January 19, 2007
Glaxo to conduct head-to-head trial as stakes rise in vaccine sector
GlaxoSmithKline will pit its experimental cervical cancer vaccine Cervarix against Merck’s Gardasil in a head-to-head clinical trial, the drug maker said.
The study, set to enroll more than 1,000 women, is a somewhat risky move for GSK. The results could support Gardasil, which was approved last June and is expected to generate upward of $700 million in sales this year.
But favorable data could give Cervarix, which is still in development, a marketing edge. The company plans to submit the vaccine to the FDA in 2009, and results would become available by then. In 2009, Gardasil will generate $2.5 billion in sales, compared with $850 million for Cervarix, according to a report from investment bank Friedman, Billings, Ramsey cited by Forbes. From there, sales of both will level off.
The stakes for the two drug companies rose today when the American Cancer Society issued recommendations that girls should get the new vaccine for human papilloma virus (HPV) at age 11-12. The American Academy of Pediatrics did the same when it updated its own immunization schedule earlier this year. HPV types 16 and 18 are responsible for at least 70% of all cervical cancers worldwide. At least one state, West Virginia, is considering legislation that would require HPV vaccinations for girls.
GSK’s phase III trial will be designed to compare the vaccines’ immune responses to types 16 and 18, as well as to other cancer-causing HPV types.
Merck’s vaccine is designed to protect against four strains of HPV; GSK is testing its vaccine to protect against two. Cervarix’s proprietary adjuvant system stimulates "a more robust immune memory response," according to GSK. Merck says its technology is well established.
Some question whether the head-to-head trial will enable a meaningful comparison, though. “Whether [immune response] has anything to do with protection against disease has not been proven,” Kevin Ault, a professor of obstetrics and gynecology at Emory University who consults for both Merck and Glaxo, told Forbes.
But a study to show a difference in preventing precancerous lesions or cancer would take years and involve perhaps 12 times as many patients.