Randomized controlled trial of an adjuvanted human papillomavirus (HPV) type 6 L2E7 vaccine: infection of external anogenital warts with multiple HPV types and failure of therapeutic vaccination.

Abstract

Cellular immunity is involved in spontaneous clearance of anogenital warts caused, most typically, by human papillomavirus (HPV) type 6 or 11, supporting the concept of therapeutic vaccination. A therapeutic vaccine composed of HPV-6 L2E7 fusion protein and AS02A adjuvant was evaluated in conjunction with conventional therapies in subjects with anogenital warts. A total of 457 subjects with anogenital warts were screened, of which 320 with HPV-6 and/or HPV-11 infection were enrolled into 2 double-blind, placebo-controlled substudies. Three doses of vaccine or placebo were administered along with either ablative therapy or podophyllotoxin. Although a positive trend toward clearance was seen in patients infected with only HPV-6, in neither substudy did the vaccine significantly increase the efficacy of conventional therapies, despite induction of adequate immune responses. Extensive HPV typing by polymerase chain reaction demonstrated that a majority of screened subjects (73.7%) were infected with HPV-6 and/or HPV-11 and that a large proportion (40.1%) were infected with multiple HPV types. HPV types that put subjects at high risk of development of cervical cancer were detected in 39.8% of subjects. Infection with multiple HPV types, including high-risk types, is common in anogenital wart disease. Therapeutic vaccination failed to increase the efficacy of conventional therapies.