J-TAIL-2: A prospective, observational study of atezolizumab (atezo) combined with carboplatin and etoposide (CE) in patients (pts) with extensive-stage small cell lung cancer (ES-SCLC) in Japan.

8092 Background: Atezo + CE is approved for the first-line treatment of ES-SCLC based on IMpower133 (IMp133; NCT02763579). Due to the limited data available in Japanese pts, J-TAIL-2 (NCT04501497) is evaluating the efficacy and safety of atezo + CE in Japanese pts in the clinical setting. Methods: Pts from Japan had ES-SCLC, were aged ≥20 y and were scheduled to start atezo + CE in clinical practice. The primary endpoint was 12-mo OS rate. Secondary endpoints included OS, PFS and safety. Efficacy and safety were evaluated in these subgroups: IMp133-unlike (e.g., ECOG PS 2-4, CNS metastases, history/complication of autoimmune or interstitial lung disease, previous treatment for ES-SCLC) vs IMp133-like (met IMp133 eligibility criteria), age <70 vs ≥70 y and geriatric score (G8) < median vs ≥ median. G8 was assessed in pts aged ≥70 y at baseline, with lower vs higher scores indicating poorer health status. Results: From Aug 21, 2020, to data cutoff (Feb 3, 2023), 403 pts were enrolled from 150 sites. Baseline characteristics are shown in the Table. In the efficacy analysis population (n=399), the 12-mo OS rate was 63.7% (95% CI: 58.6, 68.3), median OS (mOS) was 16.5 mo and mPFS was 5.1 mo. In the IMp133-unlike vs -like groups, mOS was 15.5 vs 19.1 mo (HR, 1.32; 95% CI: 0.98, 1.77) and mPFS was 4.8 vs 5.4 mo (HR, 1.14; 95% CI: 0.90, 1.45). In pts aged <70 vs ≥70 y, mOS was 17.9 vs 16.4 mo (HR, 1.18; 95% CI: 0.90, 1.55) and PFS was 5.1 vs 5.1 mo (HR, 1.07; 95% CI: 0.86, 1.33). The median G8 score was 12; in pts with a G8 score < median vs ≥ median, mOS was 11.1 vs 18.4 mo (HR, 1.95; 95% CI: 1.38, 2.77) and mPFS was 4.8 vs 5.2 mo (HR, 1.25; 95% CI: 0.94, 1.67). In the safety analysis population (n=400), treatment-related AEs occurred in 36.0% of pts, Grade (Gr) ≥3 AEs in 66.3% and Gr 5 AEs in 2.8%. Safety outcomes were similar for the IMp133-unlike vs -like and age <70 vs ≥70 y groups. In pts with a G8 score < median vs ≥ median, Gr ≥3 AEs occurred in 70.8% vs 63.5% of pts and Gr 5 AEs occurred in 5.2% vs 0.8% of pts. Conclusions: The efficacy and safety of atezo + CE in Japanese pts treated in clinical practice were consistent with those seen in IMp133. Subgroup analyses support the use of atezo + CE in pts who would have been ineligible for IMp133, although clinical outcomes favored the IMp133-like group. Efficacy and safety were similar for pts aged <70 vs ≥70 y but were worse for those with lower vs higher G8 scores, suggesting that this assessment may be a useful tool for therapeutic strategies. These data support the use of atezo + CE in Japanese pts with ES-SCLC, including in subgroups excluded from IMp133. Clinical trial information: NCT04501497 . Table: see text