Phase IIa safety and immunogenicity of a therapeutic vaccine, TA-GW, in persons with genital warts

A fusion protein vaccine consisting of human papillomavirus 6 L2E7 with Alh ydrogel was developed for the treatment of genital warts. Twenty-seven subj ects with genital warts received 3 immunizations over 4 weeks in an open-la bel study. The vaccine was well-tolerated, and all subjects made serum IgG antibodies, predominantly IgG1, against L2E7. Nineteen of 25 tested persons made antigen-specific T cell proliferative responses to L2E7, and peripher al blood mononuclear cells when cultured with L2E7 in vitro produced both i nterferon-gamma and interleukin (IL)-5, although IL-5 predominated after th e final vaccination. Five subjects completely cleared warts within 8 weeks. Subjects whose warts were not cleared by 8 weeks were offered conventional therapy. Recurrence of warts was not seen in any of the 13 persons whose w arts cleared by vaccine alone or with conventional therapy. While these pre liminary results of the use of this therapeutic immunogen are encouraging, proof of efficacy will require randomized double-blind trials.