OBJECTIVES: The purpose of this study was to assess the cost-effectiveness of Nivolumab (NIV) plus Ipilimumab (IPI) combination treatment compared to chemotherapy alone.

METHODS: A partitioned survival analysis model was developed to predict costs and quality-adjusted life years (QALYs) in NIV+IPI and chemotherapy. Direct medical costs were considered from the perspective of the Japanese healthcare system. Lifetime horizon and annual discount rate of 2% was applied. The data on over survival and progression-free survival was derived from CheckMate 649. Cost parameters were estimated by using the JMDC claims database in Japan. Utility weights were referred from published studies. The incremental cost-effectiveness ratio (ICER) of NIV+IPI was estimated. Sensitivity analyses were performed to assess heterogeneity and parameter uncertainty.

RESULTS: In comparison with chemotherapy, costs of NIV+IPI increased JPY14,845,176, and QALYs increased 0.217. This resulted in the ICER of JPY68,435,573/QALY. Settings on utility weights had relatively strong influence on the ICER, with JPY3,701,344/QALY in the best case and “Dominated” in the worst case. In the patients with PD-L1 CPS≧5, the ICER decreased to JPY56,672,649/QALY. However, the probability that NIV+IPI became cost-effective was estimated to be 0%, assuming the willingness to pay threshold of JPY15 million/QALY.

CONCLUSIONS: Applying the threshold of JPY15 million/QALY, NIV+IPI treatment was not cost-effective. Further research on utility weights in the Japanese population and more valid biomarkers is needed for more refined analysis.