A new vaccine developed to create an immune response against a cancer-causing human papillomavirus (HPV-16) can clear chronic infection by the virus and may promote regression of precancerous genital lesions in women, according to a report published in the Nov. 5 issue of the New England Journal of Medicine. The vaccine induced HPV-specific immune responses in 100% of patients with advanced vulvar intraepithelial neoplasia (VIN3), a precancerous condition usually caused by HPV infection and for which there is no effective therapy. Seventy-nine percent of study participants experienced measurable regression of their VIN3 lesions within one year of vaccination; 47% experienced complete disappearance of lesions and were still symptom-free two years following vaccination.

According to researchers who conducted the phase II study at the Leiden (The Netherlands) University Medical Center, spontaneous regression of HPV-16 positive VIN3 lesions normally occurs in less than 1.5% of patients.

Unlike recently approved vaccines that prevent against infection by HPV, such as Merck’s Gardasil and GlaxoSmithKline’s Cervarix, this is a vaccine for people who have already been exposed to HPV. The university developed the vaccine in partnership with ISA Pharmaceuticals. The vaccine is composed of HPV synthetic long peptides, a proprietary technology.