Cervical cancer vaccine hailed as breakthrough

CTV.ca News Staff
November 13, 2004 9:54 AM ET

Researchers and the medical community alike are excited by a new cervical cancer vaccine. It's been found to be 100 per cent effective in clinical trials -- the first vaccine ever to prevent a cancer.

"When you look at cervical cancer and you look at the worldwide numbers and what we see in Canada, this is very, very exciting," CTV's medical correspondent Marla Shapiro said on Canada AM.

According to the Canadian Cancer Society, 1,350 women will be diagnosed with cervical cancer in Canada this year, and 410 of them will die of the disease. "We're talking about a quarter of a million worldwide," Shapiro said.

The study's findings are reported in Friday's edition of the journal Lancet. It finds that the vaccine provokes a strong immune response from two subtypes of the human papillomavirus, also known as HPV. HPV16 and HPV18 are responsible for causing 70 per cent of cervical cancer.

In the trials, researchers studied 1,113 women aged 15 to 25 who had no antibodies to HPVs in their blood. Of the women who received three doses of the vaccine, 100 per cent developed high levels of antibodies.

"The antibody levels were a thousand times more than what we see in the natural course of the infection, so it will stop persistent infection and it may be that the three vaccines may give you life-long immunity."

Dr. Michael Shier, one of the study's principal investigators and a gynecological oncologist in Toronto, says the impact of the vaccine could reach far beyond eradicating cervical cancer.

"In Canada, once the vaccine is introduced it would virtually eliminate cervical cancer, almost all vaginal cancers, most vulvar cancers, anal cancer in men and women and penile cancer," Shier says.

Shier says larger, longer trials are needed to confirm the results. He says that once the vaccine is approved, it would theoretically be given to young, healthy girls between the ages of 5 and thirteen.

According to the study, "mathematical modelling predicts that a prophylactic vaccine programme, directed at young adolescent women, is likely to be cost-effective in both screened and unscreened populations."

It adds that there may be additional benefits from vaccinating older women. Also, doctors will reduce the cost of treating cancer. "In the USA, these preventable costs are estimated at several billion dollars per year."

Made by GlaxoSmithKline, this isn't the only cervical cancer vaccine in development. Merck and Co. has also reported success with a vaccine that protects against the single subtype HPV16.

A commentary in the Lancet suggested the vaccine would be brought to market quickly since the findings are so positive.