Ins and outs of clinical trials with peptide-based vaccines

Peptides are the smallest antigenic components that are recognized by T cells when presented in MHC molecules on the cell surface. After the identification of peptides from tumor associated and tumor specific antigens, the exploration of the use of peptides in immunotherapy of cancer was instigated. From initial exploration of peptide-mediated induction of immune responses in mice, the peptide based vaccines have evolved to clinical testing in cancer patients. Many different clinical trials have been performed to address the ability of peptide-based vaccines to induce both clinical and immunological responses in patients. This review will provide an overview of the results of the majority of the clinical trials with peptide-based vaccines directed against various antigens in patients with solid tumors.