December 17, 2005

Cancer Vaccine Has Strong Response

By Ransdell Pierson

NEW YORK (Reuters) - Girls aged 10 to 14 who received GlaxoSmithKline Plc's vaccine to prevent infection with the virus that causes cervical cancer had immune responses twice as strong as women 15-25 years old given the vaccine, the company said on Saturday, describing results of a late-stage trial.

Glaxo said the first published data from a Phase III trial of its Cervarix vaccine suggest it may provide the strongest and most-prolonged protection if given to girls at very young ages, long before they encounter the sexually transmitted virus.

"The concentrations of antibodies to the virus were twice as high in the bloodstreams of the young girls," said Gary Dubin, a senior research official at Glaxo who was the lead author on the study.

Antibodies are immune-system proteins that seek out and destroy bacteria and viruses. Vaccines, by introducing the body to snippets of specific bacteria or viruses, train the body to crank out tailor-made antibodies that attack them.

Dubin said the trial was not designed to confirm actual effectiveness of the vaccine because few girls in the 10 to 14 age group are yet sexually active. Instead, he said the immune response is the best "surrogate" indicator of the vaccine's potential ability to protect them from prolonged infection with the virus.

Results of the trial were presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Washington, D.C.

The Glaxo-financed trial, conducted in Europe and Russia, involved 158 healthy girls aged 10-14 and 458 women aged 15-25 who received three doses of the vaccine over a six month period.

Cervarix, which has not yet been submitted for regulatory approvals, is one of the most important experimental products being developed by the British drugmaker. It is expected to eventually compete with a similar Merck and Co. vaccine, Gardasil, that is already awaiting approval from U.S. and European regulators.

Like Gardasil, the Glaxo product blocks infection with two strains of human papillomavirus that are responsible for about 70 percent of cases of cervical cancer. It is the second most common fatal cancer in women.