Treatment of Established Lesions Caused by High-risk Human Papilloma Virus Using a Synthetic Vaccine

Here, we review a novel vaccine modality, characterized by the administration of long (23 to 45 amino acids) synthetic peptides in incomplete Freund's adjuvant (mineral oil based, Montanide ISA-51), delivered subcutaneously. Such vaccines were first demonstrated to be much more potent in preclinical T-cell response induction and tumor therapy experiments than were short major histocompatibility complex class I-binding peptides. Nevertheless, a recent study has shown the clinical efficacy of an anchor-modified short gp100 peptide in melanoma patients. We now review the evidence and mode of action of a long peptide vaccine consisting of 13 overlapping peptides, together covering the entire length of the 2 oncogenic proteins E6 and E7 of high-risk human papilloma virus type 16 (HPV16), causing complete regression of all lesions and eradicating virus in 9 of 20 women with high-grade vulvar intraepithelial neoplasia. The nature and strength of the vaccine-induced T-cell response correlated significantly with the clinical response. This vaccine promises to be of use not only in patients with premalignant lesions caused by high-risk HPV16 but also in malignant tumors caused by this virus, including HPV16-positive cervical cancer, vulvar cancer, anal cancer, and head and neck cancer.