Enhancing efficacy of therapeutic vaccinations by combination with other modalities

Novel strategies are emerging from preclinical and clinical investigations for combining vaccines with conventional and experimental anticancer therapies. Several lines of research show that combining either radiation or certain chemotherapeutic agents with vaccine can alter the phenotype of tumor cells, rendering them more susceptible to T cell-mediated killing. Furthermore, there is emerging data suggesting that an immune response elicited by vaccine may augment the antitumor effectiveness of subsequent therapies. This article reviews and discusses therapeutic cancer strategies that employ vaccines sequentially or in combination with conventional cytotoxic therapies such as local radiation, chemotherapy, and hormone therapy, or immunopotentiating therapies such as anti-CTLA-4 monoclonal antibodies. Preliminary results of clinical studies using these combination strategies have demonstrated a postvaccination antigen cascade, prolonged time to disease progression, and preliminary evidence of improved overall survival. Large randomized studies are currently underway to further investigate these findings.