The US FDA approved Biogen Idec's Eloctate for patients with hemophilia A. The June approval was based on data from a clinical trial that showed reduced severity and frequency of bleeding episodes. Eloctate is a recombinant factor VIII molecule attached to the Fc domain of human immunoglobulin G1, which avoids lysosomal degradation and extends the protein's half-life. Eloctate needs one injection every three to five days based on clinical response, whereas existing treatments require injections every two to four days. Biogen's other long-lasting agent Alprolix, a recombinant factor IX for hemophilia B treatment, was approved in March (Nat. Biotechnol. 32, 506, 2014). Analysts expect Eloctate to generate annual sales of $1.5 billion by 2019.