Emicizumab prophylaxis is effective for supporting low bleeding rates and is well-tolerated in patients with hemophilia A and inhibitors, according to a study published in Haemophilia. 

Emicizumab has emerged as an important drug in treating hemophilia A, complementing traditional factor replacement therapy. It is a prophylactic drug that activates factor X, a task usually performed by factor VIII in healthy individuals. As the joints are often negatively impacted by uncontrolled bleeding, emicizumab offers the hope of greater joint protection, preserving mobility and ensuring quality of life. 

The authors of this study sought to determine the efficacy and safety profile of emicizumab prophylaxis in patients with hemophilia A and inhibitors. They collected data from the UK National Hemophilia Database, which contains information on all UK individuals with hemophilia A and inhibitors. They also used data obtained from Haemtrack, a national patient-reported database used by many hemophilia centers across the UK, between January 1, 2018, and September 30, 2021. 

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The authors prospectively collected bleeding outcomes in participants with 6 or more months of emicizumab data as registered in Haemtrack. The clinical condition of selected participants on emicizumab was then compared with the period when they were on a different drug, if such data was available. In a subgroup of individuals, Hemophilia Joint Health Scores (HJHS) were assessed after patients began taking emicizumab. The research team also took note of any adverse events associated with emicizumab treatment. 

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The final analysis included 117 persons with hemophilia A and inhibitors. The research team reported that the mean annualized bleeding rate in patients on emicizumab was 0.32 over a median treatment period of 42 months. Notably, patients who switched from a previous treatment to emicizumab demonstrated an 89% reduction in annualized bleeding rates; they also experienced an increase in their zero-treated bleed rate from 45% to 88%. 

As for the subgroup of participants in which HJHS was measured (n=37), total scores improved in 36% of individuals, remained unchanged in 46%, and deteriorated in 18%. The adverse events reported in this study were generally nonsevere and were limited to early treatment. 

“Emicizumab prophylaxis is associated with sustained low bleeding rates and was generally well-tolerated in people with hemophilia A and inhibitors,” the authors concluded. 


Wall C, Xiang H, Palmer B, et al. Emicizumab prophylaxis in haemophilia A with inhibitors: three years follow-up from the UK Haemophilia Centre Doctors’ Organisation (UKHCDO)Haemophilia. Published online February 22, 2023. doi:10.1111/hae.14762