Experimental HPV Vaccine Adds Protection Against 5 More Cancer-Causing Strains

By Amy Orciari Herman

A vaccine that protects against nine human papillomavirus serotypes — the four included in the currently available quadrivalent vaccine (Gardasil) plus five additional cancer-causing strains — shows promising results in two phase III trials. The findings, the Wall Street Journal reports, will be presented this week at the Eurogin conference in Italy.

One study randomized over 16,000 women aged 16 to 26 to a three-dose series, either with the experimental vaccine (called V503) or Gardasil. Immune responses to the four shared HPV types were similar with the two vaccines. In addition, the incidence of precancerous lesions caused by the five additional strains was cut by 97% with V503. A second study found that immune responses to V503 in boys and girls aged 9 to 15 were similar to those seen in women aged 16 to 26.

Injection site reactions were higher with V503 than with Gardasil (91% vs. 85%).