Cervical Cancer Vaccine on the Way
Study Says Vaccine Also Prevents Genital Warts
100% Protective Against Disease continued...
Thirty-five women in the placebo group developed persistent infection with one of the HPV strains, compared with four women who received the vaccine.
There were six diseases associated with HPV infection in the placebo group and none in the vaccine group.
The vaccine reduced persistent HPV infection by 90% and was 100% effective three years later in preventing precancerous cervical lesions and genital warts. The findings are published in the April 7 online edition of The Lancet Oncology.
Researchers are developing many vaccines to prevent different cancers, but the HPV vaccine is considered the closest to approval.
Merck is one of two drug giants racing to develop an effective and safe HPV vaccine. GlaxoSmithKline also reported promising results late last year in a study involving 1,100 young women. The vaccine used in that trial targeted HPV strains that cause cervical cancer but not genital warts.
Both Merck and GlaxoSmithKline have begun much larger trials of their respective vaccines. Villa tells WebMD that early results from Merck's investigation are expected later this year. If the trials go well, the company hopes to introduce the vaccine late in 2006, she says.
Most experts agree that the vaccine will have the most impact if given to young girls in countries that don't screen for cervical cancer and before they become sexually active.
But its impact in the U.S. and other developed nations, where cervical cancer rates are low due to screening, is unclear, says Debbie Saslow, PhD, director of breast and gynecological cancers for the American Cancer Society.
The vaccine will not replace Pap smears, she says, because the vaccine does not protect against about a dozen HPV strains that cause between 25% and 30% of cervical cancers. And there is some concern that vaccinating against the two major cervical cancer agents will lead to an increase in these other cancer-causing strains.
"This vaccine could have a huge impact if you could vaccinate young girls in countries that don't have routine cervical cancer screening," Saslow tells WebMD. "But these are the countries that are going to be least able to afford it. And within the U.S. it isn't likely that people who are not being screened will get vaccinated."