A new ion-exchange chromatographic procedure has been developed to produce a highly purified factor VIII (FVIII) concentrate from plasma cryoprecipitate. Solubilized cryoprecipitate, after adsorption on aluminium hydroxide and cold precipitation, was treated with 0.3% tri(n-butyl)phosphate and 1% Tween 80 at 25 degrees C for at least 8 h to inactivate lipid-enveloped viruses. The fraction was then loaded onto a column packed with DEAE-Fractogel TSK 650 M and chromatographed. Most proteins and TnBP-Tween 80 flowed through the gel unretarded. FVIII:c, which bound to the gel, was eluted by increasing the ionic strength, then was directly filter-sterilized without ultrafiltration or addition of a protein stabilizer. Chromatographic recovery of FVIII:c was 80-90%. After freeze-drying, FVIII:c was at a concentration of 42.5 +/- 9.5 IU/ml and had a specific activity of 175.4 +/- 37.8 IU/mg (n = 40), corresponding to a purification factor of over 12,000 from plasma. The typical yield of the freeze-dried FVIII:c from cryoprecipitate was 55-65%. FVIII:c was stable for over 24 h at room temperature in the liquid state. The mean content of fibrinogen and immunoglobulin G was only 65 and 100 mg/l, respectively, corresponding to 1.4 and 2.3 mg/1,000 IU FVIII:c. This concentrate, which is much purer than traditional FVIII concentrates, has been found to be well tolerated and effective in clinical treatment of hemophilia A patients.

We have validated the use of two new regenerated multilayered structured cellulose membranes (BMM), Planova 15 N and Planova 35 N, with respective mean pore sizes of 15 and 35 nm, as a new filtration system to eliminate viruses in highly purified factor IX and factor XI concentrates. Virus spiking experiments indicated that single dead-end filtration on the membranes could remove more than 5.7-7.8 log10 of human immunodeficiency virus, bovine viral diarrhoea virus, porcine pseudorabies virus, reovirus type 3, and simian virus 40, as well as the small non-enveloped viruses, poliovirus Sabin type 1 and bovine parvovirus. In vitro control tests and animal studies (Wessler stasis model, rat hypotension model) of the two concentrates did not reveal any significant differences with the non-nanofiltered material. Viral filtration of plasma derivatives on porous polymeric membranes might be an essential step in the improvement of their viral safety.

A highly purified factor XI (FXI) concentrate was prepared from human plasma by a process comprising a filter adsorption step and chromatography on a cation exchange resin. The freeze-dried FXI, which solubilized quickly, had high specific activity (130-150 U/mg protein), high potency (approx. 100 U/mL), and excellent stability for at least 24 hours at room temperature in the liquid state. The overall recovery was about 220 U of FXI per liter of plasma. Minor protein contaminants (C1-inhibitor, fibronectin, IgG, and alpha-2-macroglobulin) were found to be between 0.13 and 0.46 mg per 1000 U of FXI. Fibrinogen and relevant coagulation factors (factors II, V, VII, IX, X, XII, XIII, and VIII/von Willebrand factor) were undetectable, as evidenced by immunologic and immunoelectrophoretic data. Components of the kinin system were present in trace amounts or were undetectable. No evidence of activated factors such as factors Xa and IXa was found. Proteolytic activity, as assessed by S-2288 chromogenic substrate, was negligible and thrombin was undetectable. A solvent-detergent treatment was included prior to chromatographic purification to enhance viral safety against lipid-enveloped viruses. In vitro and in vivo animal studies demonstrated the absence of thrombogenic, hypotensive, or toxic effects. No thrombogenic activity was found in the Wessler model in rabbits at doses of 900 to 1100 U of FXI per kg of body weight. This FXI preparation could be beneficial in substitution therapy of congenital or acquired FXI deficiency, especially as a way to avoid the use of fresh-frozen plasma.

A fibrin glue preparation has been obtained from pooled human plasma using a procedure which includes a solvent-detergent (SD) treatment to inactivate lipid-enveloped viruses. The SD treatment inactivated greater than or equal to 5.5 log10 of HIV in less than 45 min, and greater than or equal to 5 log10 and greater than or equal to 6.5 log10 of VSV and Sindbis virus, respectively, in less than 2 h. The product was found to contain high quantities of fibrinogen (116 +/- 2.49 g/l; n = 12), factor XIII (35 +/- 2.88 U/ml) and von Willebrand factor (23 +/- 1.9 U/ml ristocetin cofactor activity), and relatively low levels of fibronectin (5.9 +/- 0.51 g/l). Plasminogen, the precursor of plasmin, which may play a negative role by decreasing the resistance of the fibrin clot, was at only 0.03 g/l. Cellulose acetate electrophoresis showed 95% gamma-proteins and 5% alpha-2-beta proteins. Sodium dodecyl sulfate polyacrylamide gel electrophoresis under reducing conditions detected three main protein bands with apparent molecular weights of 65, 56 and 47 kilodaltons, probably corresponding to the alpha, beta, and gamma fibrinogen subunits. Other characteristics of the product included (1) high clottability of fibrinogen (over 85%); (2) absence of low molecular weight fibrin degradation products; (3) rapid solubilization at room temperature (less than 10 min); (4) high tensile strength (202 +/- 27 g/cm2 after 2 h of application), and (5) high elasticity of the fibrin clot. In addition, scanning electron microscopy revealed a highly organized structure showing tridimensional arrangement of the fibrin fibers. SD treated fibrin glue should efficiently replace autologous fibrinogen or cryoprecipitate preparations for surgical application.

A therapeutic highly purified von Willebrand factor (vWF) concentrate has been prepared from cryoprecipitate by a three-step chromatographic procedure. After solvent/detergent treatment to inactivate viruses, the cryoprecipitate solution was chromatographed on DEAE-fractogel TSK 650 M to separate vWF from most cryoprecipitate proteins, including factor VIII (FVIII) and fibrinogen. A second DEAE-fractogel TSK 650 M was then performed to further purify vWF and to allow concentrating it to over 100 U ristocetin cofactor activity/ml. The last step on immobilized gelatin removed fibronectin and increased the purity of vWF. vWF was recovered with about 18 and 40% yield in antigen and collagen-binding (CB) activity, respectively, from cryoprecipitate. vWF was obtained in an essentially pure state corresponding to a purification factor of over 10,000-fold from plasma. Immunonephelometric and SDS-PAGE analyses of the concentrate did not reveal any detectable cryoprotein contaminants, especially fibrinogen, fibronectin, immunoglobulins and albumin. The content in intermediate- and high-molecular-weight multimers in the concentrate was similar or higher than that of plasma, as the ion-exchanger selectively favored the binding and concentration of the larger multimeric forms while reducing the amount of the smaller forms with abnormal structure and low activity. Other characteristics of the concentrate included a CB activity to antigen ratio of 1.69 and a high capacity (86%) to correct platelet adhesion in a perfusion system. Clinical use of this standardized vWF concentrate has been shown to be efficacious in the treatment of vWF patients.