Summary
Monoclonal antibody purified factor IX concentrate, Mononine® (Armour Pharmaceutical
Company, Kankakee, Illinois, USA), is a recently developed replacement factor concentrate
for the treatment of patients with hemophilia B. The pharmacokinetic properties of
monoclonal antibody purified factor IX concentrate (MAb Factor IX concentrate) have
been evaluated in only small samples of patients, and little is known about those
factors that might influence in vivo recovery of factor IX after infusion in a larger
patient population. In vivo recovery of factor IX was therefore evaluated for 80 different
indications in 72 patients who received MAb Factor IX concentrate for the management
of spontaneous or trauma-induced bleeding, or as prophylaxis with surgery. The average
recovery after infusions for presurgical pharmacokinetic analysis (mean ± standard
deviation) was 1.28 ± 0.56 U/dl rise per U/kg infused (range 0.41-2.80), and the average
recovery after all infusions for treatment was 1.23 ± 0.49 U/dl rise per U/kg infused
(range -0.35-2.92). Recovery values for multiple MAb Factor IX doses in a given patient
were also variable; the average recovery was 1.22 ± 0.53 U/dl rise per U/kg given,
and standard deviations ranged from 0.03 to 1.26. Patient age, weight, and MAb Factor
IX concentrate dose minimally but significantly influenced factor IX recovery. There
was no significant effect of either race, history of previous thrombotic complications
during treatment with other replacement factor concentrates, or bleeding state on
recovery. All of the patients treated with this preparation experienced excellent
hemostasis, and no thrombotic complications were observed.
