Therapeutic cancer vaccines have become increasingly qualified for use in personalized cancer immunotherapy. A deeper understanding of tumor immunology and novel antigen delivery technologies has assisted in optimizing vaccine design. Therapeutic cancer vaccines aim to establish long-lasting immunological memory against tumor cells, thereby leading to effective tumor regression and minimizing non-specific or adverse events. However, due to several resistance mechanisms, significant challenges remain to be solved in order to achieve these goals. In this review, we describe our current understanding with respect to the use of the antigen repertoire in vaccine platform development. We also summarize various intrinsic and extrinsic resistance mechanisms behind the failure of cancer vaccine development in the past. Finally, we suggest a strategy that combines immune checkpoint inhibitors to enhance the efficacy of cancer vaccines.
Keywords: combination immunotherapy; immune checkpoint inhibitor; therapeutic cancer vaccine; tumor microenvironment.