The predictive value of YAP-1 for efficacy of immunotherapy among patients with ES-SCLC.

Abstract

8578 Background: IMpower133 showed benefits in both progression-free survival (PFS) and overall survival (OS) of etoposide/carboplatin plus atezolizumab (ECT) regimen in extensive-stage small-cell lung cancer (ES-SCLC), but the absolute benefit was limited. Previous studies have classified SCLC patients by RNA-seq clustering analysis to explore the dominant population for treatment, but was difficult for clinical application. We aimed to explore whether expressive status of Yes-Associated Protein 1 (YAP-1) can screen dominant population of immunotherapy among ES-SCLC patients. Methods: We selected ES-SCLC patients treated in our hospital from Jan, 2018 to Jul, 2021, and enrolled 21 patients with ES-SCLC received ECT regimen whose formaldehyde-fixed, paraffin-embedded sample was reachable. Assessments of complete remission (CR), partial remission (PR), disease stable (SD) and progressive disease (PD) were according to the efficacy evaluation criteria of solid tumor (RECIST) version 1.1. Immunohistochemistry (IHC) of YAP-1 (ET1608-30, 1/100) was conducted. The H-score was calculated by IHC Profiler. All statistical analyses were evaluated using SPSS 22.0, X-tile 3.6.1, and Excel. P values < 0.05 were considered statistically significant. Results: Baseline information was provided in table. The median H-score of responders (CR/PR patients) and non-responders were 13.97 (95%CI: 8.97-16.30) and 23.72 (95%CI: 8.13-75.40) that were significantly different (P＜0.05). H-score and PFS showed negative correlation by spearman (r = -0.603). Patients were divided into two groups as low expression group (H-score ≤25.00, n = 16) and high expression group (H-score ＞25.00, n = 5) according to the cut-off value of H-score. The median PFS of these two groups were 7.1m (95%CI: 2.6-11.6m) and 3.4m (95%CI: 0.9-5.9m), respectively. K-M curves of PFS were significantly different (P＜0.05). Conclusions: Our preliminary results have indicated a potential efficacy predictive value of YAP-1 protein. And the expression level of YAP-1 protein was negatively correlated with efficacy of ECT in ES-SCLC patients. [Table: see text]