Future prospects of hemostatic treatment for hemophilia patients.

In the treatment of hemophilia patients, factor (F) VIII or FIX product prophylaxis results in arthropathy prevention and quality of life (QOL) improvement. Serious issues concerning hemostatic treatment of hemophilia include frequent intravenous administration of products, inhibitor development, and hemostatic treatment of patients with inhibitors. To overcome these challenges, products with extended half-life were developed. Furthermore, alternative products based on new concepts of hemostatic therapy were developed. Regarding ACE910, a bispecific antibody recognizing FIX and FX, a clinical extension 1/2 study in Japan and an international phase 3 study are ongoing. Phase 1 results demonstrated that there were few severe ACE910-related adverse events. The t1/2 was approximately 30 days, and bleeding events were significantly reduced upon weekly subcutaneous administration in severe hemophilia A patients, independent of inhibitors. Two therapies, namely si-RNA anti-antithrombin therapy and anti-TFPI antibody therapy, aimed at rebalancing coagulation, are also under development. In addition, a gene therapy for hemophilia B has been developed by improving the vector. These new therapies could further improve the QOL of hemophilia patients.