The GlaxoSmithKline cervical cancer candidate vaccine, CERVARIX(R), demonstrated 100 percent efficacy in preventing precancerous lesions due to cancer-causing human papillomavirus types 16 and 18 for up to 5.5 years in an extended follow-up trial, according to data presented at the American Association for Cancer Research.
The trial results demonstrate the longest duration of protection seen in any cervical cancer vaccine trial reported to date.
The GSK cervical cancer candidate vaccine also showed 68 percent vaccine efficacy against precancerous lesions (CIN2+) and 38 percent vaccine efficacy against abnormal Pap smears, regardless of the type of cancer-causing virus detected. These results suggest evidence of protection beyond what might be expected from a vaccine that is designed to target virus types 16 and 18 alone. More specifically, the study confirmed that the candidate vaccine provides further preliminary evidence of cross-protection against incident infection with cancer-causing virus types 45 and 31 that also extended up to 5.5 years after vaccination.
“These new data from this extended follow-up trial are exciting for those of us who are working to prevent cervical cancer, and for women around the world,” said Dr. Stanley Gall, lead investigator and Professor of Obstetrics, Gynecology and Women’s Health at the University of Louisville, Kentucky. “Demonstrating 100 percent efficacy and sustained immune response for more than five years is a significant contribution to the scientific understanding of preventing cervical cancer and precancerous lesions through vaccination.”
Additionally, the trial found that the candidate vaccine induced a strong immune response in virtually 100 percent of women in the study, which was maintained over 5.5 years for both virus types 16 and 18. At the end of the 5.5 year observation period, the average level of antibodies against both virus types 16 and 18 was at least 11 times greater than antibody levels associated with natural infection with the virus.
“The results of this study confirm our confidence in our cervical cancer candidate vaccine, which includes a novel proprietary adjuvant system, called AS04, intended to enhance immune response and increase duration of protection,” said Dr. Hugues Bogaerts, Vice President of Worldwide Medical Affairs, Human Papillomavirus Vaccines, GSK. “We believe that the best possible prevention of cervical cancer will include routine screening together with a vaccine designed to provide broad and durable protection against the most common cancer-causing virus types.”