Clinical implications of neutrophil-to-lymphocyte ratio and MDSC kinetics in gastric cancer patients treated with ramucirumab plus paclitaxel

Objective: We aimed to investigate the prognostic value of neutrophil-to-lymphocyte ratio(NLR) and myeloidderived suppressor cells(MDSCs) in gastric cancer patients treated with second-line ramucirumab plus paclitaxel.Methods: A total of 116 patients with advanced or metastatic gastric cancer who receive ramucirumab plus paclitaxel were prospectively enrolled. Fresh blood samples were collected before and after treatment, and flow cytometry was performed to assess the proportions of monocytic(m MDSCs) and granulocytic MDSCs(g MDSCs).Results: Median age was 58 years and 71(61.2%) patients were male. A baseline NLR≥2.94 was associated with significantly poorer progression-free survival(PFS) and overall survival(OS) vs. an NLR<2.94(P=0.011 and P=0.002, respectively). In multivariate analysis, an NLR≥2.94 was independently associated with poorer PFS[hazard ratio(HR)=1.58;95% confidence interval(95% CI): 1.01-2.49, P=0.046] and OS(HR=1.77;95% CI:1.04-3.04, P=0.036). While m MDSC counts did not significantly change following two cycles of therapy(P=0.530),g MDSC counts decreased significantly after two treatment cycles(P=0.025) but tended to increase in patients with progressive disease after two treatment cycles(P=0.098). A progressive increase in g MDSC counts(≥44%) was associated with a significantly shorter PFS and OS vs. a g MDSC count increase <44%(P=0.001 and P=0.003,respectively).Conclusions: The baseline NLR may help guide clinical decisions during ramucirumab plus paclitaxel therapy for gastric cancer. Our g MDSC kinetics data warrant further clinical validation and mechanistic investigation.

PD-1 blockade-unresponsive human tumor-infiltrating CD8^(+)T cells are marked by loss of CD28 expression and rescued by IL-15

Blockade of programmed death-1(PD-1)reinvigorates exhausted CD8^(+)T cells,resulting in tumor regression in cancer patients.Recently,reinvigoration of exhausted CD8^(+)T cells following PD-1 blockade was shown to be CD28-dependent in mouse models.Herein,we examined the role of CD28 in anti-PD-1 antibody-induced human T cell reinvigoration using tumor-infiltrating CD8^(+)T cells(CD8^(+)TILs)obtained from non-small-cell lung cancer patients.Single-cell analysis demonstrated a distinct expression pattern of CD28 between mouse and human CD8^(+)TILs.Furthermore,we found that human CD28^(+)CD8^(+)but not CD28^(–)CD8^(+)TILs responded to PD-1 blockade irrespective of B7/CD28 blockade,indicating that CD28 costimulation in human CD8^(+)TILs is dispensable for PD-1 blockade-induced reinvigoration and that loss of CD28 expression serves as a marker of anti-PD-1 antibody-unresponsive CD8^(+)TILs.Transcriptionally and phenotypically,PD-1 blockade-unresponsive human CD28^(–)PD-1^(+)CD8^(+)TILs exhibited characteristics of terminally exhausted CD8^(+)T cells with low TCF1 expression.Notably,CD28^(–)PD-1^(+)CD8^(+)TILs had preserved machinery to respond to IL-15,and IL-15 treatment enhanced the proliferation of CD28^(–)PD-1^(+)CD8^(+)TILs as well as CD28^(+)PD-1^(+)CD8^(+)TILs.Taken together,these results show that loss of CD28 expression is a marker of PD-1 blockade-unresponsive human CD8^(+)TILs with a TCF1–signature and provide mechanistic insights into combining IL-15 with anti-PD-1 antibodies.