Earlier the better: convalescent plasma

zumab may help to reduce the required FVIII dose, which is associated with enormous cost.10 The observation that FVIII provides additional prohemostatic effects in the presence of emicizumab in the mouse model is therefore noteworthy.1 Key for any prohemostatic therapy in hemophilia is how the development of hemophilic arthropathy is affected. Early experimental data in monkeys indicate that emicizumab prevents joint bleeds,8 but clinical trial data indicate that emicizumab does not reduce joint bleeds to 0 in all patients (and neither does FVIII)2,5-7; thus, a better understanding of the effect of emicizumab on the progression and management of hemophilic arthropathy is urgently needed. The emicizumab-adapted hemophilia A mousemodel will encompass an important tool to obtain such insights. However, it should be noted that additional modifications are needed, as indicated, before this model is suited for longer-term hemophilic arthropathy studies.1