Analysis Of The Impact Of Growth Factor On The Haematological Safety Of Dose-Dense Regimen In The Randomized Phase Ii Adjuvant Trial Bo3

605 Background: In a randomized phase II study, P. Piedbois et al. explored a dose-dense docetaxel (T) followed by epirubicin/cyclophosphamide (EC) every two weeks versus the reverse sequence, versus standard-dose docetaxel, epiribucin and cyclophosphamide (TEC) every 3 weeks. The main purpose of this second analysis was to further explore the haematological safety of each regimen in patients receiving primary prophylactic pegfilgrastim. Methods: One hundred patients with node-positive invasive breast adenocarcinoma were randomized between (arm A) docetaxel 75 mg/m2, epiribucin 75 mg/m2 and cyclophosphamide 500 mg/m2 (TEC) every 3 weeks for 6 cycles (35 patients) or (arm B) epiribucin 100 mg/m2 and cyclophosphamide 600 mg/m2 every 2 weeks for 4 cycles, followed by T 100 mg/m2 (EC→T) every 2 weeks for 4 cycles (31 patients) or (arm C) T→ EC (34 patients). Among the 99 patients who received chemotherapy, 79 received pegfilgrastim 6 mg subcutaneous day 1 from the first cycle (27 in arm A, 23 in arm B and 29 in arm C). The safety data of these 79 patients were reported here. Results: Our results showed grade 3/4: neutropenia (arm A 30 %, arm B 39 %, arm C 31 %) and febrile neutropenia (FN) (arm A 11 %, arm B 13 %, arm C 3 %), grade 2–4: anaemia (arm A 26 %, arm B 61 %, arm C 55 %) and thrombocytopenia (arm A 15 %, arm B 9 %, arm C 3 %), respectively. Crude proportion and time to toxicity summaries showed that in dose-dense arms, patients allocated to the EC→ T sequence were more exposed to FN than patients allocated to the T→ EC. In the Cox model taking into account all allocated treatment and age, treatment was a predictor of grade 2–4 anaemia, whereas age was significantly correlated to grade 2–4 thrombocytopenia. There was no clear relationship between haematological toxicity and dose intensity across all treatment arms. Except for nausea (17 % versus 3 %) and neurological toxicity (13 % versus 3 %), non-haematological toxicities were similar in arm B and C. Conclusions: These analyzes confirmed that dose-dense regimens EC→ T or T→ EC are feasible with pegfilgrastim primary prophylaxis. The T→ EC sequence seems to be associated with a better haematological tolerance, and should be the preferred dose-dense regimen providing similar efficacy. The trial was supported by Amgen. No significant financial relationships to disclose.