Early Change In Peripheral Blood Cd4+T Cells Associated With The Clinical Outcome In Gastrointestinal Cancer Patients Receiving Immune Checkpoint Inhibitors

Purpose: Predictive biomarkers for immune checkpoint inhibitors (ICIs) are urgently needed in advanced gastrointestinal (GI) carcinoma. Methods: Peripheral blood lymphocyte, lymphocyte subset and early dynamic changes of them were retrospectively analyzed in patients with GI cancer treated with ICIs. Cox regression and Kaplan-Meier analyses were conducted to analyze survival. Results: Eighty patients were enrolled. According to whether tumor progression occurred by 6 months after the initial ICI, patients were divided into two cohorts, 6m-progressive disease (PD) (N=40) and 6m-non-PD (nPD) (N=40).BaselineCD4+/CD8+ T cell (CD4/CD8) ratio was higher in the 6m-nPD cohort than in the 6m-PD cohort. Lymphocyte subsets were obtained both at baseline and before the second dose of ICIs in 61 patients. In total, 54.1% (33/61) of patients experienced tumor progression within 6 months of the initial ICI treatment, and these patients showed significant declines in CD4+ T cell counts (CD4-C1-decline) (p=0.0002) and the CD8+ T cell counts (CD8-C1-decline) (p=0.045) after the first dose of ICIs. In multivariate analyses, CD4-C1-decline (HR=12.66; 95% CI: 2.17-73.91; p=0.005) was an independent prognostic factor for OS. Furthermore, Stratified analyses indicated that CD4-C1-decline was a poor prognostic factor for tumor progression in patients with a deficient mismatch repair (dMMR)/microsatellite instability-high (MSI-H). Conclusion: Early change in CD4+ T cell counts in peripheral blood samples may help as prognostic biomarkers for GI cancer patients treated with ICIs. Further prospective studies are needed to validate this conclusion. Citation Format: Zhi-Hao Lu, Chang Liu, Yan-ni Wang, Shuang Li, Xi Jiao, Jian-ling Zou, Zheng-hang Wang, Chang-song Qi, Xiao-tian Zhang, Jian Li, Lin Shen. Early change in peripheral blood CD4+T cells associated with the clinical outcome in gastrointestinal cancer patients receiving immune checkpoint inhibitors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3162.