Natural history of SCLC patients treated in third-line and beyond: A retrospective real world study

Objectives: To describe treatment patterns and estimate outcomes among real-world small cell lung cancer (SCLC) patients in the US who received three or more lines of therapy. Materials and methods: We conducted a retrospective analysis of adult patients with SCLC who received a front-line platinum-based regimen and two additional lines of therapy (ie., a cohort of at least three lines of therapy). De-identified patients were selected from a United States Flatiron Health oncology database of electronic health records. Treatment patterns were captured by line of therapy. Outcomes evaluated by line of therapy included real-world overall survival (rwOS), real-world progression free survival (rwPFS), real-world response rate (rwRR) and real-world duration of response (rwDOR). Results: The analysis included 326 3L SCLC patients, of which 103 (32 %) received 4L treatment, and 38 % (39/103) of 4L treated received 5L of therapy. Among the 3L cohort, the average age was 67 years, 49 % were male, and nearly all had a history of smoking (96 %). In the 3L setting, the median rwOS was 5.3 months (95 % Confidence Interval (CI): 4.5, 6.0), median rwPFS was 2.5 months (95 % CI: 2.1, 2.7), rwRR was 19.3 % (95 % CI: 15.2, 24.0) and median DOR was 3.4 months (95 % CI: 2.8, 4.4). No differences were seen in outcomes between the overall cohort and a subgroup of patients treated with front-line platinum-based regimen with an anti-programmed cell death ligand 1 (PD-L1) agent (atezolizumab or durvalumab), in each respective line of therapy. Conclusion: Results from this large, real-world study of US patients with SCLC in the 3L setting and beyond highlight the poor treatment outcomes in advanced SCLC patients with existing therapies and underscore the dire need for new therapies for SCLC patients.