In vitro and in vivo Characterization of Factor VIII Preparations

Abstract

An in vitro and in vivo comparison of 9 commercial and noncommercial factor [F] VIII preparations was made. These consisted of 1 lyophilized cryoprecipitate, 4 intermediate (IPC) and 4 high purity concentrates (HPC). Protein, fibrinogen, F VIII complex, Ig[immunoglobulin]G, IgM and anti-A and B alloagglutinins levels were measured. These 3 qualities of product were defined by 2 ratios: units of F VIII:C [F VIII procoagulant activity] per mg of protein and per mg of fibrinogen. They were, respectively, < 0.5 and < 1 in cryoprecipitate, 0.5-1 and 1-3 in IPC and > 1 and > 3 in HPC. The F VIII:C/F VIII:AG [F VIII-related antigen] ratio ranged from 0.3-0.6 and the F VIII:C/F VIII:VWF ratio was always lower than 1. Varying titers of alloagglutinins were found, unrelated to IgG or IgM levels. Seven of these preparations were injected into several classical hemophilia A patients for treatment of minor hemorrhages. The peak of F VIII:C activity was always found 1 h postinjection. The F VIII:C recovery ranged from 80-140% and the half-life from 8-15 h. No significant difference was found among these products and the clinical efficacy was similar.