Acute-on-Chronic Liver Failure Incited by Cyclin-Dependent Kinase Inhibitor Therapy for Breast Cancer Effectively Treated With Liver Transplantation.

Cyclin-dependent kinase 4/6 inhibitors are targeted therapies demonstrated to significantly improve overall survival as adjuvant treatment of estrogen receptor-positive breast cancers. Although intended to preferentially arrest cell cycle transitions in tumor cells, these agents can have undesirable systemic side effects, including hepatotoxicity. We report the first case of cyclin-dependent kinase 4/6 inhibitor therapy leading to acute-on-chronic liver failure requiring liver transplantation.