OBJECTIVES: The aim of this study is to describe the effectiveness of atezolizumab in patients with previously untreated extensive-stage small cell lung cancer (ES-SCLC) and to analyze the cost-effectiveness of treatment in the context of a risk-sharing agreement (RSA) between hospital and pharmaceutical company.

METHODS: We conducted a retrospective observational study of all atezolizumab treatments for ES-SCLC initiated between August 2021 and April 2023 in a hospital. The effectiveness variables collected were overall survival (OS) and progression-free survival (PFS). Kaplan-Meier analysis was performed for OS and PFS. The economic variable was the cost of treatment and applicable discounts according to effectiveness, for which OS was categorized into 4 values. The cost per life year gained (LYG) was calculated.

RESULTS: Thirty-five patients (69% male) with a mean age of 62 years (range 44-76) were included. Performance status was ECOG 0 (43%), ECOG 1 (54%), ECOG 2 (3%). 26% of patients had brain metastases at baseline. Twenty-three patients discontinued treatment at the cut-off date, 16 due to progression, 4 due to death, 2 due to adverse events and 1 due to loss to follow-up. The median number of doses administered per patient was 7 (range 1-29). The median PFS was 5.6 months [95%CI 4.8-6.3] and the median OS was 11.0 months [95% CI 6.6-15.3]. Sixteen patients had died at the study cut-off date, 12 with OS of 10 months or less, 2 with 11-13 months, 1 with 14-17 months and 1 with 18 months or more. The estimated OS benefit was 65.5 months. With applicable RSA-EO discounts, the calculated cost per LYG was €27,189 [95% CI: €16,692-€133,535].

CONCLUSIONS: The real-world outcomes of atezolizumab in our population were similar to those reported IMpower133 trial. The cost per LYG applying risk-sharing discounts did not reach the willingness-to-pay threshold in our setting. We considered the therapy to be cost-effective.