Circulating T-cell Immunosenescence in Patients with Advanced Non-small Cell Lung Cancer Treated with Single-agent PD-1/PD-L1 Inhibitors or Platinum-based Chemotherapy.

Purpose: CD28, CD57, and KLRG1 have been previously identified as markers of T-cell immunosenescence. The impact of immunosenescence on anti-PD(L)-1 (ICI) or platinum-based chemotherapy (PCT) in patients with advanced non-small cell lung cancer (aNSCLC) is unknown.
Experimental Design: The percentage of CD28 ^- , CD57 ⁺ , KLRG1 ⁺ among CD8 ⁺ T cells [senescent immune phenotype (SIP)] was assessed by flow cytometry on blood from patients with aNSCLC before single-agent ICI (discovery cohort). A SIP cut-off was identified by log-rank maximization method and patients with aNSCLC treated with ICI (validation cohort) or PCT were classified accordingly. Proliferation and functional properties of SIP ⁺ CD8 ⁺ T cells were assessed in vitro .
Results: In the ICI discovery cohort ( N = 37), SIP cut-off was 39.5%, 27% of patients were SIP ⁺ . In the ICI validation cohort ( N = 46), SIP ⁺ status was found in 28% of patients and significantly correlated with worse objective response rate (ORR; 0% vs. 30%, P = 0.04), median progression-free survival (PFS) [1.8 (95% confidence interval (CI), 1.3-NR) vs. 6.4 (95% CI, 2-19) months, P = 0.009] and median overall survival, OS [2.8 (95% CI, 2.0-NR) vs. 20.8 (95% CI, 6.0-NR) months, P = 0.02]. SIP ⁺ status was significantly associated with circulating specific immunephenotypes, in vitro lower CD8 ⁺ T cells proliferation, lower IL2 and higher TNFα and IFNγ production. In the ICI-pooled population ( N = 83), SIP ⁺ status did not correlate with any clinical characteristics and it was associated with significantly worse ORR, PFS, and OS. In PCT cohort ( N = 61), 11% of patients were SIP ⁺ . SIP status did not correlate with outcomes upon PCT.
Conclusions: Circulating T-cell immunosenescence is observed in up to 28% of patients with aNSCLC and correlates with lack of benefit from ICI but not from PCT. See related commentary by Salas-Benito et al., p. 374 .
(©2020 American Association for Cancer Research.)