Promising particle-based vaccines in cancer therapy.

Immunotherapy and preventative cancer vaccines offer the hope of controlling cancer in humans with few of the undesirable side effects associated with current chemotherapy-based methods. Particulate vaccines are effectively taken up by dendritic cells, inducing both T-cell and antibody responses. Virus-like particles (VLPs) have shown preventive efficacy against cervical cancer. Herein we review a range of leading particle-based vaccine approaches: VLPs, immunostimulating complexes, liposomes, synthetic nanoparticles and microparticles (both biocompatible and biodegradable, such as polylactide-co-glycolides and poly[D,L-lactic-co-glycolic] acid). Immune efficacy, regulatory and safety issues, as well the application of immunotherapeutics to immunosuppressed patients with high levels of Tregs are also discussed. We argue that developmental issues (cost and intellectual property lifespan) and the lack of reliable preclinical animal models, rather than the lack of innovative vaccine approaches, currently present a major obstacle to rapid and effective vaccine development.