Researchers have discovered through a survey that patients with hemophilia A overwhelmingly preferred emicizumab treatment to factor VIII (FVIII) prophylaxis, according to a letter to the editor published in Haemophilia.

The most common medical approach to treating patients with hemophilia A is through prophylactic infusions of FVIII a few times a week. However, some patients find this treatment approach to be burdensome enough to skip treatment and only undergo FVIII administration when they experience bleeding episodes. This approach is unsafe and can lead to progressive hemophilic arthropathy. 

The research team wrote, “Emicizumab, a recombinant bispecific monoclonal antibody that bridges activated [factor IX] and [factor X], mimicking the function of activated FVIII and restoring thrombin generation and hemostasis, provides a novel treatment option.” In addition, studies have shown that it has an acceptable safety profile. Importantly, it differs from FVIII prophylaxis in that it can be self-administered subcutaneously. Emicizumab has a half-life of about 30 days, giving users versatility in maintaining dosing once weekly, every 2 weeks, or every 4 weeks.  

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The researchers noted, “As the development of new therapies for patients with hemophilia A takes us closer to the World Federation of Hemophilia guidelines’ goal of achieving zero bleeds for all patients with hemophilia A, patient-reported outcomes will be essential for evaluating how new treatments compare with those already available.” Therefore, they sent a survey to patients with hemophilia A who were previously recruited in 2 phase III clinical trials (HAVEN 3 and HAVEN 4) evaluating the efficacy and safety of emicizumab prophylaxis. 

This survey asked patients which treatment they preferred: their previous hemophilia treatment, the new study treatment (emicizumab), or no preference. Patients expressing a preference were asked to rank the top 3 factors that influenced their choice. Finally, patients were given the option to provide free text responses regarding their experience with emicizumab. 

The survey revealed a remarkable consensus among patients with hemophilia A regarding their preference for emicizumab treatment. The authors of the study wrote, “Overall, 92% of respondents indicated that they were ‘much more’ or ‘a lot more’ satisfied with their current emicizumab prophylaxis compared with their prior FVIII prophylaxis, while none indicated that they were less satisfied.”

Among the important influencing factors were that emicizumab treatment required a lower frequency of administration and that patients worried less about bleeding episodes when on emicizumab treatment. 


Parnes A, Mahlangu JN, Pipe SW, et al. Patient preference for emicizumab versus prior factor therapy in people with haemophilia A: results from the HAVEN 3 and HAVEN 4 studies. Haemophilia. Published online October 8, 2021. doi:10.1111/hae.14421