Adjuvants for cancer vaccines

Abstract

The recent FDA approval of sipuleucel-T (Provenge), a patient-specific immunotherapy for androgen-independent prostate cancer developed by Dendreon Corporation, has provided support for the concept of cellular immunotherapy as an approach to cancer treatment. Adjuvants are compounds that enhance the potency of the antigen-specific immune response and can be an essential component of an efficacious vaccine. Cervarix is a prophylactic vaccine against human papilloma virus (HPV) types 16 and 18, which can cause cervical cancer, and recently received approval from the FDA, due in part to the protective immunity it conferred against not only HPV types contained in the vaccine but in addition to oncogenic HPV strains that were not contained in the vaccine. Cervarix is formulated with MPL (monophosphoryl lipid A), a TLR-4 targeted adjuvant shown to promote immune response broadening. The recent FDA approvals of these pioneering vaccines are landmark events, and will likely usher in renewed interest and investment in the development of new therapeutic cancer vaccine candidates. In this review, we examine new molecularly defined adjuvants and formulations and its application to cancer vaccines under development.