Activated Factor X delivered by Adeno-Associated virus significantly inhibited bleeding and alleviated hemophilia A/B arthropathy in hemophilia mice

Abstract

In hemophilia, deficient factor VIII or IX in hemophilia prevents activation of the common coagulation pathway, inhibiting conversion of FX to activated FXa required for thrombin generation. We hypothesized that delivering FXa could activate the common pathway and restore coagulation in hemophilia patients. In this study, we tried to deliver FXa by adeno-associated virus (AAV) for treating hemophilia and hemophilic arthropathy. The cassettes that expressed FXa, FXa (FXaop) and FXa-FVII was constructed and were packaged into an engineered AAV capsid, AAV843. Delivered AAVs into hemophilia A and B mice by intravenous injection. We evaluated the therapeutic efficacy by tail clip bleeding assay and D-Dimer test. Further, FXa was transduced into hemophilia A mice with FVIII inhibitor or hemophilic arthropathy for evaluating its efficacy. AAV-FXa could stably express in vivo, and AAV-FXaop showed the best immediate and prolonged hemostatic effects that was similar to the positive drug groups (Xyntha and Benefix). Compared to other two AAVs, AAV-FXaop could significantly inhibit bleeding of hemophilia A mice with inhibitor. In addition, long-term expression of FXa in vivo significantly alleviated the occurrence of hemophilia arthropathy. AAV-delivered FXa may be a novel target to treating hemophilia A/B and hemophilia arthropathy.