Abstract P1-15-03: Comparison of efficacy of primary prophylaxis with pegfilgrastim, filgrastrim and a biosimilar filgrastim in TAC regimen (docetaxel, doxorubicin and cyclophosphamide)

Abstract Background: Febrile neutropenia (FN) is a major toxicity of myelosupressive chemotherapy. Primary prophylactic use of granulocyte colony stimulating factors (G-CSF) is recommended in high risk FN regimens. The comparison of pegfilgrastim (Peg) and filgrastim (Fil) FN prophylactic effectiveness is still an issue of debate. Very recently Nivestim (Niv), a new biosimilar filgrastim, has also become commercially available. We aimed to compare the efficacy of the 3 mentioned types of G-CSF in the primary prophylaxis of FN. Methods: Single-center, retrospective study to evaluate the incidence of FN in women with breast cancer treated with adjuvant or neo-adjuvant TAC (FN risk ≥20%). Patients (Pt) were divided in 3 consecutive cohorts according to G-CSF primary prophylaxis (Fil, Peg and Niv) FN was defined as axillary temperature ≥38,3 °C and absolute neutrophil count < 500/ul. Results: We included a total of 421 women (median age 51 y, 25–76) with Stage II (56%) and Stage III (44%) breast cancer. Age and stage distribution were similar in the 3 cohorts. A single dose of Peg was administered in all 767 cycles (cy). The standard dose of Fil and Niv was 7 daily injections, only in in 13% Fil pt and 10% Niv pt < 7 administrations were done. The incidence of FN per patient and per cycle is presented in Table 1. In all cohorts, approximately half of NF episodes occurred in the 1st cycle (48% Fil, 59% Peg, 42% Niv). Conclusions: No differences in terms of efficacy existed between Biosimilar Niv and original biological reference Fil. Seven daily injections of Fil and Niv seem equivalent to single dose Peg. Besides efficacy, questions like cost-effectiveness and convenience of administration should be taken into account when approaching this topic. Our data showed a predominance of events in the 1st cycle (regardless of the type of G-CSF). This has been consistently described in the literature and may support the necessity to recommend other NF preventive measures in this cycle. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-15-03.