By Ed Susman
SAN DIEGO, CA -- October 12, 2007 -- An investigational tetravalent glycoconjugate vaccine appears safe and retains greater immunogenicity than the currently in use quadrivalent polysaccharide vaccine after 12 months in children 2 through 10 years old, doctors noted here at the Infectious Diseases Society of America (IDSA) 45th Annual Meeting.
The investigational vaccine is designed to protect all age groups against the most prevalent serogroups of the meningococcal bacterium: A, C, Y, and W-135. The MenACWY-CRM vaccine is now in phase 3 trials.
In a poster presented here on October 5, researchers described a study that enrolled 618 healthy children aged 2 to 10 years. Significantly more of the study subjects achieved human complement source titers greater than or equal to 1:4 in the MenACWY group than in the group receiving the polysaccharide vaccine 1 month postvaccination.
Twelve months postvaccination, significantly more subjects in the MenACWY group than the polysaccharide group had a human complement source titer of 1:4 greater against all four serogroups:
· Serogroup A: 28% receiving MenACWY versus 19% receiving the polysaccharide vaccine (95% confidence interval [CI]: 1%-16%)
· Serogroup C: 68% receiving MenACWY versus 53% receiving the polysaccharide vaccine (95% CI: 7%-24%)
· Serogroup W: 93% receiving MenACWY versus 49% receiving the polysaccharide vaccine (95% CI: 37%-51%)
· Serogroup Y: 86% receiving MenACWY versus 38% receiving the polysaccharide vaccine, (95% CI: 40%-55%)
"These data show that MenACWY induces statistically superior persistence of protection in 2- to 10-year-olds," said Nicola Klein, MD, Codirector, Vaccine Study Center, Kaiser Permanente, Oakland, California.
Dr. Klein said the research does not yet answer the question as to whether children will require a booster of the vaccine, nor when that booster would be delivered if needed.
A group of 308 children were administered a single dose of the MenACWY vaccine intramuscularly in the left deltoid muscle. A group of 310 children were administered a single dose of the polysaccharide vaccine in the left upper arm.
No serious adverse events judged to be probably or possibly related to the vaccines were reported, Dr. Klein said.
"MenACWY-CRM vaccine provides persistent immune responses for at least 1 year postvaccination," noted Dr. Klein.
Meningococcal disease is caused by infection with the bacterium Neisseria meningitidis. It is estimated that 5% to 10% of the population carries this type of bacteria. The disease is transmitted from close face-to-face exchange between people who are sick or who are carriers of the bacteria.
The tetravalent glycoconjugate vaccine (MenACWY-CRM) is being developed by Novartis. The quadrivalent polysaccharide vaccine (Menomune) is marketed by sanofi-aventis.
Funding for this study was provided by Novartis Vaccines and Diagnostics.
[Presentation title: Safety and Immunogenicity 12 Months Post-Vaccination With Novartis Vaccines' Tetravalent Glycoconjugate Meningococcal ACWY Vaccine in Children Aged 2-10 Years. Abstract 191]
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