Biogen Idec Inc. said the Food and Drug Administration has agreed to review its experimental drug Eloctate as a treatment for hemophilia A. It would be injected once or twice a week; existing treatments are taken three or four times a week. Hemophilia A, which is inherited, occurs in one of 5,000 male births. Those with the disease don’t have enough factor VIII, a blood clotting protein. The FDA in March started reviewing Biogen Idec’s Alprolix for hemophilia B, which is even rarer and caused by a different deficiency.