While the Gardasil 9 vaccine prevents infection with nine types of human papillomavirus (HPV) that cause cancer or genital warts, an experimental treatment vaccine could halt disease progression in women who have already developed precancerous cervical lesions. Researchers in the Netherlands tested Vvax001, a therapeutic vaccine containing a weakened Semliki Forest virus that encodes the oncogenic E6 and E7 proteins from HPV type 16. In a Phase II trial, 18 patients with high-grade cervical intraepithelial neoplasia (CIN3) received three doses of the vaccine given three weeks apart. Cervical biopsies taken up to 19 weeks after immunization showed that all but one had smaller lesions, six regressed to low-grade dysplasia and three had complete regression. “If confirmed in a larger trial, our results could mean that at least half of the patients with CIN3 might be able to omit surgery and avoid all its possible side effects and complications,” says Refika Yigit, MD, of University Medical Centre Groningen.