Non-factor replacement therapy for haemophilia: a current update.

One of the most challenging issues facing us in the treatment of haemophilia is the development of alloantibodies against infused factor VIII (FVIII) or factor IX (FIX). Inhibitors render factor replacement therapy ineffective, exposing patients to an unacceptably high risk of morbidity and mortality. Besides the well-known bypassing agents (i.e. activated prothrombin complex concentrate and recombinant activated factor VII) used to treat or prevent bleeding in haemophilia patients with inhibitors, there is growing interest in a new class of therapeutic agents which act by enhancing coagulation (i.e. emicizumab) or inhibiting anticoagulant pathways (i.e. fitusiran and concizumab). This review will focus on these innovative therapies, providing an update on their current stage of clinical development.