Low risk of viral infection after administration of vapor‐heated factor VII concentrate or factor IX complex in first‐time recipients of blood components. International Factor Safety Study Group

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Abstract
BACKGROUND: Vapor‐heated human factor VII concentrate and human factor IX complex are both obtained from prothrombin complex, undergo similar methods of manufacture, and are subjected to an identical two‐step vapor‐heating process for virus inactivation. STUDY DESIGN AND METHODS: Intermediate‐purity vapor‐heated human factor VII concentrate and vapor‐ heated human factor IX complex were monitored for safety with regard to viral infection in the context of an International Factor Safety Study, a prospective study that follows the revised recommendations from the International Congress of Thrombosis and Hemostasis (ICTH). Because the rarity of the respective hereditary deficiencies would have made separate analyses unrealizable, the results were combined for the final analysis. Entry required that patients have no history of transfusion with any blood derivative. After the first infusion of the study drug, patients were monitored for 6 months for the development of non‐A, non‐ B hepatitis (NANBH) and infection with hepatitis B virus (HBV) and for 15 months for infection with hepatitis C virus (HCV) and human immunodeficiency virus (HIV). An event was defined as a positive result on any test for any infection. An alanine aminotransferase level more than 2.5 times the upper limit of normal on two consecutive occasions was defined as an event for NANBH. HBV infection was monitored with tests for three different HBV markers: the HBV surface antigen, antibody against the HBV surface antigen, and antibody against HBV core antigen. HCV and HIV infection were monitored with tests for HCV and HIV antibodies. RESULTS: The 25 patients who completed the study (1 has not completed the study and 1 dropped out) received a total of 434 infusions comprising 17 different production lots of the concentrates. Twenty patients were analyzable for NANBH and 25 for HCV and HIV infection. Since most patients had been given HBV vaccination, only 4 patients were analyzable for this end point. None of the patients showed evidence of having developed an event. These data satisfy ICTH criteria when the products are considered together, but vapor‐heated factor VII concentrate does not qualify alone because there were only five patients in this group. CONCLUSION: Vapor‐heated factor VII concentrate and vapor‐heated factor IX complex are associated with a low risk of viral infection. Preliminary results are also presented, indicating that the concentrates are safe with regard to inhibitor development.