Active Specific Immunotherapy – A New Modality of Cancer Treatment Involving the Patient’s Own Immune System

Abstract

This review deals with active specific immunotherapy (ASI) – a type of cancer immunotherapy which involves the use of cancer vaccines for active immunization of cancer patients. It starts with theoretical foundations, then summarizes preclinical data from animal models and then presents and discusses clinical observations from respective immunotherapy trials. Based on new insights into T-cell stimulation (two-signal activation) and on own experience in immunological cancer rejection in metastasizing animal tumor models, we propose for ASI studies the use of a two-component cancer vaccine for postoperative active immunization. As a specific component, we use intact, viable, radiation-inactivated autologous tumor cells, which should represent the closest match to a patient’s own cancer. If this is not possible, cells from allogeneic corresponding tumors or from homologous tumor cell lines could be used. As a second nonspecific component, we have good experience with a virus, the Newcastle Disease Virus (NDV), which can easily attach to the cells of the vaccine to facilitate the delivery of costimulatory signals to tumor-reactive T cells. Clinical experience with ASI and variables of potential importance for the design of cancer vaccines are also reviewed.