Immune Checkpoint Inhibitor-Induced Hepatitis: A Case Report of Challenging Management.

Pembrolizumab is an immune checkpoint inhibitor (ICI) that is demonstrated to enhance the prognosis of patients with advanced lung cancer. However, adding immunotherapy to clinical practice has brought new challenges, such as immune-related adverse events (irAEs), which have changed chemotherapy's previously well-understood safety profile. Immune-mediated hepatitis, although less prevalent and less extensively studied, represents a significant toxicity that may evolve into a potentially severe complication, particularly when it becomes refractory to conventional treatments. In this report, we present the case of a 67-year-old male patient with non-small cell lung cancer who developed severe corticosteroid (CS)-refractory hepatitis following two cycles of pembrolizumab. Differential diagnosis workup excluded alternative diagnosis. A liver biopsy evidenced both hepatitis and cholestasis. Due to persistent cytolysis, it was necessary to add mycophenolate mofetil (MMF). Additionally, ursodeoxycholic acid (UDCA) was introduced due to persistent cholestasis, resulting in the normalization of laboratory parameters. The lack of prospective evidence regarding immune-related hepatitis treatment makes it challenging to draw definitive conclusions about the optimal therapeutic approach.