Abstract
Background: Factor VIII (FVIII) trough levels > 1 IU/dL in patients with severe hemophilia A receiving regular prophylaxis may optimize bleed protection. Objectives: In this post hoc analysis of patients receiving tertiary prophylaxis for approximately 1 year, the relationship between estimated FVIII levels and reported bleeds was investigated to predict the potential for zero bleeds. Methods: Sixty-three patients (median [range] age, 28 [7-59] years) with severe hemophilia A (229 bleeds) were included. FVIII levels at time of each bleed were estimated from single-dose individual pharmacokinetics. The highest estimated FVIII level at which patients experienced a bleed was considered the potentially effective trough level for that bleed type. Kaplan-Meier estimates of proportions of patients with no bleeds above certain estimated FVIII levels were determined. Those not experiencing a bleed in the trial were assumed to have a bleed at 0 IU/dL (pragmatic approach) or at their median trough level (conservative approach). Results: Kaplan-Meier estimates based on pragmatic approach predicted zero all bleeds, joint bleeds, and spontaneous joint bleeds in 1 year in 40, 43, and 63% of patients, respectively, when the potentially effective trough FVIII level was set at 1 IU/dL. Between 1 and 10 IU/dL, every 1 IU/dL rise in estimated FVIII level was associated with an additional 2% of patients having zero all bleeds. Conclusion: This post hoc analysis confirms benefits with trough levels of approximately 1 to 3 IU/dL in most patients starting tertiary prophylaxis; prophylaxis with higher trough levels may help patients to achieve zero bleeds.
Original language | English |
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Pages (from-to) | 728-736 |
Number of pages | 9 |
Journal | Thrombosis and Haemostasis |
Volume | 120 |
Issue number | 5 |
DOIs | |
Publication status | Published - 2020 May 5 |
Subject classification (UKÄ)
- Hematology
Free keywords
- coagulation factors
- factor VIII
- hemophilia A/B
- pharmacodynamics