Modeling Therapeutic Antibody–Small Molecule Drug-Drug Interactions Using a Three-Dimensional Perfusable Human Liver Coculture Platform

Traditional in vitro human liver cell culture models lose key hepatic functions such as metabolic activity during short-term culture. Advanced 3D liver co-culture platforms offer the potential for extended hepatocyte functionality, allowing for the study of more complex biological interactions that can improve and refine human drug safety evaluation. Here, we utilize a perfusion flow 3D microreactor platform for the co-culture of cryopreserved primary human hepatocytes and Kupffer cells to study the regulation of CYP3A4 activity by chronic IL-6-mediated inflammation over two weeks. Hepatocyte cultures remained stable over two weeks, with consistent albumin production and basal IL-6 levels. Direct IL-6 stimulation that mimics an inflammatory state induced a dose-dependent suppression of CYP3A4 activity, an increase in C-reactive protein (CRP) secretion, and a decrease in shed soluble IL-6R levels, indicating expected hepatic IL-6 bioactivity. Tocilizumab, an anti-IL-6R monoclonal antibody used to treat rheumatoid arthritis, has been demonstrated clinically to impact small molecule drug pharmacokinetics by modulating cytochrome P450 enzyme activities, an effect not observed in traditional hepatic cultures. We have now recapitulated the clinical observation in a 3D bioreactor system. Tocilizumab was shown to de-suppress CYP3A4 activity while reducing CRP concentration after 72 hours in the continued presence of IL-6. This change in CYP3A4 activity decreased the half-life and AUClast of the small molecule CYP3A4 substrate simvastatin hydroxy acid, measured before and after tocilizumab treatment. We conclude that next-generation in vitro liver culture platforms are well-suited for these types of long-term treatment studies and show promise for improved drug safety assessment.