Cost-effectiveness study of atezolizumab (ATZ) vs. durvalumab (DUR) in elderly extensive disease small cell lung cancer (ED-SCLC) patients (pts): Real-world data (RWD) on first-line chemotherapy combined with immune-checkpoint inhibitors (Chemo-ICIs)

BackgroundAging society is a global issue, and cost-effectiveness, including toxicity balance has become important in cancer treatment for elderly pts. Chemo-ICIs, ATZ and DUR are the standard of care in first-line treatment of ED-SCLC. The aim of our study was to investigate medical cost, effectiveness, and toxicity of ATZ vs. DUR in elderly ED-SCLC pts.MethodsThis is a multicenter retrospective study of RWD. Propensity score matching (PSM) was performed to adjust difference of pts' backgrounds within two groups (ATZ vs. DUR), and the total monthly medical costs incurred during ICI administration for both groups were compared by cost minimization analysis to evaluate cost-effectiveness.ResultsFrom August 2018 to December 2022, 274 pts (ATZ/DUR: 176/98) were registered from 8 hospitals in Japan. Among them, 158 elderly pts aged ³71 were extracted. After PSM and exclusion of cisplatin-treated pts, total 76 pts: 38 pts in each group were evaluated. The mean total medical costs per month during ICIs were 1,003,922 (±310,192) JPY (6,159 EUR) in the ATZ and 1,596,511 (±371,405) JPY (9,795 EUR) in the DUR (Wilcoxon rank sum test: p<0.001). Median overall survivals (OSs) of ATZ vs. DUR were 11.9 (95% confidence interval [CI]: 7.0-18.5) vs. 13.6 (95% CI: 11.1-17.7) months, respectively (p=0.937). Cox-proportional hazard model did not find ATZ vs. DUR as a significant factor for OS (hazard ratio: 1.02, p=0.953). Median progression-free survivals (PFSs) of ATZ vs. DUR were 3.9 (95% CI: 3.4-5.1) vs. 5.3 (95% CI: 4.8-6.4) months, respectively (p=0.025). Response rate was 63.2% for ATZ and 73.7% for DUR (p=0.460). ATZ revealed lower incidences of immune-related adverse events (irAEs) ³grade 2 (2.6 vs. 21.1%, p=0.028) and interstitial lung disease (ILD) (5.3 vs. 21.1%, p=0.086) than DUR.ConclusionsOur RWD of elderly ED-SCLC pts showed similar OSs and higher cost of DUR, suggesting a superior cost-effectiveness of ATZ to DUR. PFS of DUR was longer than ATZ, whereas irAEs and ILD were lower in ATZ. Further consideration is necessary regarding not only financial toxicity but also time toxicity: every 3 weeks vs. 4 weeks.Clinical trial identificationUMIN:000053483.Legal entity responsible for the studyThe authors.FundingHealthcare Consulting, inc.DisclosureA. Hata: Financial Interests, Personal, Invited Speaker: MSD, Eli Lilly, Chugai, Taiho, Boehringer Ingelheim, AstraZeneca, Pfizer. T. Sumi: Financial Interests, Personal, Invited Speaker: Ono Pharmaceutical Co., LTD., AstraZeneca, Nippon Boehringer Ingelheim Co., Ltd. Y. Sato: Financial Interests, Personal, Invited Speaker: MSD, Eli Lilly, AstraZeneca, Novartis, Chugai Pharmaceutical, Ono Pharmaceutical, Taiho Pharmaceutical, Nippon Kayaku, Bristol Myers Squibb, Takeda, Kyowa Kirin, Daiichi Sankyo, Boehringer Ingelheim. N. Katakami: Financial Interests, Personal, Invited Speaker: AstraZeneca, Takeda Pharmaceutical, Chugai Pharmaceutical, Kyorin Pharmaceutical, Bristol Myer Squibb Ono Pharmaceutical, Boehringer Ingelheim, Kyowa-Kirin, Taiho Pharmaceutical; Financial Interests, Institutional, Research Grant: MSD; Financial Interests, Institutional, Local PI: Chugai Pharmaceutical. K. Kokubo: Financial Interests, Personal, Invited Speaker: TOPPAN Holdings, Japan Medical and Industrial Manufacturing Commons. A. Igarashi: Financial Interests, Personal, Advisory Role: Takeda, GSK, Ono Pharmaceutical, Lilly, Argenx, Novo Nordisk, Pfizer, Asahi Kasei, Novartis, Janssen; Financial Interests, Personal, Invited Speaker: Chugai, MSD, Moderna; Financial Interests, Personal, Funding: Taiho, Intuitive Japan, Becton Dickinson, Janssen, Takeda, Eisai. All other authors have declared no conflicts of interest.