The results of the SIPPET (Survey of Inhibitors in Plasma-Products Exposed Toddlers) study were published today in the New England Journal of Medicine. The paper suggests that, in previously untreated patients ( PUPs), the  risk of developing an inhibitor when using recombinant factor VIII products is higher than when using plasma-derived factor VIII concentrates. This is a significant study and the results may prove to be important. There is no evidence of a higher risk of inhibitors with recombinant FVIII in previously treated patients (PTPs).

The study was conducted between 2010 and 2014 and included PUPs with severe hemophilia A who were treated at 42 participating sites in 14 countries from Africa, Asia, the Americas, and Europe. In the study, 251 PUPs were randomized so that 125 patients received plasma-derived FVIII (which contained von Willebrand factor) and 126 received recombinant FVIII. The study used a variety of plasma-derived and recombinant FVIII clotting factor concentrates. The study compared two classes of FVIII concentrates – plasma-derived and recombinant – so no conclusions can be made about the risk associated with specific products.

EHC will make further comments in the coming week.

The paper can be viewed here.