Rifapentine Population Pharmacokinetics and Dosing Recommendations for Latent Tuberculosis Infection.

RATIONALE: Rifapentine has been investigated at various doses, frequencies, and dosing algorithms but clarity on the optimal dosing approach is lacking. OBJECTIVES: In this individual participant data meta-analysis of rifapentine pharmacokinetics, we characterize rifapentine population pharmacokinetics, including autoinduction, and determine optimal dosing strategies for short-course rifapentine-based regimens for latent tuberculosis infection. METHODS: Rifapentine pharmacokinetic studies were identified though a systematic review of literature. Individual plasma concentrations were pooled, and non-linear mixed effects modeling was performed. A subset of data was reserved for external validation. Simulations were performed under various dosing conditions including current weight-based methods and alternative methods driven by identified covariates. MEASUREMENTS AND MAIN RESULTS: We identified 9 clinical studies with a total of 863 participants with pharmacokinetic data (n=4301 plasma samples). Rifapentine population pharmacokinetics were described successfully with a one-compartment distribution model. Autoinduction of clearance was driven by rifapentine plasma concentration. The maximum effect was a 72% increase in clearance and was reached after 21 days. Drug bioavailability decreased by 27% with HIV infection, decreased by 28% with fasting, and increased by 49% with a high-fat meal. Body weight was not a clinically relevant predictor of clearance. Pharmacokinetic simulations showed that current weight-based dosing leads to lower exposures in low weight individuals, which can be overcome with flat dosing. In HIV-positive patients, 30% higher doses are required to match drug exposure in HIV-negative patients. CONCLUSIONS: Weight-based dosing of rifapentine should be removed from clinical guidelines and higher doses for HIV-positive patients should be considered to provide equivalent efficacy

Advancing evidence-based treatment of infectious diseases in children with real-world data: Opportunities and challenges

There is an increased interest in utilizing real-world data (RWD) for pharmaceutical research and regulatory decision-making. The development and use of pediatric medicines could benefit greatly from real-world data studies given nearly half of drugs prescribed to children are "off-label", meaning there is a lack of pediatric-specific evidence from controlled trials, while there is an abundance of data from routine clinical practice. Currently, the use of real-world data, such as data from electronic health records, is lacking in pediatric research, especially within infectious diseases. Here, we discuss opportunities and challenges for real-world data to generate evidence on the optimal treatment and management of infectious diseases in children

Model-Based Efficacy and Toxicity Comparisons of Moxifloxacin for Multidrug-Resistant Tuberculosis.

BackgroundMoxifloxacin (MOX) is used as a first-choice drug to treat multidrug-resistant tuberculosis (MDR-TB); however, evidence-based dosing optimization should be strengthened by integrative analysis. The primary goal of this study was to evaluate MOX efficacy and toxicity using integrative model-based approaches in MDR-TB patients.MethodsIn total, 113 MDR-TB patients from 5 different clinical trials were analyzed for the development of a population pharmacokinetics (PK) model. A final population PK model was merged with a previously developed lung-lesion distribution and QT prolongation model. Monte Carlo simulation was used to calculate the probability target attainment value based on concentration. An area under the concentration-time curve (AUC)-based target was identified as the minimum inhibitory concentration (MIC) of MOX isolated from MDR-TB patients.ResultsThe presence of human immunodeficiency virus (HIV) increased clearance by 32.7% and decreased the AUC by 27.4%, compared with HIV-negative MDR-TB patients. A daily dose of 800 mg or a 400-mg, twice-daily dose of MOX is expected to be effective in MDR-TB patients with an MIC of ≤0.25 µg/mL, regardless of PK differences resulting from the presence of HIV. The effect of MOX in HIV-positive MDR-TB patients tended to be decreased dramatically from 0.5 µg/mL, in contrast to the findings in HIV-negative patients. A regimen of twice-daily doses of 400 mg should be considered safer than an 800-mg once-daily dosing regimen, because of the narrow fluctuation of concentrations.ConclusionsOur results suggest that a 400-mg, twice-daily dose of MOX is an optimal dosing regimen for MDR-TB patients because it provides superior efficacy and safety

Comparative efficacy of rifapentine alone and in combination with isoniazid for latent tuberculosis infection: A translational pharmacokinetic-pharmacodynamic modeling study

Rifapentine has facilitated treatment shortening for latent tuberculosis infection (LTBI) in combination with isoniazid once weekly for 3 months (3HP) or daily for 1 month (1HP). Our objective was to determine the optimal rifapentine dose for a 6-week monotherapy regimen (6wP) and predict clinical efficacy. Rifapentine and isoniazid pharmacokinetics were simulated in mice and humans. Mouse lung CFU data were used to characterize exposure-response relationships of 1HP, 3HP, and 6wP and translated to predict clinical efficacy. A 600-mg daily dose for 6wP delivered greater cumulative rifapentine exposure than 1HP or 3HP. The maximum regimen effect (Emax) was 0.24 day21. The regimen potencies, measured as the concentration at 50% of Emax (EC50), were estimated to be 2.12 mg/liter for 3HP, 3.72 mg/liter for 1HP, and 4.71 mg/liter for 6wP, suggesting that isoniazid contributes little to 1HP efficacy. Clinical translation predicted that 6wP reduces bacterial loads at a higher rate than 3HP and to a greater extent than 3HP and 1HP. 6wP (600 mg daily) is predicted to result in equal or better efficacy than 1HP and 3HP for LTBI treatment without the potential added toxicity of isoniazid. Results from ongoing and future clinical studies will be required to support these findings

Tuberculosis in children with severe acute malnutrition

IntroductionWith growing attention globally to the childhood tuberculosis epidemic after decades of neglect, and with the burden of severe acute malnutrition (SAM) remaining unacceptably high worldwide, the collision of these two diseases is an important focus for improving child health.Areas coveredThis review describes the clinical and public health implications of the interplay between tuberculosis and SAM, particularly for children under the age of five, and identifies priority areas for improved programmatic implementation and future research. We reviewed the literature on PubMed and other evidence known to the authors published until August 2021 relevant to this topic.Expert opinionTo achieve the World Health Organization's goal of eliminating deaths from childhood tuberculosis and to improve the abysmal outcomes for children with SAM, further research is needed to 1) better understand the epidemiologic connections between child tuberculosis and SAM, 2) improve case finding of tuberculosis in children with SAM, 3) assess unique treatment considerations for tuberculosis when children also have SAM, and 4) ensure tuberculosis and SAM are strongly addressed in decentralized, integrated models of providing primary healthcare to children

Tuberculosis in children with severe acute malnutrition

INTRODUCTION: With growing attention globally to the childhood tuberculosis epidemic after decades of neglect, and with the burden of severe acute malnutrition (SAM) remaining unacceptably high worldwide, the collision of these two diseases is an important focus for improving child health. AREAS COVERED: This review describes the clinical and public health implications of the interplay between tuberculosis and SAM, particularly for children under the age of five, and identifies priority areas for improved programmatic implementation and future research. We reviewed the literature on PubMed and other evidence known to the authors published until August 2021 relevant to this topic. EXPERT OPINION: To achieve the World Health Organization's goal of eliminating deaths from childhood tuberculosis and to improve the abysmal outcomes for children with SAM, further research is needed to 1) better understand the epidemiologic connections between child tuberculosis and SAM, 2) improve case finding of tuberculosis in children with SAM, 3) assess unique treatment considerations for tuberculosis when children also have SAM, and 4) ensure tuberculosis and SAM are strongly addressed in decentralized, integrated models of providing primary healthcare to children