Advanced human liver models for the assessment of drug-induced liver injury

Drug safety issues continue to occur even with drugs that are approved after the completion of clinical studies. Drug-induced liver injury (DILI) is a major obstacle to drug development, because the liver is the primary site of drug metabolism, and injuries caused during this process are severe. Conventional in vitro human liver models, such as 2-dimensional hepatic cell lines, lack in vivo physiological relevance, and animal studies have limitations in the form of species differences and regulatory restrictions. To resolve this issue, an increasing number of 3-dimensional human liver systems, including organoids, are being developed. In this review, we provide an overview of recent assessments of DILI prediction, approaches for in vitro hepatotoxicity evaluation, and a variety of advanced human liver models. We discuss the advantages, limitations, and future perspectives of current human liver models for accurate drug safety evaluations.