PB0204 - Emicizumab prophylaxis in previously untreated and minimally treated boys with severe haemophilia A: summary of United Kingdom experience

Sunday, June 23, 2024

13:45 – 14:45 ICT

Room: Exhibition Hall

Co-Author(s)

MM

Mary C. Mathias

Haemophilia Centre Director
Great Ormond Street Hospital for Children NHS Foundation Trust
London, England, United Kingdom

Co-Author(s)

AK

Anne M. Kelly

Paediatric Haematologist
Great Ormond Street Hospital for Children NHS Foundation Trust
London, England, United Kingdom
JA

Jayanthi Alamelu

Consultant Paediatric Haematologist
Evelina London Haemophilia Centre
London, England, United Kingdom
NB

Neha Bhatnagar

Consultant Paediatric Haematologist
Paediatric Haemostasis Unit, Oxford Haemophilia and Thrombosis Centre
Oxford, England, United Kingdom
TB

Tina T. Biss

Consultant Haematologist
Newcastle Haemophilia Comprehensive Care Centre
Newcastle upon Tyne, England, United Kingdom

Presenting Author(s)

JG

John D. Grainger, MRCP FRCPath MD

Consultant Paediatric Haematologist
Manchester University NHS Foundation Trust
Manchester, England, United Kingdom

Co-Author(s)

SG

Simone Green

Consultant Paediatric Haematologist
Hull Royal Infirmary
Hull, England, United Kingdom
JM

Jayashree Motwani, MBBS,FRCPATH

Haematology consultant
Birmingham Children's Hospital
Birmingham, England, United Kingdom
JP

Jeanette H. Payne

Consultant Paediatric Haematologist
Sheffield Childrens Hospital
Sheffield, England, United Kingdom
SS

Simone Stokley

Consultant Paediatric Haematologist
Nottingham Children's Hospital
Nottingham, England, United Kingdom

Background: Emicizumab, was licensed for prophylaxis for severe haemophilia A (SHA) in 2019. We present real-world data (2019-2023) for previously untreated (PUP) and minimally treated (MTP) patients (≤ 5 exposure days).

Aims: To collect UK data on PUP/MTP patients, age at start of prophylaxis with emicizumab, treated bleeds and any AEs.

Methods: UK patients with IBD are registered with the National Haemophilia database (NHD). The NHD supplied an anonymised list of PUP/MTPs treated with emicizumab to the Paediatric Working Party of the United Kingdom Haemophilia Centre Doctor’s Organisation (UKHCDO). Centres supplied information on age at diagnosis/start of prophylaxis, FVIII exposure prior to prophylaxis, bleeds, bleed treatment and surgical procedures.

Results: Data was returned on 88 boys from 19/23 centres with eligible patients: 41 PUPs and 47 MTPs. Two had inhibitors at commencement of emicizumab; one proceeded to ITI and was tolerised, subsequently switching to factor; the other family declined ITI. One inhibitor was detected after 2 months of emicizumab. Mean age at diagnosis 5.4 months (0-48) and at commencement of emicizumab 12.9 months (1-48). Mean number of exposure days prior to emicizumab was 1.1 (0-5). Thirty-one bleed events on emicizumab led to at least 1 dose of FVIII. These were mild in 24, moderate in 5 and severe in 2. There were 3 joint bleeds in 3 patients (all moderate severity), 4 muscle bleeds in 3 patients (2 mild, 2 severe). Median number of days of FVIII required for bleed treatment (including joint, muscle or other) was 1 (1-7). Eight boys had surgery (9 procedures) 5/9 with tranexamic acid alone. One patient developed an injection site abscess; injection site reactions were the only other AEs, none leading to change of therapy.

Conclusion(s): Emicizumab is efficacious in this population, with no patient requiring switch to Factor VIII prophylaxis due to failure of efficacy or adverse events.