Feasibility of pegfilgrastim as haematopoietic support for dose-dense every-2-week adjuvant chemotherapy in breast cancer

Abstract

18606 Background: Dose-dense sequential chemotherapy has been safety supported with Filgrastim (F). Pegfilgrastim (PEGF) is a pegylated recombinant human granulocyte colony-stimulating factor (G-CSF) that has a long half-life, a fact that facilitates a less frequent dosing. Its safety and efficacy has been established in 21- and 28-days schedules. Methods: We have performed a retrospective analysis of medical records of 2 cohort of patients (n=38) treated at our institution between December 2003 and November 2005. All patients received Adriamicin 60 mg/m2 plus Ciclophosphamide 600 mg/m2 q2w for 4 cycles followed by Paclitaxel 175 mg/m2 q2w for 4 cycles. As G-CSF support, in Cohort A (n=29) PEGF was administered 6 mg on day 2 of each cycle and in Cohort B (n=9) F days 3 to 10 at 5 μg/kg. The primary end point was to explore the feasibility and safety in terms of febrile neutropenia (FN) events, number of treatment delays (TD), incidence of neutropenia grade 3 (NPG3) and 4 (NPG4) and mean absolute neutrophil count (ANC) on day 14 of cycle 1 to 7 for both groups. Indirect comparisons have been performed. Results: Patients characteristics in both cohorts were well balanced, except for age in cohort A compared with cohort B (44,89 versus 52,5, p = 0,02). FN events and TD were increased in cohort B compared with cohort A (22% versus 0%, p=0.051, both comparisons). No statistically significant difference in number of episodes of NPG3 and NPG4 was observed. Median ANC on day 14 for each treatment cycle was significantly greater for Cohort A than Cohort B, except for cycle 6. Conclusions: PEGF is very safe and efficacy in patients treated with dose-dense sequential adjuvant chemotherapy for breast cancer. It could be even more efficient than F in preventing febrile neutropenia events. [Table: see text]