Immune Checkpoint Blockade: Subjugation of the Masses

Abstract

Osteosarcoma remains the most common form of bone cancer in adolescents. Standard of care treatment for osteosarcoma includes chemotherapy combined with limb-salvage surgery or amputation. Survival rates for compliant patients are 60-80% for those with localized tumors and 15-30% if the tumor metastasizes or reoccurs. Given the successes of monoclonal antibody blockades in other cancers, clinical trials for applying immunotherapies to osteosarcoma are underway. Antibody blockades reinvigorate T cells to eliminate cancer cells thereby leading to decreased tumor burden and long-term regression. Single monoclonal antibody therapy has shown modest efficacy compared to standard of care.However, treating with only a single antibody can ultimately result in immune evasion by heterogeneous tumors via selection of cells expressing other inhibitory ligands. Hence, combination immunotherapies have yielded the most promising results for eliminating tumors or preventing reoccurrence in other cancer types and will likely be the most efficacious strategy for treating osteosarcoma. Here, we review current immunotherapies for other cancers and their potential application to osteosarcoma.