OBJECTIVES: In the first-line treatment of metastatic non-small cell lung cancer(mNSCLC), tremelimumab plus durvalumab plus chemotherapy(T+D+CT) and D+CT have shown additional benefit over CT alone in OS or PFS, but their cost-effectiveness is not necessarily clear. This study aimed to evaluate the cost-effectiveness of T+D+CT and D+CT in Japanese patients with mNSCLC.

METHODS: A PartSA model was developed to predict costs and quality-adjusted life years(QALY). Direct medical costs were considered in terms of the Japanese healthcare system. OS and PFS data were obtained from the POSEIDON study. Cost parameters were estimated using JMDC claims database. Utilities were obtained from published sources outside of Japan. The incremental cost-effectiveness ratio(ICER) of T+D +CT and D+CT compared to CT alone were estimated. In addition, we evaluated the cost-effectiveness of strategy of identifying responders with PD-L1 testing and providing T+D+CT or D+CT. Sensitivity analyses (SA) were performed to assess parameter uncertainty.

RESULTS: The base case analysis showed the ICER of T+D+CT and D+CT was estimated to be JPY 79,548,053/QALY(=JPY39,834,984/0.501) and JPY76,516,737/QALY(=JPY22,670,176/0.296), respectively. The ICER for strategy of using T+D+CT for patients with PD-L1≧50% and CT for PD-L1<50% was estimated to be JPY 79,914,159/QALY(=JPY12,005,495/ 0.150). Similarly, the ICER for strategy using D+CT limited to responders was estimated at JPY 77,135,527/QALY(=JPY 6,856,053/0.089). Deterministic SA showed utilities of PFS status strongly affected the ICER. Probabilistic SA estimated a 0% probability that T+D+CT or D+CT would be cost-effective assuming the ICER threshold of JPY15 million/QALY. Also, the probability that strategy using T+D+CT or D+CT limited to responders would be cost-effective was 0%.

CONCLUSIONS: Applying the threshold of JPY15 million/QALY, T+D+CT and D+CT was not cost-effective compared to CT alone. Even when limited to responder, effectiveness declined, and cost-effectiveness did not improve. It is necessary to consider the desirable use of these treatments in terms of cost-effectiveness in Japan's public medical insurance system.