Cancer vaccines

Abstract

Cancer vaccines have been extensively tested in animal models, and in humans. Initial studies focused on first generation vaccines based on whole cell preparations or tumor lysates derived from autologous or allogeneic tumors. Clinical studies conducted with such candidate vaccines contributed to establish the feasibility of immunizing cancer patients against their own tumors. Significant clinical benefits were observed, both in terms of long term survival and recurrence rate, in some of these trials. More recently, however, cancer vaccines targeting well-characterized tumor-associated antigens, i.e. molecules selectively or preferentially expressed by cancer cells but not by normal cells, have been designed and tested in humans. Results obtained as of today with these second-generation vaccines suggest that they are safe and that they can elicit humoral and cellular responses against tumor-specific antigens, without inducing unacceptable clinical signs of autoimmunity. Advances in tumor biology and tumor immunity have helped to better understand the mechanisms displayed by a number of tumors to escape host immunity. This bulk of new knowledge will be used to design future cancer vaccines, which will likely target multiple TAAs, presented by different antigen presentation platforms, in association with synthetic adjuvants and/or immunostimulatory cytokines. Lastly, specific tools allowing to assess in a qualitative and quantitative manner immune responses are critically needed in order to establish correlates between clinical and immune responses in patients receiving experimental vaccines.