Prospectives of developing therapeutic HPV vaccines

Abstract

Human papillomavirus (HPV) represents one of the most serious global public health problems. Malignant female and male diseases mainly result from persistent HPV infection. Cancer belongs to a high mortality rate disease. It has been established that HPV infection causes about 70% vaginal cancer, 50% male genital cancer, 90% anal cancer and 60% head-and-neck cancer. Annually, a large number of people develop various HPV-caused cancer types, dominated by cervical cancer, one of the most common and aggressive types of cancer that threatens health holding the fourth place among most female common cancer worldwide. According to the World Health Organization (WHO), in 2020, about 600 cases of cervical cancer are recorded daily in different countries. Emergence of cervical cancer is closely related to factors such as long-term (persistent) HPV infection and somatic mutations of the host genome. Although HPV infection can be detected and cured early with highly effective screening methods and surgical procedures, the carcinogenic risk of HPV related diseases constantly increases, which elimination faces certain difficulties, especially in low- and mid-developed countries. The most acceptable solution to this is development and implementation of therapeutic vaccines for prevention and treatment of HPV related diseases. Three licensed HPV vaccines based on L1 type virus-like particles (L1-VLPs) technology are available globally: bivalent (HPV-2), quadrivalent (HPV-4) and nonavalent (HPV-9) vaccines. These vaccines demonstrated effectiveness in reducing HPV-related cervical cancer rate by up to 90% worldwide. However, the therapeutic effect of these vaccines on persistent HPV infection and lesions has not been observed. Therapeutic HPV vaccines candidates targeted Ye6/Ye7 cancer proteins activate cellular immunity that eliminates existing HPV infection. Here we review types, mechanisms of action and clinical effects of therapeutic HPV vaccines, as well as current and future developments in the field for prevention and treatment of HPV related diseases.

Keywords

• human papillomavirus (hpv)
• virus-like particles (vlp)
• cervical cancer
• preventive vaccines
• therapeutic vaccines
• immunogenicity of vaccines