Comparative in Vitro and in Vivo Study of Various Factor VIII Preparations

Abstract

A comparison of nine commercial and non-commercial Factor VIII preparations was made. They consisted of llyophilized cryoprecipitate, 4 intermediate and 4 high purity concentrates. Protein, Fibrinogen, Factor VIII complex, IgG, anti-A and anti-B antibody levels were measured. Factor VIII:C content varied from 4-7 u/ml in cryoprecipitate, 12-31 u/ml in intermediate and 21-40 u/ml in high purity concentrates. These three categories of Factor VIII preparations can be better defined by 2 ratios: u FVIII/mg proteins and u F VIII/mg fibrinogen. They were respectively < 0.5 and < 1 in cryo, 0.5-1 and 1-3 in intermediate purity concentrates, > 1 and > 3 in high purity concentrates. The F VIII :C/F VIII : AG ratio ranged from 0.3 to 0.6 in any preparation. The F VIII:C/F VIII :VWF ratio was always lower than 1.Each preparation was injected to several classic hemophilia A patients for treatment of minor hemorrhages. The peak of activity was always found 1 hour post-injection and the recovery ranged from 80 to 105%. The Factor VIII half-life ranged from 10 to 12.5 hours. No significant differences in half-life or recovery was found, and the clinical efficacy was similar. With the exception of fibrinogen load, all products carry similar risk for hepatitis, anti-IgG immunization and hemolysis. The differences lie in the ease of injection, the price and the yield of Factor VIII from starting plasma. Nevertheless, high purity concentrates should be used when high doses are reauired for surgery or treatment of patients with inhibitor.