Multiple Dedicated Measures Result in a Plasma-Derived FVIII Concentrate with High Margin of Safety Regarding Pathogen Transmission

Abstract 4355

A minimal load of infectious virus, if any, in human plasma, the starting material for the production of a FVIII concentrate, is achieved by selecting donor centers and donors, by testing donations for viral markers and genomic material of HAV, HBV, HCV, HIV-1 and high titers of parvovirus B19 (B19V), and by releasing plasma pools for fractionation when non-reactive for these blood-borne viruses. Two dedicated virus reduction steps and further steps of the manufacturing process of this FVIII concentrate [Beriate] were investigated: heat treatment in aqueous, stabilized solution (“pasteurization”), virus filtration (filter with a mean pore size of approx. 19 nm (Planova 20N)), and a chromatography step. The virus and prion reduction capacity of the manufacturing process of this FVIII concentrate was evaluated in in vitro studies.

Product intermediates from selected steps of the manufacturing process for the FVIII concentrate, derived from different production lots, were spiked with enveloped and non-enveloped viruses of diverse physico-chemical characteristics and processed according to a scaled-down, validated manufacturing process. The virus panel employed in these studies consisted of HIV, BVDV (bovine viral diarrhea virus, a specific model virus for HCV and WNV), HAV, parvoviruses (B19V and CPV (canine parvovirus)) and PRV (pseudorabies virus, a non-specific enveloped DNA virus). The prion reduction capacity was studied by spiking cryoprecipitate with two different spike preparations and performing the whole manufacturing process including the virus filtration according to a valid down scaled process.

Pasteurization (heat treatment) inactivates all blood-borne viruses or their specific model viruses effectively, i.e. HIV, BVDV, HAV and B19V were inactivated in the order of 4 log₁₀ or more. Virus filtration removed effectively all enveloped viruses and HAV and removed CPV, a small non-enveloped virus, to a very high degree. Further manufacturing steps reliably contribute to the overall virus reduction capacity of the manufacturing process of this FVIII concentrate.

Two different prion preparations prepared from brain homogenate of 263K infected hamsters were used in prion evaluation studies: a membrane-associated preparation of prion material (microsomes) and a PrP^Sc preparation without membranes (purified PrP^Sc) were used to evaluate the prion reduction capacity of the FVIII production process. Studying the whole manufacturing process in a combined step approach documented the removal of both spike preparations below the limit of detection. Prion material in the different fractions was quantified using a biochemical/serological method, the Conformation-Dependent Immunoassay (CDI). Spiking different manufacturing steps independently and adding the individual reduction factors to the overall prion reduction factor was considered not appropriate as conditioning of the spiked prion material by the production process may impact the reduction capacity.

The pathogen reduction capacity for the FVIII concentrate Beriate is shown in the following table:

Based on the epidemiology in the donor population and donation frequency, the sensitivity of the NAT assay, the amount of plasma needed to produce one vial of FVIII concentrate and the virus reduction factors demonstrated, it can be concluded that the measures taken result in a FVIII concentrate [Beriate] with a very high margin of safety for a wide range of viruses and other pathogens.