Background: The three-drug combination of a 5-hydroxytryptamine type 3 receptor antagonist, a neurokinin 1 receptor antagonist and dexamethasone is recommended for patients receiving highly emetogenic chemotherapy. However, standard antiemetic therapy is not completely effective in all patients.
Methods: We conducted an open-label, single-center, single-arm Phase II study to evaluate the efficacy of olanzapine in combination with standard antiemetic therapy in preventing chemotherapy-induced nausea and vomiting in patients with thoracic malignancy receiving their first cycle of cisplatin-based chemotherapy. Patients received 5 mg oral olanzapine on Days 1-5 in combination with standard antiemetic therapy. The primary endpoint was complete response (no vomiting and no use of rescue therapy) during the overall Phase (0-120 h post-chemotherapy).
Results: Twenty-three men and seven women were enrolled between May and October 2015. The median age was 64 years (range: 36-75 years). The most common chemotherapy regimen was 75 mg/m2 cisplatin and 500 mg/m2 pemetrexed, which was administered to 14 patients. Complete response rates in acute (0-24 h post-chemotherapy), delayed (24-120 h post-chemotherapy) and overall phases were 100%, 83% and 83% (90% confidence interval: 70-92%; 95% confidence interval: 66-93%), respectively. There were no Grade 3 or Grade 4 adverse events. Although four patients (13%) experienced Grade 1 somnolence, no patients discontinued olanzapine.
Conclusions: The addition of 5 mg oral olanzapine to standard antiemetic therapy demonstrates promising efficacy in preventing cisplatin-based chemotherapy-induced nausea and vomiting and an acceptable safety profile in patients with thoracic malignancy.
Keywords: chemotherapy-induced nausea and vomiting; cisplatin; highly emetogenic chemotherapy; olanzapine.
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