Switching from standard to extended half‐life FVIII prophylaxis in haemophilia A: Comparison of factor product use, bleed rates and pharmacokinetics
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AbstractIntroductionMajority of haemophilia A patients in our comprehensive care centre have switched from standard half‐life (SHL) to extended half‐life (EHL) FVIII products in a short time.AimWe compared the clinical and laboratory outcomes between SHL and EHL FVIII prophylaxis in product switchers.MethodsThis is a retrospective inception cohort of all adult haemophilia A patients switched to EHL (rFVIIIFc or rFVIII‐PEG) prophylaxis in our centre. Dosing, product utilization, annualized bleed rates (ABR), treatment regimen and pharmacokinetics by Web Accessible Population Pharmacokinetic Service (WAPPS)‐Hemo were compared between SHL and EHL.ResultsWe included 38 patients, whose median age was 38 years (range 17–75). Median FVIII dose was 23 IU/kg for SHL versus 25 IU/kg for EHL. After switching, weekly infusions decreased by 29% from median 2.8 (every 2.5 days) to 2.0 (every 3.5 days) (P = <.001) and factor consumption for prophylaxis by 17% from 60 to 50 IU/kg/week (P = <.001). Weekly infusions decreased in 71% and FVIII utilization in 55% of patients. ABR remained low (1.0 for SHL and .5 for EHL, respectively). In pharmacokinetics, the half‐life of FVIII increased from median 13 to 21 h after switching. Times above .01 and .03 IU/ml improved from 85 to 131 h and from 65 to 106 h. Half‐lives of the SHL products and von Willebrand factor levels predicted half‐lives with the EHL products.ConclusionsOur cohort study confirms the successful experience of switching to EHL FVIII products, with decreased infusion frequency, factor consumption and excellent clinical efficacy.
