This randomized trial involving young boys with severe hemophilia showed that prophylaxis with regular infusions of recombinant factor VIII was associated with clinically and statistically significant reductions in joint damage, as compared with episodic infusions at the time of a clinically evident hemarthrosis. Because of the high cost of recombinant factor VIII, its widespread use for prophylaxis may be impractical. Prophylaxis with regular infusions of recombinant factor VIII was associated with clinically and statistically significant reductions in joint damage, as compared with episodic infusions. Before the development of cryoprecipitate, a plasma fraction that contains concentrated factor VIII, boys with severe hemophilia A had a diminished life expectancy. 1 – 3 These children are at risk for many types of hemorrhages, but the predominant source of chronic coexisting disease is crippling, painful arthritis due to hemarthrosis. 4 Small trials were conducted in the 1960s to determine whether routine administration of factor VIII concentrate was effective as prophylaxis against hemophilic arthropathy. 5 – 8 Clinically effective prophylactic schedules were developed empirically, without the benefit of data from controlled trials, 9 and many clinicians began to recommend prophylaxis with factor VIII. 10 In the . . .