CD4+ T-cell immunity predicts long-lasting antitumor immunity after PD-1 blockade therapy.

Abstract

2545 Background: Patients treated with programmed cell death 1 (PD-1)-blockade therapy fall into 3 distinct subgroups: non-responders presenting early disease progression, long survivors who achieve durable disease control, and the remaining short-term responders. We reported that the prediction formula comprised of the percentages of CD62L-downregulated (CD62Llow) and CD25+FOXP3+CD4+T cells in the peripheral blood predicted non-responders of non-small cell lung cancer patients (n = 50) scheduled to receive anti-PD-1-antibody (nivolumab) therapy in the 2017 ASCO meeting. In this study, we included 171 patients with NSCLC who were scheduled for nivolumab treatment after obtaining written informed consent. Peripheral blood mononuclear cells (PBMC) were examined before and after Nivolumab therapy up to 2 years to investigate the differences between long survivors and short-term responders. Methods: The patients received Nivolumab at a dose of 3 mg per kilogram of body weight every 2 weeks. Tumor response was assessed with the use of the Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1, at week 8 and every 8 weeks thereafter. PBMCs were analyzed with a 18-color microfluorometer, LSR Fortessa and a masscytometer, CyTOF. Results: The responder-type patient group whose prediction formula values were greater than 192 showed significantly longer PFS ( P< 0.0001) and OS ( P< 0.0001). The long survivors who consisted of tail plateau of PFS exhibited significantly more CD62LlowCD4+T cells than the short-term responders as pre-existing immunity. The remaining responders kept significantly higher percentages of CD62LlowCD4+T cells ( P= 0.0088) and prediction formula values ( P= 0.017) than the patients with acquired resistance. Conclusions: The pre-existing CD4+T cell balance between primed effector and regulatory T cells correlated with anti-PD-1 therapy response. Further, CD62Llowcell-dominant CD4+T cell immunity was required to maintain durable antitumor reactivity induced by anti-PD-1 antibody therapy. These results have important clinical implication, as they support anti-PD-1 therapy provision to all potentially responding patients and pave the way for new treatment strategies for patients with distinct CD4+T cell immune statuses. Clinical trial information: UMIN000020719.