Merck & Co has moved a step closer to bringing a vaccine for human papillomavirus to market, after the results of a Phase III clinical trial showed that its Gardasil candidate stimulated an antibody response in adolescent males and females aged 10 to 15.

Last month, a study reported in the Lancet Oncology journal showed that Gardasil reduced the incidence of HPV infections – and related diseases including genital warts, precancerous cervical lesions and cervical cancer - in adult young women. But the new study is the first to show that it can prevent infections in younger females, as well as males.

“It is important to consider the role of both sexes when talking about the public health impact of HPV,” said Professor Terry Nolan of the University of Melbourne in Australia, one of the study's lead investigators. And the age of the patient population is significant, as it suggests the vaccine could be used to protect young people before they become sexually active and exposed to the risk of contracting HPV.

Gardasil is one of the front-runners among the prophylactic HPV vaccines currently in development, with the other main candidate being GlaxoSmithKline’s Cervarix. Both vaccines are in Phase III testing, with Merck predicting that Gardasil will be filed later this year, and GSK planning to submit Cervarix in 2006 [[05/05/05a]].

The 1,529-patient study found that 100% of the patients who received Gardasil developed antibodies against all four HPV strains, and only three adolescents (0.3%) failed to complete the course due to an adverse experience. The data were presented at the annual meeting of the European Society of Pediatric Infectious Diseases in Valencia, Spain, which ends today.