Overview of the clinical development and results of a quadrivalent HPV (types 6, 11, 16, 18) vaccine.

BACKGROUND Human papillomaviruses (HPVs) play an obligatory role in cervical cancer development. Thus, immunization of women using a prophylactic vaccine against the most common high-oncogenic risk types (e.g., HPV 16 and 18) and HPV 6 and 11, which contribute to development of low-grade cervical lesions and cause most anogenital warts, represents a logical primary prevention strategy. PERSPECTIVES At the time of licensure, Phase II/Phase III studies showed that administration of a quadrivalent HPV (types 6, 11, 16, 18) vaccine to young women (16 to 26 years) naïve to the vac- cine HPV types resulted in 100% efficacy against HPV 16- and 18-related precancerous cervical lesions, 100% efficacy against HPV 16- and 18-related high-grade vulvar/vaginal neoplasias, 95% efficacy against HPV 6, 11, 16, or 18-related cervical intraepithelial neoplasia/adenocarcinoma in situ, and 99% efficacy against HPV 6, 11, 16, or 18-related genital lesions. The quadrivalent HPV vaccine is highly immunogenic in adolescent males and females, and long-term follow up of young women did not detect evidence of waning immunity through 5 years. CONCLUSIONS The quadrivalent vaccine is generally well tolerated. The efficacy and safety of the quadrivalent vaccine is continuing to be investigated in young men and mid-adult women. Nordic cancer registries are providing ongoing long-term pharmacovigilance.