The U.S. FDA has approved the second hemophilia drug in nearly six months from Pfizer Inc. This one, Hympavzi (marstacimab), is for preventing or reducing bleeding in those age 12 and older with hemophilia A and B. Hympavzi heralds a couple of market boundary breakers: it’s the first and only anti-tissue factor pathway inhibitor approved in the U.S. for hemophilia A or B and the first hemophilia medicine approved in the U.S. to be administered using a pre-filled, auto-injector pen.