A recombinant factor VIII Fc fusion protein (rFVIIIFc/efmoroctocog alfa, Eloctate/Elocta) can prevent and control bleeding in previously treated children with severe hemophilia A, results of the phase 3 KIDS A-LONG study suggest.
Children who were previously receiving factor VIII prophylaxis saw their median annualized bleeding rate (ABR) decrease with rFVIIIFc, and close to half of the children on this study did not have any bleeding episodes while they were receiving rFVIIIFc.
None of the patients developed inhibitors to rFVIIIFc. And researchers said adverse events on this trial were typical of a pediatric hemophilia population.
The team reported these results in the Journal of Thrombosis and Haemostasis. The trial was sponsored by Biogen Idec and Sobi, the companies developing rFVIIIFc.
The study included 71 boys younger than 12 years of age who had severe hemophilia A. The patients had at least 50 prior exposure days to factor VIII and no history of factor VIII inhibitors.
The children were set to receive twice-weekly prophylactic infusions of rFVIIIFc, 25 IU/kg on day 1 and 50 IU/kg on day 4, but the researchers made adjustments to dosing as needed.
The median average weekly rFVIIIFc prophylactic dose was 88.11 IU kg. About 90% of the patients were on twice-weekly dosing at the end of the study. Seventy-four percent of patients were able to reduce their dosing frequency with rFVIIIFc compared to factor VIII prophylaxis.
About 46% of patients did not have any bleeding events on study. The median ABR was 1.96 overall and 0 for spontaneous and traumatic bleeding episodes, as well as for spontaneous joint bleeding episodes.
Among patients who were previously receiving factor VIII prophylaxis, their median ABR decreased with rFVIIIFc. For children younger than 6 years of age, the median ABR fell from 1.50 to 0. For children ages 6 through 11, the median ABR fell from 2.50 to 2.01.
About 86% of patients had at least one adverse event while on rFVIIIFc, but none of them discontinued treatment as a result.
Two non-serious events (myalgia and erythematous rash) were considered related to rFVIIIFc. And 5 patients experienced 7 serious adverse events that were not related to treatment.
