Sanofi-Pasteur is criticizing Glaxo’s new Cervarix in an attempt to bolster its lead in the burgeoning market for HPV vaccines, The Financial Times writes. The vaccine maker, which sells Merck’s Gardasil in Europe, has been wooing investors this week with presentations claiming greater proven health benefits from Gardasil in preventing human papilloma virus infections, which is the leading cause of cervical cancer.

Didier Hoch, who heads a joint venture between Sanofi-Aventis and Merck for European vaccine marketing, says published Glaxo results on Cervarix were less conclusive and dismissed as “a marketing gimmick” a clinical study that directly compares the two products. He lambasted the head-to-head study of Cervarix and Gardasil for its small sample size, use of people older than the vaccine’s target population, and use of a test of efficacy that was not standardized. And claims that Cervarix would provide protection against a number of strains of HPV remained speculative.

His ‘charm offensive,’ as the paper puts it, comes as Glaxo faces questions over delays in winning FDA approval for Cervarix. Cervarix won European approval last year but the FDA is still demanding extra info, which could delay its US launch until 2010.

Philippe Monteyne, head of Glaxo’s global vaccine development, tells the Times that ‘positive and constructive exchanges’ were continuing with the FDA. “The scientific evidence shows we have the best possible cervical cancer vaccine,” he says. “…the confidence is there.” The fight between Gardasil and Cervarix reflects the importance of a fast-expanding market for high-priced vaccines estimated to be worth billions of dollars in annual sales, the paper notes.

Hoch boasts that Gardasil had sold 3 million courses in Europe last year and generated nearly $500 million in sales, making it one of the fastest-expanding and highest-earning launches in recent years of any drug or vaccine, according to the Times. Curiously, Merck recently reported that Gardasil growth appears to be slowing. Sales were $339 million in last year’s fourth quarter, less than $418 million in the same period a year earlier.

Separately, new data touting Gardasil was released today. Look here.