Immunotherapy and Liver Transplantation: A Narrative Review of Basic and Clinical Data

SIMPLE SUMMARY: Hepatocellular carcinoma (HCC) represents one of the main indications for liver transplantation. Over recent years, immune checkpoint inhibitor (ICI) therapy has improved its management, making patients with more advanced HCC potential candidates for transplantation. However, acute rejection has been observed after ICI therapy, challenging its safety in transplant settings. We summarize and discuss the preclinical and clinical data exploring the use of ICI prior to and after liver transplantation. We identify a three-month ideal minimum period between ICI and transplantation to decrease the risk of rejection. We also warn about its use after liver transplantation and speak about the need for more robust prospective data in the field. ABSTRACT: Immune checkpoint inhibitors (ICIs) have improved the management of patients with intermediate- and advanced-stage HCC, even making some of them potential candidates for liver transplantation. However, acute rejection has been observed after ICI therapy, challenging its safety in transplant settings. We summarize the key basic impact of immune checkpoints on HCC and liver transplantation. We analyze the available case reports and case series on the use of ICI therapy prior to and after liver transplantation. A three-month washout period is desirable between ICI therapy and liver transplantation to reduce the risk of acute rejection. Whenever possible, ICIs should be avoided after liver transplantation, and especially so early after a transplant. Globally, more robust prospective data in the field are required.