The European Medicines Agency (EMA) concluded that there is no difference in the risk of inhibitor development for patients taking factor VIII medicines derived from plasma or recombinant factor VIII medicines.
EMA first revised one of the latest papers on the results of the SIPPET study (Survey of Inhibitors in Plasma-Products Exposed Toddlers). This research has established that patients who were prescribed medicines made by recombinant DNA technology had a higher incidence of inhibitor development than patients taking plasma-derived factor VIII medicines. Further review of other international interventional clinical trials and observational studies has shown that there is no evidence of the fact that taking these two classes of medicines are associated with different risk of inhibitor development.
Factor VIII is one of the key factors insuring normal coagulation processes. This factor is lacking in patients with hemophilia A, which means that blood does not clot normally and these patients may develop severe bleeding. Factor VIII medicines substitute the absent factor. Though it has been reported that taking these medicines is associated with developing proteins-inhibitors in the body in response to the therapy which blocks the effects of the factor VIII drugs. This results in the fact that the medicines do not work anymore and the risk of bleeding significantly increases.
The prescribing information will be updated. The inhibitor development will be included as a very common side effect in naïve patients and as a rare side effect in previously treated patients. It will be also mentioned that low concentrations of inhibitors in blood are associated with lower risk of bleeding. On the contrary, high levels of inhibitors make patients predispose to severe bleeding.
EMA has outlined that the incidence of inhibitor development is equal in patients taking different classes of factor VIII medicines. Thus, doctors should evaluate this risk of this side effect individually for each patient.