title: Viral safety of Nanogam, a new 15 nm-filtered liquid immunoglobulin product.
abstract: OBJECTIVE
  Producers of plasma derivatives continuously improve the viral safety of their products by, for example, introducing additional virus-reducing steps into the manufacturing process. Here we present virus-elimination studies undertaken for a number of steps employed in a new manufacturing process for liquid intravenous immunoglobulin (Nanogam) that comprises two specific virus-reducing steps: a 15-nm filtration step combined with pepsin treatment at pH 4.4 (pH 4.4/15NF); and solvent-detergent (SD) treatment. The manufacturing process also includes precipitation of Cohn fraction III and viral neutralization, which contribute to the total virus-reducing capacity of the manufacturing process. In addition, the mechanism and robustness of the virus-reducing steps were studied.
  
  
  METHODS
  Selected process steps were studied with spiking experiments using a range of lipid enveloped (LE) and non-lipid-enveloped (NLE) viruses. The LE viruses used were bovine viral diarrhoea virus (BVDV), human immunodeficiency virus (HIV) and pseudorabies virus (PRV); the NLE viruses used were parvovirus B19 (B19), canine parvovirus (CPV) and encephalomyocarditis virus (EMC). After spiking, samples were collected and tested for residual infectivity, and the reduction factors were calculated. For B19, however, removal of B19 DNA was measured, not residual infectivity. To reveal the contribution of viral neutralization, bovine parvovirus (BPV) and hepatitis A virus (HAV) were used.
  
  
  RESULTS
  For the pH 4.4/15NF step, complete reduction (> 6 log(10)) was demonstrated for all viruses, including B19, but not for CPV (> 3.4 but < or = 4.2 log(10)). Robustness studies of the pH 4.4/15NF step with CPV showed that pH was the dominant process parameter. SD treatment for 10 min resulted in complete inactivation (> 6 log(10)) of all LE viruses tested. Precipitation of Cohn fraction III resulted in the significant removal (3-4 log(10)) of both LE and NLE viruses. Virus-neutralization assays of final product revealed significant reduction (> or = 3 log(10)) of both BPV and HAV.
  
  
  CONCLUSIONS
  The manufacturing process of Nanogam comprises two effective steps for the reduction of LE viruses and one for NLE viruses. In addition, the precipitation of Cohn fraction III and the presence of neutralizing antibodies contribute to the total virus-reducing capacity of Nanogam. The overall virus-reducing capacity was > 15 log(10) for LE viruses. For the NLE viruses B19, CPV and EMC, the overall virus-reducing capacities were > 10, > 7 and > 9 log(10), respectively. Including the contribution of immune neutralization, the overall virus-reducing capacity for B19 and HAV is estimated to be > 10 log(10).
authors.affiliation: Sanquin, Division of Research and Development, Amsterdam, the Netherlands.
authors.forename: F G
authors.initials: FG
authors.lastname: Terpstra
authors.forename: J
authors.initials: J
authors.lastname: Parkkinen
authors.forename: H
authors.initials: H
authors.lastname: Tölö
authors.forename: A H L
authors.initials: AH
authors.lastname: Koenderman
authors.forename: H G J
authors.initials: HG
authors.lastname: Ter Hart
authors.forename: L
authors.initials: L
authors.lastname: von Bonsdorff
authors.forename: E
authors.initials: E
authors.lastname: Törmä
authors.forename: F A C
authors.initials: FA
authors.lastname: van Engelenburg
mesh_terms: D003257:Consumer Product Safety; D064420:Drug-Related Side Effects and Adverse Reactions / Q000517:prevention & control / Q000821:virology; D006801:Humans; D016756:Immunoglobulins, Intravenous / Q000737:chemistry; D038301:Virus Inactivation
chemical_list: D016756:Immunoglobulins, Intravenous