Latent TB treatment regimens in 2023: Wetmore TB clinic in New Orleans

The USPSTF has updated Latent TB Infection (LTBI) screening and treatment recommendations in 2023; describing treatment courses, side effects and benefits associated with each regimen. Overall, rifampin-containing shortened regimens are the preferred modality for LTBI treatment. A recent study in 2023 evaluated adherence and tolerance of the isoniazid(INH) + rifapentine(RPT), or "3HP" regimen and identified patient groups that may be at higher risk for non-completion of this regimen. It emphasized the need for targeted education at the beginning of treatment, to avoid early discontinuation. Our experience in New Orleans demonstrated that the 3HP is well-tolerated, with higher completion rates than other LTBI regimens. Utilizing a retrospective chart review model, we reviewed 756 patients who were treated for LTBI over a two-year period from 1/2021--12/2022. The three possible treatment regimens included isoniazid (INH) alone, rifampin (RIF) alone, or INH + RPT (3HP). Of these regimens, the highest completion rate was in the 3HP group, despite literature suggesting this regimen is difficult to tolerate. Our experience suggests that this may still be an efficacious regimen that is well-tolerated if there is good access to clinicians to discuss mitigating side effects. More data is needed to determine factors that led to the success or failure for each regimen. Our clinic does have increased availability of nursing and medical staff to discuss side effects and answer questions, which may have contributed to our relatively higher success rate. In addition, we applied the review recommendations to our patient population, and would recommend the consideration of diabetes, heavy alcohol use, and tobacco use as risk factors for patients that would benefit from LTBI screening and treatment.

Twice-Daily Dolutegravir Based Antiretroviral Therapy with One Month of Daily Rifapentine and Isoniazid (1HP) for TB Prevention

BACKGROUND

One month of daily rifapentine + isoniazid (1HP) is an effective, ultrashort option for TB prevention in people with HIV (PWH). However, rifapentine may decrease antiretroviral drug concentrations and increase the risk of virologic failure. ACTG A5372 evaluated the effect of 1HP on the pharmacokinetics of twice daily dolutegravir.

METHODS

A5372 was a multicenter, pharmacokinetic study in PWH (≥18 years) already on dolutegravir-containing antiretroviral therapy with HIV RNA < 50 copies/mL. Participants received daily rifapentine/isoniazid (600mg/300mg) for 28 days as part of 1HP. Dolutegravir was increased to 50mg twice daily during 1HP and intensive pharmacokinetic sampling was performed on day 0 (before 1HP) and on the final day of 1HP treatment.

RESULTS

Thirty-two participants (41% female; 66% Black/African; median (Q1, Q3) age 42 (34, 49) years) were included in the pharmacokinetic analysis. Thirty-one of 32 had HIV RNA levels <50 copies/mL at the end of 1HP dosing. One participant had an HIV RNA of 160 copies/mL at day 28, with HIV RNA <50 copies/mL upon repeat testing on day 42. The median (Q1, Q3) dolutegravir trough concentration was 1751 ng/mL (1195, 2542) on day 0 vs. 1987ng/mL (1331, 2278) on day 28 (day 28:day 0 GMR 1.05, [90% CI 0.93-1.2]; p = 0.43). No serious adverse events were reported.

CONCLUSION

Dolutegravir trough concentrations with 50mg twice daily dosing during 1HP treatment were greater than those with standard dose dolutegravir once daily without 1HP. These pharmacokinetic, virologic, and safety data provide support for twice daily dolutegravir use in combination with 1HP for TB prevention.

A mechanism study on the synergistic effects of rifapentine and fluconazole against fluconazole-resistant Candida albicans in vitro

Candida albicans (C. albicans) is one of the most common clinical isolates of systemic fungal infection. Long-term and inappropriate use of antifungal drugs can cause fungal resistance, which poses a great challenge to the clinical treatment of fungal infections. The combination of antifungal drugs and non-antifungal drugs to overcome the problem of fungal resistance has become a research hotspot in recent years. Our previous study found that the combination of rifapentine (RFT) and fluconazole (FLC) has a significant synergistic against FLC-resistant C. albicans. The present study aimed to further verify the synergistic effect between FLC and RFT against the FLC-resistant C. albicans 100, and explore the underlying mechanism. The growth curve and spot assay test not only showed the synergistic effect of FLC and RFT on FLC-resistant C. albicans in vitro but exhibited a dose-dependent effect on RFT, indicating that RFT may play a principal role in the synergic effect of the two drugs. Flow cytometry showed that the combined use of RFT and FLC arrested cells in the G2/M phase, inhibiting the normal division and proliferation of FLC-resistant C. albicans. Transmission electron microscopy (TEM) demonstrated that FLC at a low concentration could still cause a certain degree of damage to the cell membrane in the FLC-resistant C. albicans, as represented by irregular morphologic changes and some defects observed in the cell membrane. When FLC was used in combination with RFT, the nuclear membrane was dissolved and the nucleus was condensed into a mass. Detection of the intracellular drug concentration of fungi revealed that the intracellular concentration of RFT was 31-195 fold that of RFT alone when it was concomitantly used with FLC. This indicated that FLC could significantly increase the concentration of RFT in cells, which may be due to the damage caused to the fungal cell membrane by FLC. In short, the present study revealed a synergistic mechanism in the combined use of RFT and FLC, which may provide a novel strategy for the clinical treatment of FLC-resistant C. albicans.

The incorporation of the 3HP regimen for tuberculosis preventive treatment in the Brazilian health system: a secondary-database nationwide analysis

Introduction

The recommendation of rifampin-based shorter - and safer - regimens for tuberculosis preventive treatment (TPT) is progressively replacing monotherapy with isoniazid by different countries. The Brazilian Ministry of Health (MoH) approved the incorporation of the Rifapentine + isoniazid regimen (3HP) at the end of 2020, with free distribution in the Brazilian Unified Health System (SUS) started from the last quarter of 2021. The objectives were to describe the implementation of the IL-TB System (Information System of TPT Notification) and uptake of Rifapentine + isoniazid (3HP) and Isoniazid (6H or 9H) in Brazil.

Methods

A quantitative observational and descriptive was performed using the IL-TB National System as the main data source, from January 2018 to December 2022.

Results and discussion

There was a steady increase of the number of TPT prescription quarterly throughout the period, which reflects the implementation of the system itself and the progressive adherence of the health system to the non-compulsory notification of new TPT. The substitution of isoniazid (6H or 9H) by 3HP is progressing. The 3HP regimen represented less than 4% of the total administered by the end of 2021, reaching around 30% in the second half of 2022 and 40% in the last quarters of 2022. The study points not only to the need to expand TPT in the country, but also to accelerate 3HP uptake and to encourage the municipalities to notify to the IL-TB system, since there is still a high level of underreporting.

The pipeline for drugs for control and elimination of neglected tropical diseases: 2. Oral anti-infective drugs and drug combinations for off-label use

In its 'Road map for neglected tropical diseases 2021-2030', the World Health Organization outlined its targets for control and elimination of neglected tropical diseases (NTDs) and research needed to achieve them. For many NTDs, this includes research for new treatment options for case management and/or preventive chemotherapy. Our review of small-molecule anti-infective drugs recently approved by a stringent regulatory authority (SRA) or in at least Phase 2 clinical development for regulatory approval showed that this pipeline cannot deliver all new treatments needed. WHO guidelines and country policies show that drugs may be recommended for control and elimination for NTDs for which they are not SRA approved (i.e. for 'off-label' use) if efficacy and safety data for the relevant NTD are considered sufficient by WHO and country authorities. Here, we are providing an overview of clinical research in the past 10 years evaluating the anti-infective efficacy of oral small-molecule drugs for NTD(s) for which they are neither SRA approved, nor included in current WHO strategies nor, considering the research sponsors, likely to be registered with a SRA for that NTD, if found to be effective and safe. No such research has been done for yaws, guinea worm, Trypanosoma brucei gambiense human African trypanosomiasis (HAT), rabies, trachoma, visceral leishmaniasis, mycetoma, T. b. rhodesiense HAT, echinococcosis, taeniasis/cysticercosis or scabies. Oral drugs evaluated include sparfloxacin and acedapsone for leprosy; rifampicin, rifapentin and moxifloxacin for onchocerciasis; imatinib and levamisole for loiasis; itraconazole, fluconazole, ketoconazole, posaconazole, ravuconazole and disulfiram for Chagas disease, doxycycline and rifampicin for lymphatic filariasis; arterolane, piperaquine, artesunate, artemether, lumefantrine and mefloquine for schistosomiasis; ivermectin, tribendimidine, pyrantel, oxantel and nitazoxanide for soil-transmitted helminths including strongyloidiasis; chloroquine, ivermectin, balapiravir, ribavirin, celgosivir, UV-4B, ivermectin and doxycycline for dengue; streptomycin, amoxicillin, clavulanate for Buruli ulcer; fluconazole and isavuconazonium for mycoses; clarithromycin and dapsone for cutaneous leishmaniasis; and tribendimidine, albendazole, mebendazole and nitazoxanide for foodborne trematodiasis. Additional paths to identification of new treatment options are needed. One promising path is exploitation of the worldwide experience with 'off-label' treatment of diseases with insufficient treatment options as pursued by the 'CURE ID' initiative.

Cost-effectiveness of 3-months isoniazid and rifapentine compared to 9-months isoniazid for latent tuberculosis infection: a systematic review

BACKGROUND

We conducted a systematic review examining the cost effectiveness of a 3-month course of isoniazid and rifapentine, known as 3HP, given by directly observed treatment, compared to 9 months of isoniazid that is directly observed or self-administered, for latent tuberculosis infection. 3HP has shown to be effective in reducing progression to active tuberculosis and like other short-course regimens, has higher treatment completion rates compared to standard regimens such as 9 months of isoniazid. Decision makers would benefit from knowing if the higher up-front costs of rifapentine and of the human resources needed for directly observed treatment are worth the investment for improved outcomes.

METHODS

We searched PubMed, Embase, CINAHL, LILACS, and Web of Science up to February 2022 with search concepts combining latent tuberculosis infection, directly observed treatment, and cost or cost-effectiveness. Studies included were in English or French, on human subjects, with latent tuberculosis infection, provided information on specified anti-tubercular therapy regimens, had a directly observed treatment arm, and described outcomes with some cost or economic data. We excluded posters and abstracts, treatment for multiple drug resistant tuberculosis, and combined testing and treatment strategies. We then restricted our findings to studies examining directly-observed 3HP for comparison. The primary outcome was the cost and cost-effectiveness of directly-observed 3HP.

RESULTS

We identified 3 costing studies and 7 cost-effectiveness studies. The 3 costing studies compared directly-observed 3HP to directly-observed 9 months of isoniazid. Of the 7 cost-effectiveness studies, 4 were modelling studies based in high-income countries; one study was modelled on a high tuberculosis incidence population in the Canadian Arctic, using empiric costing data from that setting; and 2 studies were conducted in a low-income, high HIV-coinfection rate population. In five studies, directly-observed 3HP compared to self-administered isoniazid for 9 months in high-income countries, has incremental cost-effectiveness ratios that range from cost-saving to $5418 USD/QALY gained. While limited, existing evidence suggests 3HP may not be cost-effective in low-income, high HIV-coinfection settings.

CONCLUSION

Cost-effectiveness should continue to be assessed for programmatic planning and scale-up, and may vary depending on existing systems and local context, including prevalence rates and patient expectations and preferences.

Pharmacokinetics of isoniazid and rifapentine in young paediatric patients with latent tuberculosis infection

OBJECTIVES

This study investigated the steady-state pharmacokinetic profiles of 3-month weekly rifapentine plus isoniazid (3HP) in children with latent tuberculosis infection (LTBI). Factors including tablet integrity, food, and pharmacogenetics were also assessed.

METHODS

During the 3HP treatment, blood and urine samples were collected on week 4. Isoniazid and rifapentine levels were measured using a high-performance liquid chromatography technique. Genetic variation of arylamine N-acetyltransferase 2 (NAT2) and arylacetamide deacetylase (AADAC) were assessed by the MassARRAY®. Safety and clinical outcomes at week 48 were monitored.

RESULTS

Twelve LTBI children [age 3.8 (range 2.1-4.9 years old)] completed the treatment [isoniazid and rifapentine dose 25.0 (range 21.7-26.8) and 25.7 (range 20.7-32.1) mg/kg, respectively]. No serious adverse events or active tuberculosis occurred. Tablet integrity was associated with decreased area under the concentration-time curve (91 vs 73 mg.hr/L, p = 0.026) and increased apparent oral clearance of isoniazid (0.27 vs 0.32 L/hr/kg, p = 0.019) and decreased rifapentine's renal clearance (CL_R, 0.005 vs 0.003 L/hr, p = 0.014). Food was associated with increased CL_R of isoniazid (3.45 vs 8.95 L/hr, p = 0.006) but not rifapentine. Variability in NAT2 and AADAC did not affect the pharmacokinetics of both drugs.

CONCLUSIONS

There is high variability in the pharmacokinetic profiles of isoniazid and rifapentine in young LTBI children. The variability was partly influenced by tablet integrity and food, but not pharmacogenetics. Further study in a larger cohort is warranted to display the relationship of these factors to treatment outcomes.

Rifapentine and isoniazid for prevention of tuberculosis in people with diabetes (PROTID): protocol for a randomised controlled trial

Background

Diabetes mellitus (DM) increases the risk of tuberculosis (TB) and will hamper global TB control due to the dramatic rise in type 2 DM in TB-endemic settings. In this trial, we will examine the efficacy and safety of TB preventive therapy against the development of TB disease in people with DM who have latent TB infection (LTBI), with a 12-week course of rifapentine and isoniazid (3HP).

Methods

The ‘Prevention of tuberculosis in diabetes mellitus’ (PROTID) consortium will randomise 3000 HIV-negative eligible adults with DM and LTBI, as evidenced by a positive tuberculin skin test or interferon gamma release assay, to 12 weeks of 3HP or placebo. Participants will be recruited through screening adult patients attending DM clinics at referral hospitals in Tanzania and Uganda. Patients with previous TB disease or treatment with a rifamycin medication or isoniazid (INH) in the previous 2 years will be excluded. The primary outcome is the occurrence of definite or probable TB disease; secondary outcome measures include adverse events, all-cause mortality and treatment completion. The primary efficacy analysis will be intention-to-treat; per-protocol analyses will also be carried out. We will estimate the ratio of TB incidence rates in intervention and control groups, adjusting for the study site using Poisson regression. Results will be reported as efficacy estimates (1-rate ratio). Cumulative incidence rates allowing for death as a competing risk will also be reported. Approximately 1000 LTBI-negative, HIV-negative participants will be enrolled consecutively into a parallel cohort study to compare the incidence of TB in people with DM who are LTBI negative vs positive. A number of sub-studies will be conducted among others to examine the prevalence of LTBI and active TB, estimate the population impact and cost-effectiveness of LTBI treatment in people living with DM in these African countries and address gaps in the prevention and therapeutic management of combined TB-DM.

Discussion

PROTID is anticipated to generate key evidence to guide decisions over the use of TB preventive treatment among people with DM as an important target group for better global TB control.

Trial registration

ClinicalTrials.govNCT04600167. Registered on 23 October 2020

Validation and application of a quantitative liquid chromatography tandem mass spectrometry assay for the analysis of rifapentine and 25-O-desacetyl rifapentine in human milk

A robust analytical method based on liquid chromatography coupled to tandem mass spectrometry was developed and validated to quantify rifapentine and 25-O-desacetyl rifapentine in human breast milk to aid in determining the breastfed infant risk to the excreted drug in human milk. Samples were extracted by a combination of protein precipitation and solid phase extraction using rifampicin-d3 as an internal standard. An Agilent® Poroshell 120 EC-C18 (4.6 mm × 50 mm, 2.7 µm) column was used for chromatographic separation employing an isocratic mobile phase consisting of acetonitrile: methanol: 0.1% formic acid (55/5/40, v/v/v) at a flow rate of 450 µL/min, and with a total run time of four minutes. Mass detection was on an AB Sciex API 4000 mass spectrometer using electrospray ionization in the positive mode and based on multiple reaction monitoring data acquisition. Rifapentine was accurately quantified across a concentration range of 2.00-2000 ng/mL and 25-O-desacetyl rifapentine from 4.00 to 2000 ng/mL. During validation, the inter- and intra-day accuracy and precision at the tested QC concentrations (N = 18) for rifapentine were between 97.4% and 100.6%, and 3.1% and 8.3%, respectively. The inter- and intra-day accuracy and precision for 25-O-desacetyl rifapentine were between 96.4% and 106.3%, and 6.7% and 11.8%, respectively. No significant matrix effects were observed, and the method was shown to be specific for rifapentine and 25-O-desacetyl rifapentine. Human milk samples (N = 22) generated during a phase I/II clinical trial were successfully analysed for rifapentine and 25-O-desacetyl rifapentine using this validated method. Concentrations for rifapentine and 25-O-desacetyl rifapentine in human milk samples (N = 22) ranged from 11.2-1180 ng/mL and 7.11-573 ng/mL, respectively.

An open label, randomised controlled trial of rifapentine versus rifampicin based short course regimens for the treatment of latent tuberculosis in England: the HALT LTBI pilot study

BACKGROUND

Ending the global tuberculosis (TB) epidemic requires a focus on treating individuals with latent TB infection (LTBI) to prevent future cases. Promising trials of shorter regimens have shown them to be effective as preventative TB treatment, however there is a paucity of data on self-administered treatment completion rates. This pilot trial assessed treatment completion, adherence, safety and the feasibility of treating LTBI in the UK using a weekly rifapentine and isoniazid regimen versus daily rifampicin and isoniazid, both self-administered for 12 weeks.

METHODS

An open label, randomised, multi-site pilot trial was conducted in London, UK, between March 2015 and January 2017. Adults between 16 and 65 years with LTBI at two TB clinics who were eligible for and agreed to preventative therapy were consented and randomised 1:1 to receive either a weekly combination of rifapentine/isoniazid ('intervention') or a daily combination of rifampicin/isoniazid ('standard'), with both regimens taken for twelve weeks; treatment was self-administered in both arms. The primary outcome, completion of treatment, was self-reported, defined as taking more than 90% of prescribed doses and corroborated by pill counts and urine testing. Adverse events were recorded.

RESULTS

Fifty-two patients were successfully enrolled. In the intervention arm 21 of 27 patients completed treatment (77.8, 95% confidence interval [CI] 57.7-91.4), compared with 19 of 25 (76.0%, CI 54.9-90.6) in the standard of care arm. There was a similar adverse effect profile between the two arms.

CONCLUSION

In this pilot trial, treatment completion was comparable between the weekly rifapentine/isoniazid and the daily rifampicin/isoniazid regimens. Additionally, the adverse event profile was similar between the two arms. We conclude that it is safe and feasible to undertake a fully powered trial to determine whether self-administered weekly treatment is superior/non-inferior compared to current treatment.

TRIAL REGISTRATION

The trial was funded by the NIHR, UK and registered with ISRCTN ( 26/02/2013-No.04379941 ).

Protocol for the 3HP Options Trial: a hybrid type 3 implementation-effectiveness randomized trial of delivery strategies for short-course tuberculosis preventive therapy among people living with HIV in Uganda

Background

Recently, a 3-month (12-dose) regimen of weekly isoniazid and rifapentine (3HP) was recommended by the World Health Organization for the prevention of tuberculosis (TB) among people living with HIV (PLHIV) on common antiretroviral therapy regimens. The best approach to delivering 3HP to PLHIV remains uncertain.

Methods

We developed a three-armed randomized trial assessing optimized strategies for delivering 3HP to PLHIV. The trial will be conducted at the Mulago Immune Suppression Syndrome (i.e., HIV/AIDS) clinic in Kampala, Uganda. We plan to recruit 1656 PLHIV, randomized 1:1 to each of the three arms (552 per arm). Using a hybrid type 3 effectiveness-implementation design, this pragmatic trial aims to (1) compare the acceptance and completion of 3HP among PLHIV under three delivery strategies: directly observed therapy (DOT), self-administered therapy (SAT), and informed patient choice of either DOT or SAT (with the assistance of a decision aid); (2) to identify processes and contextual factors that influence the acceptance and completion of 3HP under each delivery strategy; and (3) to estimate the costs and compare the cost-effectiveness of three strategies for delivering 3HP. The three delivery strategies were each optimized to address key barriers to 3HP completion using a theory-informed approach. We hypothesize that high levels of treatment acceptance and completion can be achieved among PLHIV in sub-Saharan Africa and that offering PLHIV an informed choice between the optimized DOT and SAT delivery strategies will result in greater acceptance and completion of 3HP. The design and planned evaluation of the delivery strategies were guided by the use of implementation science conceptual frameworks.

Discussion

3HP—one of the most promising interventions for TB prevention—will not be scaled up unless it can be delivered in a patient-centered fashion. We highlight shared decision-making as a key element of our trial design and theorize that offering PLHIV an informed choice between optimized delivery strategies will facilitate the highest levels of treatment acceptance and completion.

Trial registration

ClinicalTrials.gov: NCT03934931; Registered 2 May 2019.

Efficacy and safety of weekly rifapentine and isoniazid for tuberculosis prevention in Chinese silicosis patients: a randomized controlled trial

OBJECTIVE

The aim was to evaluate the efficacy, safety and completion rate of 3-month, once-weekly rifapentine and isoniazid for tuberculosis (TB) prevention among Chinese silicosis patients.

METHODS

Male silicosis patients without human immunodeficiency virus infection, aged 18 years to 65 years, with or without latent TB infection, were randomized 1:1 to receive rifapentine/isoniazid under direct observation (3RPT/INH group) or were untreated (observation group). Active TB incidence was compared between the two groups with 37 months of follow-up. Safety profile and complete rates were evaluated.

RESULTS

A total of 1227 adults with silicosis were screened; 513 eligible participants were enrolled and assigned to 3RPT/INH (n = 254) vs. observation (n = 259). Twenty-eight participants were diagnosed with active TB, and 9 and 19 in the 3RPT/INH group and observation groups, respectively. In the intention-to-treat analysis, the cumulative active TB rate was 3.5% (9/254) in the 3RPT/INH group and 7.3% (19/259) in the observation group (log rank p 0.055). On per protocol analysis, the cumulative active TB rates were 0.7% (1/139) and 7.3% (19/259), respectively (log rank p 0.01). Owing to an unexpected high frequency of adverse events (70.4%) and Grade 3 or 4 AEs (7.9%), the completion rate of the 3RPT/INH regimen was 54.7% (139/254). Twenty-six (10.8%) participants had flu-like systemic drug reactions; five (2.1%) experienced hepatotoxicity.

DISCUSSION

Weekly rifapentine/isoniazid prophylaxis prevented active TB among Chinese people with silicosis when taken, irrespective of LTBI screening; efficacy was reduced by lack of compliance. The regimen must be used with caution because of the high rates of adverse effects.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov number: NCT02430259.

Treatment of Latent Tuberculosis Infection-An Update

Treatment of latent tuberculosis infection (LTBI) is an important component of TB control and elimination. LTBI treatment regimens include once-weekly isoniazid plus rifapentine for 3 months, daily rifampin for 4 months, daily isoniazid plus rifampin for 3-4 months, and daily isoniazid for 6-9 months. Isoniazid monotherapy is efficacious in preventing TB disease, but the rifampin- and rifapentine-containing regimens are shorter and have similar efficacy, adequate safety, and higher treatment completion rates. Novel vaccine strategies, host immunity-directed therapies and ultrashort antimicrobial regimens for TB prevention, such as daily isoniazid plus rifapentine for 1 month, are under evaluation.

Development and in vitro characterization of rifapentine microsphere-loaded bone implants: a sustained drug delivery system

BACKGROUND

This study aimed to develop and evaluate a sustained drug delivery system for the treatment of osteoarticular tuberculosis (TB) to address the issues surrounding low drug concentration in lesions and bone defects or nonunion after debridement.

METHODS

The effects of rifapentine on the proliferation and cell cycle of bone marrow mesenchymal stem cells (BMSCs) were evaluated by Cell Counting Kit-8 (CCK-8) and flow cytometry. Rifapentine polylactic acid (PLA) sustained-release microspheres (RPSMs) were prepared through the double emulsion solvent evaporation method and investigated the antibacterial activity in vitro. In this study, two sustained drug delivery systems were prepared by integrating RPSMs and BMSCs into hydroxyapatite/β-tricalcium phosphate (HA/β-TCP) or allogeneic bone. We evaluated these drug delivery systems for dynamics of drug release and osteogenic ability by in vitro release test, alkaline phosphatase (ALP) and alizarin red staining, and real-time PCR.

RESULTS

The results showed that rifapentine concentrations up to 45.0 μg/mL had no effect on cell proliferation and cell cycle. The encapsulation and drug loading efficiency of the fabricated RPSMs were 78.11%±1.16% and 35.57%±0.85%, respectively. The RPSMs had uniform particle size distribution and a long-term anti-bacterium effect. The HA/β-TCP-implanted drug delivery system was found to be more effective in reducing the burst release and having a longer duration of sustained release and retention compared to allogeneic bone. The ALP and alizarin red staining and real-time PCR results showed that it had excellent osteoconductive and osteoinductive properties.

CONCLUSIONS

In conclusion, the sustained drug delivery system with HA/β-TCP as scaffold material represents a potential new strategy for TB infections and bone defects.

High-dose rifapentine with or without moxifloxacin for shortening treatment of pulmonary tuberculosis: Study protocol for TBTC study 31/ACTG A5349 phase 3 clinical trial

INTRODUCTION

Phase 2 clinical trials of tuberculosis treatment have shown that once-daily regimens in which rifampin is replaced by high dose rifapentine have potent antimicrobial activity that may be sufficient to shorten overall treatment duration. Herein we describe the design of an ongoing phase 3 clinical trial testing the hypothesis that once-daily regimens containing high dose rifapentine in combination with other anti-tuberculosis drugs administered for four months can achieve cure rates not worse than the conventional six-month treatment regimen.

METHODS/DESIGN

S31/A5349 is a multicenter randomized controlled phase 3 non-inferiority trial that compares two four-month regimens with the standard six-month regimen for treating drug-susceptible pulmonary tuberculosis in HIV-negative and HIV-positive patients. Both of the four-month regimens contain high-dose rifapentine instead of rifampin, with ethambutol replaced by moxifloxacin in one regimen. All drugs are administered seven days per week, and under direct observation at least five days per week. The primary outcome is tuberculosis disease-free survival at twelve months after study treatment assignment. A total of 2500 participants will be randomized; this gives 90% power to show non-inferiority with a 6.6% margin of non-inferiority.

DISCUSSION

This phase 3 trial formally tests the hypothesis that augmentation of rifamycin exposures can shorten tuberculosis treatment to four months. Trial design and standardized implementation optimize the likelihood of obtaining valid results. Results of this trial may have important implications for clinical management of tuberculosis at both individual and programmatic levels.

TRIAL REGISTRATION

NCT02410772. Registered 8 April 2015,https://www.clinicaltrials.gov/ct2/show/NCT02410772?term=02410772&rank=1.

Adverse event and treatment completion rates of a 12-dose weekly isoniazid and rifapentine course for South Korean healthcare workers

PURPOSE

We investigated the adverse events (AEs) and treatment completion rates of a 3 month course of once-weekly isoniazid and rifapentine (3H₁P₁) in South Korean health care workers (HCWs) with latent tuberculosis infection (LTBI).

METHODS

HCWs who were candidates for LTBI treatment were enrolled from two tertiary referral centers between December 2016 and October 2017. From December 2016 through March 2017, HCWs who agreed were treated with the 3H₁P₁ regimen (3H₁P₁ group). Their compliance and AEs were prospectively collected. From April 2017 onward, HCWs who required LTBI treatment received 3 months of isoniazid plus rifampin (3HR group), and their medical records were retrospectively reviewed.

RESULTS

During the study period, 406 HCWs were treated, 226 (55.7%) in the 3H₁P₁ group, and 180 (44.3%) in the 3HR group. The number of subjects with AEs was significantly greater in the 3H₁P₁ group (75.2% vs 56.7%, P < 0.001), in particular a flu-like syndrome (19.0% vs. 0%, P < 0.001). However, hepatotoxicity occurred less frequently in those receiving 3H₁P₁ (7.5% vs. 20.0%, P < 0.001). Per protocol definition, anaphylaxis developed in 1.8% of the 3H₁P₁ group. The overall treatment completion rate was greater in the 3H₁P₁ group (92.9% vs 86.7%, P = 0.036).

CONCLUSIONS

The 3H₁P₁ regimen had a higher treatment completion rate and lower hepatotoxicity compared with the 3HR regimen. However, it resulted in a higher rate of flu-like syndromes. Additionally, a few subjects had anaphylaxis, although there were no fatalities.

Treatment completion for latent tuberculosis infection in Norway: a prospective cohort study

Background

Successful treatment of latent tuberculosis infection (LTBI) is essential to reduce tuberculosis (TB) incidence rates in low-burden countries. This study measures treatment completion and determinants of non-completion of LTBI treatment in Norway in 2016.

Methods

This prospective cohort study included all individuals notified with LTBI treatment to the Norwegian Surveillance System for Infectious Diseases (MSIS) in 2016. We obtained data from MSIS and from a standardized form that was sent to health care providers at the time of patient notification to MSIS. We determined completion rates. Pearson’s chi squared test was used to study associations between pairs of categorical variables and separate crude and multivariable logistic regression models were used to identify factors associated with treatment completion and adverse drug effects.

Results

We obtained information on treatment completion from 719 of the 726 individuals notified for LTBI treatment in 2016. Overall, 91% completed treatment. Treatment completion was highest in the foreign-born group [foreign-born, n = 562 (92%) vs Norwegian-born, n = 115 (85%), p = 0.007]. Treatment completion did not differ significantly between prescribed regimens (p = 0.124). Adverse events were the most common reason for incomplete treatment. We found no significant differences in adverse events when comparing weekly rifapentine (3RPH) with three months daily isoniazid and rifampicin (3RH). However, there were significantly fewer adverse events with 3RPH compared to other regimens (p = 0.037). Age over 35 years was significantly associated with adverse events irrespective of regimen (p = 0.024), whereas immunosuppression was not significantly associated with adverse events after adjusting for other variables (p = 0.306). Treatment under direct observation had a significant effect on treatment completion for foreign-born (multivariate Wald p-value = 0.017), but not for Norwegian-born (multivariate Wald p-value = 0.408) individuals.

Conclusions

We report a very high treatment completion rate, especially among individuals from countries with high TB incidence. The follow-up from tuberculosis-coordinators and the frequent use of directly observed treatment probably contributes to this. Few severe adverse events were reported, even with increased age and in individuals that are more susceptible. While these results are promising, issues of cost-effectiveness and targeting treatment to individuals at highest risk of TB are important components of public health impact.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3468-z) contains supplementary material, which is available to authorized users.

Twelve-dose weekly rifapentine plus isoniazid for latent tuberculosis infection: A multicentre randomised controlled trial in Taiwan

Treatment of latent tuberculosis (TB) infection (LTBI) effectively prevents its progression to active TB. However, long treatment duration and drug-related hepatotoxicity limit the effectiveness of the 9-month daily isoniazid (9H). Data on the 3-month weekly rifapentine plus isoniazid (3 HP) in Asian populations are currently unavailable. We prospectively randomised the LTBI contacts aged ≥12 years with positive tuberculin skin test into 9H and 3 HP groups in four hospitals between January 2014 and May 2016 in Taiwan. The primary and secondary outcomes were treatment completion rate and adverse drug reactions (ADRs), respectively. Overall, 263 participants with LTBI were randomised into the 3 HP (n = 132) and 9H groups (n = 131); 14 (10.6%) and 29 (22.1%) participants in the 3 HP and 9H groups, respectively, discontinued therapy (p = 0.011). Discontinuation rates owing to ADRs were 9.1% (3 HP) and 5.3% (9H) (p = 0.241). Clinically relevant hepatotoxicity was more common in the 9H than in the 3 HP group (5.3% vs. 1.5%; p = 0.103), whereas systemic drug reaction was more common in the 3 HP than in the 9H group (3.8% vs. 0%; p = 0.060). Women had a significantly higher rate of Grade II fever than men (13.7% vs. 1.2%; p = 0.003). Compared with the 9H regimen, the 3 HP regimen had a higher completion rate with lower hepatotoxicity and well-tolerated ADR.

CLINICAL TRIALS REGISTRATION

number NCT02208427.

Three months of rifapentine and isoniazid for latent tuberculosis infection in hemodialysis patients: High rates of adverse events

The consequences of once-weekly rifapentine plus isoniazid for 3 months (3HP) against latent tuberculosis infections in hemodialysis patients have not been studied before. This is the first study to evaluate the safety and tolerability of 3HP in this population and revealed a completion rate of 65.4%. The therapy was not associated with hepatotoxicity, but with high rates of adverse events (69.2%).

Assessment of vocation of rifabutin and rifapentine in replace of rifampcin in drug resistance leprosy patients: a molecular simulation study

The emergence of drug resistance in leprosy is a major hurdle in leprosy elimination programme. Although the problem of drug resistance is presently not acute, it is important that we collect data more systematically and monitor the trend carefully so that effective measures to combat this problem can be developed. The present study aimed at the explication of cross resistance of rifabutin and rifapentine to rifampicin which would be helpful to programme managers for implementing rifabutin or rifapentine in replace of rifampicin. In this study we built 3D model of the M. leprae rpoB using Swiss Model and the modelled structure was docked with rifampicin, rifabutin and rifapentine. We established that these 3 antibiotics interact with the same binding region in the modelled rpoB of M. leprae. Thus we conclude that vocation of rifabutin and rifapentine could not be suitable in replace of rifampicin to combat with drug resistance leprosy.

Factors That Influence Treatment Completion for Latent Tuberculosis Infection

INTRODUCTION

The aim of this study is to describe factors associated with noncompletion of latent tuberculosis infection (LTBI) therapy.

METHODS

We conducted a retrospective cohort study of adults who initiated LTBI treatment with isoniazid, rifampin, or isoniazid-rifapentine at 5 clinics. Demographic, treatment, and monitoring characteristics were abstracted. We estimated descriptive statistics and compared differences between completers and noncompleters using t tests and χ2 tests.

RESULTS

The rate of completion across LTBI regimens was 66% (n = 393). A greater proportion of noncompleters were unmarried, used tobacco and/or alcohol, and had more medical problems than completers (all P < .05). A larger proportion of noncompleters received charity care compared with completers (P < .001). The most common reason for treatment discontinuation was loss to follow-up; the majority of these participants were treated with the longest isoniazid-only regimen.

CONCLUSIONS

Patients at risk of progression to active tuberculosis with factors associated with noncompletion may benefit from interventions that enhance adherence to LTBI therapy. These interventions could include enhanced outreach, incentive programs, or home visits.

Three months of weekly rifapentine plus isoniazid for latent tuberculosis treatment in solid organ transplant candidates

BACKGROUND

Isoniazid daily for 9 months is the recommended regimen for latent tuberculosis infection (LTBI) in solid organ transplant (SOT) candidates, but its use is controversial, due to reports of hepatotoxicity and low treatment completion rates. A 12-week course of once weekly directly observed therapy (DOT) with isoniazid plus rifapentine (3HP) is a new LTBI treatment regimen. Tolerability and safety data of 3HP LTBI treatment in SOT candidates are limited.

METHODS

Twelve consecutive SOT candidates who underwent DOT with 3HP for LTBI at Westchester Medical Center, Valhalla, New York, USA, between January 2013 and August 2016 were prospectively evaluated for tolerability and safety of 3HP. The diagnosis of LTBI was made in a person with a positive interferon-gamma release test, without a history of previously treated active or latent tuberculosis infection, and without signs, symptoms, or radiographic evidence of active tuberculosis. Patients were followed up 1 month after treatment completion and at routine follow-up visits with their transplant providers.

RESULTS

Eleven patients were men, and the median age was 60 years (range 44-72). Eight patients were liver, and four kidney transplant candidates. The median Model for End-Stage Liver Disease (MELD score) was 17 (range 10-31). All patients completed treatment. Only a single patient developed transaminitis greater than twice the baseline value. Three patients underwent liver transplantation. None of them developed tuberculosis at 9, 22, or 40 months following transplantation.

CONCLUSION

Directly observed 3HP LTBI treatment was not associated with hepatotoxicity, even in patients with higher MELD scores. Further studies are needed to confirm the safety and efficacy of this LTBI treatment regimen in the SOT population.

Treatment completion for latent tuberculosis infection: a retrospective cohort study comparing 9 months of isoniazid, 4 months of rifampin and 3 months of isoniazid and rifapentine

BACKGROUND

The U.S. Centers for Disease Control and Prevention (CDC) recommended a new regimen for treatment of latent tuberculosis (three months of weekly isoniazid and rifapentine) in late 2011. While completion rates of this regimen were reported to be higher than nine months of isoniazid, little is known about the completion rates of three months of isoniazid and rifapentine compared to nine months of isoniazid or four months of rifampin in actual use scenarios.

METHODS

We conducted a retrospective cohort study comparing treatment completion for latent tuberculosis (TB) infection in patients treated with nine months of isoniazid, three months of isoniazid and rifapentine or four months of rifampin in outpatient clinics and a public health TB clinic in Seattle, Washington. The primary outcome of treatment completion was defined as 270 doses of isoniazid within 12 months, 120 doses of rifampin within six months and 12 doses of isoniazid and rifapentine within four months.

RESULTS

Three hundred ninety-three patients were included in the study. Patients were equally likely to complete three months of weekly isoniazid and rifapentine or four months of rifampin (85% completion rate of both regimens), as compared to 52% in the nine months of isoniazid group (p < 0.001). These associations remained statistically significant even after adjusting for clinic location and type of monitoring. Monitoring type (weekly versus monthly versus less often than monthly) had less impact on treatment completion than the type of treatment offered.

CONCLUSIONS

Patients were equally as likely to complete the three months of isoniazid and rifapentine as four months of rifampin. Four months of rifampin is similar in efficacy compared to placebo as isoniazid and rifapentine but does not require directly observed therapy (DOT), and is less expensive compared to combination therapy with isoniazid and rifapentine, and thus can be the optimal treatment regimen to achieve the maximal efficacy in a community setting.

In vitro evaluation of novel inhalable dry powders consisting of thioridazine and rifapentine for rapid tuberculosis treatment

Thioridazine is an orally administered antipsychotic drug with potential for treatment of drug-resistant tuberculosis (TB). However, drug-induced adverse cardiac effects have been reported when thioridazine was used at an efficacious oral dose of 200mg/day to treat TB. Pulmonary delivery of thioridazine could be a rational approach to reduce dose-related side effects while enabling high drug concentrations at the primary site of infection. The present study compares in vitro aerosol performance, storage stability, and in vitro antimicrobial activity and cytotoxicity of two inhalable powders composed of thioridazine and a first-line anti-TB drug, rifapentine. Formulation 1 is a combination of amorphous thioridazine and crystalline rifapentine, while Formulation 2 consisted of both drugs as amorphous forms. Both thioridazine-rifapentine formulations were found suitable for inhalation with a total fine particle fraction (<5μm) of 68-76%. The two powders had similar MIC90 to rifapentine alone, being 0.000625μg/mL and 0.005μg/ml against Mycobacterium tuberculosis H37Ra and M. tuberculosis H37Rv, respectively. In contrast, thioridazine alone had a MIC90 of 12.5μg/mL and 500μg/mL, against M. tuberculosis H37Ra and M. tuberculosis H37Rv, respectively, demonstrating no synergistic anti-TB activity. However, thioridazine and rifapentine in a ratio of 1:3 enhanced the killing of M. tuberculosis H37Ra within the human monocyte-derived macrophages (THP-1) compared to the single drug treatments. Both powders showed an acceptable half maximal inhibitory concentration (IC50) of 31.25μg/mL on both THP-1 and human lung epithelial (A549) cells. However, Formulation 1 showed greater chemical stability than Formulation 2 after three months of storage under low humidity (vacuum) at 20±3°C. In conclusion, we have demonstrated a novel inhalable powder consisted of amorphous thioridazine and crystalline rifapentine (Formulation 1) with a good aerosol performance, potent anti-TB activity and storage stability, which deserves further in vivo investigations.

Rifapentine-loaded PLGA microparticles for tuberculosis inhaled therapy: Preparation and in vitro aerosol characterization

Inhaled delivery of drugs incorporated into poly (lactic-co-glycolic acid) (PLGA) microparticles allows a sustained lung concentration and encourages phagocytosis by alveolar macrophages that harboring Mycobacterium tuberculosis. However, limited data are available on the effects of physicochemical properties of PLGA, including the monomer ratio (lactide:glycide) and molecular weight (MW) on the aerosol performance, macrophage uptake, and toxicity profile. The present study aims to address this knowledge gap, using PLGAs with monomer ratios of 50:50, 75:25 and 85:15, MW ranged 24 - 240kDa and an anti-tuberculosis (TB) drug, rifapentine. The PLGA-rifapentine powders were produced through a solution spray drying technique. The particles were spherical with a smooth surface and a volume median diameter around 2μm (span ~2). When the powders were dispersed using an Osmohaler(®) at 100L/min for 2.4s, the fine particle fraction (FPFtotal, wt.% particles in aerosol <5μm relative to the total recovered drug mass) was ranged between 52 and 57%, with no significant difference between the formulations. This result suggests that the monomer ratio and MW are not crucial parameters for the aerosol performance of PLGA. The phagocytosis analysis was performed using Thp-1 monocyte-derived macrophages. The highest rate of uptake was observed in PLGA 85:15 followed by 75:25 and 50:50 with about 90%, 80% and 70%, respectively phagocytosis over 4h of exposure. Furthermore, the cytotoxicity analysis on Thp-1 and human lung adenocarcinoma epithelial cells demonstrated that PLGA concentration up to 1.5mg/mL, regardless of the monomer composition and MW, were non-toxic. In conclusion, the monomer ratio and MW are not crucial in determining the aerosol performance and cytotoxicity profile of PLGA however, the particles with high lactide composition have a superior tendency for macrophage uptake.

Determination of the rifamycin antibiotics rifabutin, rifampin, rifapentine and their major metabolites in human plasma via simultaneous extraction coupled with LC/MS/MS

A novel assay using high pressure liquid chromatography (HPLC) coupled to mass spectrometer (MS) detection was developed and validated for the rifamycin anti-tuberculosis antibiotics rifampicin (RIF), rifabutin (RBT), rifapentine (RPT) and their active desacetyl metabolites (dRIF, dRBT and dRPT, respectively) in human plasma. The assay uses 50 μL of human plasma with a quick and simple protein-precipitation extraction to achieve a dynamic range of 75-30,000 ng/mL for RIF, RBT and RPT and 37.5-15,000 ng/mL for dRIF, dRBT and dRPT, respectively. The average %CV and %deviation were less than 20% at the lower limit of quantitation and less than 15% over the range of the curve. The method was fully validated according to FDA criteria for bioanalytical assays and has successfully been used to support three large international tuberculosis trials.

Recent advances in tuberculosis: New drugs and treatment regimens

The current treatment regimen against drug susceptible tuberculosis (DS-TB) was defined by the 1980s. Since then the emergence of the global HIV pandemic and the escalation of drug resistant (DR-) forms of TB have presented new challenges for therapeutic research. Priority goals include shortening DS-TB treatment, improving DR-TB treatment and making combined TB-HIV therapy easier. To help achieve these goals, a range of new drugs and treatment strategies are currently being evaluated. Phase IIb and III clinical trials are ongoing to assess combinations involving the high-dose rifamycins, the 8-methoxyquinolones, a diarylquinoline (bedaquiline) and the nitroimidazoles. Other compounds (e.g. novel oxazolidinones and ethylenediamines) are at earlier stages of clinical development. Overall, there are grounds for optimism that recent advances will contribute towards achievement of new treatment regimens in the foreseeable future. However, long-term investment, political commitment and scientific endeavour are crucial to ensure that progress is sustained and the benefits of recent advances reach those in the greatest need.