Olanzapine 5 mg for Nausea and Vomiting in Patients with Nasopharyngeal Carcinoma Receiving Cisplatin-Based Concurrent Chemoradiotherapy

PURPOSE: To explore the efficacy and safety of adding olanzapine (5 mg or 10 mg) to 5-hydroxytryptamine type 3 receptor antagonists (5-HT(3) RA), neurokinin-1 receptor antagonists (NK1 RA), and dexamethasone for nausea and vomiting in patients with nasopharyngeal carcinoma (NPC) receiving cisplatin-based concurrent chemoradiotherapy. METHODS: Patients receiving olanzapine 5 mg or 10 mg combined with 5-HT(3) RA, NK1 RA, and dexamethasone during the cisplatin-based concurrent chemoradiotherapy were included. The primary endpoint was the complete response (CR) (no vomiting) rate, and the secondary endpoint was the incidence of no nausea. RESULTS: A total of 150 chemotherapy cycles were administrated for 88 patients (75 in the olanzapine 5 mg group and 75 in the olanzapine 10 mg group). The proportions of CR in the olanzapine 5 mg group were comparable to those in the olanzapine 10 mg group in acute (93.3% vs. 94.7%, P = 0.731), delayed (76% vs. 78.7%, P = 0.697), and overall phase (73.3% vs. 77.3%, P = 0.570). Moreover, no nausea rates were also comparable between the two groups in acute (76% vs. 78.7%, P = 0.697), delayed (54.7% vs. 60%, P = 0.509), and overall period (50.7% vs. 57.3%, P = 0.111). Regarding the adverse effects, the incidence of somnolence in the 10 mg group (58.6%) was significantly higher than that in the 5 mg group (41.3%) (P = 0.034), while constipation (20.0% vs. 24.0%, P = 0.554) and hiccups (9.3% vs. 10.6%, P = 0.785) rates were comparable in two groups. CONCLUSIONS: Patients receiving olanzapine plus standard antiemetic therapy has excellent antiemetic effect in NPC patients receiving cisplatin-based concurrent chemoradiotherapy, and patients with olanzapine 5 mg have a similar antiemetic effect and lower adverse effects compared with those with olanzapine 10 mg.