Drug-resistant tuberculosis treatments, the case for a phase III platform trial.

Most phase III trials in drug-resistant tuberculosis have either been underpowered to quantify differences in microbiological endpoints or have taken up to a decade to complete. Composite primary endpoints, dominated by differences in treatment discontinuation and regimen changes, may mask important differences in treatment failure and relapse. Although new regimens for drug-resistant tuberculosis appear very effective, resistance to new drugs is emerging rapidly. There is a need for shorter, safer and more tolerable regimens, including those active against bedaquiline-resistant tuberculosis. Transitioning from multiple regimen A versus regimen B trials to a single large phase III platform trial would accelerate the acquisition of robust estimates of relative efficacy and safety. Further efficiencies could be achieved by adopting modern adaptive platform designs. Collaboration among trialists, affected community representatives, funders and regulators is essential for developing such a phase III platform trial for drug-resistant tuberculosis treatment regimens.

La majorité des essais de phase III relatifs à la tuberculose pharmacorésistante soit n'étaient pas assez puissants pour quantifier les fluctuations au niveau des critères microbiologiques, soit étaient trop longs, se poursuivant parfois pendant dix ans. Les critères primaires composites, dominés par des différences dans l'interruption du traitement et les changements de schéma, pourraient dissimuler d'importantes variations en termes d'échec thérapeutique et de rechute. Bien que les nouveaux traitements contre la tuberculose pharmacorésistante semblent très efficaces, la résistance aux nouveaux médicaments évolue rapidement. Il est donc nécessaire d'opter pour des traitements plus courts, plus sûrs et mieux tolérés, y compris ceux actifs contre la tuberculose résistant à la bédaquiline. Délaisser la multitude d'essais opposant un schéma de traitement A à un schéma de traitement B pour se diriger vers un unique essai plateforme de phase III de grande envergure permettrait d'obtenir plus vite des estimations solides concernant l'innocuité et l'efficacité relative. En outre, adopter des modèles de plateforme modernes et adaptatifs contribuerait à de meilleures performances. Enfin, la collaboration entre investigateurs, représentants des communautés concernées, bailleurs de fonds et organismes de réglementation est essentielle à l'élaboration de ce type d'essai plateforme de phase III sur les traitements contre la tuberculose pharmacorésistante.

La mayoría de los ensayos en fase III sobre tuberculosis resistente a los fármacos no ha tenido la potencia suficiente para cuantificar diferencias en los criterios de valoración microbiológicos o ha tardado hasta una década en completarse. Los criterios de valoración principales compuestos, dominados por las diferencias en la interrupción del tratamiento y los cambios de régimen, pueden ocultar diferencias importantes en el fracaso del tratamiento y la recaída. Aunque los nuevos regímenes de tratamiento para la tuberculosis resistente a los fármacos parecen muy eficaces, la resistencia a los nuevos fármacos está apareciendo rápidamente. Se necesitan regímenes de tratamiento más cortos, seguros y tolerables, incluidos los activos contra la tuberculosis resistente a la bedaquilina. La transición de múltiples ensayos de régimen A frente a régimen B a un único gran ensayo de plataforma en fase III aceleraría la obtención de estimaciones sólidas de la eficacia y seguridad relativas. Podrían lograrse mayores eficiencias si se adoptaran diseños de plataforma adaptativos modernos. La colaboración entre los autores de los ensayos, los representantes de las comunidades afectadas, los financiadores y los reguladores es esencial para desarrollar un ensayo de plataforma en fase III de este tipo para los regímenes de tratamiento de la tuberculosis resistente a los fármacos.

Effectiveness of bedaquiline containing all oral longer regimens in treating multidrug/rifampicin resistant tuberculosis in Pakistan.

BACKGROUND: Despite the introduction of bedaquiline (Bdq) containing all-oral regimens for treating patients with rifampicin resistant/multidrug resistant tuberculosis (MDR/RR-TB) in 2019, data on its effectiveness in Pakistan, which has the fifth highest MDR-TB burden, is lacking. This study evaluates treatment outcomes and identifies factors associated with unsuccessful outcomes among MDR/RR-TB patients treated with an all-oral longer treatment regimen (LTR). METHODS: This retrospective record review included all microbiologically confirmed pulmonary MDR/RR-TB patients treated with an all-oral LTR between August 2019 and February 2021 across nine PMDT centres in Pakistan. Sociodemographic and clinical data were retrieved from the Electronic Nominal Recording and Reporting System. Treatment outcomes, defined by WHO criteria, were analysed using SPSS and multivariate binary logistic regression to identify factors associated with unsuccessful outcomes. A p-value < 0.05 was considered statistically significant. RESULTS: The final analysis included 644 MDR/RR-TB patients (mean age 37.9 ± 17.6 years), mostly male (53.0 %), underweight (68.0 %), with TB treatment history (66.1 %), MDR-TB (84.9 %), lung cavitation (71.0 %), and no comorbidities (86.4 %). Fluoroquinolone resistance was found in 41.9 %, 16 % had used second-line drugs, and 9.8 % had previous MDR-TB treatment. A total of 400 (62.1 %) patients were declared cured, 53 (8.2 %) treatment completed, 117 (18.2 %) died, 37 (5.7 %) lost to follow-up (LTFU), and 37 (5.7 %) treatment failures. Overall treatment success rate was 70.3 % (n = 453). In multivariate analysis, history of TB treatment (OR:1.63, 95 %CI:1.09-2.64, p = 0.023), previous SLD use (OR:2.09, 95 %CI: 1.20-3.37, p = 0.012), resistance to Z (OR:0.43, 95 %CI: 0.20-0.81, p = 0.023), and resistance to > 5 drugs (OR:3.12, 95 %CI:1.36-11.64, p = 0.013) were significantly associated with death and treatment failure. Whereas, lung cavitation had statistically significant association with LTFU (OR:2.66, 95 %CI:1.10-7.32, p = 0.045). CONCLUSION: Treatment success rate (70.3 %) in this study fell below the WHO recommended target success rate (>90 %). Enhanced clinical management, coupled with special attention to patients exhibiting identified risk factors could improve treatment outcomes.

Establishing the Safety and Efficacy of Bedaquiline-Containing Regimen for the Treatment of Drug-Resistant Tuberculosis: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.

The risks and benefits of bedaquiline (BDQ) for treatment of drug-resistant tuberculosis (DR-TB) have not been firmly established. We aimed to assess the safety and efficacy of BDQ-containing regimens for the treatment of DR-TB as evidenced in available randomized controlled trials (RCTs). In this systematic review and meta-analysis, five databases (i.e., ClinicalTrials.gov, Cochrane CENTRAL, PubMed, ScienceDirect, and SinoMed) were searched. RCTs among DR-TB patients that had a control arm were eligible. The safety endpoints were all-cause mortality and serious adverse effects (SAEs). Efficacy outcomes were sputum culture conversion rate at 8-12 weeks and 24-26 weeks, treatment success, and time to culture conversion. A total of 476 records were screened; 18 met the eligibility criteria. The pooled analysis included 2520 participants (55.8% received BDQ-containing regimens, n = 1408). Pooled safety outcomes showed no significant reduction in all-cause mortality (relative risk [RR] [95%confidence interval (CI)] = 0.94 [0.41-2.20]) or SAEs (RR [95%CI] = 0.91 [0.67-1.23]) in the BDQ-regimen group. Pooled efficacy outcomes showed significantly superior culture conversion rates at 8-12 weeks (RR [95%CI] = 1.35 [1.10-1.65]) and 24-26 weeks (RR [95%CI] = 1.25 [1.15-1.36]), more treatment success (RR [95%CI] = 1.30 [1.17-1.44]), and a 17-day reduction in the time to culture conversion (standardized mean difference [SMD] [95%CI] = -17.46 [-34.82 to -0.11]) in the BDQ-regimen group (reference: non-BDQ regimen). Overall, BDQ regimens showed significant treatment effect against DR-TB but did not reduce mortality or SAEs.

Dose optimization of TBI-223 for enhanced therapeutic benefit compared to linezolid in antituberculosis regimen.

TBI-223, a novel oxazolidinone for tuberculosis, is designed to provide improved efficacy and safety compared to linezolid in combination with bedaquiline and pretomanid (BPaL). We aim to optimize the dosing of TBI-223 within the BPaL regimen for enhanced therapeutic outcomes. TBI-223 is investigated in preclinical monotherapy, multidrug therapy, and lesion penetration experiments to describe its efficacy and safety versus linezolid. A translational platform incorporating linezolid and BPaL data from preclinical experiments and 4 clinical trials (NCT00396084, NCT02333799, NCT03086486, NCT00816426) is developed, enabling validation of the framework. TBI-223 preclinical and Phase 1 data (NCT03758612) are applied to the translational framework to predict clinical outcomes and optimize TBI-223 dosing in combination with bedaquiline and pretomanid. Results indicate that daily doses of 1200-2400 mg TBI-223 may achieve efficacy comparable to the BPaL regimen, with >90% of patients predicted to reach culture conversion by two months.

Clinical application of whole-genome sequencing in the management of extensively drug-resistant tuberculosis: a case report.

BACKGROUND: Whole-genome sequencing (WGS)-based prediction of drug resistance in Mycobacterium tuberculosis has the potential to guide clinical decisions in the design of optimal treatment regimens. METHODS: We utilized WGS to investigate drug resistance mutations in a 32-year-old Tanzanian male admitted to Kibong'oto Infectious Diseases Hospital with a history of interrupted multidrug-resistant tuberculosis treatment for more than three years. Before admission, he received various all-oral bedaquiline-based multidrug-resistant tuberculosis treatment regimens with unfavourable outcomes. RESULTS: Drug susceptibility testing of serial M. tuberculosis isolates using Mycobacterium Growth Incubator Tubes culture and WGS revealed resistance to first-line anti-TB drugs, bedaquiline, and fluoroquinolones but susceptibility to linezolid, clofazimine, and delamanid. WGS of serial cultured isolates revealed that the Beijing (Lineage 2.2.2) strain was resistant to bedaquiline, with mutations in the mmpR5 gene (Rv0678. This study also revealed the emergence of two distinct subpopulations of bedaquiline-resistant tuberculosis strains with Asp47f and Glu49fs frameshift mutations in the mmpR5 gene, which might be the underlying cause of prolonged resistance. An individualized regimen comprising bedaquiline, delamanid, pyrazinamide, ethionamide, and para-aminosalicylic acid was designed. The patient was discharged home at month 8 and is currently in the ninth month of treatment. He reported no cough, chest pain, fever, or chest tightness but still experienced numbness in his lower limbs. CONCLUSION: We propose the incorporation of WGS in the diagnostic framework for the optimal management of patients with drug-resistant and extensively drug-resistant tuberculosis.

Bedaquiline: An Insight Into its Clinical Use in Multidrug-Resistant Pulmonary Tuberculosis.

Every year, the World Health Organization reports 500,000 new cases of drug-resistant tuberculosis (TB), which poses a serious global danger. The increased number of XDR-TB and MDR-TB cases reported worldwide necessitates the use of new therapeutic approaches. The main issues with the antitubercular medications now in use for the treatment of multidrug-resistant tuberculosis are their poor side effect profile, reduced efficacy, and antimicrobial resistance. One possible remedy for these problems is bedaquiline. The need for better treatment strategies is highlighted by the strong minimum inhibitory concentrations that bedaquiline (BDQ), a novel anti-TB medicine, exhibits against both drug-resistant and drug-susceptible TB. Bedaquiline may be able to help with these problems. Bedaquiline is a medication that is first in its class and has a distinct and particular mode of action. Bedaquiline is an ATP synthase inhibitor that is specifically directed against Mycobacterium tuberculosis and some nontuberculous mycobacteria. It is metabolized by CYP3A4. Bedaquiline preclinical investigations revealed intralesional drug biodistribution. The precise intralesional and multi-compartment pharmacokinetics of bedaquiline were obtained using PET bioimaging and high-resolution autoradiography investigations. Reduced CFU counts were observed in another investigation after a 12-week course of therapy. Meta-analyses and systematic reviews of phase II trials on bedaquiline's efficacy in treating drug-resistant tuberculosis in patients reported higher rates of cure, better culture conversion, and lower death rates when taken in conjunction with a background regimen. Here is a thorough medication profile for bedaquiline to aid medical professionals in treating individuals with tuberculosis.

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.

Impact of bedaquiline regimen on the treatment success rates of multidrug-resistant tuberculosis patients in Egypt.

Bedaquiline (BDQ), an innovative anti-tuberculous (TB) agent, has attracted attention for its potential effectiveness against drug-resistant TB. This study investigated the impact of BDQ-containing regimens on treatment success rates among multi-drug resistant tuberculosis (MDR-TB) patients in Egypt. We conducted a prospective cohort study that included all adult non-pregnant patients treated in MDR-TB centers in Egypt from April 1, 2020, to June 30, 2021, with follow-up extended until December 31, 2022. The study compared patients prescribed BDQ according to national protocols with those receiving conventional treatments for MDR-TB. Treatment success rates, mortality rates, and adverse events were analyzed using descriptive statistics, chi-square tests, logistic regression, and Kaplan-Meier survival curves. Adjustment for potential confounders was conducted using propensity score matching and Cox-hazard regressions. A total of 84 patients were included in this study. The median age of the study participants was 39 years; 22.6% were women, 57.1% were unemployed or housewives, and 1.2% had human immunodeficiency virus (HIV). Regarding the treatment regimen, 67.8% were exposed to BDQ-based treatment. Among the 55 patients (65.5%) with treatment success, a significantly higher success rate was observed in the BDQ group (73.7%) compared to the conventional group (48.1%), P = 0.042. Additionally, the incidence of skin discoloration was significantly higher in the BDQ group compared to the conventional group (38.6% versus 0.0%, P < 0.001). Despite the lower mortality incidence in the BDQ-group (14.0% versus 22.2% in the conventional group), the Kaplan-Meier survival analysis revealed no excess mortality associated with the BDQ-group, with a hazard ratio (HR) of 0.62 (95% CI 0.21-1.78, P = 0.372). Propensity score matching, while considering factors such as lesion site, diabetes mellitus, hepatitis C virus, and smoking, revealed a significant increase in the success rate associated with BDQ inclusion, with an HR of 6.79 (95% CI 1.8-25.8). In conclusion, BDQ is an effective and tolerable medication for treating MDR-TB, associated with lower mortality rates compared to conventional treatment.

Update on drug-resistant pulmonary tuberculosis treatment in hemodialysis patients.

World Health Organization (WHO) issued the latest recommendations regarding the management of drug-resistant Tuberculosis (TB) in 2022, allowing the replacement of ethambutol (6 months) with linezolid (2 months). This recommendation also introduced a new regimen, namely bedaquiline, pretomanide, linezolid, moxifloxacin (BPaLM) for fluoroquinolone-sensitive patients and bedaquiline, pretomanide, linezolid, (BPaL) for patients insensitive to fluoroquinolone (6-9 months). The latest TB regimen introduced by WHO provides a shorter-course treatment, however not much has been discussed about the impact of this new regimen on chronic kidney disease (CKD) patients, particularly on hemodialysis (HD). The condition of CKD can interfere with the pharmacokinetics of TB medication, thus could reduce effectiveness and increase toxicity. The drugs used on this new regimen are mostly safe for renal impairment patients due to the dominant metabolism in the liver. Particular precaution is given to the administration of linezolid due to increased hematology side effects and bedaquiline with the side effect of QTC interval lengthening and increased risk of arrhythmias. Although this regimen research has not been in many studies in renal failure patients, no significant side effects nor kidney damage evidence was found. This remains to be proven by more research on the patient population with renal failure.

In-silico transcriptome analysis of antibiotic-treated Mycobacterium tuberculosis identifies novel antibiotic resistance factors.

The emergence of drug resistant Mycobacterium tuberculosis strains increases the burden on the treatment of tuberculosis. In this study, through in-silico transcriptome analysis of drug-treated M. tuberculosis samples, novel drug targets for the treatment of drug resistance in tuberculosis were identified. Gene expression datasets of tuberculosis patients samples treated with different antibiotics (Isoniazid, Rifampicin, Pyrazinamide, Bedaquiline and Linezolid) were considered in this study. DESeq2 was used to identify the differentially regulated genes. Novel genes which were up-regulated during antibiotic treatment were identified which could be antibiotic resistance factors. Further, to understand the resistance mechanism of the novel genes, we performed gene ontology and gene network analysis for the differentially up-regulated genes. Thus, the in-silico transcriptome analysis paves way for a deeper understanding of the antibiotic resistance in M. tuberculosis.

Treatment outcomes of multidrug resistant tuberculosis (MDR TB) treated with bedaquiline under programmatic management of drug resistant tuberculosis at a tertiary care hospital in Punjab, India.

INTRODUCTION: MDR TB is a serious global concern which is hampering TB elimination goals badly. Standardized MDR TB regimen had high default rates, more side effects and poor treatment outcomes. Bedaquiline is a newer anti-tubercular drug which has made oral regimens possible for MDR TB. We aimed to study the outcomes of MDR TB patients treated with Bdq containing regimens. METHODS: 155 patients of MDR TB on Bdq containing regimen enrolled at GMC, Patiala under NTEP from 2017 to 2020 were enrolled retrospectively. RESULTS: Out of 155 patients enrolled, 82 (52.9 %) were cured, 31 (20 %) completed treatment, 18 (11.6 %) defaulted, 22 (14.2 %) died and 2 (0.12 %) failed treatment. CONCLUSION: Bdq is well tolerated with very less side effects and has better outcomes as compared to standard MDR regimens which were followed earlier.

How much should we still worry about QTc prolongation in rifampicin-resistant tuberculosis? ECG findings from TB-PRACTECAL clinical trial.

Regimens for the treatment of rifampicin-resistant tuberculosis currently rely on the use of QT-prolonging agents. Using data from the randomized controlled trial, TB-PRACTECAL, we investigated differences in QTcF among participants in the three interventional arms: BPaL (bedaquiline, pretomanid, and linezolid), BPaLC (BPaL with clofazimine), and BPaLM (BPaL with moxifloxacin). Additionally, we assessed whether age, body mass index, and country were causally associated with QTcF prolongation. The trial included participants from South Africa, Uzbekistan, and Belarus. A post hoc analysis of electrocardiogram data was undertaken. Random effects regression was used to model QTcF longitudinally over 24 weeks and causal frameworks guided the analysis of non-randomized independent variables. 328 participants were included in BPaL-based arms. The longitudinal analysis of investigational arms showed an initial QTcF steep increase in the first week. QTcF trajectories between weeks 2 and 24 differed slightly by regimen, with highest mean peak for BPaLC (QTcF 446.5 ms). Overall, there were 397 QTcF >450 ms (of 3,744) and only one QTcF >500 ms. The odds of QTcF >450 ms among participants in any investigational arm, was 8.33 times higher in Uzbekistan compared to Belarus (95% confidence interval: 3.25-21.33). No effect on QTcF prolongation was found for baseline age or body mass index (BMI). Clinically significant QTc prolongation was rare in this cohort of closely monitored participants. Across BPaL-based regimens, BPaLC showed a slightly longer and sustained effect on QTcF prolongation, but the differences (both in magnitude of change and trajectory over time) were clinically unimportant. The disparity in the risk of QTc prolongation across countries would be an important factor to further investigate when evaluating monitoring strategies. CLINICAL TRIALS: This study is registered with ClinicalTrials.gov as NCT02589782.

Drug Exposure and Treatment Outcomes in Patients With Multidrug-Resistant Tuberculosis and Diabetes Mellitus: A Multicenter Prospective Cohort Study From China.

BACKGROUND: The management of multidrug-resistant tuberculosis (MDR-TB) remains challenging. Treatment outcome is influenced by multiple factors; the specific roles of diabetes and glycemic control remain uncertain. This study aims to assess the impact of glycemic control on drug exposure, to investigate the association between drug exposure and treatment outcomes, and to identify clinically significant thresholds predictive of treatment outcome, among patients with diabetes. METHODS: This multicenter prospective cohort study involved patients with confirmed MDR-TB and diabetes. Drug exposure level was estimated by noncompartmental analysis. The minimum inhibitory concentrations (MICs) were determined for the individual Mycobacterium tuberculosis isolates. The influence of poor glycemic control (glycated hemoglobin ≥7%) on drug exposure and the associations between drug exposure and treatment outcome were evaluated by univariate and multivariate analysis. Classification and regression tree analysis was used to identify the drug exposure/susceptibility thresholds. RESULTS: Among the 131 diabetic participants, 43 (32.8%) exhibited poor glycemic control. Poor glycemic control was independently associated with decreased exposure to moxifloxacin, linezolid, bedaquiline, and cycloserine, but not clofazimine. Additionally, a higher ratio of drug exposure to susceptibility was found to be associated with a favorable MDR-TB treatment outcome. Thresholds predictive of 6-month culture conversion and favorable outcome were bedaquiline area under the concentration-time curve (AUC)/MIC ≥245 and moxifloxacin AUC/MIC ≥67, demonstrating predictive accuracy in patients, regardless of their glycemic control status. CONCLUSIONS: Glycemic control and optimal TB drug exposure are associated with improved treatment outcomes. This dual management strategy should be further validated in randomized controlled trials of patients with MDR-TB and diabetes.

Comparison of Individual Regimen Containing Bedaquiline with Delamanid and Bedaquiline without Delamanid on Efficacy and Safety in Multidrug-resistant Tuberculosis Patients: Implementation in Dr. Soetomo General Academic Hospital, Indonesia.

BACKGROUND: Bedaquiline is one of the core drugs used to treat multidrug-resistant TB (MDR-TB). Delamanid is one of the companion drugs in group C which is used to complete the treatment regimen when drugs in groups A and B can not be used. This study was conducted to analyze the efficacy and safety between individual regimens containing bedaquiline with delamanid and bedaquiline without delamanid. METHODS: This was an observational analytic study with a retrospective design in MDR-TB patients treated with individual regimens containing bedaquiline with delamanid (bedaquiline-delamanid group) and bedaquiline without delamanid (bedaquiline group). Efficacy was measured according to the time to Acid Fast Bacilli (AFB) conversion and Mycobacterium tuberculosis culture conversion, while safety was measured specifically on QTc interval prolongation. RESULTS: The median (range) time to AFB conversion in bedaquiline-delamanid group was faster than bedaquiline group, although there was no significant difference (1.5 (1-4) months vs. 1 (1-6) months, P=0.429), the median time to culture conversion in bedaquiline-delamanid group also faster than bedaquiline group, although there was no significant difference (1 (1-6) months vs. 2 (1-6) months, P=0.089). The incidence of QTc interval prolongation in bedaquiline-delamanid group was less than bedaquiline group, although there was no significant difference (26.9% vs. 40.3%, P=0.223). CONCLUSIONS: Individual regimens containing bedaquiline with delamanid was proven to provide similar efficacy and safety profiles with individual regimens containing bedaquiline without delamanid. Delamanid should be preferred when selecting drugs to complete the treatment regimen when drugs in groups A and B can not be used.

Bedaquiline-pretomanid-moxifloxacin-pyrazinamide for drug-sensitive and drug-resistant pulmonary tuberculosis treatment: a phase 2c, open-label, multicentre, partially randomised controlled trial.

BACKGROUND: The current tuberculosis (TB) drug development pipeline is being re-populated with candidates, including nitroimidazoles such as pretomanid, that exhibit a potential to shorten TB therapy by exerting a bactericidal effect on non-replicating bacilli. Based on results from preclinical and early clinical studies, a four-drug combination of bedaquiline, pretomanid, moxifloxacin, and pyrazinamide (BPaMZ) regimen was identified with treatment-shortening potential for both drug-susceptible (DS) and drug-resistant (DR) TB. This trial aimed to determine the safety and efficacy of BPaMZ. We compared 4 months of BPaMZ to the standard 6 months of isoniazid, rifampicin, pyrazinamide, and ethambutol (HRZE) in DS-TB. 6 months of BPaMZ was assessed in DR-TB. METHODS: SimpliciTB was a partially randomised, phase 2c, open-label, clinical trial, recruiting participants at 26 sites in eight countries. Participants aged 18 years or older with pulmonary TB who were sputum smear positive for acid-fast bacilli were eligible for enrolment. Participants with DS-TB had Mycobacterium tuberculosis with sensitivity to rifampicin and isoniazid. Participants with DR-TB had M tuberculosis with resistance to rifampicin, isoniazid, or both. Participants with DS-TB were randomly allocated in a 1:1 ratio, stratified by HIV status and cavitation on chest radiograph, using balanced block randomisation with a fixed block size of four. The primary efficacy endpoint was time to sputum culture-negative status by 8 weeks; the key secondary endpoint was unfavourable outcome at week 52. A non-inferiority margin of 12% was chosen for the key secondary outcome. Safety and tolerability outcomes are presented as descriptive analyses. The efficacy analysis population contained patients who received at least one dose of medication and who had efficacy data available and had no major protocol violations. The safety population contained patients who received at least one dose of medication. This study is registered with ClinicalTrials.gov (NCT03338621) and is completed. FINDINGS: Between July 30, 2018, and March 2, 2020, 455 participants were enrolled and received at least one dose of study treatment. 324 (71%) participants were male and 131 (29%) participants were female. 303 participants with DS-TB were randomly assigned to 4 months of BPaMZ (n=150) or HRZE (n=153). In a modified intention-to-treat (mITT) analysis, by week 8, 122 (84%) of 145 and 70 (47%) of 148 participants were culture-negative on 4 months of BPaMZ and HRZE, respectively, with a hazard ratio for earlier negative status of 2·93 (95% CI 2·17-3·96; p<0·0001). Median time to negative culture (TTN) was 6 weeks (IQR 4-8) on 4 months of BPaMZ and 11 weeks (6-12) on HRZE. 86% of participants with DR-TB receiving 6 months of BPaMZ (n=152) reached culture-negative status by week 8, with a median TTN of 5 weeks (IQR 3-7). At week 52, 120 (83%) of 144, 134 (93%) of 144, and 111 (83%) of 133 on 4 months of BPaMZ, HRZE, and 6 months of BPaMZ had favourable outcomes, respectively. Despite bacteriological efficacy, 4 months of BPaMZ did not meet the non-inferiority margin for the key secondary endpoint in the pre-defined mITT population due to higher withdrawal rates for adverse hepatic events. Non-inferiority was demonstrated in the per-protocol population confirming the effect of withdrawals with 4 months of BPaMZ. At least one liver-related treatment-emergent adverse effect (TEAE) occurred among 45 (30%) participants on 4 months of BPaMZ, 38 (25%) on HRZE, and 33 (22%) on 6 months of BPaMZ. Serious liver-related TEAEs were reported by 20 participants overall; 11 (7%) among those on 4 months of BPaMZ, one (1%) on HRZE, and eight (5%) on 6 months of BPaMZ. The most common reasons for discontinuation of trial treatment were hepatotoxicity (ten participants [2%]), increased hepatic enzymes (nine participants [2%]), QTcF prolongation (three participants [1%]), and hypersensitivity (two participants [<1%]). INTERPRETATION: For DS-TB, BPaMZ successfully met the primary efficacy endpoint of sputum culture conversion. The regimen did not meet the key secondary efficacy endpoint due to adverse events resulting in treatment withdrawal. Our study demonstrated the potential for treatment-shortening efficacy of the BPaMZ regimen for DS-TB and DR-TB, providing clinical validation of a murine model widely used to identify such regimens. It also highlights that novel, treatment-shortening TB treatment regimens require an acceptable toxicity and tolerability profile with minimal monitoring in low-resource and high-burden settings. The increased risk of unpredictable severe hepatic adverse events with 4 months of BPaMZ would be a considerable obstacle to implementation of this regimen in settings with high burdens of TB with limited infrastructure for close surveillance of liver biochemistry. Future research should focus on improving the preclinical and early clinical detection and mitigation of safety issues together and further efforts to optimise shorter treatments. FUNDING: TB Alliance.

Impact and cost-effectiveness of the 6-month BPaLM regimen for rifampicin-resistant tuberculosis in Moldova: A mathematical modeling analysis.

BACKGROUND: Emerging evidence suggests that shortened, simplified treatment regimens for rifampicin-resistant tuberculosis (RR-TB) can achieve comparable end-of-treatment (EOT) outcomes to longer regimens. We compared a 6-month regimen containing bedaquiline, pretomanid, linezolid, and moxifloxacin (BPaLM) to a standard of care strategy using a 9- or 18-month regimen depending on whether fluoroquinolone resistance (FQ-R) was detected on drug susceptibility testing (DST). METHODS AND FINDINGS: The primary objective was to determine whether 6 months of BPaLM is a cost-effective treatment strategy for RR-TB. We used genomic and demographic data to parameterize a mathematical model estimating long-term health outcomes measured in quality-adjusted life years (QALYs) and lifetime costs in 2022 USD ($) for each treatment strategy for patients 15 years and older diagnosed with pulmonary RR-TB in Moldova, a country with a high burden of TB drug resistance. For each individual, we simulated the natural history of TB and associated treatment outcomes, as well as the process of acquiring resistance to each of 12 anti-TB drugs. Compared to the standard of care, 6 months of BPaLM was cost-effective. This strategy was estimated to reduce lifetime costs by $3,366 (95% UI: [1,465, 5,742] p < 0.001) per individual, with a nonsignificant change in QALYs (-0.06; 95% UI: [-0.49, 0.03] p = 0.790). For those stopping moxifloxacin under the BPaLM regimen, continuing with BPaL plus clofazimine (BPaLC) provided more QALYs at lower cost than continuing with BPaL alone. Strategies based on 6 months of BPaLM had at least a 93% chance of being cost-effective, so long as BPaLC was continued in the event of stopping moxifloxacin. BPaLM for 6 months also reduced the average time spent with TB resistant to amikacin, bedaquiline, clofazimine, cycloserine, moxifloxacin, and pyrazinamide, while it increased the average time spent with TB resistant to delamanid and pretomanid. Sensitivity analyses showed 6 months of BPaLM to be cost-effective across a broad range of values for the relative effectiveness of BPaLM, and the proportion of the cohort with FQ-R. Compared to the standard of care, 6 months of BPaLM would be expected to save Moldova's national TB program budget $7.1 million (95% UI: [1.3 million, 15.4 million] p = 0.002) over the 5-year period from implementation. Our analysis did not account for all possible interactions between specific drugs with regard to treatment outcomes, resistance acquisition, or the consequences of specific types of severe adverse events, nor did we model how the intervention may affect TB transmission dynamics. CONCLUSIONS: Compared to standard of care, longer regimens, the implementation of the 6-month BPaLM regimen could improve the cost-effectiveness of care for individuals diagnosed with RR-TB, particularly in settings with a high burden of drug-resistant TB. Further research may be warranted to explore the impact and cost-effectiveness of shorter RR-TB regimens across settings with varied drug-resistant TB burdens and national income levels.