said Monday its experimental vaccine against a virus that causes cervical cancer appears to be effective among middle-age women as well as teenagers and young women.
The British drug giant said a late-stage clinical trial of its Cervarix vaccine reveals that all women ages 15 to 55 showed a positive response against two types of human papillomavirus, or HPV. These two types -- HPV 16 and HPV 18 -- are the most common causes of cervical cancer among the many versions of the virus.
"These results are encouraging as they open the possibility that all women, regardless of age, would benefit from vaccination against
tumor-causing HPV infection to protect them against cervical cancer," said Dr. Philippe Monteyne, head of global vaccine development at GlaxoSmithKline.
"For the first time, we see that a vaccine against cervical cancer is highly immunogenic in women over 25 years of age," said Dr. Tino F. Schwarz, the lead investigator, as he commented on Cervarix's ability to produce an immune response. "These are important data as older women remain at significant risk of acquiring infections with cancer-causing HPV types."
GlaxoSmithKline announced the results at the annual meeting of the American Society of Clinical Oncology in Atlanta, just a few days before the Food and Drug Administration is scheduled to rule on Gardasil, a competing HPV vaccine from
An FDA advisory committee of medical experts
voted unanimously last month to support Gardasil as a vaccine that could be administered to girls as young as nine and women as old as 26. Merck is proposing that the FDA approve Gardasil to prevent the two leading types of cervical cancer-causing HPV. In addition, Merck is seeking approval for Gardasil as a prevention for two types of HPV that cause most genital warts.
GlaxoSmithKline expects to file its application with the FDA by year-end. In March, it asked the European Union to approve Cervarix. It also has sought approval in Australia as well as in some Asian and Latin American countries. Merck also has applied to the EU and other markets.
GlaxoSmithKline says HPV infection is "very common," adding that cervical cancer is "a major global health problem." The company says nearly 500,000 new cases occur worldwide each year and an estimated 270,000 women die each year. Cervical cancer is the world's second most common cancer among women and the third leading cause of cancer deaths among women.
The GlaxoSmithKline study said all of the women tested demonstrated an antibody response against HPV 16 and HPV 18 one month after completing the vaccine dose. Maintaining a strong, sustained antibody response -- the defense against invaders -- is crucial for a vaccine's success. GlaxoSmithKline said all of the women remained seropositive -- showing a high level of antibodies -- when tested 12 months after having received the first dose.
"The antibody levels were indeed greater or equal to those observed during a separate long-term follow up efficacy study in which women 15 to 25 years of age were shown to have 100% protection over 4.5 years against HPV 16 and HPV 18 infections and associated cervical lesions," the company said. "
The vaccine was generally safe and well-tolerated in women of all study age groups, extending the safety profile already demonstrated in former studies."
The vaccine also has been effective in guarding against two other types of cervical cancer-causing HPV. The company says the four HPV types covered by Cervarix are responsible for 80% of cervical cancers worldwide.
The company tested 666 women from Germany and Poland, ages 15 to 55, who were given three doses of Cervarix within six months. All of the women had "detectable antibodies" antibodies for HPV 16 and HPV 18 at teh seven-month and at 12-month marks, the company said. More than 16,000 women worldwide have been vaccinated with Cervarix as part of completed and ongoing clinical trials.