Favipiravir pharmacokinetics in Thai adults with mild COVID-19: A sub-study of interpatient variability and ethnic differences in exposure
Issued Date
2024-12-01
Resource Type
eISSN
20521707
Scopus ID
2-s2.0-85208432887
Journal Title
Pharmacology Research and Perspectives
Volume
12
Issue
6
Rights Holder(s)
SCOPUS
Bibliographic Citation
Pharmacology Research and Perspectives Vol.12 No.6 (2024)
Suggested Citation
Prasanchaimontri I.o., Manosuthi W., Pertinez H., Owen A., Niyomnaitham S., Sirijatuphat R., Charoenpong L., Cressey T., Copeland K., Mokmued P., Chokephaibulkit K. Favipiravir pharmacokinetics in Thai adults with mild COVID-19: A sub-study of interpatient variability and ethnic differences in exposure. Pharmacology Research and Perspectives Vol.12 No.6 (2024). doi:10.1002/prp2.1233 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/102016
Title
Favipiravir pharmacokinetics in Thai adults with mild COVID-19: A sub-study of interpatient variability and ethnic differences in exposure
Corresponding Author(s)
Other Contributor(s)
Abstract
This sub-study sought to characterize the pharmacokinetics (PK) of favipiravir (FPV) within Thai adults and quantitatively assess differences in exposure to those previously reported in other populations as a basis to understand putative differences in efficacy between studies conducted in different regions. It was nested within a prospective trial of adults with symptomatic COVID-19 infection without pneumonia receiving 1800 mg FPV twice-daily on day 1 and 800 mg twice-daily thereafter. Individual PK profiles were fitted with a one-compartment disposition model (first-order absorption). Eight adults (seven female) with a median age of 39 years and BMI of 27.9 kg/m2 were included. Seven adults achieved plasma concentrations above the EC90 in vitro target (25 mg/L), with minimum–maximum concentrations decreasing with repeat dosing. The mean FPV apparent clearance observed in this study was 1.1 L/h (coefficient of variation [CV]: 60%), apparent volume of distribution 20.6 L (CV: 40%), absorption rate constant 6.1 h (CV: 100%), and 2.4 daily % change in apparent clearance (CV: 315%). Higher exposures were observed in these Thai adults compared with data from previous studies in Chinese, Japanese, and Turkish populations, respectively. Current FPV doses recommended in Thailand achieved target plasma concentrations with higher exposures than those described previously in other populations. The limited sample size prohibits firm conclusions from being drawn but the presented data warrants confirmation with a view to interrogate the appropriateness of doses used in randomized clinical trials that failed to demonstrate efficacy.