Pharmacokinetics under the COVID‐19 Storm

AIMS The storm-like nature of the health crises caused by COVID-19 has led to unconventional clinical trial practices such as the relaxation of exclusion criteria. The question remains: how can we conduct diverse trials without exposing sub-groups of populations to potentially harmful drug exposure levels? The aim of this study was to build a knowledge-base of the effect of intrinsic/extrinsic factors on the disposition of several repurposed COVID-19 drugs. METHODS PBPK models were used to study the change in PK of drugs repurposed for COVID-19 in geriatric patients, different race groups, organ impairment, DDI risks. These models were also used to predict epithelial lining fluid (ELF) exposure which is relevant for COVID-19 patients under elevated cytokine levels. RESULTS The simulated PK profiles suggest no dose adjustments are required based on age and race for COVID-19 drugs; however, dose adjustments may be warranted for COVID-19 patients also exhibiting hepatic/renal impairment. PBPK model simulations suggest ELF exposure to attain a target concentration was adequate for most drugs, except for hydroxychloroquine, azithromycin, atazanavir and lopinavir/ritonavir. CONCLUSION We demonstrate that systematically collated data on the ADME, human PK parameters, DDIs, and organ impairment can be used to verify simulated plasma and lung tissue exposure for drugs repurposed for COVID-19, justifying broader patient recruitment criteria. In addition, the PBPK model developed was used to study the effect of age and ethnicity on the PK of repurposed drugs, and to assess the correlation between lung exposure and relevant potency values from in vitro studies for SARS-CoV-2.