Current use of animal models of disease for nonclinical safety testing

Potential impact of underlying diseases influencing ADME in nonclinical safety assessment

Nonclinical studies involve in vitro, in silico, and in vivo experiments to assess the toxicokinetics, toxicology, and safety pharmacology of drugs according to regulatory requirements by a national or international authority. In this review, we summarize the potential effects of various underlying diseases governing the absorption, distribution, metabolism, and excretion (ADME) of drugs to consider the use of animal models of diseases in nonclinical trials. Obesity models showed alterations in hepatic metabolizing enzymes, transporters, and renal pathophysiology, which increase the risk of drug-induced toxicity. Diabetes models displayed changes in hepatic metabolizing enzymes, transporters, and glomerular filtration rates (GFR), leading to variability in drug responses and susceptibility to toxicity. Animal models of advanced age exhibited impairment of drug metabolism and kidney function, thereby reducing the drug-metabolizing capacity and clearance. Along with changes in hepatic metabolic enzymes, animal models of metabolic syndrome-related hypertension showed renal dysfunction, resulting in a reduced GFR and urinary excretion of drugs. Taken together, underlying diseases can induce dysfunction of organs involved in the ADME of drugs, ultimately affecting toxicity. Therefore, the use of animal models of representative underlying diseases in nonclinical toxicity studies can be considered to improve the predictability of drug side effects before clinical trials.

Opinion on the Use of Animal Models in Nonclinical Safety Assessment: Pros and Cons

Nonclinical evaluation of human safety risks for new chemical entities (NCEs) is primarily conducted in conventional healthy animals (CHAs); however, in certain instances, animal models of diseases (AMDs) can play a critical role in the understanding of human health risks. Animal models of diseases may be especially important when there is a need to understand how disease conditions associated with the intended indication might impact risk assessment of NCEs or when CHAs lack the human-specific target of interest (receptor, etc). Although AMDs have potential benefits over CHAs, they also have limitations. Understanding these limitations and optimizing the AMDs of interest should be done prior to proceeding with studies that will guide development of NCE. The purpose of this manuscript is to provide an overview of the major pros and cons of utilization of AMDs in nonclinical safety assessment.