333MO Cost-utility analysis of olanzapine in Japanese patients treated with cisplatin-containing highly emetogenic chemotherapy

Abstract

Olanzapine has been shown to have an additive effect on triple antiemetic therapy consisting of aprepitant, palonosetron, and dexamethasone in cisplatin-containing highly emetogenic chemotherapy. Although olanzapine may be cost-effective compared with aprepitant or palonosetron because of its low prices, its cost-effectiveness has not been analyzed. We conducted cost-utility analysis to evaluate the cost-effectiveness of olanzapine in Japan. We simulated model patients treated with cisplatin-containing highly emetogenic chemotherapy and developed a decision analytical model of patients receiving olanzapine plus triple antiemetic therapy or only triple antiemetic therapy. The costs, probabilities, and incremental cost-effectiveness ratio (ICER) of each treatment were calculated from health insurers’ perspectives, and the ICER threshold was set at 50,000 US dollars (USD) per quality-adjusted life-years (QALYs). The costs calculated in Japanese yen (JPY) were converted to USD; 1 USD = 109 JPY. In the base case analysis, the cost of olanzapine per 5-mg tablet was set at 1.54 USD based on the National Health Insurance Drug Price Standard listed in 2019. The probabilities, utility scores, and other costs were obtained from published sources. The robustness of this model was validated by probabilistic sensitivity analysis and one-way sensitivity analysis. The ICER was calculated to be 4,478 USD/QALY, which was below the threshold. Under our conditions, the probabilistic sensitivity analysis revealed a 100% probability that olanzapine was cost-effective. In one-way sensitivity analysis, if the cost of olanzapine was less than 13.38 USD, the ICER would be below the threshold. Olanzapine is very cost-effective in Japanese patients treated with cisplatin-containing highly emetogenic chemotherapy. Although it is necessary to pay attention to adverse effects such as hyperglycemia and QT prolongation, it is considered that olanzapine may be recommended, not only in terms of its effects, but also from a cost-effectiveness perspective.