A 49-year-old woman with ER-positive/PR-negative/HER2-negative metastatic breast cancer experienced Grade 3 hepatotoxicity following initiation of a clinical trial of fulvestrant, palbociclib, and erdafitinib. Fulvestrant was determined to be the drug most likely responsible for this hepatotoxic effect. This case report details the timing and nature of this drug-induced liver injury, adding support to an area that has yet to be described adequately in the existing literature.