Abstract

8087 Background: Chemo-immunotherapy is the standard 1st-line therapy for patients with extensive-stage small-cell lung cancer (ES-SCLC). Our large previous real-world prospective analysis showed outcomes of chemo-immunotherapy for these patients according to potential clinical trial eligibility with a minimum follow-up period of 1 year. However, long-term outcomes have not been studied in the real-world setting. Methods: We conducted a 32-hospital prospective cohort study of consecutive patients with ES-SCLC who received carboplatin and etoposide with atezolizumab as 1st-line therapy between September 2019 and September 2020. Patients who met eligibility criteria for pivotal phase 3 clinical trials were considered “trial-eligible.” We present 3-year outcomes from this study. Results: In total, 207 patients with ES-SCLC were analyzed. The median (range) time from the start of treatment to data cutoff (September 30, 2023) was 42.2 (35.8.-48.2) months. The median age was 72 years, and 64 patients (31%) were elderly (≥75 years). Most patients (89%) had a performance status (PS) of 0 or 1. As a result, 132 (64%) were categorized as trial-eligible patients. The 3-year PFS and OS probability of all patients was 6.1 % (95%CI:3.5-10.4%) and 20.9 % (95%CI:15.6-27.3%), respectively. Patients achieving 3-year OS included significantly higher proportions of trial-eligible patients (30 out of 132 versus 5 out of 75, respectively; p = 0.002). Kaplan-Meier estimates of the 3-year OS rate were 26.7% for the trial-eligible group and 9.5 % for the trial-ineligible group. Conclusions: This is the first real-world study to show the long-term efficacy of chemo-immunotherapy for ES-SCLC by using the largest prospective cohort of its kind. Additionally, this study demonstrated that trial eligibility was associated with long-term efficacy. Our study suggests that long-term clinical outcomes among trial-eligible patients may not translate to ineligible patients.