F2 and hemophilia: [49] found that when activated prothrombin complex concentrate (APCC) was spiked into simulated hemophilia inhibitor plasma with emicizumab in vitro, the thrombin generation measurements were significantly different to when APCC was administered to the same patients in vivo, suggesting that in vitro spiking studies of APCC and emicizumab using thrombin generation may not be valid in this setting.