Therapeutic Human Papillomavirus Vaccines : A Review

Human Papillomavirus (HPV) is the most common sexually transmitted disease which can infect different parts of the body including uterus. Cervical cancer is the second most common cancer among women worldwide. The HPV-related disease appears to be increasing but treatment is limited, difficult and insufficient with high relapse rate. This growth in disease burden had made the development of two an effective prophylactic Human Papillomavirus vaccines namely Gardasil quadrivalent (Merck) and CervarixTM bivalent (GlaxoSmithKline). These vaccines are widely marketed internationally. However, pre-existing HPV infection is a highly prevalent in public health of developed and developing countries. According to published literature, antigen-specific T cellmediated immunity is required for treatment of established HPV infection. Therefore, it is an important to develop vaccines that induce cell-mediated immune responses which are specific for early viral proteins in order to effect regression of established HPV associated lesions and malignant tumours. The aim of therapeutic vaccine is to eliminate pre-existing lesions or cancer cells. As a result E1, E2, E5, E6 and E7 could be best candidate targets for therapeutic vaccine antigens. Research currently focuses on the development of various forms of HPV vaccines such as live-vector vaccines, peptide vaccines, protein vaccines, nucleic acid vaccines, cell-based vaccines, edible vaccines.