Comparison of Real-World Efficacy and Safety of Atezolizumab and Durvalumab in Combination with Chemotherapy for First-Line Treatment of Extensive-Stage Small-Cell Lung Cancer

Purpose: The combination of programmed cell death ligand 1 inhibitors and platinum-based chemotherapy has become the standard treatment for first-line therapy in extensive-stage small-cell lung cancer (ES-SCLC). This study compared the efficacy and safety of atezolizumab plus chemotherapy and durvalumab plus chemotherapy in the treatment of ES-SCLC in clinical practice. Methods: We retrospectively analyzed 40 patients with ES-SCLC treated with atezolizumab plus chemotherapy or durvalumab plus platinum-based chemotherapy at our hospital between October 2019 and November 2022. Results: Among the 40 patients, 20 were treated with atezolizumab and 20 were treated with durvalumab. There was no significant difference in patient characteristics between the two groups; five patients who received atezolizumab and one who received durvalumab showed a performance status of 2 or higher. The median progression-free survival of the patients who received atezolizumab or durvalumab was 5.6 and 5.4 months, respectively (p=0.881). The median overall survival of the patients who received atezolizumab or durvalumab was 10.0 and 17.1 months, respectively (p=0.163). The objective response rate of the patients who received atezolizumab or durvalumab was 80.0% and 85.0%, respectively. There was no significant difference in the incidence of immune-related adverse events between the groups. Conclusion: This retrospective study was the first to compare the efficacy and safety of PD-L1 antibody, atezolizumab or durvalumab, in combination with carboplatin and etoposide in treatment-naïve ES-SCLC Japanese patients in a real-world setting. Both regimens, atezolizumab or durvalumab with carboplatin and etoposide, were effective and well-tolerated in Japanese ES-SCLC patients, aligning with clinical trial findings.