Developing Predictive Models of rFVIII-Fc Half Life for Personalized Prophylaxis in Patients with Hemophilia A

Chia-Yau Chang, Shiue Wei Lai, Jia-Ruey Tsai, C. H. Tsai, C. N. Cheng, S. H. Hu, Jung Tzu Ku, Y.-C. Chen

Research output: Contribution to journalConference articlepeer-review


Background: Pharmacokinetics (PK) of extended half-life products is important for individualized prophylaxis of patients with hemophilia A (PwHA). Great variation in real world of rFVIII-Fc half life have been reported in some developed countries.

Aims: We aimed to develop a predictive model of rFVIII-Fc half life in PwHA.

Methods: Totally 50 PwHA on rFVIII-Fc replacement therapy were enrolled from two hemophilia centers. Clinical data, including age, BW, BMI, Hct, ABO blood group, von Willebrand factor (VWF) levels, inhibitor history, HCV status, and individual PKs calculated by WAPPS-hemo were collected from charts reviewed retrospectively. Linear regression by SAS software was used for searching out predictors of rFVIII-Fc half life from all the covariates.

Results: The mean age was 34.6±15.9 y/o (8-64). The mean Hct was 43.8% (29.9-52.6%). Twenty-one patients were blood-group O, and 29 were non-O. Mean VWF:Ag was 112.5±54.1% (50-294.7%). Mean ratio of VWF:activity or Rco over VWF:Ag (defined as VWF:Quality) was 0.93 (0.67-1.21). For PwHA of non-O group and O group, rFVIII-Fc half lives were 22.83±6.46h and 16.26±4.61h, respectively (p<0.001***) and VWF:Ag levels were 132.10±63.72% and 86.93±19.30%, respectively (p<0.01**). After multivariate linear regression analysis, for all blood groups, VWF:Ag, HCV infection, and Hct were identified as positive predictors and O blood group and inhibitor history as negative predictors of rFVIII-Fc half life. For non-O group, BMI was an extra positive predictor. For O group, BW was an extra positive predictor and VWF:Quality was an extra negative predictor. Three predictive equations were developed (Table 1), explaining 51.97%,75.17%, and 66.38% of all variability in rFVIII-Fc half-life for PwHA of non-O group, O group, and all blood groups, respectively.
Original languageEnglish
JournalResearch and Practice in Thrombosis and Haemostasis
Issue numberSuppl 2
Publication statusPublished - 2021


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