Pegfilgrastim (Neulasta®, Amgen, Thousand Oaks, CA), the polyethylene glycol‐conjugated form of G‐CSF, is a long‐acting myeloid growth factor that is administered subcutaneously (SC) on a more convenient, less frequent dosing schedule (i.e., as a single dose administered once‐per‐cycle of chemotherapy) and has demonstrated improved reduction of neutropenia over both placebo and filgrastim 7, 8, 9, 10, 11, 12, 13. Here, CSF3 is linked to Decreased total neutrophil count.