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.