A vaccine developed by French biotech Transgene has been shown to reverse precancerous changes of the cervix caused by human papillomavirus in a Phase II trial.

The vaccine, TG4001, is targetted against HPV type 16 which is responsible for more than half of cervical intraepithelial neoplasia (CIN) lesions, which can go on to develop into full-blown cervical cancer.

HPV vaccination is on the brink of becoming available in both Europe and the USA, with preventative vaccines from GlaxoSmithKline and Merck & Co/Sanofi Pasteur MSD already submitted for approval and under regulatory review. But these vaccines are designed for preventing infection with HPV strains associated with cervical cancer. Transgene’s product would be used to treat women who are already infected and have already gone on to develop CIN, and could eventually be used to treat cervical cancer itself.

The Phase II trial involved 21 women with high-grade CIN caused by HPV 16. These patients would ordinarily have to be treated with surgery to remove the lesions, although roughly 20% of cases resolve spontaneously. Using TG4001, surgery was avoided in nine out of 18 women whose results were available at six months, giving a CIN regression rate of 50% for the vaccine.

Philippe Archinard, Transgene’s chief executive, said: "These data constitute a significant breakthrough and validate our vaccine technology platform. Our objective is an effective vaccine for pre-cancerous lesions to speed up the fight against cervical cancer which remains a serious health concern globally."

The company is hoping to find a partner to take the vaccine into Phase III testing, and either GSK and Merck would make a rational partner for the project, said analysts.

HPV infection is the most common sexually transmitted disease affecting about 400 million women worldwide. Most infections are spontaneously eliminated in less than one year, but a minority persist, eventually leading to CIN and cervical cancer, which kills more than a quarter of a million women each year.