Advances of new drugs bedaquiline and delamanid in the treatment of multi-drug resistant tuberculosis in children

Tuberculosis (TB) is a major public health problem, with nearly 10 million new cases and millions of deaths each year. Around 10% of these cases are in children, but only a fraction receive proper diagnosis and treatment. The spread of drug-resistant (DR) strain of TB has made it difficult to control, with only 60% of patients responding to treatment. Multi-drug resistant TB (MDR-TB) is often undiagnosed in children due to lack of awareness or under-diagnosis, and the target for children's DR-TB treatment has only been met in 15% of goals. New medications such as bedaquiline and delamanid have been approved for treating DR-TB. However, due to age and weight differences, adults and children require different dosages. The availability of child-friendly formulations is limited by a lack of clinical data in children. This paper reviews the development history of these drugs, their mechanism of action, efficacy, safety potential problems and current use in treating DR-TB in children.

Early experience of delamanid in extensively drug-resistant pulmonary tuberculosis

Tuberculosis is a leading cause of death in our country. Multidrug-resistant tuberculosis increases the morbidity and mortality due to severe manifestations and difficult and prolonged medications. Newer antitubercular drugs like delamanid have been approved by WHO in management of these cases, but the real-world experience of this drug is lacking in our country. We present our early experience of use of delamanid in extensively drug-resistant pulmonary tuberculosis.

Mechanism of Action, Resistance, Synergism, and Clinical Implications of Delamanid Against Multidrug-Resistant Mycobacterium tuberculosis

Multidrug-resistant (MDR) isolates of Mycobacterium tuberculosis (MTB) remain a primary global threat to the end of tuberculosis (TB) era. Delamanid (DLM) is a nitro-dihydro-imidazooxazole derivative utilized to treat MDR-TB. DLM has distinct mechanism of action, inhibiting methoxy- and keto-mycolic acid (MA) synthesis through the F420 coenzyme mycobacteria system and generating nitrous oxide. While DLM resistance among MTB strains is uncommon, there are increasing reports in Asia and Europe, and such resistance will prolong the treatment courses of patients infected with MDR-TB. In this review, we address the antimycobacterial properties of DLM, report the global prevalence of DLM resistance, discuss the synergism of DLM with other anti-TB drugs, and evaluate the documented clinical trials to provide new insights into the clinical use of this antibiotic.

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.

Culture Conversion at 6 Months in Patients Receiving Delamanid-containing Regimens for the Treatment of Multidrug-resistant Tuberculosis

Delamanid should be effective against highly resistant strains of Mycobacteriumtuberculosis, but uptake has been slow globally. In the endTB (expand new drug markets for TB) Observational Study, which enrolled a large, heterogeneous cohorts of patients receiving delamanid as part of a multidrug regimen, 80% of participants experienced sputum culture conversion within 6 months. Clinical Trials Registration. NCT02754765.

Integration of drug safety monitoring in tuberculosis treatment programmes: country experiences

New drugs and shorter treatments for drug-resistant tuberculosis (DR-TB) have become available in recent years and active pharmacovigilance (PV) is recommended by the World Health Organization (WHO) at least during the early phases of implementation, with active drug safety monitoring and management (aDSM) proposed for this. We conducted a literature review of papers reporting on aDSM. Up to 18 April, 2019, results have only been published from one national aDSM programme. Because aDSM is being introduced in many low- and middle-income countries, we also report experiences in introducing it into DR-TB treatment programmes, targeting the reporting of a restricted set of adverse events (AEs) as per WHO-recommended aDSM principles for the period 2014-2017. Early beneficial effects of active PV for TB patients include increased awareness about the occurrence, detection and management of AEs during TB treatment, and the increase of spontaneous reporting in some countries. However, because PV capacity is low in most countries and collaboration between national TB programmes and national PV centres remains weak, parallel and coordinated co-development of the capacities of both TB programmes and PV centres is needed.

[Multidrug-resistant tuberculosis: A management problem that weighs heavily on the University Hospitals of Strasbourg]

INTRODUCTION

Multidrug-resistant tuberculosis (MDR-TB) is a major public health problem with great regional disparities. The aim of this study was to describe the epidemiological, clinical, and therapeutics aspects of MDR-TB in Alsace, France.

PATIENTS AND METHODS

A 10 years retrospective study, conducted for the years 2006 to 2016, of all MDR-TB cases diagnosed in Alsace and particularly in Strasbourg University Hospitals.

RESULTS

We included 22 patients with MDR-TB of whom 90% originated from Eastern Europe, 13.6% had extensively-resistant strains, and 41% reported previously treated tuberculosis. Clinically, 86,4% had a pulmonary form of tuberculosis. The mean length of antibiotic treatment was 21 months with several changes of drugs because of severe side effects. The mean follow-up was 48 months, during which time 2 patients were lost from contact and the 20 remaining patients were cured.

CONCLUSIONS

Management of MDR-TB is a real social and medical challenge. Our study shows that the therapeutic protocols used in the management of these patients lead to an unusually high rate of success despite the occurrence of several, sometimes severe, side effects.

In Vitro Activity of Bedaquiline and Delamanid against Nontuberculous Mycobacteria, Including Macrolide-Resistant Clinical Isolates

We evaluated the in vitro activities of the antimicrobial drugs bedaquiline and delamanid against the major pathogenic nontuberculous mycobacteria (NTM). Delamanid showed high MIC values for all NTM except Mycobacterium kansasii However, bedaquiline showed low MIC values for the major pathogenic NTM, including Mycobacterium avium complex, Mycobacterium abscessus subsp. abscessus, M. abscessus subsp. massiliense, and M. kansasii Bedaquiline also had low MIC values with macrolide-resistant NTM strains and warrants further investigation as a potential antibiotic for NTM treatment.

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.

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.

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.