Cervical Cancer Vaccines: More Promise
New Studies Show Broader, Longer Protection in Vaccines' Trials
April 26, 2006 -- Two not-yet-approved vaccines that fight the leading cause of cervical cancer may hold broader promise than researchers had previously noted.
The vaccines are Gardasil, made by Merck, and Cervarix, made by GlaxoSmithKline. The vaccines both target types of human papillomavirus (HPV) that can -- but don't always -- lead to cervical cancer. Merck and GlaxoSmithKline are WebMD sponsors.
New data on the vaccines include these findings:
- Gardasil may offer some protection against cervical cancer, precancerous lesions, and genital warts in women previously exposed to certain types of HPV.
- Gardasil may protect against cervical cancer, genital warts, and persistent infection with four types of HPV for five years.
- Cervarix may be effective for more than four years and may offer broader protection against HPV infection than previously thought.
About HPV and Cervical Cancer
HPV is transmitted through sexual contact. It's very common; many people are infected and don't know it.
HPV is a leading cause of cervical cancer, the No. 2 cause of cancer deaths among women worldwide. But HPV doesn't always lead to cervical cancer.
The American Cancer Society estimates that 9,710 women in the U.S. will be diagnosed with invasive cervical cancer in 2006. Cervical cancer is a major problem in developing countries that don't have good access to screening tests, such as the Pap test, which checks for abnormalities of the cervix (the narrow neck of a woman's uterus) that may be cancerous or precancerous.
About the Vaccines
There are more than 100 types of HPV. Gardasil targets four high-risk types (types 6, 11, 16, and 18). Cervarix targets HPV types 16 and 18, the highest-risk types.
The vaccines would not wipe out cervical cancer, since not all cervical cancers are caused by HPV. Gardasil has gone through phase II and phase III trials, which are required for FDA approval. Phase III trials of Cervarix are under way.
Both vaccines are given in three doses. The second dose is given two months after the first dose. The third dose is given four months after the second dose.
Neither vaccine has been approved in the U.S. yet. Gardasil is currently getting a priority review by the FDA, and Cervarix is expected to be submitted for FDA approval by the end of 2006.
Other HPV vaccines are also in the works.