[Advances in hemophilia treatment].

Advances in replacement therapy with clotting factor (F) VIII or FIX product have contributed greatly to reducing the incidence of hemophilic arthropathy and improving quality of life (QOL) in patients with hemophilia. However, frequent intravenous administration of clotting factor products, blood access, and development of alloantibodies (inhibitors) have been important issues. Clinical studies aimed at addressing these issues have been conducted in Japan as well, including a multicenter study to determine factors involved in inhibitor development. Drug development has also progressed: several clotting factor products with extended half-life and non-clotting factor therapies have been introduced in quick succession. Anti-FIX/FX bispecific antibody in particular has a long half-life when administered subcutaneously and controls bleeding in patients with hemophilia A. Anti-antithrombin therapy and anti-TFPI monoclonal antibody products that work by rebalancing coagulation have also been developed. In addition, gene therapy has been approved for adults in U.S. and Europe, where improved vectors and codon optimization have enabled protein expression up to the near-therapeutic hemostatic range. Recent significant developments in hemophilia treatment are expected to overcome long-standing problems and further improve QOL.