Real-world treatment patterns and survival outcomes in extensive-stage small cell lung cancer across first-line induction and maintenance therapy

BACKGROUND: Platinum-etoposide (PE) chemotherapy combined with a PD-L1 inhibitor is the current first-line (1 L) standard of care for extensive-stage small cell lung cancer (ES-SCLC). Real-world evidence describing outcomes across induction and maintenance phases remains limited. PATIENTS AND METHODS: This descriptive retrospective observational study used the US-based, electronic health record-derived deidentified Flatiron Health Research Database (January 2013-December 2024). Adults with pathologically confirmed ES-SCLC at initial diagnosis initiating 1 L therapy were included. Patients were categorized by 1 L regimen: PE plus a PD-L1 inhibitor (chemo-immunotherapy), PE alone, or other regimens. Maintenance was defined as at least two consecutive doses of post-induction PD-L1 inhibitor monotherapy. Real-world overall survival (rwOS) and progression-free survival (rwPFS) were estimated using the Kaplan-Meier method. RESULTS: Among 5,863 1 L patients, 2,157 (36.8%) received chemo-immunotherapy, of whom ∼60% (1,284/2,157) received maintenance (atezolizumab, 85.7%; durvalumab 14.3%); 3,376 (57.6%) received PE, and 330 (5.6%) other regimens. Median rwOS and rwPFS from 1 L initiation were 8.1 months (95% CI, 8.0-8.3) and 5.1 months (95% CI, 5.0-5.2), respectively. From 1 L initiation, patients who subsequently met the maintenance definition had median rwOS of 12.2 months. From maintenance initiation, median rwOS was 8.7 months (95% CI, 8.0-9.8) with atezolizumab and 9.3 months (95% CI, 8.0-11.5) with durvalumab. CONCLUSION: In this large US real-world cohort, survival outcomes in 1 L ES-SCLC patients were poor and appeared broadly comparable between atezolizumab and durvalumab. Only ∼60% of patients receiving chemo-immunotherapy subsequently received maintenance in routine clinical practice, underscoring substantial attrition before maintenance initiation.