[Duration of filgrastim prophylaxis for chemotherapy-induced neutropenia and its predictors]

To analyze the duration of preventive filgrastim administration as support for chemotherapy and its affecting factors.

Single institutional data from a phase Ⅱ clinical trial and a phase Ⅲ clinical trial of pegylated filgrastim were combined. In the two randomized cross-over trials, patients with previously untreated cancer received two cycles of chemotherapy of the same regimen. In the study group, the patients received a single subcutaneous injection of 100 μg/kg pegylated filgrastim, and in the control group, they received daily subcutaneous injections of 5 μg/kg filgrastim.

In 53 chemotherapy cycles, the median duration of filgrastim administration was (9.57±2.10)d. 83.0% (44/53) of them received filgrastim for 7-11 days. Patients with baseline absolute neutrophil count of <4×10(9)/L or body mass index less than 22 received a longer filgrastim prophylaxis(P<0.05). RESULTS of multivariate analysis showed that the baseline absolute neutrophil count is associated with the time of filgrastim administration(P=0.019). The most common adverse event of rhG-CSF was skeletal pain, generally mild and no treatment-related death occurred.

The median duration of filgrastim support for chemotherapy was 10 days. Patients with lower baseline neutrophil count require a longer filgrastim prophylaxis.

: ClinicalTrials.gov identifier, NCT01285219.