A vaccine that blocks infection by four types of human papillomavirus could cut global deaths from cervical cancer by more than two-thirds, its manufacturer said in seeking federal approval.
Merck wants Food and Drug Administration approval for its Gardasil vaccine against the two of those four types of human papillomavirus, or HPV, believed responsible for about 70% of cervical cancer cases.
HPV is the most common sexually transmitted disease, affecting more than 50% of sexually active adults. The cervical cancer it can cause kills each year roughly 290 000 women worldwide. The other two types the vaccine protects against 90% of genital wart cases.
On Thursday, a panel of FDA advisers was to begin discussing whether to recommend FDA approval for the vaccine against HPV. The FDA isn’t required to follow the advice of its expert panels but usually does. An agency’s decision is expected by June 8.
FDA reviewers said Gardasil appears safe and effective, but cautioned that it may lead to an increased number of cases of a cancer precursor among patients already infected by any of the four virus types at the time they receive the vaccine, and whose immune systems have not cleared the virus from their bodies.
Furthermore, any advantage the vaccine provides in protecting against the four virus types could be offset by infection by any of the multiple other types of HPV that the vaccine does not cover, according to FDA briefing documents released ahead of Thursday’s meeting.
FDA staff also asked that the committee examine five cases where children with birth defects were born to women who had received the vaccine around the time of conception.
According to the documents, the FDA’s vaccines and related biological products advisory committee should discuss those items only if its members first agree that studies show the vaccine is safe and effective. That suggests the FDA favours its approval.
Whitehouse Station, New Jersey-based Merck developed the vaccine and tested it in both women and men, but Thursday’s discussion is expected to focus on its use in preventing HPV-related disease in women.
Pending FDA action, the national advisory committee on immunisation practices will decide later in June whether to endorse routine vaccination with the vaccine. The committee’s HPV vaccine workgroup is recommending the vaccine be given to girls 11 and 12, and the committee will consider recommendations for females 13 to 26.
Widespread vaccination with the vaccine could help bounce cervical cancer from its dubious distinction as the number two cancer in women worldwide. However, the anticipated cost of the vaccine, administered in three shots over six months, is $300 to $500 and could pose a barrier to that goal.
Early opposition to Gardasil, based on concerns it could encourage sexual activity in the young, largely dissipated, in part because of the vaccine’s cancer-reduction implications. – Sapa-AP