Chemo safe, effective when given 12 to 14 days from pegfilgrastim use

Dose-dense chemotherapy regimens administered less than 2 weeks from pegfilgrastim use remains safe and effective in patients with breast cancer, suggests a study at a multi-hospital health system.

Patients who received pegfilgrastim as primary prophylaxis following dose-dense chemotherapy scheduled every 14 days were recruited to this study. The impact of <14 elapsed days between pegfilgrastim use and subsequent chemotherapy cycle on the change in mean absolute neutrophil count (ANC) was the primary endpoint.

The authors fitted a generalized linear mixed-effects model with fixed effects for pegfilgrastim delivery method, elapsed days between pegfilgrastim and chemotherapy (fixed categorical effect for 12, 13, 14 days), and ANC at next cycle to the change in ANC between chemotherapy cycles.

Overall, 164 patients with breast cancer (mean age 52±12 years) administered pegfilgrastim support for dose-dense doxorubicin and cyclophosphamide (ddAC) met the eligibility criteria. Of these, 88 percent received pegfilgrastim on-body infector and 13 percent received pegfilgrastim injection.

The mean number of elapsed days from pegfilgrastim administration to the next chemotherapy cycle was 13±0.5 days. The method of pegfilgrastim delivery (p=0.8663) and elapsed days between pegfilgrastim and chemotherapy administration (p=0.8434) did not show a significant impact on the change in ANC, but patient age (p=0.0125) did show a significant effect on the change in ANC.

“In clinical practice, waiting 14 days between the administration of pegfilgrastim and subsequent chemotherapy cycle (as recommended by the prescribing information) is sometimes not feasible with multi-cycle dose-dense regimens,” the authors said.