title: A Physiologically Based Pharmacokinetic Model of Isoniazid and Its Application in Individualizing Tuberculosis Chemotherapy.
abstract: Due to its high early bactericidal activity, isoniazid (INH) plays an essential role in tuberculosis treatment. Genetic polymorphisms of N-acetyltransferase type 2 (NAT2) cause a trimodal distribution of INH pharmacokinetics in slow, intermediate, and fast acetylators. The success of INH-based chemotherapy is associated with acetylator and patient health status. Still, a standard dose recommended by the FDA is administered regardless of acetylator type or immune status, even though adverse effects occur in 5 to 33% of all patients. Slow acetylators have a higher risk of development of drug-induced toxicity, while fast acetylators and immune-deficient patients face lower treatment success rates. To mechanistically assess the trade-off between toxicity and efficacy, we developed a physiologically based pharmacokinetic (PBPK) model describing the NAT2-dependent pharmacokinetics of INH and its metabolites. We combined the PBPK model with a pharmacodynamic (PD) model of antimycobacterial drug effects in the lungs. The resulting PBPK/PD model allowed the simultaneous simulation of treatment efficacies at the site of infection and exposure to toxic metabolites in off-target organs. Subsequently, we evaluated various INH dosing regimens in NAT2-specific immunocompetent and immune-deficient virtual populations. Our results suggest the need for acetylator-specific dose adjustments for optimal treatment outcomes. A reduced dose for slow acetylators substantially lowers the exposure to toxic metabolites and thereby the risk of adverse events, while it maintains sufficient treatment efficacies. Vice versa, intermediate and fast acetylators benefit from increased INH doses and a switch to a twice-daily administration schedule. Our analysis outlines how PBPK/PD modeling may be used to design and individualize treatment regimens.
authors.affiliation: Institute of Applied Microbiology (iAMB), Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, Aachen, Germany henrik.cordes@rwth-aachen.de lars.kuepfer@rwth-aachen.de.
authors.forename: Henrik
authors.initials: H
authors.lastname: Cordes
authors.affiliation: Institute of Applied Microbiology (iAMB), Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, Aachen, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Thiel
authors.affiliation: Institute of Applied Microbiology (iAMB), Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, Aachen, Germany.
authors.forename: Hélène E
authors.initials: HE
authors.lastname: Aschmann
authors.affiliation: Institute of Applied Microbiology (iAMB), Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, Aachen, Germany.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Baier
authors.affiliation: Institute of Applied Microbiology (iAMB), Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, Aachen, Germany.
authors.forename: Lars M
authors.initials: LM
authors.lastname: Blank
authors.affiliation: Institute of Applied Microbiology (iAMB), Aachen Biology and Biotechnology (ABBt), RWTH Aachen University, Aachen, Germany henrik.cordes@rwth-aachen.de lars.kuepfer@rwth-aachen.de.
authors.forename: Lars
authors.initials: L
authors.lastname: Kuepfer
mesh_terms: D000107:Acetylation; D000995:Antitubercular Agents / Q000097:blood / Q000493:pharmacokinetics*; D001191:Arylamine N-Acetyltransferase / Q000235:genetics / Q000378:metabolism*; D001682:Biological Availability; D001711:Biotransformation; D003198:Computer Simulation; D004334:Drug Administration Schedule; D054796:Drug Dosage Calculations; D015870:Gene Expression; D005838:Genotype; D006801:Humans; D007113:Immunity, Innate; D016867:Immunocompromised Host; D007538:Isoniazid / Q000097:blood / Q000493:pharmacokinetics*; D008168:Lung / Q000187:drug effects / Q000276:immunology / Q000382:microbiology; D015233:Models, Statistical; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000276:immunology; D011110:Polymorphism, Genetic; D057285:Precision Medicine; D014397:Tuberculosis, Pulmonary / Q000097:blood / Q000188:drug therapy* / Q000276:immunology / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D001191:Arylamine N-Acetyltransferase; C478900:NAT2 protein, human; D007538:Isoniazid