Real-world effectiveness of lurbinectedin in extensive stage small cell lung cancer (ES-SCLC).

e20133 Background: Small cell lung cancer (SCLC) is an aggressive subtype of lung cancer that usually presents with disseminated disease and relapses within months despite treatment. Patients who relapse or become platinum chemotherapy resistant, have very poor outcomes. Until 2020, topotecan was the only second-line approved treatment for SCLC, when in a single-arm phase 2 study for patients with SCLC, Lurbinectedin was found to improve overall response. Before the recent approval of Tarlatamab-dlle, National Comprehensive Cancer Network (NCCN) guidelines recommended Lurbinectedin for subsequent systemic therapy if the chemotherapy free interval is less than or equal to 6 months with the only other options being topotecan and irinotecan. However, the real-world efficacy data is lacking. Methods: This was a retrospective study where data from 256 patients treated at Allegheny Health Network was collected from clinical and claims records of Highmark Health. These adult patients had a diagnosis of extensive stage (ES) SCLC and had received lurbinectedin for disease progression between January 1, 2020 and November 30, 2024. The primary objective of this study was to determine the effectiveness of lurbinectedin in ES-SCLC by assessing overall survival (OS) and time to treatment discontinuation (TTD). Univariate and multivariate regression models were used to analyze predictors of response to lurbinectedin, t-test was used to compare means and chi-square test was used to compare percentages. Results: We identified 256 patients that were diagnosed with ES-SCLC and received lurbinectedin for disease progression after platinum-based chemotherapy. The median age was 64 years (IQR 61-71). 19% of patients received at least 1 dose of lurbinectedin and 45% of patients received 2-4 doses. Average length of treatment was 63 days (IQR 0-792). Median time to treatment discontinuation was 91.7 days (3.01 mo). OS rate was 68.3% [0.683 , 95% CI 0.681-0.685] at 1 year, 51.4% [0.514, 95% CI 0.511 - 0.517] at 2 years and 37.4% [0.374, 95% CI 0.371-0.377] at 3 years. Conclusions: In our real-world analysis, lurbinectedin demonstrated good activity as a single agent in the second line treatment of ES-SCLC with an OS rate of 68.3% at 1 year and 37.4% at 3 years. If the median TTD can be considered a potential surrogate for progression free survival (PFS), then we would have a PFS of 3 months which is slightly shorter in our cohort compared to 3.5 months reported by Trigo et al in their original paper. Retrospective nature of the study and lack of control group, however, limit the predictor variables.