Abstract Number: PB1076
Meeting: ISTH 2020 Congress
Background: Pharmacokinetics guided dosing may be based on at least actual FVIII trough and peak levels instead of current FVIII estimates based on body weight and in-vivo recovery based dosing.
Aims: To assess the trough and peak level of factor VIII in patients with hemophilia A on low dose prophylaxis and its impact on the clinical and radiological joint status.
Methods: A follow up study was performed in Ain-Shams University, Pediatrics Hospital, Hemophilia Clinic. It included 25 children and adolescents with hemophilia A on prophylactic factor VIII Recombinant 3rd generation with a dose of 45 IU/Kg/week in 2 doses was used. Trough level of factor VIII was done before prophylactic dose and peak level post-infusion through chromogenic assay using STAGO-Immuno-Def VIII reagent. Clinical joint score and Functional Independence Score of Hemophilia (FISH) were done. Radiological joint scores were done using conventional x-ray, ultrasound and MRI. Cut-off level of trough levels was studied at 1% and 1%-5% of factor VIII.
Results: 4 patients (21.1%) had trough level < 1%, 13 patients (68.4%) had trough level between 1%-5%, 2 patients (10.5%) had trough level > 5%. No significant difference between trough level of factor VIII and clinical joint scores and FISH scores of patients. Median score of the worst joint of patients with trough level >5% was 5 in comparison to 8 and 7 in patients with trough level 1%-5% and < 1% respectively. Mean FISH of patients with trough level >5% was 9.50 ± 2.12 in comparison to 12.92 ± 5.41 and 11.00 ± 3.56 for patients with troughs 1%-5% and < 1% that was respectively.
Conclusions: Low trough levels alone did not warrant intensification of the prophylaxis regimen; the dose and dosing frequency may need be adjusted according to individual activity and bleeding pattern.
To cite this abstract in AMA style:Tantawy A, Ragab I, Khalil M, Mostafa S. Factor VIII trough Levels in Patients with Hemophilia A on Secondary Prophylaxis in Relation to Clinical and Radiological Outcomes [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/factor-viii-trough-levels-in-patients-with-hemophilia-a-on-secondary-prophylaxis-in-relation-to-clinical-and-radiological-outcomes/. Accessed December 2, 2022.
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