Aprepitant is a neurokinin-1 (NK1) receptor antagonist that has been shown to improve the control of chemotherapyinduced nausea and vomiting. Aprepitant is administered for 3 days with a 5-HT3 receptor antagonist and dexamethasone to patients receiving highly emetogenic chemotherapy as antiemetic prophylaxis according to the guidelines of the American Society of Clinical Oncology (ASCO), National Comprehensive Cancer Network (NCCN), and the Japanese antiemetic guidelines used in the National Cancer Center Hospital East. In the Japanese phase II clinical trial, the effectiveness of aprepitant was certified by a 5-day duration of administration. The package insert and the antiemetic guidelines recommend 3 days of administration. However, the optimal duration of administration for Japanese is not yet clear. The purpose of this study was to evaluate the efficacy of a 3-day administration period for aprepitant in high-dose cisplatin-containing regimens. Between June 2009 and June 2010, 224 chemotherapy-naive patients (aprepitant group: 92 patients and non-aprepitant group: 132 patients) received high-dose (≥ 50 mg/m2) cisplatin-containing regimens as 1st line chemotherapy. The primary end point was complete response (no vomiting and no use of rescue therapy) in the overall phase (Day 1-5 post-cisplatin). The complete response rates were significantly higher in the aprepitant group than in the non-aprepitant group in the overall phase (62％ vs 40％; P < 0.01), as were rates of no vomiting (91％ vs 64％; P < 0.001). The 3-days regimen of aprepitant, which was recommended based on antiemetic guidelines, was effective in improving the complete response rate and also percentage without vomiting.
