Aprepitant for the treatment of breakthrough chemotherapy-induced nausea and vomiting in patients receiving moderately emetogenic chemotherapy

Background Our aim was to evaluate the efficacy of oral aprepitant in rescue treatment after the primary rescue for breakthrough chemotherapy-induced nausea and vomiting (CINV) in chemotherapy-naive patients receiving moderately emetogenic chemotherapy (MEC). Methods This was a single-institutional phase 2 study. Patients who had received MEC regimens and developed breakthrough CINV despite antiemetic prophylaxis without aprepitant were treated with primary rescue antiemetic treatments chosen by physicians. When the primary rescue (1st rescue) failed, patients received oral aprepitant as the second rescue (2nd rescue). The primary endpoint of this study was the proportion of patients requiring aprepitant as the 2nd rescue and experiencing successful rescue (SR). SR was defined as no vomiting and no need for additional rescue therapy, with nausea up to grade 1 on Common Terminology Criteria for Adverse Events and a Visual Analog Scale score of 25 mm, for 48 h after initiation of aprepitant. Results Eighty patients were eligible for this analysis. Thirty-eight (47.5%) developed breakthrough emesis and received 1st rescue. The 1st rescue was ineffective in 29 (76.3%) patients, and they received the 2nd rescue with aprepitant. Thirteen of these 29 patients (16.3% of the total patients) satisfied the criteria for SR. The primary endpoint, SR rate, in patients treated with aprepitant, was 44.8% (95% confidence interval 26.4-64.4). Conclusion Since the lower end of the 95% confidence interval of SR is 26.4%, the SR in our study did not meet the predefined primary endpoint threshold. However, aprepitant was estimated to be useful in suppressing breakthrough CINV in 16% of the patients treated with MEC.