Costa, Andressa Dias

Observational studies have demonstrated that aspirin and/or PTSG2 inhibitor (e.g., celecoxib) use, before or after colon cancer (CC) diagnosis, is associated with a lower risk of recurrence. However, a randomized trial of adjuvant celecoxib therapy in stage III CC did not show improved survival compared to placebo treatment. We therefore hypothesized that immune microenvironment features may identify patient subgroups with stronger survival benefits from anti-inflammatory celecoxib treatment. Drawing from an NCI-Intergroup trial (Cancer and Leukemia Group B [now Alliance for Clinical Trials in Oncology]/SWOG 80702) for patients with stage III resected CC that compared 3 versus 6 months of adjuvant fluorouracil, leucovorin, and oxaliplatin ± 3 years of celecoxib, we conducted tissue-based tumor microenvironment profiling on 1,098 resected tumors using a custom 9-plex, T-cell multiplex immunofluorescence assay coupled with digital image analysis and supervised machine learning. The Kaplan-Meier method was used to describe disease-free survival, based on T cell density, and log-rank testing was performed. Cox proportional hazards models were used to examine unadjusted and adjusted associations between T cell density and disease-free survival (DFS). Two-sided P values ≤0.05 were considered statistically significant. We found that higher CD3+ T cell density was associated with longer DFS with an adjusted hazard ratio (HR) of 0.69 (95% confidence interval [CI] 0.52-0.91) for patients with densities in the highest tertile as compared the lowest tertile (P=0.01). T cell subset analysis showed that stromal regulatory T helper cells (HR 0.42 comparing highest to lowest tertile, CI 0.31-0.58, P<0.001) and stromal memory cytotoxic T cells (HR 0.55 comparing highest to lowest tertile, CI 0.42-0.74, P<0.001) were most strongly associated with longer DFS. Compared to the placebo group, adjuvant celecoxib use associated with improved DFS for patients with low but not high stromal CD3+ T cell density (adjusted HRs of 0.45 [CI 0.31-0.65] for lowest tertile and 1.13 [CI 0.73-1.74] for highest tertile; Pinteraction=0.01). This association was also seen when the analysis was restricted to microsatellite stable tumors (HR 0.50 [CI 0.32-0.80] for lowest density tertile and 1.50 [CI 0.87-2.59] for highest density tertile; Pinteraction=0.01). T cell subset analysis showed that DFS benefit for celecoxib use most strongly associated with stromal memory helper T cell density (HR 0.38 [CI 0.26-0.56] for lowest density tertile and 1.26 [CI 0.80-1.97] for highest density tertile; Pinteraction<0.001). Together, these results show that while higher T cell infiltration is associated with improved DFS, lower T cell infiltration is associated with improved DFS for patients treated with celecoxib. This unexpected finding may inform immunomodulatory treatment strategies for CC. Citation Format: Yasutoshi Takashima, Chao Ma, Qian Shi, Andressa Dias Costa, Tyler Twombly, Juha P. Väyrynen, Melissa Zhao, Ardaman Shergill, Pankaj Kumar, Felix Couture, Philip Kuebler, Smitha Krishnamurthi, Benjamin Tan, Eileen M. O'Reilly, Anthony F. Shields, Shuji Ogino, Charles S. Fuchs, Jeffrey A. Meyerhardt, Jonathan A. Nowak. Prognostic and predictive role of T cell infiltration in stage III colon cancer (CC) treated with celecoxib: CALGB/SWOG 80702 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5858.

Background Pancreatic ductal adenocarcinoma (PDAC) is a challenging target for immunotherapy because it has an immunosuppressive tumor microenvironment. Neoadjuvant chemoradiotherapy can increase tumor-infiltrating lymphocyte (TIL) density, which may predict overall survival (OS). We hypothesized that adding programmed cell death protein 1 (PD-1) blockade to chemoradiotherapy would be well tolerated and increase TILs among patients with localized PDAC. Methods Patients were randomized 2:1 to Arm A (receiving pembrolizumab plus chemoradiotherapy (capecitabine and external beam radiation)) or Arm B (receiving chemoradiotherapy alone) before anticipated pancreatectomy. Primary endpoints were (1) incidence and severity of adverse events during neoadjuvant therapy and (2) density of TILs in resected tumor specimens. TIL density was assessed using multiplexed immunofluorescence histologic examination. Results Thirty-seven patients were randomized to Arms A (n=24) and B (n=13). Grade ≥3 adverse events related to neoadjuvant treatment were experienced by 9 (38%) and 4 (31%) patients in Arms A and B, respectively, with one patient experiencing dose-limiting toxicity in Arm A. Seventeen (71%) and 7 (54%) patients in Arms A and B, respectively, underwent pancreatectomy. Median CD8+ T-cell densities in Arms A and B were 67.4 (IQR: 39.2–141.8) and 37.9 (IQR: 22.9–173.4) cells/mm2, respectively. Arms showed no noticeable differences in density of CD8+Ki67+, CD4+, or CD4+FOXP3+ regulatory T cells; M1-like and M2-like macrophages; or granulocytes. Median OS durations were 27.8 (95% CI: 17.1 to NR) and 24.3 (95% CI: 12.6 to NR) months for Arms A and B, respectively. Conclusions Adding pembrolizumab to neoadjuvant chemoradiotherapy was safe. However, no convincing effect on CD8+ TILs was observed.

Abstract Purpose: Pancreatic ductal adenocarcinoma (PDAC) trials have evaluated CTLA-4 and/or PD-(L)1 blockade in patients with advanced disease in which bulky tumor burden and limited time to develop antitumor T cells may have contributed to poor clinical efficacy. Here, we evaluated peripheral blood and tumor T cells from patients with PDAC receiving neoadjuvant chemoradiation plus anti–PD-1 (pembrolizumab) versus chemoradiation alone. We analyzed whether PD-1 blockade successfully reactivated T cells in the blood and/or tumor to determine whether lack of clinical benefit could be explained by lack of reactivated T cells versus other factors. Experimental Design: We used single-cell transcriptional profiling and TCR clonotype tracking to identify TCR clonotypes from blood that match clonotypes in the tumor. Results: PD-1 blockade increases the flux of TCR clonotypes entering cell cycle and induces an IFNγ signature like that seen in patients with other GI malignancies who respond to PD-1 blockade. However, these reactivated T cells have a robust signature of NF-κB signaling not seen in cases of PD-1 antibody response. Among paired samples between blood and tumor, several of the newly cycling clonotypes matched activated T-cell clonotypes observed in the tumor. Conclusions: Cytotoxic T cells in the blood of patients with PDAC remain sensitive to reinvigoration by PD-1 blockade, and some have tumor-recognizing potential. Although these T cells proliferate and have a signature of IFN exposure, they also upregulate NF-κB signaling, which potentially counteracts the beneficial effects of anti–PD-1 reinvigoration and marks these T cells as non-productive contributors to antitumor immunity. See related commentary by Lander and DeNardo, p. 474