Maxy-G34

MAXY-G34 is a pegylated variant of human granulocyte-colony stimulating factor (G-CSF). This variant contains multiple non-naturally occurring lysines that have been introduced into alpha helixes of wild type human G-CSF as PEGylation sites, and from which multiple undesired, naturally occurring lysines have been removed as compared to wild type human G-CSF to avoid PEGylation of such sites. Specifically, the amino acid sequence of MAXY-G34 differs from that of human wild type G-CSF at residues 16, 34, 40, 105 and 159. This was accomplished by removing the three lysine residues at positions 16, 34 and 40, and replacing them with arginine, and substituting two new lysine residues at positions 105 and 159. MAXY-G34 is pegylated with 5 kd mPEG SPA (succinimidyl propionate) groups at 3 amino acid residues, including PEG groups attached at the amino terminal end of the protein and at two internal lysine residues, while Neulasta has a single 20 Kd PEG group attached at the N terminal end of the wild type G-CSF protein. It is being developed by Maxygen, Inc. for the treatment of chemotherapy-induced neutropenia.