Efficacy of Olanzapine Combined Therapy for Patients Receiving Highly Emetogenic Chemotherapy Resistant to Standard Antiemetic Therapy

OBJECTIVE Olanzapine is proved to be effective for chemotherapy induced nausea and vomiting (CINV). But its efficacy in combination with standard antiemetic therapy is unknown. The purpose of this study is to prove the preventive effect of olanzapine for the prevention of CINV caused by highly emetogenic chemotherapy when used with standard antiemetic therapy. METHOD Gynecologic cancer patients receiving cisplatin-based chemotherapy who had grade 2 or 3 nausea in overall phase (0-120 h after chemotherapy) despite standard therapy were assigned to this study. From the next cycles to cycles in which patients developed grade 2 or 3 nausea, they received olanzapine with standard therapy. 5 mg oral olanzapine was administered for 7 days from the day before chemotherapy. The effectiveness of preventive administration of olanzapine was evaluated retrospectively. The primary endpoint was nausea control rate (grade 0 or 1) with olanzapine. RESULTS Fifty patients were evaluable. The nausea control rate with olanzapine was improved from 58% to 98% in acute phase (0-24 h after chemotherapy) and 2% to 94% in delayed phase (24-120 h after chemotherapy). In overall phase, the nausea control rate improved from 0% to 92%, and it was statistically significant (P < 0.001). CONCLUSION Preventive use of olanzapine combined with standard antiemetic therapy showed improvement in control of refractory nausea.