Emicizumab

Overview

Bispecific antibody (brand Hemlibra) co-developed by Chugai and Roche that bridges factor IX and factor X at micromolar affinity to replace factor VIII cofactor activity; approved for all hemophilia types with and without inhibitors; annualized bleeding rate 2.4; $5.4B in 2025 sales. Emicizumab is a bispecific antibody binding factor IX and factor X at approximately micromolar affinity to each arm, bringing them into proximity to allow the same proteolytic activation of factor X that factor VIII would catalyze, without activating factor IX itself. Emicizumab achieved an annualized bleeding rate of 2.4 in clinical trials, comparable to prophylaxis standard of care, and generated $5.4 billion in sales as of 2025, reflecting very broad adoption across hemophilia A patients. (Emicizumab Mechanism (10:00-15:00))