Biotech Values

[jbog]

GlaxoSmithKline PLC's Cervarix vaccine induced a higher immune response in women against the virus that causes cervical cancer than Merck & Co.'s Gardasil, according to a Glaxo-funded clinical trial.

However, the study didn't measure which vaccine was more effective at preventing actual cases of cervical cancer or precancerous lesions -- that would require a longer and larger trial, which Glaxo said it isn't planning to conduct. Both vaccines are designed to prevent infection by human papillomavirus, or HPV.

Nevertheless, U.K.-based Glaxo hopes the results, to be presented at a Swedish medical conference that began Friday, will help give Cervarix a competitive edge if it reaches the U.S. market, which Merck has had to itself since Gardasil's launch in 2006. The U.S. Food and Drug Administration is reviewing Cervarix and could decide whether to allow it to go on sale by autumn. Cervarix is already on the market in Europe.

Gary Dubin, vice president of global clinical development in Glaxo's vaccine unit, said in an interview that immune-response levels induced by vaccines "often predict levels of efficacy over time," but added that there is no evidence that this will be the case with Cervarix and Gardasil.

Before knowing the final data, a Merck executive played down the importance of comparing the vaccines' immune responses. "It's disease efficacy that's really the most important, and we certainly have very high efficacy against some very important disease endpoints," said Rick Haupt, program lead for HPV vaccines in Merck's research arm.

The head-to-head trial included more than 1,100 women aged 18 to 45. The vaccines were given in three shots over six months. According to Glaxo, the women who received Cervarix had higher levels of "neutralizing antibodies," which help fight off cancer-causing HPV types, than those receiving Gardasil one month after the last dose. For one type, the levels induced by Cervarix were more than twice as high as Gardasil and for another type they were more than six times higher, according to figures provided by Glaxo.

Glaxo said both vaccines had "acceptable" safety profiles, but rates of "injection-site reactions," which can include inflammation and rashes, were higher among Cervarix users. Both vaccines have been linked to headache and fainting.

The vaccines are designed differently. Cervarix uses a new type of additive known as an adjuvant, which Glaxo believes enhances its effectiveness, while Gardasil uses a more conventional adjuvant. Gardasil targets four HPV types including those that cause most cases of genital warts, while Cervarix targets two types and isn't intended to provide as much protection against warts.

Merck's Gardasil sales rose quickly after its 2006 U.S. launch but last year declined 5% to $1.4 billion as the company encountered difficulty convincing women between 19 and 26 to get the shots. Glaxo recorded $231 million in Cervarix sales last year.

Write to Peter Loftus at [e-mail]