Thrombotic microangiopathy (TMA). Discontinue treatment w/ bypassing agents 1 day prior to initiation. Misinterpretation of intrinsic pathway clotting-based lab tests results eg, activated clotting time, activated partial thromboplastin time may lead to under-treatment of patients experiencing bleeding episodes. Possible hypercoagulability w/ recombinant activated clotting factor VII (rFVIIa) or FVIII. Concomitant use of anti-fibrinolytics w/ activated prothrombin complex concentration (aPCC) or rFVIIa. Women of childbearing potential should use effective contraception during & for at least 6 mth after cessation of treatment. Pregnancy & lactation.