laxoSmithKline’s (GSK) experimental cervical cancer vaccine Cervarix has proven 100% effective in preventing precancerous lesions due to cancer-causing human papillomavirus (HPV) strains 16 and 18 for up to five and a half years. The results, based on an extended follow-up trial and presented at the American Association for Cancer Research, demonstrate the longest duration of protection seen in any cervical cancer vaccine trial until now, according to GSK.
The results could be a turning point in UK-based GSK’s race to get Cervarix to patients and it should now be a matter of time before the company will face its American competitor Merck in the market. Merck’s Gardasil is the first cervical cancer vaccine marketed internationally since the FDA approved it in June 2006. GSK, on the other hand, applied for FDA approval on March 30 and is expecting approval in Europe in the first half of 2007.
HPV infection is the most common sexually transmitted infection in the US Some HPV strains cause genital warts, which do not pose a major health risk, but others can cause cervical lesions that can turn cancerous. Strains 16 and 18 are known to cause 70 percent of all cervical cancer cases.
The study proved that Cervarix prevents precancerous lesions and showed that the vaccine induced a strong immune response in nearly 100% of women in the study, which was maintained over 5.5 years for both virus types 16 and 18. The vaccine also showed 68% efficacy against all precancerous lesions, regardless of the type of cancer-causing virus detected.
Gardasil, in comparison, has proved effective for five years, and Merck says that it also prevent genital warts and other dangerous HPV strains. Because Gardasil has been in clinical trials longer, Merck has been able to show a greater reduction in precancerous lesions, a condition that the FDA is thought to consider required for approval, according to Business Week
Merck has the advantage of being first to market, and most market analysts foresee Merck’s sales leading GSK’s. But others say that Merck’s head start will not bring the company a huge advantage over GSK because the market is large enough for two big players. Indeed, analysts predict that the cervical cancer vaccine market could be worth more than $3 billion by 2008, according to Business Week
. In just half a year of marketing and approval in 54 countries, Merck has showed sales of $235 million in 2006 for Gardasil, according to the Motley Fool.
Max Herrmann, an ING analyst, has predicted that Cervarix will gain 40% of the market for cervical cancer vaccines and generate sales of $2.2 billion by 2011, according to Reuters London. Herrmann expects Cervarix to win European approval in the second half of 2007 and US approval in the first quarter of 2008, the Reuters report says.
Glaxo’s positive results for Cervarix are based on an extended follow-up analysis of women who had participated in an initial efficacy study for the vaccine. Of the 1,113 women who took part in that initial study, this extended follow-up study looked at endpoints for 776 women for a period of up to 67 months. The women, between 15 and 25 years of age, were randomized to receive three doses of either Cervarix or placebo. Glaxo is now funding a head-to-head comparison to prove that Cervarix is more powerful than Gardasil.
In spite of the tremendous market potential and the vaccine’s health benefits, GSK will face the same hurdles that Merck is facing now. One is fierce social backlash from conservative groups and vaccine skeptics for marketing a vaccine against a sexually transmitted disease. The other is a hesitance to adopt the vaccine because of its high cost. At $360 for a three-shot regimen, Gardasil is considered an expensive vaccine; and while GSK has not specified the cost for Cervarix, it is planning to match Merck’s price. The vaccine’s price tag will put a strain on the already tight budgets of federal and state programs that provide vaccines for little or no cost to children of low-income families. On the private side, most insurers cover Gardasil, but some have limited their reimbursements and administrative expenses.How the Cervical Cancer Vaccines Match Up