% + white Calcofluor staining was used. The culture of fungi was performed on Sabouraud Dextrose agar, Czapek and chrome agar media. Then, data were analyzed using SPSS software (version 16) through Student's t-test, Fisher test, and Odds Ratio. P values <0.05 were considered statistically significant.

RESULTS

Of 3577 patients, 10731 smears were prepared, 3.6% (n=130) of patients were identified as smear-positive pulmonary tuberculosis, 86.4% (n=3090) were smear negative and 10% (n=357) drug-resistant TB. The mean age of patients was 48±1.8 years. With increasing age, the prevalence of TB has increased which was statistically significant (P value <0.05). Prevalence of tuberculosis in the age group over than 57 years in males and females had an ascending trend. Amongst the positive tuberculosis patients, 16/130 cases (12.3%) had the coinfection of TB with fungi microorganisms.

CONCLUSION

Our findings showed the coinfection of fungi agents in patients with tuberculosis that should be considered.

Drug targets exploited in Mycobacterium tuberculosis: Pitfalls and promises on the horizon

Tuberculosis is an ever evolving infectious disease that still claims about 1.8 million human lives each year around the globe. Although modern chemotherapy has played a pivotal role in combating TB, the increasing emergence of drug-resistant TB aligned with HIV pandemic threaten its control. This highlights both the need to understand how our current drugs work and the need to develop new and more effective drugs. TB drug discovery is revisiting the clinically validated drug targets in Mycobacterium tuberculosis using whole-cell phenotypic assays in search of better therapeutic scaffolds. Herein, we review the promises of current TB drug regimens, major pitfalls faced, key drug targets exploited so far in M. tuberculosis along with the status of newly discovered drugs against drug resistant forms of TB. New antituberculosis regimens that use lesser number of drugs, require shorter duration of treatment, are equally effective against susceptible and resistant forms of disease, have acceptable toxicity profiles and behave friendly with anti-HIV regimens remains top most priority in TB drug discovery.

New drugs and regimens for tuberculosis

Since standardized rifampin-based first-line regimens and fluoroquinolone-based second-line regimens were used to treat tuberculosis (TB), unfortunately without timely modification according to the drug resistance profile, TB and drug-resistant disease are still important public health threats worldwide. Although the last decade has witnessed advances in rapid diagnostic tools and use of repurposed and novel drugs for better managing drug-resistant TB, we need an appropriate TB control strategy and a well-functioning health infrastructure to ensure optimal operational use of rapid tests, judicious use of effective treatment regimens that can be rapidly tailored according to the drug resistance profile and timely management of risk factors and co-morbidities that promote infection and its progression to disease. We searched the published literature to discuss (i) standardized versus individualized therapies, including the choice between a single one-size-fit-all regimen versus different options with different key drugs determined mainly by rapid drug susceptibility testing, (ii) alternative regimens for managing drug-susceptible TB, (iii) evidence for using the World Health Organization (WHO) longer and shorter regimens for multidrug-resistant TB and (iv) evidence for using repurposed and novel drugs. We hope an easily applicable combination of biomarkers that accurately predict individual treatment outcome will soon be available to ultimately guide individualized therapy.

Tuberculosis elimination: where are we now?

Tuberculosis (TB) still represents a major public health issue in spite of the significant impact of the efforts made by the World Health Organization (WHO) and partners to improve its control. In 2014 WHO launched a new global strategy (End TB) with a vision of a world free of TB, and a 2035 goal of TB elimination (defined as less than one incident case per million). The aim of this article is to summarise the theoretical bases of the End TB Strategy and to analyse progresses and persistent obstacles on the way to TB elimination.The evolution of the WHO recommended strategies of TB control (Directly Observed Therapy, Short Course (DOTS), Stop TB and End TB) are described and the concept of TB elimination is discussed. Furthermore, the eight core activities recently proposed by WHO as the milestones to achieve TB elimination are discussed in detail. Finally, the recently published experiences of Cyprus and Oman on their way towards TB elimination are described, together with the regional experience of Latin America.New prevention, diagnostic and treatment tools are also necessary to increase the speed of the present TB incidence decline.

Delamanid for rifampicin-resistant tuberculosis: a retrospective study from South Africa

Experience with delamanid (Dlm) is limited, particularly among HIV-positive individuals. We describe early efficacy and safety data from a programmatic setting in South Africa.This was a retrospective cohort study of patients receiving Dlm-containing treatment regimens between November 2015 and August 2017. We report 12-month interim outcomes, sputum culture conversion (SCC) by months 2 and 6, serious adverse events (SAEs) and QT intervals corrected using the Frederica formula (QTcF).Overall, 103 patients were initiated on Dlm; 79 (77%) were HIV positive. The main indication for Dlm was intolerance to second-line anti-tuberculosis (TB) drugs (n=58, 56%). There were 12 months of follow-up for 46 patients; 28 (61%) had a favourable outcome (cure, treatment completion or culture negativity). Positive cultures were found for 57 patients at Dlm initiation; 16 out of 31 (52%) had SCC within 2 months and 25 out of 31 (81%) within 6 months. There were 67 SAEs reported in 29 patients (28%). There were four instances of QTcF prolongation >500 ms in two patients (2%), leading to permanent discontinuation in one case; however, no cardiac arrhythmias occurred.This large cohort of difficult-to-treat patients receiving Dlm for rifampicin-resistant TB treatment in a programmatic setting with high HIV prevalence had favourable early treatment response and tolerated treatment well. Dlm should remain available, particularly for those who cannot be treated with conventional regimens or with limited treatment options.

Discovery of novel anti-tuberculosis agents with pyrrolo[1,2-a]quinoxaline-based scaffold

A series of small molecules with novel pyrrolo[1,2-a]quinoxaline-based scaffold was designed via molecular hybridization of privileged agents active against Mycobacterium tuberculosis. Twenty-three compounds were synthesized and investigated for their antitubercular activities in vitro where ten compounds showed appreciable activities and moderate cytotoxicity. Compound 12g with MIC values of 5 μg/ml as a representative may possess better oral bioavailability and indicated high permeability by the parallel artificial membrane permeation assay of the blood-brain barrier (PAMPA-BBB). Further, the determination of enzyme inhibition and molecular docking study indicated that InhA may be the biological target of the active compounds. The results suggest the pyrrolo[1,2-a]quinoxaline hybrids as potential antitubercular leads for the development of new antitubercular agents.

New and repurposed drugs to treat multidrug- and extensively drug-resistant tuberculosis

Multidrug-resistant and extensively drug-resistant tuberculosis (MDR-TB and XDR-TB, respectively) continue to represent a challenge for clinicians and public health authorities. Unfortunately, although there have been encouraging reports of higher success rates, the overall rate of favorable outcomes of M/XDR-TB treatment is only 54%, or much lower when the spectrum of drug resistance is beyond that of XDR-TB. Treating M/XDR-TB continues to be a difficult task, because of the high incidence of adverse events, the long duration of treatment, the high cost of the regimens used, and the drain on health care resources. Various trials and studies have recently been undertaken (some already published and others ongoing), all aimed at improving outcomes of M/XDR-TB treatment by changing the overall approach, shortening treatment duration, and developing a universal regimen. The objective of this review was to summarize what has been achieved to date, as far as new and repurposed drugs are concerned, with a special focus on delamanid, bedaquiline, pretomanid, clofazimine, carbapenems, and linezolid. After more than 40 years of neglect, greater attention has recently been paid to the need for new drugs to fight the "white plague", and promising results are being reported.

Tuberculosis: progress and advances in development of new drugs, treatment regimens, and host-directed therapies

Tuberculosis remains the world's leading cause of death from an infectious disease, responsible for an estimated 1 674 000 deaths annually. WHO estimated 600 000 cases of rifampicin-resistant tuberculosis in 2016-of which 490 000 were multidrug resistant (MDR), with less than 50% survival after receiving recommended treatment regimens. Concerted efforts of stakeholders, advocates, and researchers are advancing further development of shorter course, more effective, safer, and better tolerated treatment regimens. We review the developmental pipeline and landscape of new and repurposed tuberculosis drugs, treatment regimens, and host-directed therapies (HDTs) for drug-sensitive and drug-resistant tuberculosis. 14 candidate drugs for drug-susceptible, drug-resistant, and latent tuberculosis are in clinical stages of drug development; nine are novel in phase 1 and 2 trials, and three new drugs are in advanced stages of development for MDR tuberculosis. Specific updates are provided on clinical trials of bedaquiline, delamanid, pretomanid, and other licensed or repurposed drugs that are undergoing investigation, including trials aimed at shortening duration of tuberculosis treatment, improving treatment outcomes and patient adherence, and reducing toxic effects. Ongoing clinical trials for shortening tuberculosis treatment duration, improving treatment outcomes in MDR tuberculosis, and preventing disease in people with latent tuberculosis infection are reviewed. A range of HDTs and immune-based treatments are under investigation as adjunctive therapy for shortening duration of therapy, preventing permanent lung injury, and improving treatment outcomes of MDR tuberculosis. We discuss the HDT development pipeline, ongoing clinical trials, and translational research efforts for adjunct tuberculosis treatment.

Bedaquiline and delamanid for the treatment of multidrug-resistant tuberculosis: a multicentre cohort study in Korea

Relatively little is known about the efficacy and safety of the programmatic use of bedaquiline and delamanid in multidrug-resistant tuberculosis (MDR-TB) treatment.

This study evaluated 61 patients with MDR-TB treated with bedaquiline (n=39), delamanid (n=11) or both, either sequentially (n=10) or in coadministration (n=1), for >1 month, combined with a World Health Organization-recommended regimen.

Of these, 49 (80.3%) were male and 12 (19.7%) were female. The median (interquartile range (IQR)) age was 53 (38.5–61.0) years. 42 (68.9%) patients had fluoroquinolone-resistant MDR-TB and 16 (26.2%) had extensively drug-resistant TB. The median (IQR) duration of treatment with bedaquiline and/or delamanid was 168 (166.5–196.5) days, with 33 (54.1%) receiving linezolid for a median (IQR) of 673 (171–736) days. Of the 55 patients with positive sputum cultures at the start of bedaquiline and/or delamanid treatment, 39 (70.9%) achieved sputum culture conversion within a median of 119 days. Treatment was halted in four patients (6.6%) because of prolonged Fridericia's corrected QT interval.

Bedaquiline and delamanid were effective and safe for treating MDR-TB, with initial evidence of sequential administration of these two drugs as a viable treatment strategy for patients when an adequate treatment regimen cannot be constructed.

New drugs and perspectives for new anti-tuberculosis regimens

Tuberculosis (TB) is the ninth cause of global death, more than any other infectious disease. With growing drug resistance the epidemic remains and will require significant attention and investment for the elimination of this disease to occur. With susceptible TB treatment not changing over the last four decades and the advent of drug resistance, new drugs and regimens are required. Recently, through greater collaboration and research networks some progress with significant advances has taken place, not withstanding the comparatively low amount of resources invested. Of late the availability of the new drugs bedaquiline, delamanid and repurposed drugs linezolid, clofazimine and carbapenems are being used more frequently in drug-resistant TB regimens. The WHO shorter multidrug-resistant tuberculosis regimen promises to reach more patients and treat them more quickly and more cheaply. With this new enthusiasm and hope we this review gives an update on the new drugs and perspectives for the treatment of drug-susceptible and drug-resistant tuberculosis.

Early safety and efficacy of the combination of bedaquiline and delamanid for the treatment of patients with drug-resistant tuberculosis in Armenia, India, and South Africa: a retrospective cohort study

BACKGROUND

Bedaquiline and delamanid have been approved for treatment of multidrug-resistant (MDR) tuberculosis in the past 5 years. Because of theoretical safety concerns, patients have been unable to access the two drugs in combination. Médecins Sans Frontières has supported the use of combination bedaquiline and delamanid for people with few treatment options since 2016. We describe early safety and efficacy of regimens containing the bedaquiline and delamanid combination in patients with drug-resistant tuberculosis in Yerevan, Armenia; Mumbai, India; and Khayelitsha, South Africa.

METHODS

We retrospectively analysed a cohort of all patients who received 6-12 months of oral bedaquiline and delamanid in combination (400 mg bedaquiline once per day for 2 weeks, then 200 mg bedaquiline three times per week and 100 mg delamanid twice per day) in MSF-supported projects. We report serious adverse events, QTc corrected using the Fridericia formula (QTcF) interval data, and culture conversion data during the first 6 months of treatment.

FINDINGS

Between Jan 1, 2016, and Aug 31, 2016, 28 patients (median age 32·5 years [IQR 28·5-40·5], 17 men) were included in the analysis. 11 (39%) of 28 patients were HIV-positive. 24 patients (86%) had isolates resistant to fluoroquinolones; 14 patients (50%) had extensively drug-resistant tuberculosis. No patient had an increase of more than 500 ms in their QTcF interval. Four patients (14%) had six instances of QTcF increase of more than 60 ms from baseline but none permanently discontinued the drugs. 16 serious adverse events were reported in seven patients. Of 23 individuals with positive baseline cultures, 17 (74%) converted to negative by month 6 of treatment.

INTERPRETATION

Use of the bedaquiline and delamanid combination appears to reveal no additive or synergistic QTcF-prolonging effects. Access to bedaquiline and delamanid in combination should be expanded for people with few treatment options while awaiting the results of formal clinical trials.

FUNDING

Médecins Sans Frontières (MSF).

Pharmacokinetics and pharmacogenetics of anti-tubercular drugs: a tool for treatment optimization?

INTRODUCTION

WHO global strategy is to end tuberculosis epidemic by 2035. Pharmacokinetic and pharmacogenetic studies are increasingly performed and might confirm their potential role in optimizing treatment outcome in specific settings and populations. Insufficient drug exposure seems to be a relevant factor in tuberculosis outcome and for the risk of phenotypic resistance. Areas covered: This review discusses available pharmacokinetic and pharmacogenetic data of first and second-line antitubercular agents in relation to efficacy and toxicity. Pharmacodynamic implications of optimized drugs and new options regimens are reviewed. Moreover a specific session describes innovative investigations on drug penetration. Expert opinion: The optimal use of available antitubercular drugs is paramount for tuberculosis control and eradication. Whilst trials are still on-going, higher rifampicin doses should be reserved to treatment for tubercular meningitis. Therapeutic Drug Monitoring with limiting sampling strategies is advised in patients at risk of failure or with slow treatment response. Further studies are needed in order to provide definitive recommendations of pharmacogenetic-based individualization: however lower isoniazid doses in NAT2 slow acetylators and higher rifampicin doses in individuals with SLCO1B1 loss of function genes are promising strategies. Finally in order to inform tailored strategies we need more data on tissue drug penetration and pharmacological modelling.

Trends in the discovery of new drugs for Mycobacterium tuberculosis therapy with a glance at resistance

Despite the low expensive and effective four-drug treatment regimen (isoniazid, rifampicin, pyrazinamide and ethambutol) was introduced 40 years ago, TB continues to cause considerable morbidity and mortality worldwide. In 2015, the WHO estimated a total of 10.4 million new tuberculosis (TB) cases worldwide. Currently, the increased number of multidrug-resistant (MDR-TB), extensively-drug resistant (XDR-TB) and in some recent reports, totally drug-resistant TB (TDR-TB) cases raises concerns about this disease. MDR-TB and XDR-TB have lower cure rates and higher mortality levels due to treatment problems. Novel drugs and regimens for all forms of TB have emerged in recent years. Moreover, scientific interest has recently increased in the field of host-directed therapies (HDTs) in order to identify new treatments for MDR-TB. In this review, we offer an update on the discovery of new drugs for TB therapy with a glance at molecular mechanisms leading to drug resistance in Mycobacterium tuberculosis.

Bedaquiline and Delamanid Combination Treatment of 5 Patients with Pulmonary Extensively Drug-Resistant Tuberculosis

We report the experiences of 5 patients taking bedaquiline with delamanid in combination: 1 patient was cured; 3 culture converted, with 2 continuing and 1 changing therapy; and 1 died from respiratory insufficiency. For 2 patients, QT-interval prolongation but no arrhythmias occurred. Use of this therapy is justified for patients with limited options.

New and Repurposed Drugs for Pediatric Multidrug-Resistant Tuberculosis. Practice-based Recommendations

It is estimated that 33,000 children develop multidrug-resistant tuberculosis (MDR-TB) each year. In spite of these numbers, children and adolescents have limited access to the new and repurposed MDR-TB drugs. There is also little clinical guidance for the use of these drugs and for the shorter MDR-TB regimen in the pediatric population. This is despite the fact that these drugs and regimens are associated with improved interim outcomes and acceptable safety profiles in adults. This review fills a gap in the pediatric MDR-TB literature by providing practice-based recommendations for the use of the new (delamanid and bedaquiline) and repurposed (linezolid and clofazimine) MDR-TB drugs and the new shorter MDR-TB regimen in children and adolescents.