Inhibitor development against FVIII in previously treated patients with haemophilia A - A retrospective data collection

Institut für Thrombophilie und Hämostaseologie, Praxis Dr. med. Hartmut Pollmann, Loerstraße 19, 48143 Münster.
Hamostaseologie (Impact Factor: 1.6). 11/2010; 30 Suppl 1(4A):S37-9.
Source: PubMed


In a retrospective study 118 haemophilia A patients from two treatment centres (Berlin and Muenster) were evaluated with respect to safety, i. e. inhibitor development, and efficacy of bleeding control of recombinant FVIII products. During approx. 57 thousand injections with more than 87 million I.U. rFVIII no de novo inhibitor was observed in patients previously treated with pFVIII after switch to a recombinant product. A total of 75 thousand injections with more than 111 million I.U. FVIII had been applied during the investigation period of 14 years. Before as well as after switch of the product type bleeding episodes could be controlled with one to two injections per bleed. Conclusion: According to our results equal safety and efficacy of plasma derived and recombinant FVIII products can be assumed.

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    ABSTRACT: The development of alloantibodies or inhibitors is the most serious complication a patient with severe hemophilia can experience from treatment with clotting factor concentrates. Although common in previously untreated patients, inhibitor development is rare in multiply exposed, well-tolerized patients. There has been a nonevidence-based reluctance to change concentrate because of a perceived greater inhibitor risk after the switch, even though most patients are now likely to be using a concentrate on which they did not begin. Inhibitors in previously treated patients are observed in approximately 2 per 1000 patient/years, which makes it difficult to study and compare rates among different products. Because the baseline inhibitor risk in previously treated patients may vary over time, it is important to compare the risk in patients switching to a new product with that in a parallel control group of nonswitching patients or within a case-controlled study. The study designs imposed by regulators are suboptimal in detecting immunogenicity signals. The issue of immunogenicity of new products is likely to gain more relevance in the near future, with a call for effective postmarketing surveillance studies for all of the new engineered factor VIII concentrates with prolonged half-lives that are likely to enter clinical practice.
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