NANOFILTRATION, A NEW SPECIFIC VIRUS ELIMINATION METHOD APPLIED TO HIGH-PURITY FACTOR-IX AND FACTOR-XI CONCENTRATES

We have validated the use of two new regenerated multilayered structur ed cellulose membranes (BMM), Planova 15 N and Planova 35 N, with resp ective mean pore sizes of 15 and 35 nm, as a new filtration system to eliminate viruses in highly purified factor IX and fat tor XI concentr ates. Virus spiking experiments indicated that single dead-end filtrat ion on the membranes could remove more than 5.7-7.8 log(10) of human i mmunodeficiency virus, bovine viral diarrhoea virus, porcine pseudorab ies 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 h ypotension model) of the two concentrates did not reveal any significa nt differences with the non-nanofiltered material. Viral filtration of plasma derivatives on porous polymeric membranes might be an essentia l step in the improvement of their viral safety.