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    Poster Networking

    Hemophilia and Rare Bleeding Disorders

    Poster Networking Session

    PB0675 - The reverse two-sample in one-clinic visit factor VIII pharmacokinetic protocol using myPKFiT: the Brazilian experience

    Monday, June 26, 2023
    18:30 – 19:30 ET
    Room: Exhibition
    Background: A pharmacokinetic (PK)-guided strategy to individualize prophylaxis can improve the efficacy of factor VIII (FVIII) preventive treatment for hemophilia A (HA) patients. Population-based PK tools, such as myPKFiT, can determine FVIII PK parameters with two blood samples, usually between 4 and 24h post-infusion.

    Aims: To assess PK parameters of octocog alfa, a third-generation standard half-life recombinant FVIII concentrate, in severe HA patients with the reverse two-sample in one-clinic visit strategy, using myPKFiT. Also, factors that may influence FVIII PK parameters were evaluated.

    Methods: PK protocol consisted of two blood samples collected without washout in a single-clinic visit. First sample was collected at the clinic, 24h after a regular prophylactic dose of octocog alfa (25-50 IU/kg) was administered at home. Then, a second infusion of octocog alfa (25 UI/kg) was administered at the clinic, and a second sample was drawn 3h post-infusion. Additionally, we evaluated variables that may influence PK parameters, such as age, body mass index, von Willebrand factor antigen (VWF:Ag), blood group, inhibitor history, and F8 genotype.

    Results: Ninety-two severe HA patients participated in this study (median age: 14.5 years; range 2-54), including 35 patients < 12y, 24 between 12-18y, and 33 >18y (table 1). We confirmed the accuracy of the reverse 2-sample PK strategy by comparing it with PK data obtained from 25 severe HA patients who were also submitted to the 6-sample PK protocol after 72hs of washout, with an intraclass correlation coefficient (ICC) of 0.725 (p < 0.001). Furthermore, in a multivariate analysis, age and VWF:Ag independently influenced PK parameters (p= 0.013 and p< 0.0001, respectively) (table 2).

    Conclusion(s): A single-visit strategy is a reliable time-saving approach for PK, an important tool in individualizing FVIII prophylaxis.