Lipegfilgrastim: A Long-Acting, Once-Per-Cycle, Glycopegylated Recombinant Human Filgrastim

e13548 Background: Lipegfilgrastim is a once-per-cycle fixed-dose glycoPEGylated granulocyte-colony stimulating factor (G-CSF) under development for the prevention of severe neutropenia in cancer patients receiving chemotherapy (CTx). PEGylation of a molecule extends its half-life in the body, requiring less frequent dosing and allowing for administration of G-CSF once per CTx cycle, making treatment potentially less expensive and enhancing patient compliance and safety. Briefly, traditional PEGylation methods use chemical conjugation through reactive groups on amino acids, which may reduce protein activity and result in non-uniform chemical and pharmaceutical properties. Here, we describe a highly site-specific GlycoPEGylation technology for site-directed PEGylation and summarize preclinical findings compared with pegfilgrastim (Neulasta). Methods: Glycosylation sequon scanning was used to identify the glycoPEGylation site with least impact on protein activity. E. coli-expressed G-CSF was selectively glycosylated at natural O-glycosylation sites and a polyethylene glycol (PEG) sialic acid derivative attached using a sialyltransferase (glycoPEGylation technology). Ligand binding affinity was assessed using the BIACORE 3000 system. Biologic activity of lipegfilgrastim was assessed in an NFS-60 cell line proliferation assay vs filgrastim and pegfilgrastim. PK and PD properties were studied in healthy and neutropenic animal models. Results: GlycoPEGylation produces long-acting G-CSF with improved PK profiles. In vitro, lipegfilgrastim had binding affinity and specific activity comparable to pegfilgrastim, and both were lower than non-PEGylated filgrastim. Comparable increases in leukocytes, neutrophilic granulocytes, and monocytes were seen with lipegfilgrastim and pegfilgrastim in rats and monkeys and were consistent with the effects expected for a long-lasting G-CSF. Conclusions: GlycoPEGylation technology platform is used to produce lipegfilgrastim – a novel, biologically active G-CSF with greater structural homogeneity and comparable pharmacologic properties to conventionally PEGylated G-CSFs.