Comparison of Mirtazapine and Olanzapine on Nausea and Vomiting following Anthracycline-cyclophosphamide Chemotherapy Regimen in Patients with Breast Cancer

We evaluated and compared the efficacy and safety of mirtazapine (MTZ) with olanzapine (OLP) for preventing chemotherapy-induced nausea and vomiting (CINV) following anthracycline plus cyclophosphamide (AC) regimen. Eligible participants were chemotherapy-naive early-stage breast cancer patients who were scheduled to undergo adjuvant AC. The patients were randomized to take oral MTZ or OLP in combination with aprepitant (A), dexamethasone (D), and granisetron (G), (ADG). The endpoints included rates of complete response (CR), complete control (CC), total control (TC), and adverse events during the acute, delayed, and overall phases in the two cycles of chemotherapy. The influence of CINV on the quality of life (QoL) was evaluated on day 6 of chemotherapy. Of 82 patients, 60 were randomized. In the first cycle, CR rates in cycle 1 were 83.3% and 76.6% during the acute period, 80% and 86.6% during the delayed period, and 66.6% and 63.3% during the overall period, for the ADG-M and ADG-O, respectively. High efficacy of both groups was maintained over 2 cycles. More patients in the ADG-M group noted minimal or no impact of CINV on daily life in cycle 2 (89.7% vs. 67.9%; p = 0.044). Incidence of somnolence and fatigue was more frequent with the olanzapine group. In this study, there was no substantial difference between mirtazapine and olanzapine in preventing CINV. Further large randomized trials are essential to demonstrate the anti-emetic effect of mirtazapine in chemotherapy.