Cancer Vaccine Works Long Term
Vaccine Protects Against Virus That Causes Cervical Cancer
April 5, 2006 -- A vaccine targeting the sexually-transmitted virus that can
cancer was still protecting women who got it after more than four years,
researchers reported Wednesday.
The findings represent the longest follow-up yet of an experimental human
papillomavirus (HPV) vaccine, which has the potential to dramatically lower
deaths from cervical cancer.
Two such vaccines are poised to hit the market in the U.S. pending approval
by the FDA. The agency is expected to rule on Merck's vaccine -- called
Gardasil -- early in June.
A spokesman for GlaxoSmithKline tells WebMD that the company plans to seek
FDA approval for its HPV vaccine -- Cervarix -- by the end of the year.
"With fast-track status, if all goes well, we could have [approval]
within six months," says Phillippe Monteyne, who heads global vaccine
development for the company.
The study included 800 women who were vaccinated with either three doses of
Cervarix or a placebo.
In November 2004, researchers reported that the vaccine was 100% effective
in preventing persistent infection with the two HPV strains that cause about
70% of cervical cancers -- HPV-16 and HPV-18.
In a follow-up, published in the latest issue of The Lancet, they
reported that the women given the vaccine continued to be protected four and a
half years after receiving the last dose of the vaccine.
The women were also protected against two other HPV strains that have also
been associated with cervical cancer -- HPV 45 and HPV 31. This
cross-protection occurred even though the vaccine was not designed to target
About half a million cases of cervical cancer are diagnosed worldwide each
year, and an estimated 280,000 women -- mostly in developing countries -- die
from the disease.
Researchers estimate that if all eligible women got the vaccine, it would
reduce the worldwide incidence of cervical cancer by almost 70%.
"This is a very exciting time," says Diane M. Harper, MD, MPH, who
led the study team. "We haven't had an advance like this in cancer care or
in women's health for 50 years. This has tremendous potential."
There are still many unanswered questions, most notably who will get the
vaccine, when they will be vaccinated, and which vaccine they will get.
The GlaxoSmithKline vaccine protects against cervical
cancer alone, while the Merck vaccine also targets two HPV viruses that
cause genital warts.
But Harper says her findings suggest that the GlaxoSmithKline vaccine may
protect women against cervical cancer longer than its competitor.
Harper directs the Gynecologic Cancer Prevention Research Group at Dartmouth
Medical School's Norris Cotton Cancer Center. The study was funded by
GlaxoSmithKline, but she says she has also done research on the Merck vaccine.
GlaxoSmithKline and Merck are WebMD sponsors.
"I'm not trying to pick a fight and say one vaccine is better than the
other," she says. "These are both good vaccines, but it is clear that
there are real differences between them."