Although it's announced as a scientific discussion on immunological markers, the April 6 meeting of FDA Vaccines and Related Biological Products Advisory Committee will have large implications for market size of Novartis' Menveo and Sanofi-Aventis' Menactra meningococcal vaccines.

The committee will discuss how to use immunological markers to demonstrate effectiveness in conjugate vaccines for meningococcal serogroups A, C, Y and W-135 for children under age 2, FDA announced March 11.

Menveo and Menactra are approved for these strains, but in the 2-55 age range. Both have applied for approval in younger children, but FDA's announcement does not characterize the advisory committee meeting as a product review session.

That description is somewhat surprising given that Menactra's user fee date on its sBLA for use infants aged 9 to 12 months is projected to be that month, given its June submission date.

Novartis does not have a currently pending application for Menveo use in infants. On Jan. 31, the firm announced it had received a refuse-to-file letter on its application in infants from 2 to 12 months. The Company is "planning to submit the indication within a few months," a spokesperson said in an email.

GlaxoSmithKline is developing a product that could also be affected by the committee's discussion. The firm's candidate meningococcal serogroups C & Y and Haemophilus influenza type b (Hib) combination vaccine MenHibrix received a "complete response" letter from FDA last year ('GlaxoSmithKline's pediatric MenHibrix vaccine gets 'complete response,'' Pharmaceutical Approvals Monthly, June 1, 2010). The proposed indicated population is infants and toddlers, with shots to be delivered at two, four, six and 12-15 months of age.

By combining the two vaccinations, GSK hopes to offer meningococcal protection without adding another shot to the number given in the first two years. The company is working on a resubmission.

Still Looking For The First Serogroup B Vaccine

On April 7, the FDA panel will take up the question of the best approaches to licensure of meningococcal serogroup B vaccines. There are no approved products in this group, as noted in an article published in the February 2010 issue of the UK medical journal The Lancet.

Attempts to develop such a vaccine over the past 40 years have encountered difficulties, the article said. "The serogroup B capsule is the most obvious candidate for a universal vaccine, but this has not elicited bactericidal antibody in human beings or animals. Some studies of complexes of the B polysaccharide and outer membrane proteins showed antibody responses, but this has not been confirmed by other studies."

But new approaches hold promise, according to the Lancet article. For example, several vaccines based on subcapsular antigens are under development.

An article currently in press at the journal Vaccine also notes recent progress on meningococcal vaccines and details the recommendations of the Global Meningococcal Initiative, including "the need for country-specific approaches to vaccine prevention of meningococcal disease" and the need to develop "vaccines covering all relevant serogroups globally, including A, B, C, W-135, X and Y."

"Because of the limitations of polysaccharide antigens, conjugate vaccines should replace polysaccharide vaccines wherever possible as allowed by cost, availability, licensing and immunization policy. However, polysaccharide vaccines are still recommended where conjugate vaccines are not available," the article says.

The authors also call for the rapid introduction of MenAfriVac, a meningococcal A conjugate vaccine developed through the Meningitis Vaccine Project, to "African meningitis belt countries." The project, which has distributed the vaccine to 19.5 million people since last September, is a partnership between the World Health Organization and the Program for Appropriate Technology in Health.

- Martin Berman-Gorvine (m.berman-gorvine@elsevier.com)

Meningococcal Vaccine Development To Get FDA Advisory Cmte. Review

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