A systematic review of adverse events of rifapentine and isoniazid compared to other treatments for latent tuberculosis infection

Recent efforts in the development of glycoconjugate vaccine and available treatment for tuberculosis

Tuberculosis (TB) continues to pose a grave threat to global health, despite relentless eradication efforts. In 1882, Robert Koch discovered that Mycobacterium tuberculosis (Mtb) is the bacterium responsible for causing tuberculosis. It is a fact that tuberculosis has claimed the lives of more than one billion people in the last few decades. It is imperative that we must take immediate and effective action to increase resources for TB research and treatment. Effective TB treatments demand an extensive investment of both time and finances, often requiring 6-9 months of rigorous antibiotic therapy. The most efficient way to control tuberculosis is by receiving a childhood Bacillus Calmette-Guérin (BCG) vaccination. Despite years of research on vaccine development, we still do not have any new approved vaccine for tuberculosis, except BCG, which is partially effective in young children. This review discusses briefly the available treatment for tuberculosis and remarkable advancements in glycoconjugate-based TB vaccine developments in recent years (2013-2024) and offers valuable direction for future research priorities.

High-dose, short-duration versus standard rifampicin for tuberculosis preventive treatment: a partially blinded, three-arm, non-inferiority, randomised, controlled trial

BACKGROUND

Tuberculosis preventive treatment (TPT) is a key component of tuberculosis elimination. To improve completion and reduce the burden for people and health systems, short, safe, and effective TPT regimens are needed. We aimed to compare safety and treatment completion of various doses and durations of rifampicin in people who were recommended to receive TPT.

METHODS

This partially blinded, parallel-arm, non-inferiority, randomised, controlled, phase 2b trial was done at seven university-affiliated clinics in Canada, Indonesia, and Viet Nam. Participants aged 10 years or older were included if they had an indication for TPT according to WHO guidelines for Indonesia and Viet Nam, or Canadian guidelines for Canadian sites, and a positive tuberculin skin test or interferon-γ release assay. Participants were randomly assigned (1:1:1) to receive oral rifampicin at 10 mg/kg once daily for 4 months (standard-dose group), 20 mg/kg daily for 2 months (20 mg/kg group), or 30 mg/kg daily for 2 months (30 mg/kg group). The randomisation sequence was computer generated with blocks of variable size (three, six, and nine) and stratified by country for Indonesia and Viet Nam, and by city within Canada. Participants and investigators were masked to dose in high-dose groups, but unmasked to duration in all groups. The two co-primary outcomes were safety (in the safety population, in which participants received at least one dose of the study drug) and treatment completion (in the modified intention-to-treat [mITT] population, excluding those ineligible after randomisation). Protocol-defined adverse events were defined as grade 3 or worse, or rash or allergy of any grade, judged by an independent and masked panel as possibly or probably related to the study. A margin of 4% was used to assess non-inferiority. This study is registered with ClinicalTrials.gov, NCT03988933 (active).

FINDINGS

Between Sept 1, 2019, and Sept 30, 2022, 1692 people were assessed for eligibility, 1376 were randomly assigned, and eight were excluded after randomisation. 1368 participants were included in the mITT population (454 in the standard group, 461 in the 20 mg/kg group, and 453 in the 30 mg/kg group). 589 (43%) participants were male and 779 (57%) were female. 372 (82%) in the standard-dose group, 329 (71%) in the 20 mg/kg group, and 293 (65%) in the 30 mg/kg group completed treatment. No participants in the standard-dose group, one (<1%) of 441 participants in the 20 mg/kg group, and four (1%) of 423 in the 30 mg/kg group developed grade 3 hepatotoxicity. Risk of protocol-defined adverse events was higher in the 30 mg/kg group than in the standard-dose group (adjusted risk difference 4·6% [95% CI 1·8 to 7·4]) or the 20 mg/kg group (5·1% [2·3 to 7·8]). There was no difference in the risk of adverse events between the 20 mg/kg and standard-dose groups (-0·5% [95% CI -2·4 to 1·5]; non-inferiority met). Completion was lower in the 20 mg/kg group (-7·8% [95% CI -13·6 to -2·0]) and the 30 mg/kg group (-15·4% [-21·4 to -9·4]) than in the standard-dose group.

INTERPRETATION

In this trial, 2 months of 30 mg/kg daily rifampicin had significantly worse safety and completion than 4 months of 10 mg/kg daily and 2 months of 20 mg/kg daily (the latter, a fully blinded comparison); we do not consider 30 mg/kg to be a good option for TPT. Rifampicin at 20 mg/kg daily for 2 months was as safe as standard treatment, but with lower completion. This difference remains unexplained.

FUNDING

Canadian Institutes of Health Research.

A Mathematical Model for the Impact of 3HP and Social Programme Implementation on the Incidence and Mortality of Tuberculosis: Study in Brazil

In this paper, we presented a mathematical model for tuberculosis with treatment for latent tuberculosis cases and incorporated social implementations based on the impact they will have on tuberculosis incidence, cure, and recovery. We incorporated two variables containing the accumulated deaths and active cases into the model in order to study the incidence and mortality rate per year with the data reported by the model. Our objective is to study the impact of social program implementations and therapies on latent tuberculosis in particular the use of once-weekly isoniazid-rifapentine for 12 weeks (3HP). The computational experimentation was performed with data from Brazil and for model calibration, we used the Markov Chain Monte Carlo method (MCMC) with a Bayesian approach. We studied the effect of increasing the coverage of social programs, the Bolsa Familia Programme (BFP) and the Family Health Strategy (FHS) and the implementation of the 3HP as a substitution therapy for two rates of diagnosis and treatment of latent at 1% and 5%. Based of the data obtained by the model in the period 2023-2035, the FHS reported better results than BFP in the case of social implementations and 3HP with a higher rate of diagnosis and treatment of latent in the reduction of incidence and mortality rate and in cases and deaths avoided. With the objective of linking the social and biomedical implementations, we constructed two different scenarios with the rate of diagnosis and treatment. We verified with results reported by the model that with the social implementations studied and the 3HP with the highest rate of diagnosis and treatment of latent, the best results were obtained in comparison with the other independent and joint implementations. A reduction of the incidence by 36.54% with respect to the model with the current strategies and coverage was achieved, and a greater number of cases and deaths from tuberculosis was avoided.

Isoniazid use, effectiveness, and safety for treatment of latent tuberculosis infection: a systematic review

BACKGROUND

The treatment strategy for latent tuberculosis infection is to reduce the number of tuberculosis cases and consequently reduce the transmission of pathogenic bacteria. This study aimed to determine the safety, effectiveness, and adherence of isoniazid use for latent tuberculosis infection treatment.

METHODS

To identify studies on isoniazid use for latent tuberculosis infection, five electronic databases were searched. The methods and results are presented in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

Most studies (53) used isoniazid for 9 months. The prevalence of use and adherence to treatment varied considerably (18% to 100%), and were evaluated by participant completion of isoniazid treatment for latent tuberculosis infection. The adverse events most frequently reported were hepatotoxicity, gastric intolerance, and neuropathy; the rates of occurrence ranged from < 1% to 48%. In the studies that evaluated the effectiveness of isoniazid for latent tuberculosis infection, the rate varied from 0 to 19.7% for patients who did not have active tuberculosis after the follow-up period.

CONCLUSIONS

The importance of maintaining follow up for patients using isoniazid should be emphasized due to the risk of developing adverse events. Despite the treatment challenges, the rates of patients who used isoniazid and developed active tuberculosis during the follow-up period were low. We believe that isoniazid continues to contribute to tuberculosis control worldwide, and better care strategies are required.

Preventive treatment for latent tuberculosis from Indian perspective

The persistent morbidity and mortality associated with tuberculosis (TB), despite our continued efforts, has been long recognized, and the rise in the incidence of drug-resistant TB adds to the preexisting concern. The bulk of the TB burden is confined to low-income countries, and rigorous efforts are made to detect, notify, and systematically treat TB. Efforts have been infused with renewed vigor and determination by the World Health Organization (WHO) to eliminate tuberculosis in the near future. Different health agencies worldwide are harvesting all possible strategies apart from consolidating ongoing practices, including prevention of the development of active disease by treating latent TB infection (LTBI). The guidelines for the same were already provided by the WHO and were then adapted in the Indian guidelines for the treatment of LTBI in 2021. While the long-term impact of TBI treatment is awaited, in this article, we aim to discuss the implications in the Indian context.

Uptake and Completion of Tuberculosis Preventive Treatment Using 12-Dose, Weekly Isoniazid-Rifapentine Regimen in Bangladesh: A Community-Based Implementation Study

BACKGROUND

The United Nations high-level meeting (UNHLM) pledged to enroll 30 million in tuberculosis preventive treatment (TPT) by 2022, necessitating TPT expansion to all at tuberculosis (TB) risk. We assessed the uptake and completion of a 12-dose, weekly isoniazid-rifapentine (3HP) TPT regimen.

METHODS

Between February 2018 and March 2019 in Dhaka, community-based TPT using 3HP targeted household contacts of 883 confirmed drug-sensitive pulmonary TB patients. Adhering to World Health Organization guidelines, contacts underwent active TB screening before TPT initiation.

RESULTS

Of 3193 contacts who were advised health facility visits for screening, 67% (n = 2149) complied. Among these, 1804 (84%) received chest X-rays. Active TB was diagnosed in 39 (2%) contacts; they commenced TB treatment. Over 97% of 1216 contacts began TPT, with completion rates higher among females, those with more education and income, non-slum residents, and those without 3HP-related adverse events. Adverse events, mainly mild, occurred in 5% of participants.

CONCLUSIONS

The 3HP regimen, with its short duration, self-administered option, and minimal side effects, achieved satisfactory completion rates. A community-focused TPT approach is feasible, scalable nationally, and aligns with UNHLM targets.

Preferences of people living with HIV for features of tuberculosis preventive treatment regimens - a discrete choice experiment

Background

Tuberculosis (TB) preventive treatment (TPT) is recommended for people living with HIV (PLHIV) in high TB burden settings. While 6 months of daily isoniazid remains widely used, shorter regimens are now available. However, little is known about preferences of PLHIV for key features of TPT regimens.

Methods

We conducted a discrete choice experiment among adult PLHIV engaged in care at an urban HIV clinic in Kampala, Uganda. In nine random choice tasks, participants chose between two hypothetical TPT regimens with different features (pills per dose, frequency, duration, need for adjusted antiretroviral therapy [ART] dosage and side effects). We analyzed preferences using hierarchical Bayesian estimation, latent class analysis, and willingness-to-trade simulations.

Results

Of 400 PLHIV, 392 (median age 44, 72% female, 91% TPT-experienced) had high quality choice task responses. Pills per dose was the most important attribute (relative importance 32.4%, 95% confidence interval [CI] 31.6 - 33.2), followed by frequency (20.5% [95% CI 19.7 - 21.3]), duration (19.5% [95% CI 18.6 - 20.5]), and need for ART dosage adjustment (18.2% [95% CI 17.2 - 19.2]). Latent class analysis identified three preference groups: one prioritized less frequent, weekly dosing (N=222; 57%); another was averse to ART dosage adjustment (N=107; 27%); and the last prioritized short and tolerable regimens (N=63; 16%). All groups highly valued fewer pills per dose. Participants were willing to accept a regimen of 2.8 months' additional duration [95% CI: 2.4 - 3.2] to reduce pills per dose from five to one, 3.6 [95% CI 2.4 - 4.8] months for weekly rather than daily dosing, and 2.2 [95% CI 1.3 - 3.0] months to avoid ART dosage adjustment.

Conclusions

To align with preferences of PLHIV, decision-makers should prioritize the development and implementation of TPT regimens with fewer pills, less frequent dosing, and no need for ART dosage adjustment, rather than focus primarily on duration of treatment.

Variation in Treatment of Pediatric Tuberculosis Infection in Different Provider Settings

OBJECTIVES

To evaluate implementation of rifamycin-based regimens (RBR) for pediatric tuberculosis infection (TBI) treatment among 3 provider settings in a high-incidence county.

STUDY DESIGN

A multicenter, retrospective observational study was performed across 3 sites in Los Angeles County: an academic center (AC), a general pediatrics federally qualified health center (FQHC), and department of public health (DPH) tuberculosis clinics. Patients initiated on TBI treatment age 1 months to 17 years between 2018 and 2020 were included. RBRs were defined as regimens: 3 months of weekly rifapentine and isoniazid, 4 months of daily rifampin, and 3 months of daily isoniazid and rifampin.

RESULTS

We included 424 patients: 51 from AC, 327 from DPH, and 46 from FQHC. RBR use nearly doubled during the study period (from 43% in 2018 to 82% in 2020; P < .001). FQHC had the shortest time to chest radiograph and treatment initiation; however, AC and DPH were 4 times as likely to prescribe an RBR compared to FQHC (95% CI, 2.1-7.8). AC and DPH had similar completion rates (74%) and were 2.6 times as likely to complete treatment compared to FQHC (95% CI, 1.4-4.9).

CONCLUSIONS

The use of RBRs for pediatric TBI varies significantly by clinical setting but is improving over time. Strategies are needed to improve RBR uptake, standardize care, and increase treatment completion, particularly among general pediatricians.

Safety and Tolerability of Six Months of Isoniazid Plus Pyridoxine or Three Months of Rifampicin for Tuberculosis among Subjects with Diabetes Mellitus: A Randomized Trial

Tuberculosis (TB) associated with diabetes mellitus (DM) is a growing problem, particularly in low- and medium-resource countries. We conducted an open-label, parallel-group, randomized, and controlled trial in a tertiary care center in Mexico City to assess TB preventive treatment (TPT) with isoniazid (INH) or rifampicin (RIF) in people with type 2 DM. Participants were assigned six months of INH 300 mg/day plus pyridoxine 75 mg or three months of RIF 600 mg/day. The primary outcomes were adverse events resulting in permanent treatment cessation and considered possibly or probably related to study drugs. We included 130 subjects, 68 randomized to INH and 62 to RIF. We prematurely halted the study based on recommendations of the Adverse Event Safety Panel. There was no difference between arms in the overall frequency of adverse events. However, the INH group had significantly more permanent treatment interruptions due to grade 2 recurrent or grade 3 or 4 hepatoxicity. In comparison, the RIF arm had more treatment interruptions due to grade 3 or 4 gastrointestinal intolerance. TPT using INH or RIF is not safe enough to be considered a universal indication to patients with type 2 DM and TB infection. These results underline the need to search for alternative TB preventions with better safety profiles for type 2 DM patients.

Long-term economic evaluation of the recombinant Mycobacterium tuberculosis fusion protein (EC) test for the diagnosis of Mycobacterium tuberculosis infection

Background: Tuberculosis continues to be a significant global burden. Purified protein derivative of tuberculin (TB-PPD) is one type of tuberculin skin test (TST) and is used commonly for the auxiliary diagnosis of tuberculosis. The recombinant Mycobacterium tuberculosis fusion protein (EC) test is a new test developed in China. Objective: Evaluate the long-term economic implications of using the EC test compared with the TB-PPD test to provide a reference for clinical decision-making. Methods: The target population was people at a high risk persons of being infected with Mycobacterium tuberculosis. The outcome indicator was quality-adjusted life years (QALY). A cost-utility analysis was used to evaluate the long-term economic implications of using the EC test compared with the TB-PPD test. We employed a decision tree-Markov model from the perspective of the whole society within 77 years. Results: Compared with the TB-PPD test, the EC test had a lower cost but higher QALY. The incremental cost-utility ratio was -119,800.7381 CNY/QALY. That is, for each additional QALY, the EC test could save 119,800.7381 CNY: the EC test was more economical than the TB-PPD test. Conclusion: Compared with the TB-PPD test, the EC test would be more economical in the long term for the diagnosis of M. tuberculosis infection according our study.

Recombinant mycobacterium tuberculosis fusion protein for diagnosis of mycobacterium tuberculosis infection: a short-term economic evaluation

Objectives

Recombinant Mycobacterium tuberculosis fusion protein (EC) was anticipated to be used for the scale-up of clinical application for diagnosis of Mycobacterium tuberculosis infection in China, but it lacked a head-to-head economic evaluation based on the Chinese population. This study aimed to estimate the cost-utility and the cost-effectiveness of both EC and tuberculin pure protein derivative (TB-PPD) for diagnosis of Mycobacterium tuberculosis infection in the short term.

Methods

From a Chinese societal perspective, both cost-utility analysis and cost-effectiveness analysis were performed to evaluate the economics of EC and TB-PPD for a one-year period based on clinical trials and decision tree model, with quality-adjusted life years (QALYs) as the utility-measured primary outcome and diagnostic performance (including the misdiagnosis rate, the omission diagnostic rate, the number of patients correctly classified, and the number of tuberculosis cases avoided) as the effective-measured secondary outcome. One-way and probabilistic sensitivity analyses were performed to validate the robustness of the base-case analysis, and a scenario analysis was conducted to evaluate the difference in the charging method between EC and TB-PPD.

Results

The base-case analysis showed that, compared with TB-PPD, EC was the dominant strategy with an incremental cost-utility ratio (ICUR) of saving 192,043.60 CNY per QALY gained, and with an incremental cost-effectiveness ratio (ICER) of saving 7,263.53 CNY per misdiagnosis rate reduction. In addition, there was no statistical difference in terms of the omission diagnostic rate, the number of patients correctly classified, and the number of tuberculosis cases avoided, and EC was a similar cost-saving strategy with a lower test cost (98.00 CNY) than that of TB-PPD (136.78 CNY). The sensitivity analysis showed the robustness of cost-utility and cost-effectiveness analysis, and the scenario analysis indicated cost-utility in EC and cost-effectiveness in TB-PPD.

Conclusion

This economic evaluation from a societal perspective showed that, compared to TB-PPD, EC was likely to be a cost-utility and cost-effective intervention in the short term in China.

Population-wide active case finding and prevention for tuberculosis and leprosy elimination in Kiribati: the PEARL study protocol

INTRODUCTION

Population-wide interventions offer a pathway to tuberculosis (TB) and leprosy elimination, but 'real-world' implementation in a high-burden setting using a combined approach has not been demonstrated. This implementation study aims to demonstrate the feasibility and evaluate the effect of population-wide screening, treatment and prevention on TB and leprosy incidence rates, as well as TB transmission.

METHODS AND ANALYSIS

A non-randomised 'screen-and-treat' intervention conducted in the Pacific atoll of South Tarawa, Kiribati. Households are enumerated and all residents ≥3 years, as well as children <3 years with recent household exposure to TB or leprosy, invited for screening. Participants are screened using tuberculin skin testing, signs and symptoms of TB or leprosy, digital chest X-ray with computer-aided detection and sputum testing (Xpert MTB/RIF Ultra). Those diagnosed with disease are referred to the National TB and Leprosy Programme for management. Participants with TB infection are offered TB preventive treatment and those without TB disease or infection, or leprosy, are offered leprosy prophylaxis. The primary study outcome is the difference in the annual TB case notification rate before and after the intervention; a similar outcome is included for leprosy. The effect on TB transmission will be measured by comparing the estimated annual risk of TB infection in primary school children before and after the intervention, as a co-primary outcome used for power calculations. Comparison of TB and leprosy case notification rates in South Tarawa (the intervention group) and the rest of Kiribati (the control group) before, during and after the intervention is a secondary outcome.

ETHICS AND DISSEMINATION

Approval was obtained from the University of Sydney Human Research Ethics Committee (project no. 2021/127) and the Kiribati Ministry of Health and Medical Services (MHMS). Findings will be shared with the MHMS and local communities, published in peer-reviewed journals and presented at international conferences.

Effect of implementation of a 12 dose once-weekly treatment (3HP) in addition to standard regimens to prevent TB on completion rates: Interrupted time series design

OBJECTIVE

We aimed to determine if offering a 12 dose once-weekly treatment (3HP) as an additional treatment option would result in an increase in the overall proportion of patients completing TB preventive treatment (TPT) above the baseline rate.

METHODS

We analyzed outcomes in consecutive adults referred to a TB clinic from January 2010 to May 2019. Starting December 2016, 3HP was offered as an alternative to standard clinic regimens which included 9 months of daily isoniazid or 4 months of daily rifampin. The primary outcome was the proportion who completed TPT among all patients who started treatment. Using segmented autoregression analysis we compared completion at the end of the study to projected completion had the intervention not been introduced.

RESULTS

A total of 2803 adults were referred for assessment over the study period. There was an absolute increase in completions among all of those who started a treatment of 19.0% at the end of the study between the observed intervention completion rate and the projected completion rate from the baseline study period (the completion rate had the 3HP intervention not been introduced) (76% observed vs 57% projected, 95% CI 6.6 to 31.4%, p = 0.004) and an absolute increase among those who were offered treatment of 17.3% 95% CI, 2.3 to 32.3%, p = 0.025).

INTERPRETATION

The introduction of 3HP for TPT as an alternative to the regular regimens offered resulted in a significant increase in the proportion of patients completing treatment. Our study provides evidence to support accelerated use of 3HP in Canada.

Providing valid evidence for decision-making: the Drug Safety and Effectiveness Network Methods and Applications Group in Indirect Comparisons (DSEN MAGIC)

In 2009, the Canadian Institutes of Health Research, Health Canada, and other stakeholders established the Drug Safety and Effectiveness Network (DSEN) to address the paucity of information on drug safety and effectiveness in real-world settings. This unique network invited knowledge users (e.g., policy makers) to submit queries to be answered by relevant research teams. The research teams were launched via open calls for team grants focused in relevant methodologic areas. We describe the development and implementation of one of these collaborating centres, the Methods and Application Group for Indirect Comparisons (MAGIC). MAGIC was created to provide high-quality knowledge synthesis including network meta-analysis to meet knowledge user needs. Since 2011, MAGIC responded to 54% of queries submitted to DSEN. In the past 5 years, MAGIC produced 26 reports and 49 publications. It led to 15 trainees who entered industry, academia, and government. More than 10 000 people participated in courses delivered by MAGIC team members. Most importantly, MAGIC knowledge syntheses influenced practice and policy (e.g., use of biosimilars for patients with diabetes and use of smallpox vaccinations in people with contraindications) provincially, nationally, and internationally.

'Practical management of suspected hypersensitivity reactions to anti-tuberculosis drugs.'

Tuberculosis (TB) is the commonest cause of death by a single infectious agent globally and ranks amongst the top ten causes of global mortality. The incidence of TB is highest in Low-Middle Income countries (LMICs). Prompt institution of, and compliance with, therapy are cornerstones for a favourable outcome in TB and to mitigate the risk of multiple drug resistant (MDR)-TB, which is challenging to treat. There is some evidence that adverse drug reactions (ADRs) and hypersensitivity reactions (HSRs) to anti-TB drugs occur in over 60% and 3-4% of patients respectively. Both ADRs and HSRs represent significant barriers to treatment adherence and are recognised risk factors for MDR-TB. HSRs to anti-TB drugs are usually cutaneous and benign, occur within few weeks after commencement of therapy and are likely to be T-cell mediated. Severe and systemic T-cell mediated HSRs and IgE mediated anaphylaxis to anti-TB drugs are relatively rare, but important to recognise and treat promptly. T-cell mediated HSRs are more frequent amongst patients with co-existing HIV infection. Some patients develop multiple sensitisation to anti-TB drugs. Whilst skin tests, patch tests and in vitro diagnostics have been used in the investigation of HSRs to anti-TB drugs, their predictive value is not established, they are onerous, require specialist input of an allergist and are resource-dependent. This is compounded by the global, unmet demand for allergy specialists, particularly in low income countries (LICs) / LMICs and now the challenging circumstances of the SARS-CoV-2 pandemic. This narrative review provides a critical analysis of the limited published evidence on this topic and proposes a cautious and pragmatic approach to optimise and standardise the management of HSRs to anti-TB drugs. This includes clinical risk stratification and a dual strategy involving sequential re-challenge and rapid drug desensitisation. Furthermore, a concerted international effort is needed to generate real-time data on ADRs, HSRs, safety and clinical outcomes of these interventions.

Association between 9-month isoniazid prophylaxis of latent tuberculosis and severe hepatitis in patients treated with TNF inhibitors

To investigate associations between isoniazid for latent tuberculosis and risk of severe hepatitis, affecting patients with rheumatoid arthritis or ankylosing spondylitis whose treatment includes tumor necrosis factor inhibitors. Our self-controlled case series study analyzed Taiwan’s National Health Insurance Database from 2003 to 2015 to identify RA or AS patients, aged ≥ 20 years, receiving TNF inhibitors and a 9-month single isoniazid treatment. The outcome of interest was hospitalization due to severe hepatitis. We defined risk periods by isoniazid exposure (days): 1–28, 29–56, 57–84, 85–168, 169–252, and 253–280. To compare risk of severe hepatitis in exposed and non-exposed periods, we performed conditional Poisson regressions to generate incidence rate ratios (IRR) and 95% confidence intervals, with adjustment of patients’ baseline covariates including age, sex, HBV, HCV and related medication. Of 54,267 RA patients and 137,889 AS patients identified between 2000 and 2015, 11,221 (20.7%) RA and 4,208 (3.1%) AS patients underwent TNFi therapy, with 722 (5%) receiving isoniazid for latent tuberculosis. We identified 31 incident cases (4.3%) of hospitalization due to severe hepatitis. Of these hospitalization events, 5 occurred in the exposed periods, 25 occurred in the INH unexposed periods, and 1 occurred in the pre-exposure period. Compared with non-exposure, the risk of severe hepatitis was higher in exposed periods (incidence rate ratio [IRR]: 5.1, 95% CI: 1.57–16.55), especially 57–84 days (IRR: 17.29, 95% CI: 3.11–96.25) and 85–168 days (IRR:10.55, 95% CI: 1.90–58.51). The INH related fatal hepatotoxicity was not identified in our study. Our findings suggest an association between risk of severe hepatitis and exposure to isoniazid in patients with RA or AS under TNFi therapy, particularly within the exposed period 57–168 days. A close monitoring of liver function is mandatory to minimize the risk, especially within the first 6 months after initiation of 9 months isoniazid.

The implementation of rifapentine and isoniazid (3HP) in two remote Arctic communities with a predominantly Inuit population, the Taima TB 3HP study

Background: The incidence of TB among Inuit is the highest in Canada. A significantly shorter latent TB infection (LTBI) treatment with rifapentine and isoniazid once weekly for 12 weeks (3HP) is now available in limited settings in Canada.Methods: A prospective open-label 2-year observational postmarketing study was conducted introducing 3HP for the first time in Canada in Iqaluit followed by a program rollout in Qikiqtarjuaq, Nunavut.Results: A total of 247 people were offered 3HP, 102 in the Iqaluit postmarketing study and 145 in the Qikiqtarjuaq program roll out. Although statistical significance was not reached, more people who started treatment completed treatment in the 3HP group (Iqaluit, 60/73 (82.2%) and Qikiqtarjuaq, 89/115 (77.4%)) than in the historical control 9INHgroup (306/420 = 72.9%) (p = 0.2). Most of the adverse events in 3HP treated patients were associated with mild discomfort but no disruption of normal daily activity. Not drinking alcohol was associated with increased 3HP completion (OR 13.33, 95% CI, 2.27-78.20) as was not taking concomitant medications (OR 7.19, 95% CI, 1.47-35.30).Conclusions: The present study supports the feasibility and safety profile of 3HP for the treatment of LTBI in Nunavut.

Cost-effectiveness analysis of 3 months of weekly rifapentine and isoniazid compared to isoniazid monotherapy in a Canadian arctic setting

OBJECTIVE

To assess the cost effectiveness of once weekly rifapentine and isoniazid for 12 weeks (3HP) to the current standard care for latent tuberculosis (TB) infection (LTBI) in Iqaluit, Nunavut.

DESIGN

A cost-effectiveness analysis using a Markov model reflecting local practices for LTBI treatment.

SETTING

A remote Canadian arctic community with a high incidence of TB.

PARTICIPANTS

Hypothetical patients with LTBI.

INTERVENTIONS

The cost effectiveness of 3HP was compared with the existing standard of care in the study region which consists of 9 months of twice weekly isoniazid (9H) given by directly observed therapy.

OUTCOME MEASURES

Effectiveness was measured in quality-adjusted life years (QALYs) with model parameters were derived from historical programmatic data, a local implementation study of 3HP and published literature. Costs from the perspective of the Nunavut healthcare system were measured in 2019 US dollars and were obtained primarily from local, empirically collected data. Secondary health outcomes included estimated TB cases and TB deaths averted using 3HP versus 9H. One way and probabilistic sensitivity analyses were performed.

RESULTS

The 3HP regimen was dominant over 9H: costs were lower (US$628 vs US$924/person) and health outcomes slightly improved (20.14 vs 20.13 QALYs/person). In comparison to 9H, 3HP treatment resulted in fewer TB cases (27.89 vs 30.16/1000 persons) and TB deaths (2.29 vs 2.48/1000 persons). 3HP completion, initiation and risk of fatal adverse events were the primary drivers of cost effectiveness.

CONCLUSION

In a remote Canadian arctic setting, using 3HP instead of 9H for LTBI treatment may result in cost savings and similar or improved health outcomes.

Safety and feasibility of 1 month of daily rifapentine plus isoniazid to prevent tuberculosis in children and adolescents: a prospective cohort study

BACKGROUND

Shorter regimens for tuberculosis prevention can improve completion rates and protection against developing active tuberculosis disease after tuberculosis exposure. We aimed to assess the safety and feasibility of 1 month of daily isoniazid and rifapentine (1HP) in children and adolescents in a low-resource setting in south Asia with low prevalence of HIV.

METHODS

This prospective cohort study was done in eight tuberculosis facilities in Karachi, Pakistan. Eligible participants were aged 2-19 years and were household contacts of patients with drug-susceptible tuberculosis infection. After clinical, radiological, and laboratory evaluation to rule out tuberculosis disease, participants were prescribed 1HP as a preventive regimen. Isoniazid was administered as 100 mg or 300 mg oral tablets and rifapentine was administered as 150 mg oral tablets. Dosing was according to participant bodyweight. The primary endpoints were the cumulative probability of a household contact completing all stages of the preventive care cascade, assessed in all eligible participants, and the proportion of household contacts completing 1HP, assessed among all those who initiated the regimen. Safety was assessed in all household contacts who initiated the 1HP regimen.

FINDINGS

Between Dec 21, 2019, and March 20, 2020, 1395 household contacts of 253 patients with tuberculosis were identified, including 678 household contacts who were eligible to participate. 628 (93%) completed evaluation, of whom ten (2%) had active tuberculosis disease. Of the 618 individuals eligible for tuberculosis prevention, 408 (66%) initiated 1HP, 385 (94%) of whom completed the regimen. The median duration of 1HP was 31 days (IQR 30-32) in those who completed the regimen. The cumulative probability of completing all steps of the tuberculosis prevention cascade was 58%. A girl aged 11 years developed tuberculosis disease within 6 months of completing 1HP. A boy aged 14 years developed a burning sensation during 1HP therapy and discontinued the regimen. No other adverse events were observed.

INTERPRETATION

1HP can be safely and feasibly implemented as tuberculosis prevention in children and adolescents in programmatic settings.

FUNDING

The Global Fund to Fight AIDS, Tuberculosis and Malaria.

The paradigm shift in the approach to management of latent tuberculosis infection in high tuberculosis burden countries

Introduction: Addressing the reservoir of Latent Tuberculosis Infection (LTBI) is critical to TB elimination because if left untreated LTBI can progress to active TB disease. This additional burden can prevent achieving the global targets of TB elimination. Management of LTBI has been a low priority target for National TB Elimination Programs (NTEP) due to various challenges in the field settings.Areas covered: This article reviews the most recent advances in the field of LTBI management including newer diagnostics, treatments, vaccines, programmatic challenges, and gaps and suggests a way forward that can be adopted by NTEPs for LTBI. We searched the electronic databases of PubMed, Scopus, and Web of Science for studies published between 2010 to 2020 using MeSH terms: Latent TB Diagnosis, TB preventive therapy, Vaccines, LTBI, and HIV/ COVID.Expert opinion: NTEPs of developing countries should offer a better, point-of-care diagnostic, and effective treatment for LTBI to reduce the number of new TB cases arising from people infected with M.tb. Awareness about LTBI should be increased among the health system staff and the public. More funding is needed to advance research as well as implement the newer findings in the NTEP to achieve the End TB targets by 2035.

Involvement of dopamine signaling pathway in neurodevelopmental toxicity induced by isoniazid in zebrafish

AIMS

This study evaluated the neurodevelopmental toxicity of isoniazid (INH) in zebrafish embryos and the underlying mechanism.

METHODS

Zebrafish embryos were exposed to different concentrations (2 mM, 4 mM, 8 mM, 16 mM, 32 mM) INH for 120 hpf. During the exposure period, the percentage of embryo/larva mortality, hatching, and morphological malformation were checked every 24 h until 120 hpf. The development of blood vessels in the brain was observed at 72 hpf and 120 hpf, and behavioral capacity and acridine orange (AO) staining were measured at 120 hpf. Alterations in the mRNA expression of apoptosis and dopamine signaling pathway related genes were assessed by real-time quantitative PCR (qPCR).

RESULTS

INH considerably inhibited zebrafish embryo hatching and caused zebrafish larval malformation (such as brain malformation, delayed yolk sac absorption, spinal curvature, pericardial edema, and swim bladder defects). High concentration of INH (16 mM, 32 mM) even induced death of zebrafish. In addition, INH exposure markedly restrained the ability of the zebrafish autonomous movement, shortened the length of dopamine neurons and inhibited vascular development in the brain. No obvious apoptotic cells were observed in the control group, whereas considerable numbers of apoptotic cells appeared in the head of INH-treated larvae at 120 hpf. PCR results indicated that INH significantly raised the transcription levels of caspase-3, -8, -9, and bax and significantly decreased bcl-2 and bcl-2/bax in the zebrafish apoptotic signaling pathway. INH also markedly decreased the genes related to dopamine signaling pathway (th1, dat, drd1, drd2a, drd3, and drd4b).

CONCLUSIONS

Experimental results indicated that INH had obvious neurodevelopmental toxicity in zebrafish. Persistent exposure to INH for 120 h caused apoptosis, decreased dopaminergic gene expression, altered vasculature, and reduced behaviors.

Development of a limited sampling strategy for the estimation of isoniazid exposure considering N-acetyltransferase 2 genotypes in Korean patients with tuberculosis

A limited sampling strategy (LSS) to estimate the exposure to isoniazid was developed considering N-acetyltransferase 2 (NAT2) genotypes in Korean patients with tuberculosis. The influence of the genotypes on the pharmacokinetics of isoniazid was also evaluated. A total of 33 participants participated in the study and received isoniazid 300 mg once daily. Evaluable participants consist of ten slow (SA), fourteen intermediate (IA) and six rapid acetylators (RA). As expected, isoniazid exposure was higher (mean AUC, 28.4 versus 7.6 mg*h/L) and systemic clearance lower (mean apparent clearance, 14.8 versus 50.6 L/h) in SAs than RAs. The formulas to estimate isoniazid exposure were constructed using one or more concentration-time points that correlate with the area under the concentration-time curve (AUC). The LSS using a formula of single concentration-time point at 4 h post dose (C₄) is applicable for all acetylators to the therapeutic drug monitoring (TDM) of isoniazid in patients with tuberculosis when evaluated using the Deming regression and Bland-Altman plot (AUC = 1.53 + 10.03*C₄, adjusted r² = 0.95, p < 0.001). Considering that SAs are more prone to adverse effects, pre-dose NAT2 genotyping would be valuable for optimal isoniazid dosing in conjunction with TDM.

Analysis of Severe Adverse Events Reported Among Patients Receiving Isoniazid-Rifapentine Treatment for Latent Mycobacterium tuberculosis Infection-United States, 2012-2016

We analyzed data from 2012 to 2016 for patients who were hospitalized or who died after ≥1 dose of isoniazid-rifapentine for treatment of latent Mycobacterium tuberculosis infection. No patients died; 15 were hospitalized. Nine patients experienced hypotension, and 5 had elevated serum aminotransferases, reinforcing the need for vigilant monitoring during treatment.

Malaria and tuberculosis as diseases of neglected populations: state of the art in chemotherapy and advances in the search for new drugs

Malaria and tuberculosis are no longer considered to be neglected diseases by the World Health Organization. However, both are huge challenges and public health problems in the world, which affect poor people, today referred to as neglected populations. In addition, malaria and tuberculosis present the same difficulties regarding the treatment, such as toxicity and the microbial resistance. The increase of Plasmodium resistance to the available drugs along with the insurgence of multidrug- and particularly tuberculosis drug-resistant strains are enough to justify efforts towards the development of novel medicines for both diseases. This literature review provides an overview of the state of the art of antimalarial and antituberculosis chemotherapies, emphasising novel drugs introduced in the pharmaceutical market and the advances in research of new candidates for these diseases, and including some aspects of their mechanism/sites of action.

Bimekizumab in patients with active psoriatic arthritis: results from a 48-week, randomised, double-blind, placebo-controlled, dose-ranging phase 2b trial

BACKGROUND

Dual neutralisation of interleukin 17A (IL17A) and interleukin 17F (IL17F) is a potential novel therapeutic approach in psoriatic arthritis. We assessed bimekizumab, a monoclonal antibody that selectively neutralises IL17A and IL17F, in patients with active psoriatic arthritis.

METHODS

BE ACTIVE was a randomised, double-blind, placebo-controlled, dose-ranging phase 2b study done at 41 sites in the Czech Republic, Germany, Hungary, Poland, Russia, and the USA. Eligible patients aged 18 years or older with active adult-onset psoriatic arthritis and symptoms for at least 6 months were randomly assigned (1:1:1:1:1) to placebo, 16 mg bimekizumab, 160 mg bimekizumab, 160 mg bimekizumab with a one-off 320 mg loading dose, or 320 mg bimekizumab, which were administered as subcutaneous injections every 4 weeks for 12 weeks. After 12 weeks, patients assigned to the placebo and 16 mg bimekizumab groups were randomly reassigned (1:1) to either 160 mg or 320 mg bimekizumab, and all other patients remained on their originally assigned initial dose up to 48 weeks. Both participants and researchers were blinded to treatment allocation in the first 12 weeks, and blinded to the dose of bimekizumab thereafter. The primary endpoint was the proportion of patients with at least 50% improvement in the American College of Rheumatology response criteria at week 12, which was assessed in all patients who received at least one dose of study treatment and had a valid measurement of the primary efficacy endpoint at baseline. The trial, including all follow-up, has been completed. This trial is registered with ClinicalTrials.gov, NCT02969525.

FINDINGS

Between Oct 27, 2016, and July 16, 2018, 308 patients were screened, and 206 were randomly assigned: 42 to the placebo group, and 41 each to the four bimekizumab groups. At 12 weeks, compared with the placebo group, significantly more patients in the 16 mg bimekizumab (odds ratio [OR] 4·2 [95% CI 1·1-15·2]; p=0·032), 160 mg bimekizumab (8·1 [2·3-28·7]; p=0·0012), and 160 mg (loading dose) bimekizumab (9·7 [2·7-34·3]; p=0·0004) groups achieved an ACR50 response. At 12 weeks, 24 (57%) of 42 patients in the placebo group and 68 (41%) of the 164 patients in the bimekizumab groups reported treatment-emergent adverse events. Most of these adverse events were mild or moderate. Serious treatment-emergent adverse events occurred in nine patients, eight of whom were receiving bimekizumab. No deaths or cases of inflammatory bowel disease were reported.

INTERPRETATION

Bimekizumab doses of 16 mg and 160 mg (with or without a 320 mg loading dose) were associated with significant improvements in ACR50 compared with placebo, with an acceptable safety profile. Our results support phase 3 investigation of bimekizumab as a treatment for psoriatic arthritis.

FUNDING

UCB Pharma.

Short-course regimens of rifapentine plus isoniazid to treat latent tuberculosis infection in older Chinese patients: a randomised controlled study

Latent tuberculosis infection (LTBI) management is now a critical component of the World Health Organization's End TB Strategy.In this randomised controlled trial (Chinese Clinical Trial Registry identifier ChiCTR-IOR-15007202), two short-course regimens with rifapentine plus isoniazid (a 3-month once-weekly regimen and a 2-month twice-weekly regimen) were initially designed to be evaluated for rural residents aged 50-69 years with LTBI in China.Due to the increasingly rapid growth and unexpected high frequency of adverse effects, the treatments were terminated early (after 8 weeks for the once-weekly regimen and after 6 weeks for the twice-weekly regimen). In the modified intention-to-treat analysis on the completed doses, the cumulative rate of active disease during 2 years of follow-up was 1.21% (14 out of 1155) in the untreated controls, 0.78% (10 out of 1284) in the group that received the 8-week once-weekly regimen and 0.46% (six out of 1299) in the group that received the 6-week twice-weekly regimen. The risk of active disease was decreased, with an adjusted hazard ratio of 0.63 (95% CI 0.27-1.43) and 0.41 (95% CI 0.15-1.09) for the treatments, respectively. No significant difference was found in the occurrence of hepatotoxicity (1.02% (13 out of 1279) versus 1.17% (15 out of 1279); p=0.704).The short regimens tested must be used with caution among the elderly because of the high rates of adverse effects. Further work is necessary to test the ultrashort regimens in younger people with LTBI.

Treatment of tuberculosis infection in children

INTRODUCTION

Identifying and treating children with tuberculosis (TB) infection in both low and high-TB burden settings will decrease the incidence of TB disease worldwide. Areas covered: This review covers each of the available TB infection treatment options for children based on effectiveness, safety, tolerability and treatment completion rates. Six to 9 months of daily administered isoniazid is no longer the treatment of choice for many children with TB infection. Shorter, rifamycin based, TB infection treatment regimens are effective, safe and easier for children to complete. Fluroquinolone-based regimens are recommended for the treatment of children infected by a source case with drug-resistant TB. Directly observed therapy (DOT) programs improve childhood TB infection treatment completion rates. Expert commentary: As shorter, rifamycin-based, TB infection treatment regimens offer superior treatment success rate in both adults and children; the widespread use of these regimens has huge potential to decrease the burden of TB disease worldwide. The implementation of these programs will involve improving patient access to the medications, decreasing their cost to the patient, and the use of novel electronic methods to document patient treatment completion.

A shorter treatment regimen for latent tuberculosis infection holds promise for at-risk Canadians

Despite recent success in reducing its incidence, tuberculosis remains a considerable challenge in Canada, particularly among foreign-born and Indigenous populations. A key component of the strategy for controlling the disease is the treatment of latent tuberculosis infection. The standard treatment consists of isoniazid (INH) daily for nine months. In recent years, shorter regimens have been developed in the hope of increasing rates of treatment acceptance and completion. Of these, the shortest and most recently developed is a combination of INH and rifapentine taken once weekly for 12 doses (3HP), typically using directly observed therapy (DOT). This regimen has been approved by the Food and Drug Administration in the United States but is not yet authorized in Canada. Based on a rapidly expanding number of observational studies and randomized controlled trials, 12 weeks of 3HP appears to have similar efficacy to nine months of INH, a favourable adverse event profile and potentially improved rates of treatment completion. Although rates of treatment acceptance, the role of self-administered therapy and the regimen's cost-effectiveness within the Canadian context remain uncertain, 3HP is a promising alternative to existing treatments for LTBI.