GlaxoSmithKline on Wednesday announced that it would begin a trial to determine whether its experimental human papillomavirus vaccine Cervarix provides better protection against cervical cancer than Merck's HPV vaccine Gardasil, the Philadelphia Inquirer reports (Ginsberg, Philadelphia Inquirer, 1/18). Gardasil and Cervarix in clinical trials have been shown to be 100% effective in preventing infection with HPV strains 16 and 18, which together cause about 70% of cervical cancer cases. FDA in July 2006 approved Gardasil for sale and marketing to girls and women ages nine to 26, and CDC's Advisory Committee on Immunization Practices later that month voted unanimously to recommend that girls ages 11 and 12 receive the vaccine (Kaiser Daily Women's Health Policy Report, 12/13/06). Researchers in a study published in the April 6, 2006, online edition of the Lancet also found that Cervarix prevented infection with HPV strains 31 and 45, which together with strains 16 and 18 cause more than 80% of cervical cancer cases (Kaiser Daily Women's Health Policy Report, 6/6/06). According to Merck, Gardasil is about 99% effective in preventing HPV strains 6 and 11, which together with strains 16 and 18 cause about 90% of genital wart cases. Gardasil also protects against vaginal and vulvar cancers, two other gynecological cancers that are linked to HPV, according to a study presented in June 2006 at a meeting of the American Society of Clinical Oncology in Atlanta (Kaiser Daily Women's Health Policy Report, 12/11/06). According to the Inquirer, GSK in April plans to file for FDA approval of Cervarix, and it expects approval by the end of this year.

GSK Trial, Merck Reaction
GSK plans to enroll 1,042 women living in the U.S. ages 18 to 45 in its clinical trial. Participants will receive three doses of either Gardasil or Cervarix over six months and will be monitored for cervical lesions and blood changes. Results will be released after one year and after 17 months (Ginsberg, Philadelphia Inquirer, 1/18). GSK researchers plan to monitor immune responses to HPV strains 16, 18, 31 and 45 (Hirschler, Reuters, 1/17). Brian Lortie, GSK's vice president for Cervarix operations, said, "We're quite confident [Cervarix] has a stronger immune response and broader protection" than Gardasil. Merck in a statement Wednesday criticized the trial's focus on immunogenicity, or immune response. "Immunogenicity data [are] not a substitute for true efficacy data," the statement said. A company spokesperson said GSK did not disclose the cost of the trial but said the new data "would be well worth the expense." Lortie said results from the trial would not be included in its FDA application for Cervarix (Ginsberg, Philadelphia Inquirer, 1/18).

Philadelphia Inquirer Examines Cost, Access of Gardasil
In related news, the Inquirer on Thursday examined how Gardasil's cost of $360 for three doses given over six months is affecting access to the vaccine. According to the Inquirer, Gardasil is the most expensive vaccine on CDC's list of recommended childhood vaccines, and many private insurance policies are not providing adequate reimbursement to cover physicians' costs to purchase, store and administer the vaccine, which can add 18% to 25% to the Gardasil base cost. Two states -- New Hampshire and South Dakota -- have plans to provide the vaccine at no cost to girls and women under age 18. Merck -- which is spending "heavily" on a marketing campaign to boost awareness of HPV and its link to cervical cancer -- will offer Gardasil at no cost to low-income women ages 19 to 26 who are uninsured, according to the Inquirer. Several colleges have begun to offer the vaccine with varying additional fees to students who are able to pay upfront. As of October 2006, Merck had $80 million in Gardasil sales (McCullough, Philadelphia Inquirer, 1/18).