It seems that Merck has not found enough of benefits its human papillomavirus vaccine known as Gardasil can offer, the company has seen new signs indicating of more protection of this vaccine against cervical cancer, BusinessWeek reported today.

The news report cited an executive as saying Tuesday that Merck & Co. has seen "encouraging" signs that its HPV vaccine may offer broader protection against cervical cancer than previously thought.

Early trials of Merck's Gardasil indicated that the vaccine can protect against HPV Types 16 and 18, which cause 70% of cervical cancer cases, Merck says on its web site at gardasil.com. In addition, the HPV vaccine can also counteract the effect of two other strains, HPV Types 6 and 11, which cause 90% of genital warts cases.

Merck, based out of New Jersey, began selling Gardasil soon after the Food and Drug Administration approved it for use in young women to prevent infection by the noted four strains of HPV, all of which are transmitted through sexual contact.

The Advisory Committee on Immunization Practices (ACIP) recommended last year that girls age 11 and 12 years receive Merck's HPV vaccine to prevent cervical cancer. The recommendation also allows girls as young as 9 and as old as 26 to get the vaccine.

The vaccine maker now suggested that Gardasil might be able to offer cross protection against additional strains, increasing its protection against cervical cancer to more than 70 percent.

According to BusinessWeek, Merck is still testing to find out whether Gardasil can indeed prevent precancerous lesions caused by the additional HPV strains. But the sign are “encouraging”.

Trials of Gardasil relied on examination of precancerous lesions to evaluate how affective the vaccine can be against the cervical cancer-causing effect of HPV strains. The trials did not directly check on the effect of the vaccine on the risk of cervical cancer.

"We're encouraged by the interim analysis of the endpoints," Bev Lybrand, a Merck vice president who heads the Gardasil commercialization effort was quoted by BusinessWeek as telling a Merrill Lynch conference in New York Tuesday in remarks broadcast over the Internet.

Merck's Gardasil is the only vaccine that has been approved by the FDA, but not the only one that protects against cervical cancer.   The "encouraging sign" of the newly found effect against additional HPV strains could add its power to complete with its rival, London-based GlaxoSmithKline PLC for the multi-billion-dollar HPV vaccine market.

Glaxo has already tested its HPV vaccine known as Cervarix in a number of countries and claimed that its vaccine can protect against more HPV strains than Gardasil does.   The vaccine, which offers cross protection, has been approved in Europe, but not yet approved by the FDA in the U.S.   The application will be initiated in April, according to news report.