Ribociclib-Induced Autoimmune Hepatitis: A Case Report.

Drug-induced autoimmune hepatitis (DI-AIH) is a condition that mimics autoimmune hepatitis both histologically and clinically, making diagnosis challenging. Ribociclib, a CDK4/6 inhibitor used in the treatment of metastatic breast carcinoma, has been associated with rare cases of DI-AIH. We present the case of a 46-year-old woman undergoing treatment with ribociclib for metastatic breast carcinoma, who developed fatigue, skin rash, and significantly elevated liver enzymes two months into therapy. Initial tests revealed ALT of 414 U/L and AST of 219 U/L, along with elevated IgG levels and positive antinuclear antibodies. A liver biopsy showed chronic active hepatitis with mixed inflammatory cell infiltrates, including plasma cells and eosinophils. Despite the discontinuation of ribociclib, the liver enzymes remained elevated, necessitating treatment with prednisolone and azathioprine. Over the course of six months, the patient's liver function improved, and immunosuppressive therapy was gradually tapered off. This case highlights the importance of recognizing ribociclib-induced DI-AIH and the effectiveness of immunosuppressive therapy in managing persistent liver injury.