US panel backs Genzyme's new version of Myozyme

WASHINGTON - Genzyme Corp.'s new version of the drug Myozyme should be approved, a US panel said yesterday, even though Food and Drug Administration reviewers reported it may trigger allergic reactions and may not be effective.

The panel of FDA advisers said at a meeting in Silver Spring, Md., that Myozyme should receive accelerated approval and that a post-approval study is needed to verify its benefits.

Genzyme, based in Cambridge, wants to make Myozyme in larger containers as a way to increase production. Doing so can alter the medication, and an FDA staff report last week said the new version wasn't shown convincingly to be effective and may trigger allergic reactions.

The company gained US approval to sell the original version of Myozyme in 2006 to treat Pompe disease, a potentially deadly disorder that disables the heart and muscles. Worldwide sales next year may total about $393 million, of which $40 million to $50 million would come from the FDA approving use of larger containers, said Matthew Osborne, an analyst with Lazard Capital Markets in New York.

The agency often follows the advice of its advisers, though it isn't obligated to do so.