A variety of clinical trials for
vaccines against
cancer have provided evidence that
DNA vaccines are well tolerated and have an excellent safety profile.
DNA vaccines require much improvement to make them sufficiently effective against
cancer in the clinic. Nowadays, it is clear that an increased
antigen expression correlates with improved immunogenicity and it is critical to
vaccine performance in large animals and humans. Similarly, additional strategies are required to activate effective immunity against poorly immunogenic tumour
antigens. This review discusses very recent scientific references focused on the development of sophisticated
DNA vaccines against
cancer. We report a selection of novel and relevant patents employed to improve their immunogenicity through several strategies such as the use of tissue-specific transcriptional elements, nuclear localisation signalling,
codon-optimisation and by targeting antigenic
proteins to secretory pathway. Recent patents validating portions or splice variants of tumour
antigens as candidates for
cancer DNA vaccines with improved specificity, such as
mesothelin and hTERT, are also discussed. Lastly, we review novel patents on the use of genetic
immunomodulators, such as "universal" T helper
epitopes derived from
tetanus toxin, E. coli heat labile
enterotoxin and
vegetable proteins, as well as
cytokines,
chemokines or costimulatory molecules such as
IL-6,
IL-15, IL- 21 to amplify immunity against
cancer.