Clinical pharmacological study of a plasma-derived factor VIIa and factor X mixture (MC710) in haemophilia patients with inhibitors – Phase I trial

Summary.  MC710, a combined product of plasma-derived activated factor VII (FVIIa) and factor X (FX) at a protein weight ratio of 1:10, is a novel bypassing agent for haemostasis in haemophilia patients with inhibitors. In this study, pharmacokinetic (PK), pharmacodynamic (PD) parameters and safety of single doses of MC710 were investigated in 11 male haemophilia patients with inhibitors in a non-bleeding state. This was a multi-centre, open-labelled, non-randomized, active controlled crossover, dose-escalation study of five doses (20–120 μg kg−1 of FVIIa) with re-administration of different MC710 dosages to the same subjects. The active controls were NovoSeven (120 μg kg−1) and/or FEIBA (50 and 75 U kg−1) which were used to compare PD parameters. The area under the curve (AUC) and maximum plasma concentration (Cmax) of MC710 active ingredients increased dose-dependently within the range of 20 and 120 μg kg−1. After administration of MC710, activated partial thromboplastin time (APTT) was dose-dependently improved and prothrombin time (PT) was shortened to approximately 6 s at 10 min, and APTT improvement and PT shortening effects were maintained until 12 h after administration of MC710 at all doses. No serious or severe adverse event was observed after administration of MC710; furthermore, several diagnostic marker values and those changes did not indicate any signs of disseminated intravascular coagulation (DIC). These results suggest that MC710 would have haemostatic potential equal to or greater than NovoSeven and FEIBA and was be tolerable when given at doses up to 120 μg kg−1.