Aprepitant (Ap) Versus Dexamethasone (D) For Preventing Delayed Emesis Induced By Anthracyclines Plus Cyclophosphamide (A Plus C) Chemotherapy (Ct) In Breast Cancer Patients (Pts): A Double-Blind, Multicenter, Randomized Study

9614 Background: A combination of AP + a 5-HT3 receptor antagonist + D and AP alone is recommended, respectively, for the prophylaxis of acute and delayed emesis induced by A+C CT in breast cancer pts. In the registrative study the role of AP in delayed emesis was not defined because prophylaxis of acute emesis was different between the two arms, and the superiority of AP on delayed emesis could be the consequence of a dependent effect on the different results achieved in acute phase. Aim of this study was to compare the efficacy of AP versus D in preventing delayed emesis in pts receiving the same prophylaxis of acute emesis. Methods: A randomized double-blind study comparing AP versus D was completed in naive breast cancer pts treated with A+C. Before CT, all pts were treated with intravenous palonosetron 0.25 mg and D 8 mg, and oral AP 125 mg. On days 2 and 3 pts randomly received D 4 mg bid or AP 80 mg qd. Primary endpoint was rate of complete response (no vomiting, no rescue treatment) from days 2 - 5 after CT. Results: From September 2009 to July 2012, 580 pts were enrolled; 551 were fully evaluated, 273 in arm D and 278 in arm AP. Day 1 complete response rates were similar: 239/273 (87.6%) in D arm and 236/278 (84.9%) in AP arm. From day 2-5, complete response was the same with both antiemetic prophylaxes (79.5%), and all secondary endpoints (complete protection, total control, no vomiting, no nausea, score of FLIE) assumed similar values. During the delayed phase, incidence of insomnia (2.9% vs. 0.4%) and heartburn (8.1% vs. 3.6%) was significantly superior in D arm. Conclusions: In breast cancer pts submitted to A+C CT and receiving the same antiemetic prophylaxis for acute emesis, D and AP present similar efficacy and toxicity. Clinical trial information: NCT 00869973.