Results of clot waveform analysis and thrombin generation test for a plasma-derived factor VIIa and X mixture (MC710) in haemophilia patients with inhibitors--phase I trial: 2nd report.

ABSTRACT

We reported the results of a clinical pharmacological study of MC710 (a mixture of plasma-derived FVIIa and FX) in haemophilia patients with inhibitors during a non-haemorrhagic state. This report provides the results of a clot waveform analysis (CWA) and thrombin generation test (TGT) using blood samples obtained in this study. CWA and TGT were conducted using blood samples obtained from a pharmacokinetic and pharmacodynamic study in which MC710 (five dose rates 20, 40, 80, 100 and 120 µg kg(-1)) was compared with NovoSeven (120 µg kg(-1)) and FEIBA (two dose rates 50 and 75 U kg(-1)) as control drugs in 11 haemophilia patients with inhibitors without haemorrhagic symptoms. CWA showed that MC710 provided significantly greater improvement than the control drugs in activated partial thromboplastin time (APTT) at 80 µg kg(-1); maximum clot velocity and maximum clot acceleration were more enhanced by MC710 than by control drugs. TGT revealed that MC710 significantly shortened the initiation time of thrombin generation in comparison to FEIBA and induced greater thrombin generation potency than NovoSeven. It was not clear whether or not MC710 caused significant dose-dependent changes in the two measurements; however, differences between MC710 and the control drugs were clarified. MC710 was confirmed to have superior coagulation activity and thrombin productivity and is expected to have superior bypassing activity.