Since the early 1990s, recombinant human clotting factor VIII (rhFVIII) produced in hamster cells has been available for haemophilia A treatment. However, the post‐translational modifications of these proteins are not identical to those of native human FVIII, which may lead to immunogenic reactions and the development of inhibitors against rhFVIII. For the first time, rhFVIII produced in a human host cell line is available.

BACKGROUND: Virus removal by partitioning into different fractions during cold ethanol fractionation has been described by several authors, demonstrating that cold ethanol fractionation can provide significant contribution to virus removal, even in those cases where virus removal is limited and must be supported by additional measures for virus inactivation during further processing.STUDY DESIGN AND METHODS: Plasma Protein Therapeutics Association (PPTA) member companies collected and evaluated 615 studies on virus removal by the steps of the cold ethanol fractionation process. The studies describe the precipitation and separation of Fraction (F)III or FI/III in the immunoglobulin fractionation process and precipitation and separation of FII/III, FI/II/III, and FIV/IV in the albumin fractionation process.RESULTS: The data indicate a significant contribution of cold ethanol fractionation to the overall clearance of a broad spectrum of viruses, at varied process variables such as pH, temperature, and alcohol concentration and demonstrate the robustness of virus removal by the cold ethanol fractionation process.CONCLUSIONS: The data presented here support the importance of the partitioning steps for virus safety for immunoglobulins and albumin. However, virus removal by cold ethanol fractionation alone cannot provide viral safety of human albumin and immunoglobulins and therefore must be completed by other virus inactivation and removal procedures.

BACKGROUND: Solvent/detergent (S/D) treatment is an established virus inactivation technology that has been applied in the manufacture of medicinal products derived from human plasma for more than 20 years. Data on the inactivation of enveloped viruses by S/D treatment collected from seven Plasma Protein Therapeutics Association member companies demonstrate the robustness, reliability, and efficacy of this virus inactivation method.STUDY DESIGN AND METHODS: The results from 308 studies reflecting production conditions as well as technical variables significantly beyond the product release specification were evaluated for virus inactivation, comprising different combinations of solvent and detergent (tri(n-butyl) phosphate [TNBP]/Tween 80, TNBP/Triton X-100, TNBP/Na-cholate) and different products (Factor [F] VIII, F IX, and intravenous and intramuscular immunoglobulins).RESULTS: Neither product class, process temperature, protein concentration, nor pH value has a significant impact on virus inactivation. A variable that did appear to be critical was the concentration of solvent and detergent.CONCLUSION: The data presented here demonstrate the robustness of virus inactivation by S/D treatment for a broad spectrum of enveloped test viruses and process variables. Our data substantiate the fact that no transmission of viruses such as human immunodeficiency virus, hepatitis B virus, hepatitis C virus, or of other enveloped viruses was reported for licensed plasma derivatives since the introduction of S/D treatment.

Reports about transfusion-related transmissions of variant Creutzfeldt-Jakob disease have urged the need for more information regarding the risk for prion contaminated units in the blood supply and the safety of transfusion plasma and biopharmaceuticals derived from this precious raw material. According to a possible epidemiological model, the risk in many European countries is the same or lower than that of human immunodeficiency virus. Comprehensive investigations have shown that the prion safety margin of both single-donor and pooled solvent/detergent treated transfusion plasma is high. Furthermore, prophylactic treatment using plasma-derivatives poses a very low risk in terms of prion disease despite extensive lifetime exposure.

It is with great interest that we read the recent publication by Mazurier[1] regarding the composition, quality control, and labeling of plasma-derived products for the treatment of von Willebrand disease (vWD). We agree that an optimal selection of the product to use in this complicated clinical setting must, among other requirements, be based on the level of safety in eliminating potential blood-born pathogens, and that such information should be made available for all products with the potential to be used in a vWD indication. Mazurier has compared characteristics of the only two products developed for this very special indication, namely Wilfactine® (Laboratoire français du Fractionnement et des Biotechnologies [LFB]; Les Ulis, France) and Wilate® (Octapharma Pharmazeutika Produktionsges. Vienna, Austria; also indicated for hemophilia A), with several other concentrates currently used to treat vWD patients.

The polysulfated polyxylan HOE/BAY 946, which has been tested in two pilot studies in ARC/AIDS patients and in asymptomatic HIV carriers in Germany, was believed to act by inhibiting virus attachment to the cell. However, the drug was also found to reduce the amount of HIV particles released from infected peripheral blood mononuclear cells (PBMC) in vitro. Furthermore, preincubation of PBMC with the drug led to a partial inhibition of a following HIV infection, suggesting that the drug also affects virus entry. Electron Paramagnetic Resonance (EPR) measurements on uninfected human lymphocytes using 5-proxyl-nonane as spin label demonstrated smaller hyperfine coupling constant (aN) values in the presence of HOE/BAY 946 or dextran sulfate 5000. Accordingly, h-1P/h-1H ratios were decreased, indicating increased plasma membrane hydrophobicity and a membrane-stabilizing effect of the drugs. Culture of the chronically HIV-infected monocytic cell line U937/HIV-2D194 in the presence of HOE/BAY 946 specifically and drastically reduced the release of virions and the intracellular synthesis of viral proteins as determined by radioimmunoprecipitation and reverse transcriptase assays. In conclusion, although the EPR studies showed a physico-chemical effect on membrane polarity, HOE/BAY 946 and dextran sulfate clearly affect processes beyond the cell membrane. Thus, in contrast to previous reports suggesting that polysulfated sugars affect HIV only by inhibiting virus binding to uninfected cells, they clearly inhibit HIV in infected cells as well and appear to have a pleiotropic mode of action. Such drugs may be less likely to result in viral resistance after prolonged application than substances acting only on one step in the life cycle of the virus.