Effectiveness of tacrolimus in a case of immune checkpoint inhibitor-induced hepatotoxicity that was refractory to steroids and mycophenolate mofetil

Immune checkpoint inhibitors (ICIs) sometimes induce immune-mediated hepatotoxicity (IMH), and corticosteroids and mycophenolate mofetil (MMF) are recommended for the treatment of IMH. However, there is no consensus on the treatment of IMH refractory to these drugs. Here, we report a case of refractory IMH that was successfully treated with tacrolimus. A 69-year-old man presented with liver injury after receiving durvalumab, an ICI, for lung cancer. He was diagnosed with IMH and received corticosteroids including methylprednisolone pulses and MMF, but his liver damage did not improve. Liver histology showed infiltration of inflammatory cells, mainly CD8 + T cells, in the portal area. Tacrolimus was added to corticosteroid and MMF to suppress mainly T cells. After the tacrolimus administration, the liver damage promptly improved. Since IMH is thought to be caused by activated CD8 + T-cell infiltration, T-cell suppression may be an effective treatment. This case suggests that tacrolimus may be an effective option for IMH refractory to corticosteroids or MMF if CD8 + T-cell infiltration is confirmed in the liver tissue.