Thromboprophylaxis in a patient with COVID‐19 and severe hemophilia A on emicizumab prophylaxis

COVID‐19 can be associated with coagulopathy (CAC, COVID‐19‐associated coagulopathy) with a high prothrombotic risk based on an intense inflammatory response to viral infection leading to immunothrombosis through different procoagulant pathways. Emerging evidence suggests that the use of heparin in these patients could be associated with lower mortality. Emicizumab is a bispecific humanized monoclonal antibody that bridges activated factor IX and factor X, thereby restoring the function of missing factor VIIIa in hemophilia A. The use of emicizumab has been associated with thrombotic events in patients who also received high cumulative amounts of activated prothrombin complex concentrates. Although this risk is extremely low, there is a lack of evidence on whether CAC increases the thrombotic risk in patients on emicizumab prophylaxis. We present the case of a patient with severe hemophilia A in prophylaxis treatment with emicizumab; due to the potential thrombotic risk we decided to administer low molecular weight heparin as prophylaxis treatment without any thrombotic or bleeding complications.