Emicizumab utilization, safety, and outcomes in people with severe hemophilia and no inhibitors: 3-year follow-up. A report from the UK Haemophilia Centre Doctors' Organisation.

David Stephensen; Caroline Wall; Hua Xiang; Ben Palmer; Pratima Chowdary; Peter W Collins; Richard Gorman; Mary Matthias; Charles Percy; Paul Sartain; Susan Shapiro; Kate Talks; Charles R M Hay

doi:10.1016/j.rpth.2025.103164

Emicizumab utilization, safety, and outcomes in people with severe hemophilia and no inhibitors: 3-year follow-up. A report from the UK Haemophilia Centre Doctors' Organisation.

David Stephensen
, Caroline Wall
, Hua Xiang
, Ben Palmer
, Pratima Chowdary
, Peter W Collins
, Richard Gorman
, Mary Matthias
, Charles Percy
, Paul Sartain
, Susan Shapiro
, Kate Talks
, Charles R M Hay

Research output: Contribution to journal › Article › peer-review

Abstract

Background
Emicizumab prophylaxis is restricted to severe hemophilia A in the UK. Treatment choice and safety remain a matter of debate.

Objectives
This study was conducted to investigate factors influencing treatment choice, continued use, safety, and clinical outcomes associated with emicizumab in a national cohort of persons with severe hemophilia A without current inhibitors.

Methods
A 3-year study was conducted in 618 persons with severe hemophilia A who switched to emicizumab and 413 who continued factor (F)VIII prophylaxis. Outcome measures included annualized bleed rates (ABRs), the Hemophilia Joint Health Score, and health-related quality of life.

Results
Switchers and nonswitchers had a similar median age (26 and 28 years, respectively). Switchers had a significantly higher median (IQR) ABR than those continuing FVIII prophylaxis, but a significantly lower proportion had an inhibitor history (13.6% vs 20.5%; P = .0005). Thirty-one adverse events were reported, including 1 thrombosis (0.2%), 8/84 recurrent inhibitors (9.5%), 1 neutralizing antidrug antibody (0.2%), and 14/618 (2.3%) patients discontinued emicizumab. A higher prestudy median (IQR) ABR was observed in switchers compared with nonswitchers (2.05 [0.43, 6.06] vs 0.68 [0, 2.7]), reducing to a median (IQR) of 0 (0, 0) with emicizumab prophylaxis. The proportion with a zero-treated bleed rate increased from 35% to 71% (P = .001). An 82% reduction in bleeding into target joints was observed in favor of emicizumab. A modest (Δ= −2; P = .02) improvement in the total Hemophilia Joint Health Score was observed.

Conclusions
Emicizumab selection was influenced by ABR and inhibitor history but not age. Emicizumab was generally well tolerated, with only 2.3% discontinuing the drug. A significant within-person improvement in all bleeding outcomes was observed with emicizumab.

Original language	English
Pages (from-to)	103164
Journal	Research and Practice in Thrombosis and Haemostasis
Volume	9
Issue number	6
DOIs	https://doi.org/10.1016/j.rpth.2025.103164
Publication status	Published - 1 Aug 2025

Keywords

Efficacy
Emicizumab
Hemophilia A
Non-inhibitor
Safety

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Stephensen, D., Wall, C., Xiang, H., Palmer, B., Chowdary, P., Collins, P. W., Gorman, R., Matthias, M., Percy, C., Sartain, P., Shapiro, S., Talks, K., & Hay, C. R. M. (2025). Emicizumab utilization, safety, and outcomes in people with severe hemophilia and no inhibitors: 3-year follow-up. A report from the UK Haemophilia Centre Doctors' Organisation. Research and Practice in Thrombosis and Haemostasis, 9(6), 103164. https://doi.org/10.1016/j.rpth.2025.103164

@article{ba94d445ab894fc1893cabf029f87960,

title = "Emicizumab utilization, safety, and outcomes in people with severe hemophilia and no inhibitors: 3-year follow-up. A report from the UK Haemophilia Centre Doctors' Organisation.",

abstract = "Background Emicizumab prophylaxis is restricted to severe hemophilia A in the UK. Treatment choice and safety remain a matter of debate. Objectives This study was conducted to investigate factors influencing treatment choice, continued use, safety, and clinical outcomes associated with emicizumab in a national cohort of persons with severe hemophilia A without current inhibitors. Methods A 3-year study was conducted in 618 persons with severe hemophilia A who switched to emicizumab and 413 who continued factor (F)VIII prophylaxis. Outcome measures included annualized bleed rates (ABRs), the Hemophilia Joint Health Score, and health-related quality of life. Results Switchers and nonswitchers had a similar median age (26 and 28 years, respectively). Switchers had a significantly higher median (IQR) ABR than those continuing FVIII prophylaxis, but a significantly lower proportion had an inhibitor history (13.6\% vs 20.5\%; P = .0005). Thirty-one adverse events were reported, including 1 thrombosis (0.2\%), 8/84 recurrent inhibitors (9.5\%), 1 neutralizing antidrug antibody (0.2\%), and 14/618 (2.3\%) patients discontinued emicizumab. A higher prestudy median (IQR) ABR was observed in switchers compared with nonswitchers (2.05 [0.43, 6.06] vs 0.68 [0, 2.7]), reducing to a median (IQR) of 0 (0, 0) with emicizumab prophylaxis. The proportion with a zero-treated bleed rate increased from 35\% to 71\% (P = .001). An 82\% reduction in bleeding into target joints was observed in favor of emicizumab. A modest (Δ= −2; P = .02) improvement in the total Hemophilia Joint Health Score was observed. Conclusions Emicizumab selection was influenced by ABR and inhibitor history but not age. Emicizumab was generally well tolerated, with only 2.3\% discontinuing the drug. A significant within-person improvement in all bleeding outcomes was observed with emicizumab.",

keywords = "Efficacy, Emicizumab, Hemophilia A, Non-inhibitor, Safety",

author = "David Stephensen and Caroline Wall and Hua Xiang and Ben Palmer and Pratima Chowdary and Collins, \{Peter W\} and Richard Gorman and Mary Matthias and Charles Percy and Paul Sartain and Susan Shapiro and Kate Talks and Hay, \{Charles R M\}",

year = "2025",

month = aug,

day = "1",

doi = "10.1016/j.rpth.2025.103164",

language = "English",

volume = "9",

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publisher = "Elsevier B.V.",

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Stephensen, D, Wall, C, Xiang, H, Palmer, B, Chowdary, P, Collins, PW, Gorman, R, Matthias, M, Percy, C, Sartain, P, Shapiro, S, Talks, K & Hay, CRM 2025, 'Emicizumab utilization, safety, and outcomes in people with severe hemophilia and no inhibitors: 3-year follow-up. A report from the UK Haemophilia Centre Doctors' Organisation.', Research and Practice in Thrombosis and Haemostasis, vol. 9, no. 6, pp. 103164. https://doi.org/10.1016/j.rpth.2025.103164

Emicizumab utilization, safety, and outcomes in people with severe hemophilia and no inhibitors: 3-year follow-up. A report from the UK Haemophilia Centre Doctors' Organisation. / Stephensen, David; Wall, Caroline; Xiang, Hua et al.
In: Research and Practice in Thrombosis and Haemostasis, Vol. 9, No. 6, 01.08.2025, p. 103164.

Research output: Contribution to journal › Article › peer-review

TY - JOUR

T1 - Emicizumab utilization, safety, and outcomes in people with severe hemophilia and no inhibitors: 3-year follow-up. A report from the UK Haemophilia Centre Doctors' Organisation.

AU - Stephensen, David

AU - Wall, Caroline

AU - Xiang, Hua

AU - Palmer, Ben

AU - Chowdary, Pratima

AU - Collins, Peter W

AU - Gorman, Richard

AU - Matthias, Mary

AU - Percy, Charles

AU - Sartain, Paul

AU - Shapiro, Susan

AU - Talks, Kate

AU - Hay, Charles R M

PY - 2025/8/1

Y1 - 2025/8/1

N2 - Background Emicizumab prophylaxis is restricted to severe hemophilia A in the UK. Treatment choice and safety remain a matter of debate. Objectives This study was conducted to investigate factors influencing treatment choice, continued use, safety, and clinical outcomes associated with emicizumab in a national cohort of persons with severe hemophilia A without current inhibitors. Methods A 3-year study was conducted in 618 persons with severe hemophilia A who switched to emicizumab and 413 who continued factor (F)VIII prophylaxis. Outcome measures included annualized bleed rates (ABRs), the Hemophilia Joint Health Score, and health-related quality of life. Results Switchers and nonswitchers had a similar median age (26 and 28 years, respectively). Switchers had a significantly higher median (IQR) ABR than those continuing FVIII prophylaxis, but a significantly lower proportion had an inhibitor history (13.6% vs 20.5%; P = .0005). Thirty-one adverse events were reported, including 1 thrombosis (0.2%), 8/84 recurrent inhibitors (9.5%), 1 neutralizing antidrug antibody (0.2%), and 14/618 (2.3%) patients discontinued emicizumab. A higher prestudy median (IQR) ABR was observed in switchers compared with nonswitchers (2.05 [0.43, 6.06] vs 0.68 [0, 2.7]), reducing to a median (IQR) of 0 (0, 0) with emicizumab prophylaxis. The proportion with a zero-treated bleed rate increased from 35% to 71% (P = .001). An 82% reduction in bleeding into target joints was observed in favor of emicizumab. A modest (Δ= −2; P = .02) improvement in the total Hemophilia Joint Health Score was observed. Conclusions Emicizumab selection was influenced by ABR and inhibitor history but not age. Emicizumab was generally well tolerated, with only 2.3% discontinuing the drug. A significant within-person improvement in all bleeding outcomes was observed with emicizumab.

AB - Background Emicizumab prophylaxis is restricted to severe hemophilia A in the UK. Treatment choice and safety remain a matter of debate. Objectives This study was conducted to investigate factors influencing treatment choice, continued use, safety, and clinical outcomes associated with emicizumab in a national cohort of persons with severe hemophilia A without current inhibitors. Methods A 3-year study was conducted in 618 persons with severe hemophilia A who switched to emicizumab and 413 who continued factor (F)VIII prophylaxis. Outcome measures included annualized bleed rates (ABRs), the Hemophilia Joint Health Score, and health-related quality of life. Results Switchers and nonswitchers had a similar median age (26 and 28 years, respectively). Switchers had a significantly higher median (IQR) ABR than those continuing FVIII prophylaxis, but a significantly lower proportion had an inhibitor history (13.6% vs 20.5%; P = .0005). Thirty-one adverse events were reported, including 1 thrombosis (0.2%), 8/84 recurrent inhibitors (9.5%), 1 neutralizing antidrug antibody (0.2%), and 14/618 (2.3%) patients discontinued emicizumab. A higher prestudy median (IQR) ABR was observed in switchers compared with nonswitchers (2.05 [0.43, 6.06] vs 0.68 [0, 2.7]), reducing to a median (IQR) of 0 (0, 0) with emicizumab prophylaxis. The proportion with a zero-treated bleed rate increased from 35% to 71% (P = .001). An 82% reduction in bleeding into target joints was observed in favor of emicizumab. A modest (Δ= −2; P = .02) improvement in the total Hemophilia Joint Health Score was observed. Conclusions Emicizumab selection was influenced by ABR and inhibitor history but not age. Emicizumab was generally well tolerated, with only 2.3% discontinuing the drug. A significant within-person improvement in all bleeding outcomes was observed with emicizumab.

KW - Efficacy

KW - Emicizumab

KW - Hemophilia A

KW - Non-inhibitor

KW - Safety

U2 - 10.1016/j.rpth.2025.103164

DO - 10.1016/j.rpth.2025.103164

M3 - Article

SN - 2475-0379

VL - 9

SP - 103164

JO - Research and Practice in Thrombosis and Haemostasis

JF - Research and Practice in Thrombosis and Haemostasis

IS - 6

ER -

Emicizumab utilization, safety, and outcomes in people with severe hemophilia and no inhibitors: 3-year follow-up. A report from the UK Haemophilia Centre Doctors' Organisation.

Abstract

Keywords

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