Perspectives on therapeutic HPV vaccines: Where are we now?

The role of Human Papillomavirus (HPV) as the key etiological factor for cervical cancer has spurred the development of preventive and therapeutic HPV vaccines for the control of HPV-associated malignancies. While the commercial preventive HPV vaccines Gardasil and Cervarix represent promising breakthroughs for the control of HPV-associated cancers through prevention, they do not exert therapeutic effects on existing lesions. In addition, their prohibitive cost and limited availability in developing countries, which account for >80% of cervical cancers, make it unlikely for the current preventive HPV vaccines to generate an immediate impact on the prevalence of cervical cancer. Thus, there is an urgent need for therapeutic HPV vaccines. HPV E6 and E7 oncoproteins represent ideal targets for therapeutic intervention because of their constitutive expression in HPV-associated tumors and their crucial role in the induction and maintenance of HPV-associated disease. This chapter focuses on the clinical development of various therapeutic HPV vaccines targeting E6 and/or E7 antigens, with perspectives on their future prospects for the control of HPV-associated malignancies.