Recent Advances and Future Directions in Immunotherapeutics for Hepatocellular Carcinoma

ABSTRACT

Systemic target therapeutic drugs, such as sorafenib, lenvatinib, or regorafenib are the only drugs that are known to be effective against advanced hepatocellular carcinoma (HCC). However, these agents show a limited efficacy in killing residual tumors. Immunotherapy is an alternative approach to this treatment and has been used to successfully treat different cancers, including HCC. HCC is an inflammation-induced cancer and represents a very interesting target for immunotherapeutics. Immunotherapies aim to reverse the immune tolerance and suppression found in tumor microenvironments and include approaches, such as adoptive cell therapy, immune checkpoint inhibition, and cancer vaccination. Adoptive cell therapy uses autologous natural killer or cytokine-induced killer cells by cultivating them ex vivo and subsequently reinfusing them into the patient. Immune checkpoint inhibitors reactivate tumor-specific T cells by suppressing checkpoint-mediated inhibitory signaling. Cancer vaccination induces a tumor-specific immune response by activating effector T lymphocytes. A wide range of potential immunotherapy-related adverse events occur; therefore, a multidisciplinary collaborative management is required across the clinical spectrum. This review summarizes the current status of immunotherapy for HCC and provides a perspective on its future applications.