The goal of this observational study is to learn about the changes of antibodies and inhibitors against the coagulation factor VIII in patients with severe hemophilia A receiving emicizumab therapy. No additional visits or procedures are planned. Patients in this study will continue to receive their routine care and analysis will be done from left over samples from routine visits.
Severe congenital hemophilia A (CHA)
Treatment with emicizumab irrespective of any other treatment
Informed consent
No therapy with emicizumab
Immunosuppressive therapy
HIV-infection with CD4 (cluster of differentiation 4) cells <200/µl
The study aims to recruit 100 patients with severe hemophilia A from 15 study sites in germany.
Other
Other
no interventions
Other interventionno intervention, only 3 different patients groups
FVIII inhibitor development in inhibitor negative subjects
Rate of FVIII inhibitor development during three years of emicizumab prophylaxis in inhibitor negative subjects. Assessed with Bethesda Assay (BU/ml). Number of patients who develop an FVIII inhibitor within the study period, but were FVIII inhibitor negative at start of the study.
FVIII antibody development in inhibitor negative subjects
Rate of FVIII antibody development during three years of emicizumab prophylaxis in inhibitor negative subjects. FVIII anti drug antibody (ADA) is assessed by FVIII specific ELISA (OD=Optical Density). Number of patients who develop an FVIII antibody (ADA) within the study period, but were FVIII inhibitor negative at start of the study.
FVIII inhibitor disappearance in inhibitor positive subjects
Rate of FVIII inhibitor disappearance during three years of emicizumab prophylaxis in inhibitor positive subjects. Assessed with Bethesda Assay (BU/ml). Number of patients who loose an FVIII inhibitor within the study period, but were FVIII inhibitor positive at start of the study.
FVIII antibody disappearance in inhibitor positive subjects
Rate of FVIII antibody disappearance during three years of emicizumab prophylaxis in inhibitor positive subjects. FVIII anti drug antibody (ADA) is assessed by FVIII specific ELISA (OD=Optical Density). Number of patients who develop an FVIII antibody within the study period, but were FVIII inhibitor positive at start of the study.
Anti-FVIII inhibitor development
Anti-FVIII inhibitor development (median BU/ml) over time. Assessed with Bethesda Assay (BU/ml). Description of inhibitor development in the different patient groups within the study period. Cut off is 0,6 BU/ml.
Anti-FVIII antibody development
Anti-FVIII antibody development (median arbitrary units, OD) over time. Description of antibody development in the different patient groups within the study period.
Time to negative inhibitor titers
Time to negative inhibitor titers. Assessed with Bethesda Assay (BU/ml). Description of the Time (days) observed for FVIII inhibitor disappearance within the study period in the patient groups. Cut off for inhibitor titer is 0,6 BU/ml.
Treatment of bleeds
Description of the use of FVIII and/or Bypassing agents treatment in addition to Emicizumab treatment in case of bleeds.
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Christoph Königs
Lead sponsor
Goethe University
Sponsor institution
Roche Pharma AG
Collaborator
Chugai Pharma Germany GmbH
Collaborator
