UNDERSTANDING INHIBITOR DEVELOPMENT A GUIDE FOR
Patients With Hemophilia A
INHIBITORS DEVELOP IN APPROXIMATELY 25-30% OF PUPs WITH SEVERE HEMOPHILIA A1-3
The development of inhibitors to plasma-derived factor VIII (pdFVIII) or recombinant FVIII (rFVIII) is the most serious complication of therapy for patients with hemophilia.4 Once inhibitors develop, they can significantly impair the effectiveness of FVIII treatment.5 In most cases, inhibitor risk is directly related to the number of exposure days (EDs) during initial treatment with FVIII, often developing in the first 20 EDs.2 These patients, with very little or no exposure to FVIII, are called previously untreated patients, or PUPs. A recent study in PUPs with severe hemophilia A showed a higher inhibitor incidence with rFVIII products derived from hamster cell-lines when compared to pdFVIII.1*
* Differences in inhibitor rates between pdFVIII and rFVIII were not statistically significant. SIPPET authors suggested this may have been due to the small sample size of the study.