Aprepitant in the Prevention of Delayed Emesis Induced by Cyclophosphamide Plus Anthracyclines in Breast Cancer Patients

This is a phase III, double-blind, randomized trial, to evaluated the efficacy and safety of aprepitant for the prevention of delayed emesis in patients with breast cancer submitted for the first time to chemotherapy with cyclophosphamide plus anthracyclines. The study will be carried out during the first cycle of chemotherapy. For the prevention of acute emesis, all patients will receive, before chemotherapy: * dexamethasone 8 mg iv in 15 minutes, 30 minutes before chemotherapy; * palonosetron 0.25 mg iv bolus, 30 minutes before chemotherapy * aprepitant 125 mg orally, 60 minutes before chemotherapy After 24 hours from chemotherapy administration, patients will be randomized to receive: A) dexamethasone 4 mg orally: 24 hours after chemotherapy and at 8 pm on day 2, then at 8 am and 8 pm on day 3. B) Aprepitant 80 mg orally: 24 hours after chemotherapy on day 2 and then at 8 am on day 3. The patients will receive prochlorperazine suppositories as rescue medication, for important nausea and vomiting (\> 2 episodes) during days 1-5 after chemotherapy. The patients will receive a diary, which includes a Visual Analogue Scale (VAS) for nausea and vomiting evaluation. All patients will fill out the diary in which, for 6 consecutive days (days 1-6), patients will report for each day the number of vomiting episodes, the intensity and duration of nausea, any antiemetic rescue medication and any adverse event and its treatment. In addition, on day 1 before chemotherapy and then on day 6, patients will fill out the FLIE (Functional Living Index-Emesis), a questionnaire concerning the impact of nausea and vomiting on their quality of life. Primary end point is the percentage of complete responses (no vomiting and no rescue treatment) on days 2-5 after chemotherapy administration