title: Establishment of the first international standard for PEGylated granulocyte colony stimulating factor (PEG-G-CSF): report of an international collaborative study.
abstract: We assessed the feasibility of developing a suitable international reference standard for determination of in vitro biological activity of human sequence recombinant PEG-G-CSF products with a 20kD linear PEG linked to the N-terminal methionyl residue of G-CSF (INN Filgrastim), produced using a conjugation process and coupling chemistry similar to that employed for the lead PEGfilgrastim product. Based on initial data which showed that the current WHO 2nd international standard, IS for G-CSF (09/136) or alternatively, a PEG-G-CSF standard with a unitage traceable to the G-CSF IS may potentially serve as the IS for PEG-G-CSF products, two candidate preparations of PEG-G-CSF were formulated and lyophilized at NIBSC. These preparations were tested by 23 laboratories using in vitro bioassays in a multi-centre collaborative study. Results indicated that on the basis of parallelism, the current WHO 2nd IS for G-CSF or any of the PEG-G-CSF samples could be used as the international standard for PEG-G-CSF preparations. However, because of the variability in potency estimates seen when PEG-G-CSF preparations were compared with the current WHO 2nd IS for G-CSF, a candidate PEG-G-CSF was suitable as the WHO IS. The preparation 12/188 was judged suitable to serve as the WHO IS based on in vitro biological activity data. Therefore, the preparation coded 12/188 was established by the WHO Expert Committee on Biological Standardization (ECBS) in 2013 as the WHO 1st IS for human PEGylated G-CSF with an assigned in vitro bioactivity of 10,000IU per ampoule.
authors.affiliation: Biotherapeutics Group, NIBSC, Blanche Lane, South Mimms, Potters Bar, Hertfordshire EN6 3QG, UK. Electronic address: Meenu.Wadhwa@nibsc.org.
authors.forename: Meenu
authors.initials: M
authors.lastname: Wadhwa
authors.affiliation: Biotherapeutics Group, NIBSC, Blanche Lane, South Mimms, Potters Bar, Hertfordshire EN6 3QG, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Bird
authors.affiliation: Technology Development and Infrastructure, NIBSC, Blanche Lane, South Mimms, Potters Bar, Hertfordshire, EN6 3QG, UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Dougall
authors.affiliation: Technology Development and Infrastructure, NIBSC, Blanche Lane, South Mimms, Potters Bar, Hertfordshire, EN6 3QG, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Rigsby
authors.affiliation: Biotherapeutics Group, NIBSC, Blanche Lane, South Mimms, Potters Bar, Hertfordshire EN6 3QG, UK; Technology Development and Infrastructure, NIBSC, Blanche Lane, South Mimms, Potters Bar, Hertfordshire, EN6 3QG, UK.
authors.forename: Adrian
authors.initials: A
authors.lastname: Bristow
authors.affiliation: Biotherapeutics Group, NIBSC, Blanche Lane, South Mimms, Potters Bar, Hertfordshire EN6 3QG, UK.
authors.forename: Robin
authors.initials: R
authors.lastname: Thorpe
mesh_terms: D001681:Biological Assay / Q000592:standards*; D002460:Cell Line; D003299:Cooperative Behavior; D000069585:Filgrastim; D016179:Granulocyte Colony-Stimulating Factor / Q000737:chemistry*; D006801:Humans; D011092:Polyethylene Glycols / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry; D012015:Reference Standards
chemical_list: D011994:Recombinant Proteins; C486981:pegylated granulocyte colony-stimulating factor, human; D016179:Granulocyte Colony-Stimulating Factor; C455861:pegfilgrastim; D011092:Polyethylene Glycols; D000069585:Filgrastim
keywords: Biological activity; Biosimilar; International standard; Modified G-CSF