NCIt definition : A long-acting, pegylated variant of filgrastim (recombinant human granulocyte colony-stimulating
factor (G-CSF)) with immunomodulating activity. Similar to endogenous G-CSF, this
agent binds to and activates specific cell surface receptors, stimulating neutrophil
progenitor proliferation and differentiation and selected neutrophil functions. The
modification of this version of filgrastim with the addition of a Y-shaped branch
of polyethylene glycol at a specific lysine residue (Lys 17) theoretically serves
to extend the half-life of the agent.;