A favourable review of Merck & Co’s cervical cancer vaccine by a Food and Drug Administration advisory committee later today seems likely, after positive comments on the application where posted by the FDA on its website.

The documents suggest that Gardasil is both safe and effective and would likely have a ‘significant impact’ on reducing the number of cases of cervical cancer if it was used routinely.

However, the FDA reviewer does put forward some points of discussion for the advisory panel, including the possibility that vaccination in women already infected with HPV may actually cause pre-malignant cervical conditions to get worse, according to a report on fdaadvisorycommittee.com.

This could have an impact on discussions about the best age to vaccinate, as earlier use of the product would reduce the likelihood that recipients were already seropositive for HPV.

The panel should also consider whether the effectiveness of the vaccine will be compromised by the fact that it protects only against the four most common strains of human papillomavirus (HPV), which are implicated in about 70% of cervical cancer cases.

The panel will also take a look at five cases of congenital abnormalities in children born to women who had taken the vaccine in trials, although the FDA said there appeared to be no pattern that would suggest a link to Gardasil.

If approved, Gardasil has been tipped to become a $3 billion product, with a rival product from GlaxoSmithKline called Cervarix, not yet submitted for approval in the USA, expected to reach $2 billion in peak sales.