Filgrastim is a granulocyte colony-stimulating factor (G-CSF) analog used to stimulate the proliferation and differentiation of granulocytes. It is produced by recombinant DNA technology. The gene for human granulocyte colony-stimulating factor is inserted into the genetic material of Escherichia coli. The G-CSF then produced by E. coli is only slightly different from G-CSF naturally made in humans. It is marketed by Amgen under the brand name Neupogen, Dr. Reddy's Laboratories under the brand name Grafeel, Reliance Life Sciences under the brand name Religrast, Zenotech Laboratories Limited under the brand name Nugraf, Raichem lifesciences under the brand name Shilgrast, Intas Biopharmaceuticals under the brand name Neukine and Emcure biopharmaceuticals under the brand name Emgrast...