The immune signatures predict gastric/gastroesophageal junction cancer response to first-line anti-PD-1 blockade or chemotherapy
摘要
Anti-programmed cell death-1 (PD-1) immunotherapy and platinum-based chemotherapy are key components of first-line treatment for advanced Gastric or Gastroesophageal Junction (G/GEJ) cancer. However, the role of immune cells infiltrating the tumor microenvironment (TME) in predicting both therapy responses is still unclear.
MethodsORIENT-16 is a randomized, double-blind, placebo-controlled, phase 3 clinical trial, and enrolled 650 patients with unresectable locally advanced or metastatic G/GEJ cancer between January 3, 2019, and August 5, 2020. For patients enrolled from the First Affiliated Hospital of Zhejiang University School of Medicine, we analyzed progression-free survival(PFS) and overall survival (OS) based on PD-L1 expression and landmark analysis, and developed a multiplexed immunofluorescence (mIF) assay for CD4, CD8, PD-L1, CD68 and FoxP3 coupled with digital image analysis and machine learning to assess prognostic survival associations of immune cells.
ResultsA total of 54 eligible patients were enrolled in this study, 35 received sintilimab plus platinum-based chemotherapy and 19 received placebo plus platinum-based chemotherapy. For patients with PD-L1 combined positive score (CPS) < 10, survival disparities between anti-PD-1 immunotherapy and chemotherapy emerged 300 days post-treatment. High PD-L1 expression correlated with longer survival in anti-PD-1 therapy but less benefit in platinum-based chemotherapy. The mIF analysis also demonstrated significantly higher stromal PD-L1 density in immunotherapy responders, but tended to be lower in chemotherapy responders. Besides, high tumor stromal CD8 expression could be used as a positive biomarker in anti-PD-1 immunotherapy, and high tumor stromal CD4 expression was found associated with worse prognosis in platinum-based chemotherapy.
ConclusionsIncreased PD-L1 expression was associated with an increased effect on anti-PD-1 immunotherapy and reduced benefit from chemotherapy. The signature of TME immune cells has the potential to predict the response of anti-PD-1 immunotherapy and chemotherapy in G/GEJ cancer.
Trial registrationClinicalTrials.gov Identifier: NCT03745170.