HPV vaccine may reach market within next 5 years. (Expert Opinion).

WHISTLER, B.C. -- A human papilloma virus vaccine that can be used to prevent infection may be available within the next 5 years, Dr. Ian H. Frazer said at an update on viral infections sponsored by the University of British Columbia.

"A vaccine should be available--I would hope--in less than 5 years, unless something very strange goes on in the clinical trials," said Dr. Frazer, director of the center for immunology and cancer research at the University of Queensland, Brisbane, Australia.

Two vaccines, one developed at the National Institutes of Health and one developed by Merck Pharmaceuticals, have entered phase III clinical trials.

Because the Food and Drug Administration requires that such a vaccine be shown not only to protect against persistent infection, but also to reduce the incidence of cervical intraepithelial neoplasias (CIN), those studies must recruit large numbers of women--20,000 each in the treatment and placebo arms--and follow them for 3 years.

The approach to a vaccine that prevents infection is relatively straightforward, Dr. Frazer said. Natural immune response to papilloma virus infection tends to be fairly weak, because the virus preferentially infects epithelial cells where it is not very well exposed to the immune system. But there is an immune response, and it is B-cell and antibody directed.

"That's really good news, because this puts this vaccine into the absolutely conventional mode. All vaccines that are currently licensed for use actually protect against infection by producing neutralizing antibody," Dr. Frazer noted at the meeting. "We can demonstrate now that with papilloma virus, you can produce neutralizing antibody that is sufficient for protection."

Papilloma virus vaccines necessarily have two ...