A Single Dose Filgastrim In the Treatment of Chemotherapy Induced Neutropenia

Chemotherapy induced neutropenia (CIN) was a challenge to physicians until the discovery of growth factors. Neutropenia predisposes the patient to infection with increased morbidity, mortality, and cost of hospitalization. Not only does CIN leads to a delay in chemotherapy but also a dose reduction, which results in decreased efficacy and impact on survival. Filgrastim is a granulocyte colony stimulating factor that leads to the proliferation, differentiation and function of neutrophils. With an increase in the neutrophil count and function, Filgrastim reduces the incidence of neutropenia and the complications associated with febrile neutropenia (FN), making it possible to deliver chemotherapy on time, without dose adjustment. ASCO guidelines recommend that Filgastrim be given at 5 mcg/kg/day starting from days 1–3 after chemotherapy for patients with the risk of FN greater than 20% until the absolute neutrophil count is near-normal. It was recently reported that two doses of Filgrastim were comparable to higher number doses to prevent the nadir. We hypothesized that only a single dose is sufficient to prevent the nadir and delay in treatment.

A retrospective analysis of chart data from all patients treated at The Brooklyn Hospital Center ambulatory clinic was reviewed after the initiation of chemotherapy. Data collected included the white cell count, neutrophil count, dates of chemotherapy and Filgrastim administration. Patients who received one dose of Filgastrim within 2–3 days, but not less than 24 hours prior to receiving subsequent chemotherapy comprised the study population. Data was analyzed for each individual cycle of chemotherapy.

The study population consisted of 11 patients with a total of 33 cycles of chemotherapy. Of the 11 patients, 9 had breast cancer, 1 had embryonal cancer, and 1 had colon cancer. Chemotherapy varied from Etoposide and Cisplatin, FOLFOX with Bevacizumab, and Adriamycin with Cyclophosphamid (AC) followed by Paclitaxel where the AC was given as a dose dense regimen. All the cycles had adequate response in neutrophil count to a single dose of Filgrastim when it was delivered within 2–3 days, but not before 24 hours of receiving chemotherapy. The mean absolute neutrophil count prior to Filgrastim was 0.8 compared to 6.0 (p=0.0001) after a single dose. There was no delay in treatment noticed as a result of the single dose of Filgrastim in all the 33 cycles.

Filgrastim as a single dose is sufficient to treat CIN and prevent delay in subsequent treatment.

No relevant conflicts of interest to declare.