Viral safety of a pasteurized, monoclonal antibody-purified factor VIII concentrate in previously untreated haemophilia A patients

The efficacy and viral safety of a pasteurized, immunoaffinity-purified procoagulant factor VIII protein (FVIII:C; Monoclate-P) was studied in two multicentre, prospective, open-label trials in 30 previously untreated patients, 18 with severe (< 1% FVIII:C activity), and 12 with moderate (1% to 5% FVIII:C activity) haemophilia A. Clinical assessments, performed at screening and regularly thereafter for 6 to > 24 months (maximum 34 months), showed that none of 24 assessable patients acquired illnesses consistent with monitored transfusion-transmissible diseases. No patients acquired hepatitis B surface antigen, or antibodies against hepatitis B core antigen, hepatitis C, or human immunodeficiency virus. Likewise, no patients acquired treatment-related hepatitis A antibodies or sustained elevations of alanine aminotransferase levels. The safety profile for Monoclate-P is brought about by a multi-step safety system that incorporates viral inactivation (through a combination of immunoaffinity chromatography and pasteurization) plus donor screening, plasma testing, and quality assurance. The inhibitor development rate (13% low titre, 10% high titre) was similar to that reported in the literature for other FVIII concentrates (24% to 52%). The most frequently reported adverse events were related to typical infant and childhood diseases. Monoclate-P was effective in all patients treated according to protocol, except in two, who developed inhibitors.