Safety and efficacy of exposure to bedaquiline−delamanid in multidrug-resistant tuberculosis: a case series from France and Latvia

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.

Real-life use of delamanid: results from the European post-authorisation safety study

BACKGROUND

A post-authorisation safety study (PASS) on delamanid (DLM) was conducted as part of a post-approval commitment to the European Medicines Agency. The aim of this study was to evaluate the use of DLM in a real-life setting, its safety, and treatment outcomes in patients with multidrug-resistant TB (MDR-TB).

METHODS

This was a prospective, multicentric, non-interventional study conducted in the European Union. MDR-TB Regimen selection and patient monitoring were conducted in accordance with existing medical practices. Data on the use of DLM, related adverse events, and treatment outcomes were collected for up to 30 months after the first DLM dose. Descriptive summary statistics were used for continuous and categorical variables.

RESULTS

Out of 86 patients, one had extrapulmonary TB. Two-thirds of the patients were treated with DLM for more than 24 weeks. The most frequent adverse drug reaction to DLM was QT interval prolongation. Resistance to DLM was detected in one patient during treatment. The treatment success rate was 77%.

CONCLUSION

No new safety concerns were revealed, including in patients treated with DLM for more than 24 weeks. QT interval prolongations were well managed and did not lead to any clinically significant cardiac effects. The treatment outcomes were in line with the WHO target for Europe.

Concomitant bedaquiline and delamanid therapy in patients with drug-resistant extra-pulmonary tuberculosis in Mumbai, India

Background

World Health Organization suggests concurrent bedaquiline-delamanid (BDQ-DLM) as part of individualised regimens for eligible patients with pulmonary drug-resistant tuberculosis (DR-TB); however, data for patients with drug-resistant extrapulmonary tuberculosis (EPTB) is extremely limited. This study documents the treatment outcomes and adverse events associated with concurrent BDQ-DLM-based regimens in patients with drug-resistant EPTB at a Médecins Sans Frontières clinic in Mumbai, India.

Methods

Retrospective cohort study based on routinely collected programmatic data. Individualised regimens were based on drug-susceptibility testing and previous drug exposure. Drug-resistant EPTB patients initiated on regimens containing concurrent BDQ and DLM from April 2016 to October 2019 were included. Patients who completed treatment were followed up at 12 months.

Results

Of 17 patients, median age was 23 years (IQR = 21-30 years) and 12/17 (71 %) were female. Pre-extensively drug-resistant tuberculosis and extensively drug-resistant TB was reported in 13/17 (76.4 %) and 2/17 (11.7 %) patients respectively. Microbiological reports were unavailable for two patients with central nervous system TB. Lymph node TB was the commonest form of EPTB in 9/17 (53 %) of patients. Median duration of treatment was 18.9 months. At least one grade three or four severe adverse event (SAE) was reported by 13/17 (76.4 %) patients. Thirteen (76.4 %) patients had favourable outcomes. None of the patients relapsed or died in the one-year period of post-treatment follow-up.

Conclusion

Concurrent BDQ-DLM-based regimens in drug-resistant EPTB were effective and associated with manageable adverse events.

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.

The Cost-Effectiveness of the BEAT-TB Regimen for Pre-Extensively Drug-Resistant TB

OBJECTIVE

To measure the economic impacts of the longer pre-XDR-TB treatment regimen and the shorter BEAT-TB India regimen.

METHODS

In the current study, the economic impacts of the current 18-month pre-XDR-TB treatment regimen and the 6-9 month BEAT-TB regimen were evaluated using an economic model via a decision tree analysis from a societal perspective. The incremental costs and quality-adjusted life years (QALYs) gained from the introduction of the BEAT-TB regimen for pre-XDR-TB patients were estimated.

RESULTS

For a cohort of 1000 pre-XDR-TB patients, we found that the BEAT-TB India regimen yielded higher undiscounted life years (40,548 vs. 21,009) and more QALYs gained (27,633 vs. 15,812) than the 18-month regimen. The BEAT-TB India regimen was found to be cost-saving, with an incremental cost of USD -128,651 when compared to the 18-month regimen. The current analysis did not consider the possibility of reduced TB recurrence after use of the BEAT-TB regimen, so it might have under-estimated the benefits.

CONCLUSION

As a lower-cost intervention with improved health outcomes, the BEAT-TB India regimen is dominant when compared to the 18-month regimen.

Bedaquiline, Delamanid, Linezolid and Clofazimine for Treatment of Pre-extensively Drug-Resistant Tuberculosis

BACKGROUND

Treatment success rates for multidrug-resistant tuberculosis (MDR-TB) remain low globally. Availability of newer drugs has given scope to develop regimens that can be patient-friendly, less toxic, with improved outcomes. We proposed to determine the effectiveness of an entirely oral, short-course regimen with Bedaquiline and Delamanid in treating MDR-TB with additional resistance to fluoroquinolones (MDR-TBFQ+) or second-line injectable (MDR-TBSLI+).

METHODS

We prospectively determined the effectiveness and safety of combining two new drugs with two repurposed drugs - Bedaquiline, Delamanid, Linezolid, and Clofazimine for 24-36 weeks in adults with pulmonary MDR-TBFQ+ or/and MDR-TBSLI+. The primary outcome was a favorable response at end of treatment, defined as two consecutive negative cultures taken four weeks apart. The unfavorable outcomes included bacteriologic or clinical failure during treatment period.

RESULTS

Of the 165 participants enrolled, 158 had MDR-TBFQ+. At the end of treatment, after excluding 12 patients due to baseline drug susceptibility and culture negatives, 139 of 153 patients (91%) had a favorable outcome. Fourteen patients (9%) had unfavorable outcomes: four deaths, seven treatment changes, two bacteriological failures, and one withdrawal. During treatment, 85 patients (52%) developed myelosuppression, 69 (42%) reported peripheral neuropathy, and none had QTc(F) prolongation >500msec. At 48 weeks of follow-up, 131 patients showed sustained treatment success with the resolution of adverse events in the majority.

CONCLUSION

After 24-36 weeks of treatment, this regimen resulted in a satisfactory favorable outcome in pulmonary MDR-TB patients with additional drug resistance. Cardiotoxicity was minimal, and myelosuppression, while common, was detected early and treated successfully.

MDR Tuberculosis Treatment

Multidrug-resistant (MDR) tuberculosis (TB), resistant to isoniazid and rifampicin, continues to be one of the most important threats to controlling the TB epidemic. Over the last few years, there have been promising pharmacological advances in the paradigm of MDR TB treatment: new and repurposed drugs have shown excellent bactericidal and sterilizing activity against Mycobacterium tuberculosis and several all-oral short regimens to treat MDR TB have shown promising results. The purpose of this comprehensive review is to summarize the most important drugs currently used to treat MDR TB, the recommended regimens to treat MDR TB, and we also summarize new insights into the treatment of patients with MDR TB.

OUP accepted manuscript

Background

Drug-resistant tuberculosis (DR-TB) is considered to be a public health threat and is difficult to cure, requiring a lengthy treatment with potent, potentially toxic drugs. The novel antimicrobial agent bedaquiline has shown promising results for patients with DR-TB, improving the rate of culture conversion and reducing TB-related mortality. However, increasing numbers of cases with acquired bedaquiline resistance (ABR) have been reported in recent years.

Methods

This systematic review aimed to assess the frequency of ABR and characteristics of patients acquiring it. Studies showing data on sequential bedaquiline drug-susceptibility testing in patients treated with a bedaquiline-containing regimen were included. The databases CENTRAL, PubMed and Embase were manually searched, and 866 unique records identified, eventually leading to the inclusion of 13 studies. Phenotypic ABR was assessed based on predefined MIC thresholds and genotypic ABR based on the emergence of resistance-associated variants.

Results

The median (IQR) frequency of phenotypic ABR was 2.2% (1.1%–4.6%) and 4.4% (1.8%–5.8%) for genotypic ABR. Among the studies reporting individual data of patients with ABR, the median number of likely effective drugs in a treatment regimen was five, in accordance with WHO recommendations. In regard to the utilization of important companion drugs with high and early bactericidal activity, linezolid was included in the regimen of most ABR patients, whereas the usage of other group A (fluoroquinolones) and former group B drugs (second-line injectable drugs) was rare.

Conclusions

Our findings suggest a relevant frequency of ABR, urging for a better protection against it. Therefore, treatment regimens should include drugs with high resistance-preventing capacity through high and early bactericidal activity.

One Step Forward: Successful End-of-Treatment Outcomes of Patients With Drug-Resistant Tuberculosis Who Received Concomitant Bedaquiline and Delamanid in Mumbai, India

BACKGROUND

The Médecins Sans Frontières Clinic in Mumbai, India, has been providing concomitant bedaquiline (BDQ) and delamanid (DLM) in treatment regimen for patients with drug-resistant tuberculosis (DR-TB) and limited therapeutic options, referred from other healthcare institutions, since 2016. The study documents the end-of-treatment outcomes, culture-conversion rates, and serious adverse events (SAEs) during treatment.

METHODS

This was a retrospective cohort study based on routinely collected program data. In clinic, treatment regimens are designed based on culture drug sensitivity test patterns and previous drug exposures, and are provided for 20-22 months. BDQ and DLM are extended beyond 24 weeks as off-label use. Patients who initiated DR-TB treatment including BDQ and DLM (concomitantly for at least 4 weeks) during February 2016-February 2018 were included.

RESULTS

Of the 70 patients included, the median age was 25 (interquartile range [IQR], 22-32) years and 56% were females. All except 1 were fluoroquinolone resistant. The median duration of exposure to BDQ and DLM was 77 (IQR, 43-96) weeks. Thirty-nine episodes of SAEs were reported among 30 (43%) patients, including 5 instances of QTc prolongation, assessed as possibly related to BDQ and/or DLM. The majority (69%) had culture conversion before 24 weeks of treatment. In 61 (87%), use of BDQ and DLM was extended beyond 24 weeks. Successful end-of-treatment outcomes were reported in 49 (70%) patients.

CONCLUSIONS

The successful treatment outcomes of this cohort show that regimens including concomitant BDQ and DLM for longer than 24 weeks are effective and can be safely administered on an ambulatory basis. National TB programs globally should scale up access to life-saving DR-TB regimens with new drugs.

Adverse effects induced by second-line antituberculosis drugs: an update based on last WHO treatment recommendations for drug-resistant tuberculosis

Introduction: Tuberculosis (TB), a common condition worldwide, is still among the main infectious diseases with high mortality rates, both in adults and infants. Drug-resistant tuberculosis (DR-TB) drugs, revised by the World Health Organization (WHO) in 2018, are a prolonged and complex therapy associated with many adverse drug effects (ADEs).

Aim: To systematically review the ADEs of second-line anti-TB drugs reported in multicentric studies published after the latest WHO guidelines, compared with those from clinical trials published before 2018.

Material and methods: A PubMed search, using keywords (TB OR DR-TB) AND (adverse effects) AND “second-line anti-TB drugs”, resulted in 56 studies. Only two studies, published after the last update of WHO guidelines in 2018, reported ADEs.

Results: A total of 223 participants were included in the two selected studies. The use of multidrug regimens has been associated with an increased incidence of ADEs: 42 ADEs were recorded in 30 patients (26.3%) in the first study, while all patients had at least one ADE that occurred or worsened during treatment; and 19 (17%) had severe ADEs in the second study. However, both studies had a good favourable outcome rate (90% and 79.8%, respectively). Gastrointestinal disturbances, hepatotoxicity, headache and dizziness are the most common ADEs induced by a majority of second-line DR-TB treatments. A special attention should be given in the case of association of drugs determining QT interval (QT) prolongation on electrocardiogram, or psychiatric disorders.

Conclusions: Proper strategies about ADE management have to be planned for timely detection of the possible ADEs that can be induced by second-line anti-TB therapy.

INCIDENCE OF HIGH GRADE QTCF PROLONGATION AND ITS MANAGEMENT AMONG PATIENTS UNDERGOING TREATMENT FOR DRUG RESISTANT TUBERCULOSIS (DR-TB): CASE SERIES

BACKGROUND

The World Health Organization (WHO) has approved the use of two new drugs, namely Bedaquiline (Bdq) and Delamanid (Dlm), for treatment of Drug Resistant Tuberculosis (DR-TB). One of the concerns raised with the use of these drugs was QT-interval prolongation. This condition could be serious and life threatening. Hence, knowing the magnitude and its management is very important. This case series identifies the incidence and discusses the management of clinically significant QT-interval prolongation amongst a cohort of patients who have been on these medicines.

MATERIALS AND METHODS

Patients with reports of high grade QT-Interval prolongation (i.e. Grade-3 and Grade-4) were identified from the cohort of 265 patients enrolled on bedaquiline and/or delamanid and discussion is made on the pattern, severity and management of each cases identified.

RESULTS

Only 4 (1.5%) out of all 265 patients enrolled on Bedaquiline and/or Delamanid have developed high grade QT-Interval prolongation. And all are managed without permanent discontinuation of both drugs.

CONCLUSION

The Incidence of clinically significant QTcF-interval prolongation among DR-TB patients taking bedaquiline and /or delamanid in Lesotho is low. And almost all cases can be managed with more frequent Electrocardiogram (ECG) monitoring and management of other possible causes of QT-interval prolongation without the need to stop one or both drugs permanently.

Impact of bedaquiline on treatment outcomes of multidrug-resistant tuberculosis in a high-burden country

BACKGROUND

Evaluation of novel anti-tuberculosis (TB) drugs for the treatment of multidrug-resistant (MDR)-TB continues to be of high interest on the TB research agenda. We assessed treatment outcomes in patients with pulmonary MDR-TB who received bedaquiline-containing treatment regimens in the Republic of Moldova, a high-burden MDR-TB country.

METHOD

We systematically analysed the SIMETB national electronic TB database and performed a retrospective propensity score-matched comparison of treatment outcomes in a cohort of patients with MDR-TB who started treatment during 2016-2018 with a bedaquiline-containing regimen (bedaquiline cohort) and a cohort of patients treated without bedaquiline (non-bedaquiline cohort).

RESULTS

Following propensity score matching, 114 patients were assigned to each cohort of MDR-TB patients. Patients in the bedaquiline cohort had a higher 6-month sputum culture conversion rate than those in the non-bedaquiline cohort (66.7% versus 40.3%; p<0.001). Patients under bedaquiline-containing regimens had a higher cure rate assessed by both World Health Organization (WHO) and TBnet definitions (55.3% versus 24.6%; p=0.001 and 43.5% versus 19.6%; p=0.004, respectively), as well as a lower mortality rate (8.8% versus 20.2%; p<0.001 and 10.9% versus 25.2%; p=0.01, respectively). In patients who previously failed on MDR-TB treatment, >40% of patients achieved a cure with a bedaquiline-containing regimen.

CONCLUSIONS

Bedaquiline-based MDR-TB treatment regimens result in better disease resolution when compared with bedaquiline-sparing MDR-TB treatment regimens under programmatic conditions in a country with a high burden of MDR-TB.

Computational and Biological Investigations on Abl1 Tyrosine Kinase: A Review

Abl1 tyrosine kinase is a validated target for the treatment of chronic myeloid leukemia. It is a form of cancer that is difficult to treat and much research is being done to identify new molecular entities and to tackle drug resistance issues. In recent years, drug resistance of Abl1 tyrosine kinase has become a major healthcare concern. Second and third-generation TKI reported better responses against the resistant forms; still they had no impact on long-term survival prolongation. New compounds derived from natural products and organic small molecule inhibitors can lay the foundation for better clinical therapies in the future. Computational methods, experimental and biological studies can help us understand the mechanism of drug resistance and identify novel molecule inhibitors. ADMET parameters analysis of reported drugs and novel small molecule inhibitors can also provide valuable insights. In this review, available therapies, point mutations, structure-activity relationship and ADMET parameters of reported series of Abl1 tyrosine kinase inhibitors and drugs are summarised. We summarise in detail recent computational and molecular biology studies that focus on designing drug molecules, investigation of natural product compounds and organic new chemical entities. Current ongoing research suggests that selective targeting of Abl1 tyrosine kinase at the molecular level to combat drug resistance in chronic myeloid leukemia is promising.

Treatment interruption patterns and adverse events among patients on bedaquiline containing regimen under programmatic conditions in India

BACKGROUND

The study aimed to analyze frequency and severity of adverse events (AEs) and other reasons for interruption of treatment and loss to follow up (LTFU) during first six months of treatment among tuberculosis patients on bedaquiline containing regimens.

METHODS

This pilot exploratory observational study included 275 patients enrolled consecutively over two years who received bedaquiline containing regimen under programmatic conditions in India.

RESULTS

Among 275 patients with median age of 25 years, 86 (31.3%) patients had at least one interruption with 122 total episodes of interruption. Among these 70 were temporary, 35 were permanent interruptions and 17 were LTFU. The AEs due to drugs were the commonest reason for interruption observed in 81.4% of temporary interruption group and 97.1% of permanent interruption group. Among a total 192 adverse event episodes, (49.5%) were minor (grade 1-2) and (50.5%) were serious (grade 3-5). Personal factors were the commonest reason for interruption observed in LTFU (94.1%) group. The most common temporarily interrupted drug was bedaquiline in 8.7% and permanently stopped drug was linezolid in 5% of patients.

CONCLUSIONS

Our study observed that drug related AEs are important risk factors associated with treatment interruptions in bedaquiline containing regimens. Bedaquiline is the most common temporarily interrupted drug due to AEs.

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.

Interim treatment outcomes in multidrug-resistant tuberculosis patients treated sequentially with bedaquiline and delamanid

OBJECTIVES

The objective of this study was to evaluate the efficacy and safety of the sequential use of bedaquiline (Bdq) and delamanid (Dlm) in patients with multidrug-resistant tuberculosis (MDR-TB) and limited treatment options.

METHODS

This study evaluated 74 MDR-TB patients treated between March 2016 and December 2018 with Bdq followed by Dlm (n = 22), or vice versa (n= 52), combined with optimized background regimens.

RESULTS

The mean age of the participants was 49.0 ± 15.8 years. Fifty-one (68.9%) of the participants were male. Fluoroquinolone resistance was identified in 54 (72.9%) patients, including 20 (27.0%) with extensively drug-resistant TB. Of the 47 (63.5%) patients with positive cultures at the commencement of the first new drug, culture conversion occurred in 44 (93.6%). The interim treatment outcome after 12 months was favourable in 68/74 patients (91.9%). Twenty-four weeks of treatment were completed in 137 of 148 episodes of new drug use (92.3%). Regarding the 11 early discontinuation events, six patients stopped using a new drug due to adverse drug reactions that were not life-threatening, including one (1.4%) who stopped Bdq due to QT-prolongation.

CONCLUSIONS

Sequential use of the two new drugs appears to be an effective and safe option for MDR-TB patients with few treatment options.

Precision medicine in the clinical management of respiratory tract infections including multidrug-resistant tuberculosis: learning from innovations in immuno-oncology

PURPOSE OF REVIEW

In the light of poor management outcomes of antibiotic-resistant respiratory tract infection (RTI)-associated sepsis syndrome and multidrug-resistant tuberculosis (MDR-TB), new management interventions based on host-directed therapies (HDTs) are warranted to improve morbidity, mortality and long-term functional outcomes. We review developments in potential HDTs based on precision cancer therapy concepts applicable to RTIs including MDR-TB.

RECENT FINDINGS

Immune reactivity, tissue destruction and repair processes identified during studies of cancer immunotherapy share common pathogenetic mechanisms with RTI-associated sepsis syndrome and MDR-TB. T-cell receptors (TCRs) and chimeric antigen receptors targeting pathogen-specific or host-derived mutated molecules (major histocompatibility class-dependent/ major histocompatibility class-independent) can be engineered for recognition by TCR γδ and natural killer (NK) cells. T-cell subsets and, more recently, NK cells are shown to be host-protective. These cells can also be activated by immune checkpoint inhibitor (ICI) or derived from allogeneic sources and serve as potential for improving clinical outcomes in RTIs and MDR-TB.

SUMMARY

Recent developments of immunotherapy in cancer reveal common pathways in immune reactivity, tissue destruction and repair. RTIs-related sepsis syndrome exhibits mixed immune reactions, making cytokine or ICI therapy guided by robust biomarker analyses, viable treatment options.

New Drugs for the Treatment of Tuberculosis

Tuberculosis (TB) has now surpassed HIV as the leading infectious cause of death, and treatment success rates are declining. Multidrug-resistant TB, extensively drug-resistant TB, and even totally drug-resistant TB threaten to further destabilize disease control efforts. The second wave in TB drug development, which includes the diarylquinoline, bedaquiline, and the nitroimidazoles delamanid and pretomanid, may offer options for simpler, shorter, and potentially all-oral regimens to treat drug-resistant TB. The "third wave" of TB drug development includes numerous promising compounds, including less toxic versions of older drug classes and candidates with novel mechanisms of action.

Drug-associated adverse events in the treatment of multidrug-resistant tuberculosis: an individual patient data meta-analysis

BACKGROUND

Treatment of multidrug-resistant tuberculosis requires long-term therapy with a combination of multiple second-line drugs. These drugs are associated with numerous adverse events that can cause severe morbidity, such as deafness, and in some instances can lead to death. Our aim was to estimate the absolute and relative frequency of adverse events associated with different tuberculosis drugs to provide useful information for clinicians and tuberculosis programmes in selecting optimal treatment regimens.

METHODS

We did a meta-analysis using individual-level patient data that were obtained from studies that reported adverse events that resulted in permanent discontinuation of anti-tuberculosis medications. We used a database created for our previous meta-analysis of multidrug-resistant tuberculosis treatment and outcomes, for which we did a systematic review of literature published between Jan 1, 2009, and Aug 31, 2015 (updated April 15, 2016), and requested individual patient-level information from authors. We also considered for this analysis studies contributing patient-level data in response to a public call made by WHO in 2018. Meta-analysis for proportions and arm-based network meta-analysis were done to estimate the incidence of adverse events for each tuberculosis drug.

FINDINGS

58 studies were identified, including 50 studies from the updated individual patient data meta-analysis for multidrug-resistant tuberculosis treatment. 35 of these studies, with 9178 patients, were included in our analysis. Using meta-analysis of proportions, drugs with low risks of adverse event occurrence leading to permanent discontinuation included levofloxacin (1·3% [95% CI 0·3-5·0]), moxifloxacin (2·9% [1·6-5·0]), bedaquiline (1·7% [0·7-4·2]), and clofazimine (1·6% [0·5-5·3]). Relatively high incidence of adverse events leading to permanent discontinuation was seen with three second-line injectable drugs (amikacin: 10·2% [6·3-16·0]; kanamycin: 7·5% [4·6-11·9]; capreomycin: 8·2% [6·3-10·7]), aminosalicylic acid (11·6% [7·1-18·3]), and linezolid (14·1% [9·9-19·6]). Risk of bias in selection of studies was judged to be low because there were no important differences between included and excluded studies. Variability between studies was significant for most outcomes analysed.

INTERPRETATION

Fluoroquinolones, clofazimine, and bedaquiline had the lowest incidence of adverse events leading to permanent drug discontinuation, whereas second-line injectable drugs, aminosalicylic acid, and linezolid had the highest incidence. These results suggest that close monitoring of adverse events is important for patients being treated for multidrug-resistant tuberculosis. Our results also underscore the urgent need for safer and better-tolerated drugs to reduce morbidity from treatment itself for patients with multidrug-resistant tuberculosis.

FUNDING

Canadian Institutes of Health Research, Centers for Disease Control and Prevention (USA), American Thoracic Society, European Respiratory Society, and Infectious Diseases Society of America.

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.

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.

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.