Scanned: The global investments in computer-aided detection and ultraportable X-ray for tuberculosis
BACKGROUND
Bedaquiline (BDQ) resistance presents a critical challenge in the fight against tuberculosis (TB), particularly multidrug-resistant (MDR) strains. The emergence of resistance to BDQ, a key drug in treating MDR-TB, poses significant threats to TB treatment effectiveness.
METHODS
The National Institute of Tuberculosis and Respiratory Diseases in Delhi and the Médecins Sans Frontières clinic in Mumbai provide BDQ, delamanid, and carbapenem-based regimens for patients with suspected or confirmed treatment failure. BDQ phenotypic drug-susceptibility testing (DST) was performed for all BDQ-exposed patients. Treatment regimens were individualized based on exposure history, comorbidities, drug interactions, prior adverse drug reactions, and DST results.
RESULTS
Of 117 BDQ-exposed patients from December 2020–December 2022, 42 (36%) exhibited a BDQ-resistant strain. Median (IQR) age was 24 (22–32) years, with 63 (54%) females and 94% with pulmonary TB. Patients with a BDQ-resistant strain were older (median age: 27 vs 23 years; P = .04), more likely to have lung cavities (risk ratio [RR]: 1.8; 95%-CI: 1.1–3.1; P = .02), and be resistant to clofazimine (RR: 2.3; 95%-CI: 1.5–3.6; P = .001). Overall, 102 patients initiated treatment. Patients with BDQ-resistance had higher risk of unfavorable outcomes compared with BDQ-susceptible patients (RR:2.1; 95%-CI: 1.5–2.8; P < .001). Overall, 87% (33/38) of patients with BDQ-resistance experienced unfavorable treatment outcomes: 15 (40%) died, 15 (40%) had treatment failure, and 3 (8%) were lost-to-follow-up.
CONCLUSIONS
The study highlights a concerning rate of BDQ-resistance among previously treated patients, resulting in poor treatment outcomes. To prevent treatment failure, we recommend implementing BDQ-DST, developing affordable and accurate rapid tests for BDQ-resistance, and intensifying research and development efforts for newer TB drugs.
BACKGROUND
Only 63% of patients initiating multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB) treatment in 2020 were treated successfully. 24-Week all-oral bedaquiline, pretomanid, and linezolid (BPaL)–based regimens have demonstrated higher rates of treatment success and have been recommended by the World Health Organization. Operational research is urgently required to evaluate these regimens in non-trial settings.
METHODS
This was a prospective cohort study of patients with microbiologically confirmed MDR/RR-TB and pre–extensively drug-resistant TB (pre-XDR-TB) initiated on BPaL-based regimens in Belarus and Uzbekistan (February 2022–June 2023). All clinical care and research procedures were delivered by treating physicians. After treatment completion, patients were followed up at 6 and 12 months, including collecting sputum to ascertain recurrence. The primary objective was to estimate the effectiveness (cured or treatment completed) and safety (the occurrence of serious adverse events) of BPaL-based regimens.
RESULTS
A total of 677 patients initiated treatment with BPaL-based regimens during the study. We documented successful treatment outcomes in 95.3% (427/448) of patients with MDR/RR-TB treated with BPaL plus moxifloxacin and 90.4% (207/229) of patients with pre–XDR-TB treated with BPaL plus clofazimine. 10.2% (69/677) experienced serious adverse events including 24 deaths (3.5%), 11 of which occurred during treatment. 83.3% (20/24) of deaths were not related to TB or TB treatment. Of patients who were successfully treated and completed 12-month follow-up, 0.5% (2/383) had recurrence.
CONCLUSIONS
BPaL-based regimens for MDR/RR-TB and pre–XDR-TB are safe and highly effective in non-trial settings. These regimens should be considered for widespread implementation globally, and further research is needed to evaluate their performance in other key populations.
BACKGROUND
There are few data on the treatment of children and adolescents with multidrug-resistant (MDR) or rifampicin-resistant (RR) tuberculosis, especially with more recently available drugs and regimens. We aimed to describe the clinical and treatment characteristics and their associations with treatment outcomes in this susceptible population.
METHODS
We conducted a systematic review and individual participant data meta-analysis. Databases were searched from Oct 1, 2014, to March 30, 2020. To be eligible, studies must have included more than five children or adolescents (0-19 years of age) treated for microbiologically confirmed or clinically diagnosed MDR or RR tuberculosis within a defined treatment cohort, and reported on regimen composition and treatment outcomes. Abstracts were screened independently by two authors to identify potentially eligible records. Full texts were reviewed by two authors independently to identify studies meeting the eligiblity criteria. For studies meeting eligiblity criteria, anonymised individual patient data was requested and individiual level data included for analysis. The main outcome assessed was treatment outcome defined as treatment success (cure or treatment completed) versus unfavourable outcome (treatment failure or death). Multivariable logistic regression models were used to identify associations between clinical and treatment factors and treatment outcomes. This study is registered with Prospero (CRD42020187230).
FINDINGS
1417 studies were identified through database searching. After removing duplicates and screening for eligibility, the search identified 23 369 individual participants from 42 studies, mostly from India and South Africa. Overall, 16 825 (72·0%) were successfully treated (treatment completed or cured), 2848 died (12·2%), 722 (3·1%) had treatment failure, and 2974 (12·7%) were lost to follow-up. In primary analyses, the median age was 16 (IQR 13-18) years. Of the 17 764 (87·1%) participants with reported HIV status, 2448 (13·8%) were living with HIV. 17 707 (89·6%) had microbiologically confirmed tuberculosis. After adjusting for significant factors associated with treatment outcome, the use of two (adjusted odds ratio [OR] 1·41 [95% CI 1·09-1·82]; p=0·008) or three (2·12 [1·61-2·79]; p<0·0001) WHO-classified group A drugs (bedaquiline, moxifloxacin, levofloxacin, and linezolid) compared with the use of no group A drugs at all was positively associated with treatment success.
INTERPRETATION
Younger and clinically diagnosed children are underrepresented among those treated for MDR and RR tuberculosis and should be a focus for case-finding efforts. Overall treatment outcomes in our analysis were better than in adults but lower than the international targets of 90% or more individuals successfully treated. Treatment with more group A drugs was associated with better treatment outcomes in children and adolescents, highlighting the need for more rapid access to these drugs and improved regimens.
BACKGROUND
New 6-month rifampicin-resistant tuberculosis treatment regimens containing bedaquiline, pretomanid, and linezolid (BPaL) with or without moxifloxacin or clofazimine, could improve treatment efficacy, safety, and tolerability, and free up resources within the health system. Following a change to WHO rifampicin-resistant tuberculosis treatment guidelines, countries are facing difficult decisions about when and how to incorporate new drug regimens into national guidelines. We aimed to assess the probability of BPaL-based regimens being cost-saving using data collected in the TB-PRACTECAL trial.
METHODS
This economic evaluation using a cost-utility analysis was embedded in five TB-PRACTECAL trial sites in Belarus, Uzbekistan, and South Africa. Between Nov 19, 2020, and Sept 27, 2022, we collected detailed primary unit cost data in six hospitals and four ambulatory health facilities and collected data on patient-incurred costs from 73 trial participants. The primary efficacy endpoint of the main trial, a composite of unfavourable outcomes (death, disease recurrence, treatment failure, early discontinuation of therapy, withdrawal, or loss to follow-up) and clinically important safety outcomes by 72 weeks of follow-up were incorporated into the analysis. Societal perspective cost data and effect outcome data were input into a Markov model to estimate the cost per disability-adjusted life-year (DALY) averted by BPaL-based regimens compared with the standard of care over a 20-year time horizon. We conducted a range of univariate and probabilistic sensitivity analyses to test our findings.
FINDINGS
BPaL-based regimens averted a mean of 1·28 DALYs and saved a mean of US$14 868 (SD 291) per person from the provider perspective compared with standard-of-care regimens over 20 years. Patient-incurred costs were reduced by a mean of $172 (SD 0·84) in BPaL-based regimen groups compared with standard of care. The main cost drivers for both providers and patients were inpatient bed-days; the duration of the inpatient period varied across countries. Varying a range of model parameters affected the degree of cost savings but did not change the finding that BPaL-based regimens are cost-saving compared with standard of care.
INTERPRETATION
This trial-based evidence adds to consistent indications from modelling studies that BPaL-based regimens are cost-saving for both the patient and health system. Urgent implementation of BPaL-based regimens in countries with a high burden of tuberculosis could improve treatment of rifampicin-resistant tuberculosis, reduce pill burden, and free up desperately needed resources within the health system.
BACKGROUND
For decades, poor treatment options and low-quality evidence plagued care for patients with rifampin-resistant tuberculosis. The advent of new drugs to treat tuberculosis and enhanced funding now permit randomized, controlled trials of shortened-duration, all-oral treatments for rifampin-resistant tuberculosis.
METHODS
We conducted a phase 3, multinational, open-label, randomized, controlled noninferiority trial to compare standard therapy for treatment of fluoroquinolone-susceptible, rifampin-resistant tuberculosis with five 9-month oral regimens that included various combinations of bedaquiline (B), delamanid (D), linezolid (L), levofloxacin (Lfx) or moxifloxacin (M), clofazimine (C), and pyrazinamide (Z). Participants were randomly assigned (with the use of Bayesian response-adaptive randomization) to receive one of five combinations or standard therapy. The primary end point was a favorable outcome at week 73, defined by two negative sputum culture results or favorable bacteriologic, clinical, and radiologic evolution. The noninferiority margin was -12 percentage points.
RESULTS
Among the 754 participants who underwent randomization, 699 were included in the modified intention-to-treat analysis, and 562 in the per-protocol analysis. In the modified intention-to-treat analysis, 80.7% of the patients in the standard-therapy group had favorable outcomes. The risk difference between standard therapy and each of the four new regimens that were found to be noninferior in the modified intention-to-treat population was as follows: BCLLfxZ, 9.8 percentage points (95% confidence interval [CI], 0.9 to 18.7); BLMZ, 8.3 percentage points (95% CI, -0.8 to 17.4); BDLLfxZ, 4.6 percentage points (95% CI, -4.9 to 14.1); and DCMZ, 2.5 percentage points (95% CI, -7.5 to 12.5). Differences were similar in the per-protocol population, with the exception of DCMZ, which was not noninferior in that population. The proportion of participants with grade 3 or higher adverse events was similar across the regimens. Grade 3 or higher hepatotoxic events occurred in 11.7% of participants overall and in 7.1% of those receiving standard therapy.
CONCLUSIONS
Consistent results across all the analyses support the noninferior efficacy of three all-oral shortened regimens for the treatment of rifampin-resistant tuberculosis. (Funded by Unitaid and others; endTB ClinicalTrials.gov number, NCT02754765.).
BACKGROUND
Tuberculosis vaccine trials using disease as the primary endpoint are large, time consuming, and expensive. An earlier immunological measure of the protection against disease would accelerate tuberculosis vaccine development. We aimed to assess whether the effectiveness of the Bacillus Calmette-Guérin (BCG) vaccine for prevention of Mycobacterium tuberculosis infection was consistent with that for prevention of tuberculosis disease.
METHODS
We conducted an individual participant data (IPD) meta-analysis on experimental and observational longitudinal studies before April 6, 2018, identified through systematic reviews, known to us through expert knowledge in the field, reporting on BCG vaccination status, M tuberculosis infection test (QuantiFERON IFN-γ release assay [IGRA] and tuberculin skin test [TST]), and tuberculosis incidence. Cohort studies were included only for countries with a mandatory neonatal BCG vaccination policy. Exclusion criteria were previous or current tuberculosis disease, HIV infection, tuberculosis preventive treatment usage, and for household contacts, a positive baseline IGRA or TST test and young children aged 0–2 years; for randomised controlled trials, TST results within 2 years after random assignation were excluded. We contacted the investigators of the identified studies to provide IPD. We compared the protective efficacy of the BCG vaccine against M tuberculosis infection with that against tuberculosis disease using mixed-effects, multivariable proportional hazards modelling, by study type, M tuberculosis infection test (IGRA and TST), cutoff for defining test positivity, age, sex, and latitude.
FINDINGS
We identified 79 studies eligible for full screening and of these, IPD datasets from 14 studies were included in our analysis: 11 household contact studies (29 147 participants), two adolescent cohort studies (11 368 participants), and one randomised controlled trial (2963 participants). Among 28 188 participants we found no protection by the BCG vaccine against TST conversion regardless of cutoff in any type of study. Among 1491 household contacts, but not among 5644 adolescents, the BCG vaccine protected against QuantiFERON conversion at the primary cutoff of 0·7 IU/mL or more with the adjusted hazard ratio (0·65, 95% CI 0·51–0·82) being consistent with that for protection against disease (0·68, 0·18–2·59). Protection against QuantiFERON conversion at cutoff of 0·35 IU/mL or more (0·64, 0·51–0·81) was similar.
INTERPRETATION
Protection from the BCG vaccination against M tuberculosis infection, measured as QuantiFERON conversion, is inconsistent across different groups. Among groups with recent household exposure, QuantiFERON conversion is consistent with protection against disease and could be evaluated as a proxy for disease in tuberculosis vaccine trials. We found that TST lacks value for prevention in phase 2b proof-of-concept trials.
BACKGROUND
The 2022 WHO guidelines on multi-drug/rifampicin resistant tuberculosis (MDR/RR-TB) recommend six months of bedaquiline (Bdq) in the all-oral 9-month shorter regimen and six months or longer for Bdq and delamanid (Dlm) in the 18-20-month longer regimen. However, lack of evidence on extended treatment using Bdq or Dlm has limited their use to six months. We examine the frequency and incidence of QT prolongation based on duration of Bdq and/or Dlm use in longer regimens.
METHODS
We analyzed a prospective cohort of MDR/RR-TB patients from 16 countries who initiated treatment with Bdq and/or Dlm containing regimens from 1 April 2015-30 September 2018. Data were systematically collected using a shared protocol. The outcome of interest was the first clinically relevant prolonged QT interval (grade 3 or above) or a Serious Adverse Event (SAE) involving prolonged QT of any grade.
RESULTS
Among 2,553 patients, 59% received >6 months of Bdq and/or Dlm. Of these, 579 (20.9%) patients experienced a prolonged QT event, the majority (95.5%) being grade 1 or 2. Sixty-four(2.5%) patients experienced the outcome of interest with only 12 (0.5%) having ≥ 1 QT prolonging drugs permanently suspended. The incidence rate of the first prolonged QT event was highest in the first six months of treatment and lower in subsequent six-month periods.
CONCLUSION
We demonstrate that Bdq and/or Dlm use beyond six months is safe in longer MDR/RR-TB regimens with most clinically relevant QT prolongation events occurring in the first six months. ECG monitoring for early identification of QT prolongating events is possible in programmatic conditions.