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Alnylam hemophilia drug garners orphan drug status

CAMBRIDGE, Mass. (AP) -- The Food and Drug Administration has granted an "orphan drug designation" to a potential hemophilia treatment from Alnylam Pharmaceuticals Inc.

Orphan drug status is awarded to drugs that could treat diseases that affect fewer than 200,000 people in the United States. It comes with some added marketing exclusivity.

The Cambridge, Mass., company said Wednesday that the agency gave the designation to a drug labeled ALN-AT3 for the treatment of hemophilia B. Alnylam has tested the drug in mice and plans to start studies involving humans early next year.

That means the drug is likely several years away from being submitted to regulators for approval.

Hemophilia is a rare, inherited disease that affects blood clotting. Hemophilia A occurs in approximately one out of every 5,000 male births. Those with the disease don't have enough of a blood clotting protein called factor VIII. Hemophilia B is less common and caused by a different deficiency

Alnylam shares climbed 40 cents to $48.96 Wednesday morning. The stock has traded between $14.88 and $51 over the past year.