Introduction: The advent of cancer immunotherapy is going to profoundly transform the therapy of cancer. In this context, therapeutic cancer vaccines will offer significant opportunities, provided an efficient and robust technology is developed.
Areas covered: Targeting tumor-associated antigens via immunization with homologous immunogens derived from other species, an approach called xeno vaccination, combined with gene delivery is believed to be a viable strategy. Xenogene vaccination has demonstrated to be more efficient than vaccination with 'self' antigens in rodent models in prophylactic and therapeutic settings against cancer. Depending upon the targeted antigen, the mechanism of action of xeno vaccines has been shown to depend upon the development of antibody and/or cytotoxic T-cell responses. More importantly, xenogene vaccination has been shown to reproducibly affect cancer growth and to improve survival in veterinary cancer patients, mainly in dogs affected by spontaneous disease. One of these vaccines against dog melanoma has been approved by regulatory authorities in USA. Finally, several xenogene vaccines have been advanced to early Phase I/II human clinical trials where they have shown to be safe, well tolerated and capable to induce detectable immune responses against human tumor antigens.
Expert opinion: Based on this compendium of results we believe that xenogene vaccination may soon become a well-established weapon in the fight against cancer.
Keywords: DNA; cross-reactivity; immune response; xenogeneic vaccine.