A newer version of MedImmune Inc.'sFluMist influenza vaccine is beneficial for use in some younger children, a panel of medical experts told U.S. regulators on Wednesday.
The Food and Drug Administration's advisory panel, in a 9 to 6 vote, said company studies showed the benefits of the nasal spray outweighed its risks in children 1 to 5 years old without known respiratory problems.
MedImmune, which last month agreed to be bought by AstraZeneca Plc , is seeking wider U.S. approval for its latest version of FluMist for children ages 1 to 5 without a history of wheezing or asthma.
The newer spray, which unlike the older version can be refrigerated rather than frozen, is already approved for healthy 5- to 49-year-olds.
While the FDA will make the final approval decision, it usually follows the advice of its expert panels.
Wider approval could be a boost for the spray, which failed take hold after it was first approved in 2003, partly because it was difficult to distribute in its frozen form.
FluMist earned $36.4 million in 2006 and about 7 million doses have been distributed commercially between 2003 and 2007, according to the company. It competes with injectable flu vaccines made by GlaxoSmithKline Plc, Sanofi-Aventis' Sanofi Pasteur unit, and Novartis AG unit Chiron.
At the meeting, panel members unanimously said data proved MedImmune's vaccine was effective but expressed concern about the risk of wheezing, especially in very young children.
It was not clear whether evidence of respiratory problems seen in the company's studies signaled a safety problem with FluMist or was due to something else, some panelists said.
"It's there, but we don't understand it," said panelist Dr. Melinda Wharton, deputy director of the National Center for Immunization and Respiratory Diseases at the U.S. Centers for Disease Control and Prevention (CDC).
According to the CDC, younger children are at a greater risk to be hospitalized with the flu than are older children, and U.S. health officials recommend influenza vaccines for those as young as 6 months old.
But MedImmune Executive Vice President and Chief Medical Officer Edward Connor told the panel the company was only seeking approval for those as young as 1 year old because of the wheezing concerns.
Company data showed an increase in hospitalizations for children 6 months to 11 months old, and children ages 12 months to 5 years old with a history of wheezing and asthma also need further evaluation, he said.
"We intend to continue to study those children, principally with lower doses of the vaccine," Connor said.
MedImmune said it would continue to monitor the product if it were to win approval. Several panelists also urged the FDA to require further safety studies on wheezing, hospitalizations and other issues.
Shares of MedImmune were up slightly.