Therapeutic cancer vaccines: Where do we stand?

Vaccines and immunotherapy have transformed the treatment modalities and prevention of several diseases including malignancy. Vaccines for infectious diseases have been in use for many decades, but very few cancer vaccines are approved for human use. These Cancer vaccines are either used prophylactically for preventing against infectious agents related to cancers or therapy for treating the existing malignancy. Therapeutic cancer vaccines undergo extensive preclinical and clinical trials in animals and human beings before its final administration. The clinical benefit of therapeutic cancer vaccines is to produce tumor regression, long-lasting antitumor memory, and prolonging the survival of individuals with lesser adverse incident. First-generation cancer vaccines were prepared from whole-cell (autologous or allogeneic) tumor lysates. The use of this cancer vaccine shows significant results in terms of survival and reduced recurrence rate of tumors. Second-generation cancer vaccines have specific tumor antigens (TA) for inducing humoral and cellular immune response without exhibiting signs of autoimmunity. Apart from whole cell, DNA, RNA, Protein, peptides can also contribute as the antigen part of a vaccine. Potent cancer vaccines deliver TAs to both MHC class I and II molecules of antigen-presenting cells which stimulate both CD4 and CD8 T-cell responses. Human papillomavirus and hepatitis B virus vaccines are the two prophylactic cancer vaccines recommended by the Food and Drug Administration for its use in cervical and hepatocellular cancers respectively. In therapeutic cancer vaccines, only three vaccines (sipuleucel-T cells, Bacillus Calmette–Guerin vaccine, and Talimogene laherparepvec) are approved for treatment of castration-resistant prostate cancer, bladder cancer, and inoperable melanoma, respectively. Cancer vaccines are now falling under the fourth modality of cancer treatment after chemotherapy, radiotherapy, and surgery. Therapeutic cancer vaccination has a promising path forward when it is combined with immunomodulation.