Current safety of clotting factor concentrates.

Earlier commercial clotting factor concentrates transmitted hepatitis viruses to 100% and acquired immunodeficiency syndrome viruses to 60% to 80% of patients with hemophilia. Transmission of the human immunodeficiency virus was nearly eliminated by heating concentrates in the lyophilized state, which has been done since 1983. However, human immunodeficiency virus infections were still transmitted by some products "dry heated" under conditions less extreme than 68 degrees C for 72 hours. Newer virus-inactivating procedures include "dry heating" at 80 degrees C for 72 hours, modified heating in n-heptane or water vapor, heating in solution, treatment with solvent-detergent mixtures, monoclonal affinity purification plus inactivation, and alkylation with beta-propiolactone (only for factor IX complex). These procedures have eliminated significant loads of human immunodeficiency virus, hepatitis B virus, and non-A, non-B hepatitis virus in laboratory studies. However, clinical studies have shown transmission of hepatitis non-A, non-B for products "dry heated" except at 80 degrees C and for products heated in n-heptane. Elimination of hepatitis B has been difficult to demonstrate, suggesting a continued need for immunization.