Multicenter phase II trial of atezolizumab plus carboplatin and etoposide for extensive-stage small cell lung cancer older patients who underwent geriatric assessment (OLCSG2002 EPAS Trial).

8099 Background: Combination therapy with anti-PD-L1 monoclonal antibodies and chemotherapy (ICI-chemotherapy) is the current standard treatment for patients(pts) with extensive-stage small cell lung cancer (ES-SCLC). However, its safety and efficacy in older pts (≥ 71 years) remain limited. Given the pivotal role of geriatric assessment (GA) in the older care, prospective data remain scarce. This study aimed to clarify the efficacy and safety of ICI-chemotherapy in older pts and to evaluate the association between GA and survival. Methods: This multicenter prospective study enrolled pts ≥ 71 years with ES-SCLC who received atezolizumab plus carboplatin and etoposide as first-line therapy. The primary endpoint was 1-year survival rate (SR). Based on existing results, the expected value was 60%, the threshold was 40% (α-error = 0.1 two-sided, power = 0.75). The calculated sample size was 32 pts. A pre-treatment G8 assessment was mandatory for all pts. Secondary endpoints included safety, objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). Results: Between August 2022 and March 2024, a total of 32 pts were enrolled: median age 77 years (range 71–83); male/female = 27/5; PS 0/1 = 8/24, G8 scores ≥12 /＜12 /not collected were 19/12/1. The 1-year SR was 62.5% (95% confidence interval CI: 43.5–76.7). Median OS was 14.6 months (95% CI: 8.2–23.3), median PFS was 5.0 months (95% CI; 4.2–5.9), and ORR was 84.4% (95% CI; 66.3–93.7). Median OS by G8 (score ≥12 vs < 12) was 15.4 vs 12.3 months. Cox regression analysis including clinically important factors for survival (age, PS, G8, bone and brain metastasis at diagnosis) identified brain (HR; 3.1, 95% CI: 1.06 to 8.87; p = 0.039) and bone metastases (HR 3.5, 95% CI: 1.20 to 10.1; p = 0.022) as an independent factor. grade ≥ 3 adverse events (AEs) occurred in 87.5% of pts, and dose reduction was required in 45.1%. The most frequent AE was neutropenia (93.8%); one treatment-related death (stroke) was reported. Conclusions: ICI-combined chemotherapy demonstrated efficacy comparable to that in existing studies, but greater caution was required regarding safety in older pts. While G8 status did not affect survival in SCLC pts, the presence of bone or brain metastasis at diagnosis was identified as an independent prognostic factor. Clinical trial information: jRCT1061200024.