The MAPTO survey: worldwide approaches on unmasking factor VIII inhibitors in children with emicizumab treatment: communication from the ISTH SSC Subcommittee on Factor VIII, Factor IX and Rare Coagulation Disorders
Issued Date
2026-01-01
Resource Type
ISSN
15387933
eISSN
15387836
Scopus ID
2-s2.0-105032428679
Pubmed ID
41643940
Journal Title
Journal of Thrombosis and Haemostasis
Rights Holder(s)
SCOPUS
Bibliographic Citation
Journal of Thrombosis and Haemostasis (2026)
Suggested Citation
van Stam L.E., Daisy Horstman B.J., Angchaisuksiri P., Carcao M., Kenet G., Königs C., Mahlangu J., Mancuso M.E., Rezende S.M., Sidonio R.F., Srivastava A., Young G., Fijnvandraat K., Gouw S.C. The MAPTO survey: worldwide approaches on unmasking factor VIII inhibitors in children with emicizumab treatment: communication from the ISTH SSC Subcommittee on Factor VIII, Factor IX and Rare Coagulation Disorders. Journal of Thrombosis and Haemostasis (2026). doi:10.1016/j.jtha.2026.01.006 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/115733
Title
The MAPTO survey: worldwide approaches on unmasking factor VIII inhibitors in children with emicizumab treatment: communication from the ISTH SSC Subcommittee on Factor VIII, Factor IX and Rare Coagulation Disorders
Author's Affiliation
Universiteit van Amsterdam
Tel Aviv University
Emory University School of Medicine
Universidade Federal de Minas Gerais
University of the Witwatersrand, Johannesburg
Keck School of Medicine of USC
The Hospital for Sick Children
Universitätsklinikum Frankfurt
Humanitas Research Hospital
Christian Medical College, Vellore
Humanitas University
Faculty of Medicine Ramathibodi Hospital, Mahidol University
Sanquin Research
Tel Aviv University
Emory University School of Medicine
Universidade Federal de Minas Gerais
University of the Witwatersrand, Johannesburg
Keck School of Medicine of USC
The Hospital for Sick Children
Universitätsklinikum Frankfurt
Humanitas Research Hospital
Christian Medical College, Vellore
Humanitas University
Faculty of Medicine Ramathibodi Hospital, Mahidol University
Sanquin Research
Corresponding Author(s)
Other Contributor(s)
Abstract
It might take years for previously untreated patients (PUPs) with hemophilia A on emicizumab prophylaxis to receive 50 factor VIII (FVIII) exposures. This corresponds to the time at risk for FVIII inhibitors under conventional FVIII prophylaxis. During emicizumab prophylaxis, it is unknown whether additional treatment with regular FVIII doses promotes FVIII tolerance, unmasks inhibitors, or rather, induces them. Therefore, we conducted a survey to describe the current global perspectives and practices of hemophilia health care providers (HCPs) in PUPs with severe hemophilia A receiving emicizumab prophylaxis. In 2024, a survey was sent by email to 1193 hemophilia treatment centers, addressing the perceived inhibitor risk with emicizumab, the potential need for concomitant regular FVIII infusions, and the perceived parental willingness to use concomitant FVIII. In total, 102 pediatric HCPs (85% physicians, 13% nurses) from 38 countries participated. Perceived inhibitor risk data were available for 63 HCPs (62%). Compared with FVIII prophylaxis, the inhibitor risk on emicizumab was estimated to be higher by 13%, equal by 41%, lower by 32%, and unknown by 14%. Among 57 of 102 HCPs with clinical access to emicizumab for children with severe hemophilia A without inhibitors, 30 (53%) offered regular concomitant FVIII infusions. However, in the experience of the HCPs, approximately 45% of parents rejected this option due to concerns about intravenous access. Ultimately, global perspectives on FVIII inhibitor risk and concomitant FVIII use in PUPs on emicizumab prophylaxis are heterogeneous due to lack of evidence, indicating the need for further research to guide treatment strategies.