What causes inhibitor formation in patients with hemophilia A?

Updated: Apr 08, 2020
  • Author: Douglass A Drelich, MD; Chief Editor: Srikanth Nagalla, MBBS, MS, FACP  more...
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The association of product used with the risk of inhibitor formation remains controversial. In a study of 574 patients with severe hemophilia A, 177 of whom developed inhibitors, the risks of inhibitor development were similar with recombinant and plasma-derived FVIII products. No association was found between the development of inhibitors and the von Willebrand factor content of products, switching from a plasma-derived to a recombinant product, or switching among brands of FVIII products. Unexpectedly, however, inhibitors developed more often with second-generation full-length recombinant products than with third-generation products. [11]

A study with 303 previously untreated or minimally treated children with hemophilia demonstrated a increased risk of inhibitor formation in patients who used recombinant products. [12] However, the European Medicines Agency (EMA) Pharmacovigilance Risk Assessment Committee (PRAC) concluded that "there is no clear and consistent evidence of a difference in the incidence of inhibitor development between the two classes of factor VIII medicines: those derived from plasma and those made by recombinant DNA technology." [13]

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