| Autor: |
Hooimeijer LH; Pediatric Hematology, Beatrix Children's Hospital, Hemophilia Treatment Centre Groningen, 10173University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands., Stein-Wit MA; Pediatric Hematology, Beatrix Children's Hospital, Hemophilia Treatment Centre Groningen, 10173University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands., Voskuilen MA; Division of Thrombosis and Hemostasis, Department of Hematology, Hemophilia Treatment Centre Groningen, 10173University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands., Lukens MV; Laboratory Special Hematology, Department of Laboratory Medicine, Hemophilia Treatment Centre Groningen, 10173University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands., Meijer K; Division of Thrombosis and Hemostasis, Department of Hematology, Hemophilia Treatment Centre Groningen, 10173University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands., Mäkelburg AB; Division of Thrombosis and Hemostasis, Department of Hematology, Hemophilia Treatment Centre Groningen, 10173University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands., Tamminga RY; Pediatric Hematology, Beatrix Children's Hospital, Hemophilia Treatment Centre Groningen, 10173University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands. |
| Abstrakt: |
In 2018, Refacto AF R , a B-domain-deleted third-generation FVIII concentrate, became our preferential product. After the introduction, the development of inhibitors was prospectively monitored; retrospectively, we sought for risk factors in the patients who developed a de-novo inhibitor. Over a period of 15 months, 4/19 adult patients with non-severe haemophilia who were treated on demand for surgery, developed high titer antibodies to FVIII after administration of Refacto AF R ; 5/52 mostly severe patients on prophylaxis, developed an inhibitor (3 ≥ 0.1 BU; 1 > 0.6 BU, 1 high titre) after they switched to Refacto AF R ; all were children <14 years of age and with >100 exposure days, none related to surgery or intensive treatment; all received Kovaltry R before. In conclusion: inhibitors were encountered in on demand patients and previously treated prophylaxis patients; this observation might be a coincidental finding, but also risk factors like genotype and surgery and/or that Refacto AF R is more immunogenic should be considered. For the patients on prophylaxis we hypothesize that loss of tolerance by preceding Kovaltry R might have contributed to inhibitor development. |
