The Safety Profile of Filgrastim and Pegfilgrastim

The discovery of endogenous proteins that regulate hematopoiesis led to the identification of human granulocyte colony-stimulating factor (G-CSF). With the advent of recombinant DNA technology, it became possible to manufacture bioactive recombinant proteins for medicinal use. Since the approval of recombinant human G-CSF (rHuG-CSF), such as filgrastim in 1991 and pegfilgrastim in 2002, millions of patients at risk for severe myelosuppression have received these products. Overall, filgrastim and pegfilgrastim have a high margin of safety for short-term use; however, rare severe adverse events have emerged and questions remain regarding the long-term safety and consequences of use of these products. This chapter primarily focuses on the safety and adverse event profile of the most widely used commercially available rHuG-CSF, Neupogen (filgrastim) and Neulasta [a modified (pegylated) filgrastim, pegfilgrastim]. As safety information can change rapidly, we suggest readers consult the latest package inserts for any changes that have occurred from the time of this writing. Other chapters in this volume discuss key studies in specific disease settings in greater detail than is the purview of this chapter, and we encourage the interested reader to reference them for further information.