The efficacy of pegfilgrastim, a prolonged-action pegylated form of G-CSF, in the prevention of FN associated with chemotherapy based on docetaxel (100 mg m–2) in breast cancer was assessed in a study of 928 patients with metastatic breast cancer randomised to either placebo or pegfilgrastim (Vogel et al, 2005). This evidence concerns the gene CSF3 and breast carcinoma.