An Update on Adoptive T-Cell Therapy and Neoantigen Vaccines

Abstract

Adoptive T-cell therapy using tumor-infiltrating lymphocytes (TILs) has demonstrated long-lasting antitumor activity in select patients with advanced melanoma. Cancer vaccines have been used for many decades and have shown some promise but overall relatively modest clinical activity across cancers. Technological advances in genome sequencing capabilities and T-cell engineering have had substantial impact on both adoptive cell therapy and the cancer vaccine field. The ability to identify neoantigens—a class of tumor antigens that is truly tumor specific and encoded by tumor mutations through rapid and relatively inexpensive next-generation sequencing—has already demonstrated the critical importance of these antigens as targets of antitumor-specific T-cell responses in the context of immune checkpoint blockade and other immunotherapies. Therapeutically targeting these antigens with either adoptive T-cell therapy or vaccine approaches has demonstrated early promise in the clinic in patients with advanced solid tumors. Chimeric antigen receptor (CAR) T cells, which are engineered by fusing an antigen-specific, single-chain antibody (scFv) with signaling molecules of the T-cell receptor (TCR)/CD3 complex creating an antibody-like structure on T cells that recognizes antigens independently of major histocompatibility complex (MHC) molecules, have demonstrated remarkable clinical activity in patients with advanced B-cell malignancies, leading to several approvals by the U.S. Food and Drug Administration (FDA).