Background: The standard treatment for patients with unresectable locally advanced esophageal squamous cell carcinoma (ESCC) is definitive chemoradiotherapy (CRT) using 5-FU plus cisplatin. However, complete response (CR) rates are low at 11–25%, resulting in 9–10 months of median overall survival (OS). An improved therapeutic efficacy by combining immunotherapy with radiation has been reported in patients with locally advanced non-small cell lung cancer. The results using ESCC cell lines suggest sequential treatment with anti-PD-L1 agents soon after completion of CRT is the most effective combination. Methods: TENERGY trial is a multicenter, phase II, proof-of-concept study to assess the efficacy and safety of atezolizumab following definitive CRT in patients with locally advanced ESCC. The main inclusion criteria are unresectable locally advanced ESCC without distant metastasis, completion of 60 Gy of radiation plus two concomitant cycles of chemotherapy (cisplatin 70 mg/m² on day 1 and 5-FU 700 mg/m² on days 1–4, every 28 days), and adequate organ function. Within 6 weeks after CRT, participants will start taking 1200 mg of atezolizumab every three weeks and continue until 12 months or disease progression. The primary endpoint is the confirmed CR rate by the investigator’s assessment. Secondary endpoints include overall response rate, progression-free survival (PFS), OS, adverse events, and confirmed CR rate by central assessment. We will enroll 50 patients (40 with primary locally advanced ESCC and 10 with postoperative locoregionally recurrent ESCC). We will obtain biopsies from the primary site and will collect blood at 3 time points (before CRT, after CRT, and four weeks after the start of atezolizumab) for an exploratory biomarker study. We will analyze the phenotype of immune-competent cells, neoantigens, tumor mutational burden, PD-L1 status, and Human Leukocyte Antigen haplotyping. Discussion: The synergistic efficacies of the sequential combination of CRT and atezolizumab should improve the CR rate, resulting in survival improvement for patients with unresectable locally advanced ESCC. Because CRT is a standard treatment option for patients with early stage to locally advanced ESCC, the sequential combination of CRT and atezolizumab has the potential to change the standard ESCC treatments. Trial registration: UMIN000034373, 10/04/2018 and EPOC1802.

Radiotherapy (RT) combined with immunotherapy is promising; however, the immune response signature in the clinical setting after RT remains unclear. Here, by integrative spatial and single-cell analyses using multiplex immunostaining (CODEX), spatial transcriptome (VISIUM), and single-cell RNA sequencing, we substantiated the infiltration of immune cells into tumors with dynamic changes in immunostimulatory and immunosuppressive gene expression after RT. In addition, our comprehensive analysis uncovered time- and cell type–dependent alterations in the gene expression profile after RT. Furthermore, myeloid cells showed prominent up-regulation of immune response–associated genes after RT. Notably, a subset of infiltrating tumor-associated myeloid cells showing PD-L1 positivity exhibited significant up-regulation of immunostimulatory (HMGB1 and ISG15), immunosuppressive (SIRPA and IDO1), and protumor genes (CXCL8, CCL3, IL-6, and IL-1AB), which can be targets of immunotherapy in combination with PD-L1. These datasets will provide information on the RT-induced gene signature to seek an appropriate target for personalized immunotherapy combined with RT and guide the timing of combination therapy.

Radiotherapy (RT) plus immunotherapy is a promising modality; however, the therapeutic effects are insufficient, and the molecular mechanism requires clarification to further develop combination therapies. Here, we found that the RNA virus sensor pathway dominantly regulates the cellular immune response in NSCLC and ESCC cell lines. Notably, transposable elements (TEs), especially long terminal repeats (LTRs), functioned as key ligands for the RNA virus sensor RIG-I, and the mTOR–LTR–RIG-I axis induced the cellular immune response and dendritic cell and macrophage infiltration after irradiation. Moreover, RIG-I-dependent immune activation was observed in ESCC patient tissue. scRNA sequencing and spatial transcriptome analysis revealed that radiotherapy induced the expression of LTRs, and the RNA virus sensor pathway in immune and cancer cells; this pathway was also found to mediate tumour conversion to an immunological hot state. Here, we report the upstream and ligand of the RNA virus sensor pathway functions in irradiated cancer tissues.

Radiotherapy (RT) is an effective treatment option for cancer; however, its efficacy remains less than optimal in locally advanced cancer. Immune checkpoint inhibitor-based therapy, including the administration of anti-PD-L1 antibodies, is a promising approach that works synergistically with RT. Proton beam therapy and carbon-ion therapy are common options for patients with cancer. Proton and carbon ions are reported to induce an immune reaction in cancer cells; however, the underlying mechanisms remain unclear. Here, we aimed to compare the immune responses after irradiation (IR) with X-ray, protons, and carbon ions in an oesophageal cancer cell line and the underlying mechanisms. An oesophageal cancer cell line, KYSE450, was irradiated with 1 fraction/15 GyE (Gy equivalent) of X-ray, proton, or carbon-ion beams, and then, the cells were harvested for RNA sequencing and gene enrichment analysis. We also knocked out STING and STAT1 in the quest for mechanistic insights. RNA sequencing data revealed that gene expression signatures and biological processes were different in KYSE450 irradiated with X-ray, proton, and carbon-ion beams 6-24 h after IR. However, after 3 days, a common gene expression signature was detected, associated with biological pathways involved in innate immune responses. Gene knock-out experiments revealed that the STING-STAT1 axis underlies the immune reactions after IR. X-Ray, proton, and carbon-ion IRs induced similar immune responses, regulated by the STING-STAT1 axis.

Platinum-based definitive chemoradiotherapy (dCRT) is the standard treatment for patients with unresectable locally advanced esophageal squamous cell carcinoma (ESCC) that invades the aorta, vertebral body or trachea; however, complete response rates remain low (11–25%), leading to poor survival. To evaluate the additive efficacy of the anti-PD-L1 antibody drug atezolizumab, we conducted a phase 2, multicenter, single-arm trial of 1 year of atezolizumab treatment following dCRT in 40 patients with unresectable locally advanced ESCC recruited from seven Japanese centers (UMIN000034373). The confirmed complete response (cCR) rate (primary end point) of the first consecutive 38 patients was 42.1% (90% CI 28.5–56.7%). Regarding the secondary end points, the median progression-free survival and 12-month progression-free survival rates of all 40 patients were 3.2 months and 29.6%, respectively, and the preliminary median overall survival with short-term follow-up and 12-month overall survival rate were 31.0 months and 65.8%, respectively. Other secondary end points evaluated included the cCR rate determined by an investigator’s assessment in the locoregionally recurrent ESCC cohort, cCR rate determined by central assessment, overall response rate and incidence of adverse events. No treatment-related death occurred during the study. Atezolizumab monotherapy after dCRT resulted in a promising cCR rate, although long-term survival data are required.