A newer version of MedImmune FluMist appears effective for children younger than 5 years old, although safety data on the influenza vaccine is still under review, U.S. Food and Drug Administration staff said in a document released today.
MedImmune , which last month agreed to be bought by AstraZeneca, is seeking FDA approval to market the spray for children ages 1 to 5 without a history of wheezing or asthma. It is already approved for healthy people between 5 and 49 years old.
The documents were released ahead of an FDA advisory panel meeting on Wednesday to discuss whether to recommend that the agency grant wider approval. While the FDA usually follows the advice of its outside experts, it will make the final decision.
Four studies conducted by MedImmune found the drug was effective against Type A and B influenza viruses, including one trial that showed the vaccine was about 90 percent effective,
according to the FDA document.
Reviewers for the FDA also said one company study of the nasal spray vaccine did not signal any widespread safety problems, but results from other studies are still being reviewed. Those findings will be presented to the panel on Wednesday.
Children who received FluMist experienced more wheezing than those who were given an inactive vaccine, but "the difference between treatment groups is quite small," one reviewer said.
Other side effects included pneumonia, among other problems. Previously known side effects with FluMist include nasal congestion, runny nose, sore throat and cough, according to the FDA.
In a separate document, MedImmune said the vaccine's safety and efficacy were proven in children 24 to 59 months old and "that the risk-benefit profile for children 12 (to) 23 months
of age without a history of wheeze or asthma warrants use of FluMist in this population as well."
It also said it would continue to monitor the drug in younger patients if approved.
FluMist, which earned $36.4 million in 2006, competes with injectable flu vaccines made by GlaxoSmithKline, Sanofi-Aventis' Sanofi Pasteur unit, and Chiron, which was recently acquired by Novartis.
MedImmune's spray failed to catch on when it was first approved in 2003 in part because it had to be frozen and was difficult to store and ship. Its newer version, also known as CAIV-T, can be refrigerated.