Analysis Of Tumor-infiltrating Lymphocytes Research Articles

Artificial Intelligence-Powered Spatial Analysis of Tumor-Infiltrating Lymphocytes as a Potential Biomarker for Immune Checkpoint Inhibitors in Patients with Biliary Tract Cancer.

Recently, anti-programmed cell death-1/anti-programmed cell death ligand-1 (anti-PD1/L1) immunotherapy has been demonstrated for its efficacy when combined with cytotoxic chemotherapy in randomized phase 3 trials for advanced biliary tract cancer (BTC). However, no biomarker predictive of benefit has been established for anti-PD1/L1 in BTC. Here, we evaluated tumor-infiltrating lymphocytes (TIL) using artificial intelligence-powered immune phenotype (AI-IP) analysis in advanced BTC treated with anti-PD1. Pretreatment hematoxylin and eosin (H&E)-stained whole-slide images from 339 patients with advanced BTC who received anti-PD1 as second-line treatment or beyond, were employed for AI-IP analysis and correlative analysis between AI-IP and efficacy outcomes with anti-PD1. Next, data and images of the BTC cohort from The Cancer Genome Atlas (TCGA) were additionally analyzed to evaluate the transcriptomic and mutational characteristics of various AI-IP in BTC. Overall, AI-IP were classified as inflamed [high intratumoral TIL (iTIL)] in 40 patients (11.8%), immune-excluded (low iTIL and high stromal TIL) in 167 patients (49.3%), and immune-desert (low TIL overall) in 132 patients (38.9%). The inflamed IP group showed a substantially higher overall response rate compared with the noninflamed IP groups (27.5% vs. 7.7%, P < 0.001). Median overall survival and progression-free survival were significantly longer in the inflamed IP group than in the noninflamed IP group (OS, 12.6 vs. 5.1 months; P = 0.002; PFS, 4.5 vs. 1.9 months; P < 0.001). In the TCGA cohort analysis, the inflamed IP showed increased cytolytic activity scores and IFNγ signature compared with the noninflamed IP. AI-IP based on spatial TIL analysis was effective in predicting the efficacy outcomes in patients with BTC treated with anti-PD1 therapy. Further validation is necessary in the context of anti-PD1/L1 plus gemcitabine-cisplatin.

Association between stromal tumor-infiltrating lymphocytes (TILs) and pathologic complete response (pCR) in patients with early breast cancer (BC) treated with neoadjuvant chemotherapy and HER2-directed therapies in NSABP B-41.

3017 Background: In the phase 3 NSABP B-41 trial, there was an association between pCR and survival in 519 women with early HER2-positive BC treated with neoadjuvant chemotherapy in combination with trastuzumab (T), lapatinib (L), or both (TL). There is a need to identify prognostic biomarkers to tailor patients’ treatment, and the quantification of stromal TILs represents a promising, accessible, and reproducible option. In this analysis, we studied the association between TILs and pCR. Methods: Eligible patients had a baseline core biopsy sample, known pCR status, and no consent withdrawal for the use of specimens. Slides were scanned using an Aperio GT 450 automated scanner to create whole slide images. TIL analysis was then completed based on the international TIL working group guidelines (RS). Patients were grouped into three TIL score categories based on tumor TIL %: low (1-5%), intermediate (6-30%), and high (31-95%). The dose-response relationship between TIL percentage and pCR was explored via generalized linear models with splines. Results: 257 patients were included. 89 (35%) received T, 92 (36%) L, and 76 (29%) TL. 149 (58%) had ER-positive BC. TIL categories in this cohort: 49% low, 22% intermediate, and 29% high. TIL expression was similar across BC intrinsic subtypes and by ER. There was no association between the TIL group and pCR, irrespective of the treatment group (p=0.98). Among tumors with low TILs, T or TL had similar pCR compared to L alone (51.3 v 49%; p=0.95). Among tumors with high TILs, T or TL had higher pCR than L (61.2 v 40.4%; p=0.04). Among patients with ER-positive BC, high TILs were associated with a numerical increase in pCR rate (56% vs 39.6%; p=0.11). Among patients with ER-negative tumors, high TILs were associated with a numerical decreased rate of pCR (50% v. 66.7%; p=0.15). The p-value of the Breslow test of homogeneity of the odds ratios across ER status was 0.016, suggesting that the association between TILs (0-30 v. &gt;30) and pCR varies across ER status.No interaction between the TIL percentage and age, nodal status, menopausal status, or histologic grade was noted. Conclusions: This analysis revealed that patients with a high TIL percentage treated with T or TL compared to L were more likely to achieve a pCR. These findings can be partially explained by the mechanism of action of the HER2-directed agents. T leads to antibody-dependent cell-mediated cytotoxicity, and a higher percentage of TILs may enhance this mechanism, whereas L has intracellular tyrosine kinase disruption. The association between TILs and pCR varied across ER status. Our next steps include additional studies assessing the interaction between TILs and long-term outcomes, as well as gene expression and TILs to validate this biomarker for future clinical trials in HER2+ early BC. Clinical trial information: NCT00486668 .

Immune Cytolytic Activity and Strategies for Therapeutic Treatment.

Intratumoral immune cytolytic activity (CYT), calculated as the geometric mean of granzyme-A (GZMA) and perforin-1 (PRF1) expression, has emerged as a critical factor in cancer immunotherapy, with significant implications for patient prognosis and treatment outcomes. Immune checkpoint pathways, the composition of the tumor microenvironment (TME), antigen presentation, and metabolic pathways regulate CYT. Here, we describe the various methods with which we can assess CYT. The detection and analysis of tumor-infiltrating lymphocytes (TILs) using flow cytometry or immunohistochemistry provide important information about immune cell populations within the TME. Gene expression profiling and spatial analysis techniques, such as multiplex immunofluorescence and imaging mass cytometry allow the study of CYT in the context of the TME. We discuss the significant clinical implications that CYT has, as its increased levels are associated with positive clinical outcomes and a favorable prognosis. Moreover, CYT can be used as a prognostic biomarker and aid in patient stratification. Altering CYT through the different methods targeting it, offers promising paths for improving treatment responses. Overall, understanding and modulating CYT is critical for improving cancer immunotherapy. Research into CYT and the factors that influence it has the potential to transform cancer treatment and improve patient outcomes.

Abstract 4068: In vitro masked effect, in vivo anti-tumor activity and toxicology study of KGX101, an interleukin-12 prodrug, in monotherapy or in combination with anti-PD-L1 antibody

Abstract Interleukin-12 (IL-12) has long been limited in its clinical use due to its short half-life (t1/2) and dose-related toxicity, despite its remarkable ability to activate effector functions in T cells and natural killer (NK) cells. To address these challenges, we engineered an IL-12 prodrug called KGX101. In KGX101, the C-terminus of IL-12 is fused with ADCC-impaired IgG1 Fc to extend its half-life. Meanwhile, the N-terminus is concealed with its corresponding receptor soluble domains, IL-12Rβ1 and IL-12Rβ2, using tumor-specific protease cleavable linkers. This innovative design prevents systemic immune system overactivation. Once the linker is cleaved by tumor microenvironment (TME)-specific proteases, KGX101 functions like IL-12, effectively stimulating T cells and NK cells, reshaping the TME, and displaying significant potential in cancer therapy. To confirm KGX101's masking effect, we conducted IFNγ induction efficacy tests using peripheral blood mononuclear cells (PBMCs) from three donors. KGX101 demonstrated a 300 to 2500-fold reduction in activity compared to unmasked IL-12-Fc. Importantly, the masking effect of KGX101 was nearly abolished after protease digestion, affirming its mechanism of action. To further establish KGX101's effectiveness, we conducted in vivo antitumor studies in hPBMC xenograft mouse models using human colorectal cancer HCT116 and PD-L1-overexpressed human malignant melanoma A375. Mice were subcutaneously implanted with a specific mixture of cancer cells and hPBMCs, and then intravenously injected with PBS or KGX101 at various dose levels twice a week for 4-5 cycles. Compared to the PBS control group, KGX101 demonstrated up to a 42% tumor growth inhibition (TGI) in the HCT116 model at 0.18 mg/kg and a 76% TGI in the hPD-L1-A375 model at 0.06 mg/kg. Analysis of tumor-infiltrating lymphocytes (TILs) revealed that KGX101 increased the percentage of T cells in the tumor environment in a dose-dependent manner. We also evaluated the combination of KGX101 with an anti-PD-L1 antibody in an HCT116/hPBMC xenograft mouse model, which showed limited response to anti-PD-L1 monotherapy. The TGI% for KGX101 at 0.06 mg/kg, anti-PD-L1 antibody at 1 mg/kg, and their combination were 36.56%, 6.93%, and 66.22%, respectively, demonstrating a promising antitumor synergy. In terms of pharmacokinetics, a single dose of KGX101 at 0.06 mg/kg and 0.18 mg/kg in the HCT116/hPBMC xenograft mouse model resulted in a serum half-life ranging from 52.75 to 64.87 hours, while the t1/2 in Cynomolgus monkeys was approximately 3 days. In a 4-week repeat dose toxicity study in Cynomolgus monkeys, the highest non-severely toxic dose (HNSTD) of KGX101 was determined to be 0.1 mg/kg. The results from nonclinical toxicology studies support the potential of KGX101 as a well-tolerated therapy for the First-in-Human (FIH) clinical trial. Citation Format: Shumin Yang, Nuo Li, Jing Wang, Li Ma, Yi Zhao, Hui Chen, Haixiang Wu, Weidong Jiang. In vitro masked effect, in vivo anti-tumor activity and toxicology study of KGX101, an interleukin-12 prodrug, in monotherapy or in combination with anti-PD-L1 antibody [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4068.

Abstract 1531: TIL analysis demonstrates different mechanisms underlying PD-1 resistance in animal models

Abstract Despite the tremendous success of PD-1 immunotherapy in treating cancer, resistance to the therapy is an inevitable risk. One of the major mechanisms underlying this resistance is alterations in the tumor microenvironment, including tumor-infiltrating lymphocyte (TIL) profiling changes after anti-PD1 treatment. To better understand the mechanism of PD-1 resistance, characterization of TILs in the tumor microenvironment was explored. First, immune cell profiling was performed in syngeneic tumor models established by 19 cancer cell lines without anti-PD-1 treatment. Depending on the tumor model, absolute numbers of CD45+ cells and immune cell subsets varied. Moreover, stratifying the analysis based on tumor size (100 mm3 to 3000 mm3) revealed alterations in the proportion of immune cell percentages in MC38 tumors, which implies alterations in TIL frequency during cancer progression. Next, we investigated the TIL profile in two PD-1 resistant models: a hPD-1 antibody-induced resistant model and a syngeneic model in aged mice. The hPD-1 antibody resistant model was induced by multiple rounds of hPD-1 antibody retreatment on MC38 tumor-bearing humanized B-hPD-1/hPD-L1 mice. Efficacy results from this model further validated their resistance to hPD-1 treatment (0% tumor growth inhibition (TGI)), while the control group, which was not serially treated, showed substantial tumor inhibition (82.2% TGI). Next, mPD-1 antibody resistance was evaluated in aged wild-type mice. While mPD-1 efficacy on MC38-bearing young mice was approximately 85.5% TGI, the efficacy of this treatment in aged mice yielded only 6% TGI. TIL analysis in these models was subsequently performed: in the hPD-1-treated control mice that were responsive to anti-PD1 treatment, the numbers of total T cells, cytotoxic T cells (CD8+) and MHC II positive cells were increased, while the anti-tumor effector cells in the serially treated resistant mice were either unchanged (total T cells and MHC II positive cells) or decreased (CD8+ cells); strikingly, an increase in inhibitory myeloid-derived suppressor cell (MDSC) populations was also observed in the resistant model post-treatment. In the anti-PD1 treated aged mice, the frequency of TILs was unchanged upon mPD-1 treatment, suggesting that resistance in aged mice may be due to non-responsiveness of the immune cells. In sum, our results demonstrate different mechanisms underlying anti-PD-1 resistance, and suggest that a more thorough analysis of the TILs present in the tumor microenvironment could predict the responsiveness to PD-1 therapy and inform treatment strategies. Citation Format: Sha Qiao, Yujia Liu, Wei Liu, Wenqian Pan, Xiaofei Zhou, Linlin Wang, Mengya Chai, Yujie Liu, Hao Yang, Zhaoxue Yu. TIL analysis demonstrates different mechanisms underlying PD-1 resistance in animal models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1531.

Abstract 3720: Utility of oncolytic virus as an immunostimulants and potential for combination therapy with ICIs

Abstract Background: Anti-PD-1 antibodies have been approved for a variety of carcinomas, but their efficacy in gastrointestinal cancers is limited. CD8-positive T cells (CD8) of tumor-infiltrating lymphocytes (TILs) and resident memory T cells (TRMs) with long-term anti-tumor immune function have been reported to be associated with the therapeutic efficacy of anti-PD-1 antibodies. Among our oncolytic adenoviruses (OVs), OBP-301, in which the human telomerase reverse transcriptase (hTERT) promoter element drives the expression of the viral E1A and E1B genes, is currently undergoing clinical trials. In the present study, we investigated the usefulness of OVs as immunostimulants and their potential efficacy in combination with anti-PD-1 antibodies. Methods: The cell lines used were the mouse colon cancer cell line CT26 and the mouse pancreatic cancer cell line PAN02. In vitro, the cytotoxic activity of the OVs and extracellular ATP in the culture supernatant were determined. OBP-502, an OBP-301 variant with the gene cassette of the RGD peptide, and anti-PD-1 antibody were used to examine the antitumor effect on subcutaneous tumors. OBP-702, another OBP-301 variant with the gene cassette of the wild-type p53 tumor suppressor gene, was used to examine the effect of long-term anti-tumor immunity. The effects on memory T-precursor cells (MPEC), CD8 and TRM were immunologically assessed in a rechallenge study. Results: OBP-502 and OBP-702 showed cytotoxic activity against CT26 and PAN02 cells in vitro, and significantly increased ATP in the culture supernatant. In vivo, the anti-PD-1 antibody/OBP-502 combination therapy significantly increased intratumor CD8 in CT26 and PAN02 subcutaneous tumors compared to each monotherapy. Complete response was achieved in 4 out of 12 mice by the combination therapy against CT26 tumors. When CT26 cells was re-seeded into tumor-free mice cured by the combination therapy, 2 out of 4 mice remained tumor-free. In the CT26 and PAN02 subcutaneous tumor model, OBP-702 increased CD44-positive CD62L-negative MPECs that differentiated into TRMs in the spleen, and this effect was blocked by ATP receptor inhibition. In CT26 and PAN02 bilateral subcutaneous tumor models, OBP-702 had a significant antitumor effect on both OBP-702-treated and -non-treated sides, and TIL analysis showed a significant increase in CD8 and TRM. In a rechallenge study, OBP-702-pretreatment showed significant growth inhibition of re-inoculated tumors. Conclusion: The OVs showed potent and long-term immune activation by inducing CD8 and TRM in tumors as well as direct anti-tumor effects, and synergistic effects with ICI. Citation Format: Daisuke Kadowaki, Shinji Kuroda, Masashi Hashimoto, Nobuhiko Kanaya, Yoshihiko Kakiuchi, Satoru Kikuchi, Kazuhiro Noma, Hiroshi Tazawa, Shunsuke Kagawa, Yasuo Urata, Toshiyoshi Fujiwara. Utility of oncolytic virus as an immunostimulants and potential for combination therapy with ICIs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3720.

Intratumoral IL-12 delivery via mesenchymal stem cells combined with PD-1 blockade leads to long-term antitumor immunity in a mouse glioblastoma model

BackgroundAlthough PD-1 blockade is effective for treating several types of cancer, the efficacy of this agent in glioblastoma is largely limited. To overcome non-responders and the immunosuppressive tumor microenvironment, combinational immunotherapeutic strategies with anti-PD-1 need to be considered. Here, we developed IL-12-secreting mesenchymal stem cells (MSC_IL-12) with glioblastoma tropism and evaluated the therapeutic effects of anti-PD-1, MSC_IL-12, and their combination against glioblastoma. MethodsTherapeutic responses were evaluated using an immunocompetent mouse orthotopic model. Tumor-infiltrating lymphocytes (TILs) were analyzed using immunofluorescent imaging. Single-cell transcriptome was obtained from mouse brains after treatments. ResultsAnti-PD-1 and MSC_IL-12 showed complete tumor remission in 25.0% (4/16) and 23.1% (3/13) of glioblastoma-implanted mice, respectively, and their combination yielded synergistic antitumor efficacy indicated by 50.0% (6/12) of complete tumor remission. Analyses of TILs revealed that anti-PD-1 increased CD8+ T cells, while MSC_IL-12 led to infiltration of CD4+ T cells and NK cells. Both therapies reduced frequencies of Tregs. All these aspects observed in each monotherapy group were superimposed in the combination group. Notably, no tumor growth was observed upon rechallenge in cured mice, indicating long-term immunity against glioblastoma provoked by the therapies. Single-cell RNA-seq data confirmed these results and revealed that the combined treatment led to immune-favorable tumor microenvironment–CD4+, CD8+ T cells, effector memory T cells, and activated microglia were increased, whereas exhausted T cells, Tregs, and M2 polarized microglia were reduced. ConclusionAnti-PD-1 and MSC_IL-12 monotherapies show long-term therapeutic responses, and their combination further enhances antitumor efficacy against glioblastoma via inducing immune-favorable tumor microenvironment.

Inflamed immune phenotype predicts favorable clinical outcomes of immune checkpoint inhibitor therapy across multiple cancer types

BackgroundThe inflamed immune phenotype (IIP), defined by enrichment of tumor-infiltrating lymphocytes (TILs) within intratumoral areas, is a promising tumor-agnostic biomarker of response to immune checkpoint inhibitor (ICI) therapy. However, it...

Abstract A005: Synergistically Engaging a b-Selective IL-2 Agonist with PD1/PDL-1 Blockade in a Bifunctional Superkine, MDNA223

Abstract Introduction: Combination treatment with a long-acting IL-2 superkine (MDNA109FEAA-Fc; aka MDNA19) and anti-PD1 or anti-CTLA4 has shown clear evidence of synergy in blunting tumor growth. To further leverage this synergism, we designed MDNA223, a BiSKIT (Bifunctional SuperKine for ImmunoTherapy) comprising MDNA109FEAA with enhanced affinity for IL-2Rb and no binding to IL-2Ra, fused to either human or mouse anti-PD1. We present in vitro and in vivo characterization of MDNA223 and demonstrate its enhanced IL-2R agonism and effective PD1/PDL-1 blockade in multiple “hot” and “cold” syngeneic tumor models. Experimental Procedure: In vitro studies included human PBMCs and cell-based reporter assays. In vivo studies were conducted in CT26, B16F10, E0771 and TRAMP-C1 tumor models by intraperiotonneal (IP) administration. Intratumoral treatment was performed in a CT26 bilateral tumor model with or without a STING agonist. Analysis of tumor infiltrating lymphocytes (TILs) was performed using flow cytometry. Results: In studies with human PBMCs, MDNA223 showed increased p-STAT5 signaling in CD8+ T cells and reduced activity in Tregs compared to rhIL-2, consistent with its enhanced receptor selectivity. MDNA223 and anti-PD1 were similarly potent at PD1/PDL-1 blockade in a cell-based reporter assay. In mice, MDNA223 induced proliferation (based on Ki67 expression) and expansion of peripheral CD8+ T cells for over 7 days. IP treatment with MDNA223 resulted in significantly greater inhibition of CT26, B16F10, E0771 and TRAMP-C1 tumor growth when compared to combination of MDNA19 with anti-PD1 at equimolar dosage. This observation is consistent with the proposed cis-binding mechanism of MDNA223 to both, IL-2R and PD1 on the same effector immune cell. In a bilateral CT26 tumor model, IT treatment with MDNA223 not only inhibited the treated tumor but also exhibited an abscopal effect by slowing growth of the untreated tumor implanted on the opposite flank. TILs analysis of B16F10 melanoma following a single dose of MDNA223 showed increased infiltration of CD8+ T cells over Tregs compared to single agent treatment with MDNA19 or anti-PD1 as well as their combination. Treatment with MDNA223 also resulted in a larger population of functional effector CD8+ T cells expressing low levels of the Tim-3 exhaustion marker and high levels of the cytotoxic Granzyme-B protease. Conclusion: MDNA223 demonstrated superior therapeutic activity over the combination of MDNA19 and anti-PD1 in both immunologically ‘hot’ (CT26) and ‘cold’ (B16F10, E0771 and TRAMP-C1) tumor models. Additional studies with variants of MDNA223 capable of tumor selective targeting and/or conditional activation within the tumor micro-environment are in progress to maximize activity at the tumor site with tunable peripheral stimulation. Citation Format: Aanchal Sharma, Minh D To, Hardeep Kataria, Qian Liu, Rosemina Merchant, Fahar Merchant. Synergistically Engaging a b-Selective IL-2 Agonist with PD1/PDL-1 Blockade in a Bifunctional Superkine, MDNA223 [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2023 Oct 1-4; Toronto, Ontario, Canada. Philadelphia (PA): AACR; Cancer Immunol Res 2023;11(12 Suppl):Abstract nr A005.

Artificial intelligence-powered spatial analysis of tumor-infiltrating lymphocytes for prediction of prognosis in resected colon cancer

Tumor-infiltrating lymphocytes (TIL) have been suggested as an important prognostic marker in colorectal cancer, but assessment usually requires additional tissue processing and interpretational efforts. The aim of this study is to assess the clinical significance of artificial intelligence (AI)-powered spatial TIL analysis using only a hematoxylin and eosin (H&E)-stained whole-slide image (WSI) for the prediction of prognosis in stage II–III colon cancer treated with surgery and adjuvant therapy. In this retrospective study, we used Lunit SCOPE IO, an AI-powered H&E WSI analyzer, to assess intratumoral TIL (iTIL) and tumor-related stromal TIL (sTIL) densities from WSIs of 289 patients. The patients with confirmed recurrences had significantly lower sTIL densities (mean sTIL density 630.2/mm2 in cases with confirmed recurrence vs. 1021.3/mm2 in no recurrence, p < 0.001). Additionally, significantly higher recurrence rates were observed in patients having sTIL or iTIL in the lower quartile groups. Risk groups defined as high-risk (both iTIL and sTIL in the lowest quartile groups), low-risk (sTIL higher than the median), or intermediate-risk (not high- or low-risk) were predictive of recurrence and were independently associated with clinical outcomes after adjusting for other clinical factors. AI-powered TIL analysis can provide prognostic information in stage II/III colon cancer in a practical manner.

EXTH-84. INTRATUMORAL IL-12 DELIVERY VIA MESENCHYMAL STEM CELLS COMBINED WITH PD-1 BLOCKADE LEADS TO LONG-TERM ANTITUMOR IMMUNITY IN A MOUSE GLIOBLASTOMA MODEL

Abstract Although PD-1 blockade is effective for treating several types of cancer, the efficacy of this agent in glioblastoma is largely limited. To overcome non-responders and the immunosuppressive tumor microenvironment, combinational immunotherapeutic strategies with anti-PD-1 need to be considered. Here, we developed IL-12-secreting mesenchymal stem cells (MSC_IL-12) with glioblastoma tropism and evaluated the therapeutic effects of anti-PD-1, MSC_IL-12, and their combination against glioblastoma using an immunocompetent mouse orthotopic model. Anti-PD-1 and MSC_IL-12 showed complete tumor remission in 25.0% (4/16) and 23.1% (3/13) of glioblastoma-implanted mice, respectively, and their combination yielded synergistic antitumor efficacy indicated by 50.0% (6/12) of complete tumor remission. Analyses of tumor-infiltrating lymphocytes using immunofluorescent imaging revealed that anti-PD-1 increased CD8+ T cells, while MSC_IL-12 led to infiltration of CD4+ T cells and NK cells. Both therapies reduced frequencies of Tregs. All these aspects observed in each monotherapy group were superimposed in the combination group. Notably, no tumor growth was observed upon rechallenge in cured mice, indicating long-term immunity against glioblastoma provoked by the therapies. Single-cell RNA-seq of mouse brains confirmed these results and revealed that the combined treatment led to immune-favorable tumor microenvironment–CD4+, CD8+ T cells, effector memory T cells, and activated microglia were increased, whereas exhausted T cells, Tregs, and M2 polarized microglia were reduced. Taken together, anti-PD-1 and MSC_IL-12 monotherapies show long-term therapeutic responses, and their combination further enhances antitumor efficacy against glioblastoma via inducing immune-favorable tumor microenvironment.

Distribution characteristics of tumor infiltrating lymphocytes in EBV-associated lymphoepithelioma-like carcinoma and their clinical significance

Objective: To investigate the association between the distribution of tumor infiltrating lymphocytes (TIL) in EBV associated lymphoepitheliomatoid carcinoma (LELC) and the pathological subtypes of LELC, as well as the clinical significance of TIL distribution. Methods: The LELC patients with sufficient tumor tissues, complete clinical data and positive EBER, who visited Zhejiang Cancer Hospital, Hangzhou, China from January 2006 to October 2018, were selected. Various immunohistochemical markers (CD20, CD138, CD4, CD8, CD56 and FOXP3) were examined for TIL typing. Two pathologists reviewed the hematoxylin and eosin (HE) staining sections and interpreted the immunohistochemical results. Correlation analysis was used to evaluate the relationship between the distribution of TIL subgroups and LELC's pathological characteristics. Survival analyses were conducted to study the prognostic values of TIL subgrouping. Results: A total of 102 patients with EBV related LELC were included. 46 of them were classic LELC (c-LELC) with rich interstitial TIL, and 56 were non-classic LELC (n-LELC) with relatively fewer interstitial TIL. The results of TIL analysis showed that all subtypes of c-LELC were rich in TIL, with B lymphocytes as the dominant subgroup. The number of TIL in n-LELC was fewer than that in c-LELC, with T lymphocytes as the dominant subgroup. There was no significant difference in the distribution of plasma cells between the two groups. Survival analysis showed that the total number of TIL, and the infiltrations of CD20+B cells, CD4+T cells, and FOXP3+Treg cells were associated with better overall survivals (P=0.004, 0.003, 0.008 and 0.025, respectively) and disease-free survivals (P=0.011, 0.003, 0.038 and 0.041, respectively) in patients with LELC. Conclusions: The morphologic subtypes of EBV-related LELC have different tumor immune characteristics. The total number of TIL in the stroma of c-LELC is significantly higher than that of n-LELC. Interestingly, B lymphocytes are the dominant TIL in c-LELC, while T lymphocytes are the dominant TIL in n-LELC. The infiltration of TIL, CD20+B cells, CD4+T cells and FOXP3+Treg cells in LELC may suggest a better prognosis.

Artificial intelligence (AI) analysis of tumor-infiltrating lymphocytes (TILs) in hematoxylin and eosin (H&amp;E) slides to explore immune phenotypes in papillary thyroid cancer.

6100 Background: Different biomarkers have been discovered to predict response to immunotherapy but the variability of response exists. TILs are a potential biomarker as infiltration of CD8+ T cells in the tumor microenvironment(TME) was related to treatment response to PD-1 blockade. Advanced well-differentiated papillary thyroid cancer(PTC) has limited standard-of-care treatment options and can exhibit a poor prognosis when exhausted. Our study aimed to classify the TME of PTC according to TILs. Methods: Using the TCGA PTC data, samples were classified into three immune phenotypes (immune-’desert’, immune-’excluded’, and ‘inflamed’) based on peri-tumor lymphocyte density from analysis of H&amp;E slides using an AI model(Lunit SCOPE). Immune and stromal cell infiltration was inferred using xCell. Cytolytic scores(CYT) and thyroid differentiation scores(TDS) were calculated using mRNA expression. Results: Total of 383 samples were included. Immune phenotype analysis showed 183(47.7%) ‘desert’, 133(34.7%) ‘excluded’, and 67(17.4%) ‘inflamed’. Median age at diagnosis was the lowest in ‘inflamed’(inflamed 41.5 vs excluded 47 vs desert 50, p = 002). TNM stages were as follows in the order of stages 1 to 4: inflamed 49/4/8/3, excluded 64/13/32/16, and desert 86/28/40/19. BRAF V600E mutation was most prevalent in ‘excluded’(97/133, 72%), followed by ‘inflamed’(32/67, 47.7%) and ‘desert’(51/183, 27.8%). CYT was the highest in ‘inflamed’(median: inflamed 186 vs excluded 53 vs desert 39, p &lt; 0.001). TDS was the highest in ‘desert’(median: inflamed -0.3 vs excluded -0.69 vs desert 0.73, p &lt; 0.001). The 6 cell types with the most statistically significant difference in infiltration were activated dendritic cells(aDCs), DCs, B cells, epithelial cells(EpCs), CD8+ central memory T cells, and CD4+ memory T cells. The ‘inflamed’ showed the highest median value for all of these cells except EpCs. The cells with the highest median value in ‘excluded’ included EpCs, sebocytes, and immature DCs. The cells with the highest median value in ‘desert’ were lymphatic endothelial cells(ECs), ECs, and osteoblasts. Three immune phenotypes were associated with differential outcomes in disease-free survival(log-rank for trend, p-value = 0.01). There was no difference in overall survival. Conclusions: Our results suggest that 15% of PTC can have immune features which were related to a higher rate of response to immunotherapy across different tumor types. A previous study showed that PTC with a low TDS or BRAF V600E mutation is related to increased immune response indices. In our study, TDS or BRAF V600E mutation status could not distinguish the ‘inflamed’ from other phenotypes. This suggests that immune phenotype classification through TILs can provide distinct information about the TME of PTC.

Artificial intelligence–powered tumor-infiltrating lymphocytes analyzer to reveal distinct immune landscapes in breast cancer by molecular subtype and HER2 score.

1049 Background: Tumor-infiltrating lymphocytes (TIL) reflect an ongoing anti-tumor immune response in the tumor microenvironment (TME) and have been studied as a predictive as well as prognostic biomarker in breast cancer (BC). The immune profile differs depending on BC molecular subtypes, with triple-negative BC (TNBC) and HER2-positive BC more frequently infiltrated by higher numbers of TIL than hormone receptor (HR)-positive tumors. In this study, we analyze TIL and immune phenotype by molecular subtype in BC and explore differences based on HER2 scores using an AI-powered TIL analyzer. Methods: A total of 1,973 cases of BC with molecular subtype, HER2 immunohistochemistry (IHC) or in situ hybridization (ISH) results, and TIL analysis from H&amp;E slides from TCGA (n=1021), Samsung Medical Center (SMC, n=663), and KyungHee Medical Center (KHMC, n=289) were included in the analysis. The density of TIL were spatially analyzed from H&amp;E WSI, and the immune phenotype (IP) was analyzed for each 1 mm2-sized patch. Tumor microenvironment (TME) was categorized into three types: inflamed (TIL distributed intratumorally), Immune-excluded (TIL excluded, out of cancer stroma), immune-desert (scant TIL in TME), and the score for each IP was calculated as the percentage of the total patches in WSI. Results: TNBC showed the highest TIL density in both cancer epithelium (214.5 ± 299.7/mm2) and stroma (1133.3 ± 1245.9/mm2), and a high percentage of inflamed IP (35.7%), IS (28.4 ± 28.1) than other subtypes (inflamed IP: 17.5%, IS 16.2±20.2, both p&lt;0.001). HER2-positive BCs showed higher sTIL density (904.0 ± 901.7/mm2) compared to HR- positive BC (616.7 ± 794.1/mm2) but were associated with a higher percentage of immune-excluded IP (71.2%) and IES (57.6 ± 24.6). HR-positive BC had a high percentage of immune-desert IP (30.4%). In both HR-positive and negative BCs, higher IES was observed as the HER2 score increased. HER2-positive BC significantly showed a higher proportion of cancer stroma in the cancer region from WSI (Stromal ratio, 0.682 ± 0.149 vs. 0.578 ± 0.176, p&lt;0.001). Conclusions: Different TIL densities and IP were seen in BC for each molecular subtype, pointing to a distinct immune landscape. HER2 score was associated with immune-excluded IP despite having higher TIL density, which should be considered for immunotherapy in BC.

Immune phenotype-driven treatment outcome of IO-only versus chemo-IO in PD-L1-high, first-line, advanced non-small cell lung cancer (NSCLC).

e21179 Background: PD-L1 tumor proportion score (TPS) is the only biomarker for clinical decision-making regarding immunotherapy (IO) in advanced NSCLC. Currently, there is uncertainty when selecting treatment options between IO monotherapy (IO-only) and in combination with chemotherapy (Chemo-IO) when solely based on PD-L1, in patients with PD-L1 TPS ≥ 50%. Here, we explored a novel biomarker, immune phenotype as assessed by artificial intelligence (AI)-powered spatial tumor infiltrating lymphocytes (TIL) analysis to provide additional information in determining first-line treatment for advanced NSCLC, using a real-world dataset. Methods: A total of 349 whole-slide images (WSIs) of H&amp;E-stained slides for advanced/metastatic NSCLC patients without actionable EGFR mutation and ALK translocation treated with IO-only or Chemo-IO as their first-line were retrospectively collected from Samsung Medical Center. An AI-powered spatial TIL analyzer, Lunit SCOPE IO classified inflamed immune phenotype (IIP, the proportion of inflamed area ≥ 33.3% in tumor microenvironment) versus non-inflamed IP (non-IIP). PD-L1 TPS was assessed based on PD-L1 pharmDx 22C3 staining. Progression-free survival (PFS) was measured by the investigators per RECIST v1.1. Results: In the analysis set, all IO-only group (n = 84) had TPS ≥ 50%, but Chemo-IO group (n = 265) consisted of 21.1%, 29.8%, and 49.1% of TPS ≥ 50%, 1-49%, and &lt; 1%, respectively. Proportions of squamous cell carcinoma were not significantly different between IO-only and Chemo-IO (32.1% vs 27.5%, p = 0.5008). Proportions of IIP were significantly correlated with the TPS group, as they were 33.6%, 19.0%, and 13.1% in TPS ≥ 50%, 1-49%, and &lt; 1%, respectively (p = 0.0002). In the merged dataset (n = 349), PFS was significantly increased in IIP (22.6%) compared to non-IIP (median PFS [mPFS] 14.6 vs 6.0 m, 6-m PFS rate 72.1% vs 49.9%, hazard ratio [HR, 95% confidence interval] 0.57 [0.39-0.82], p = 0.0014). In TPS ≥ 50% group, IIP was significantly correlated with favorable PFS in IO-only group (IIP vs non-IIP; mPFS 14.6 vs 4.6 m, 6-m rate 65.5 vs 45.2%, HR 0.55 [0.31-0.98], p = 0.0375), however, it was not statistically different in Chemo-IO (n = 56, mPFS not reached [NR] vs 8.3 m, 6-m rate 88.5 vs 65.3%, HR 0.45 [0.15-1.33], p = 0.1185). Interestingly, in the subgroup of TPS ≥ 50% with IIP (n = 47), PFS was not significantly different based on treatment regimen (Chemo-IO vs IO-only, mPFS NR vs 14.6 m, 6-m rate 88.5 vs 65.5%, HR 0.52 [0.17-1.59], p = 0.2263), but Chemo-IO was significantly superior to IO-only in TPS ≥ 50% with non-IIP group (n = 93, mPFS 8.3 vs 4.6 m, 6-m rate 65.3 vs 45.2%, HR 0.53 [0.30-0.94], p = 0.0255). Conclusions: Immune Phenotype based on AI-powered spatial TIL analysis may provide complementary information for clinical decision-making between IO-only and Chemo-IO in advanced NSCLC patients with TPS ≥ 50%.

Artificial intelligence (AI) –powered spatial analysis of tumor-infiltrating lymphocytes (TILs) for prediction of prognosis in resectable pancreatic adenocarcinoma (PDAC).

4162 Background: The degree of TIL infiltration in the tumor microenvironment has been suggested as a prognostic factor in multiple cancer types, but the significance in PDAC is not well known. The aim of this study is to assess the prognostic role of AI-based spatial TIL density assessment and immune phenotype (IP) classification in resectable PDAC. Methods: We collected hematoxylin and eosin (H&amp;E)-stained whole slide images (WSI) of tumor tissues and clinical data from stage I – III PDAC patients who received curative surgery at Samsung Medical Center, in Seoul, Korea, between Jan 2017 and Dec 2018. For spatial TIL analysis, we used Lunit SCOPE IO, an AI-powered pathology slide analyzer that can identify TIL and segment tumor epithelium and stroma from H&amp;E-stained WSI. It then estimates intratumoral (iTIL) and stromal TIL (sTIL) densities, as well as IP classification of each case. IPs were defined as follows: inflamed IP (IIP) as high iTIL and sTIL; immune-excluded as low iTIL and high sTIL; immune-desert as low TIL overall. Predetermined cutoffs prior to this study were used for the determination of IPs. Results: A total of 209 patients were identified, 182 treated with upfront surgery and 27 with preoperative chemo(radio)therapies followed by surgery. The median recurrence-free survival (RFS) and overall survival (OS) of all patients was 16.8 months (95% CI 12.1 - 21.4), and 36.8 months (95% CI 31.2 - 42.4), respectively. In the 182 patients treated with upfront surgery, the median iTIL and sTIL densities were 85.3/mm2 (IQR 56.9 – 133.0) and 672.2/mm2 (IQR 445.9 – 912.9). 85.7% of the cases were immune-excluded, while 11.5% were IIP. The patients having iTIL higher than the median exhibited longer RFS (HR 0.62, 95% CI 0.42 - 0.92, p = 0.017). Also, the patients having IIP exhibited longer OS (p = 0.045, HR 2.05, 95% CI 1.00 – 4.22) and a marginally longer RFS (p = 0.051, HR 2.03, 95% CI 0.98 – 4.18) compared to those with non-IIP. In the 27 patients who were treated with preoperative therapies, the iTIL densities in the surgical specimens were significantly higher compared to the 182 untreated samples (mean iTIL 168.8/mm2 after chemo(radio)therapies vs. 112.6/mm2 in upfront surgery, p = 0.012), although the increase in the proportion of IIP was not significant. Using the iTIL median of the 182 upfront surgery cases, 17/27(63.0%) patients had high iTIL in WSIs obtained after preoperative therapies, and these patients were observed to have a significantly better RFS (HR 0.26. 95% CI 0.09 - 0.73, p = 0.006). Conclusions: While most cases of resectable PDAC were found to have TIL infiltration mainly in stroma, relatively higher iTIL infiltration was associated with better prognosis. An increase in iTIL after chemo(radio)therapies may be associated with better outcomes.

Predictive value of tumor-infiltrating lymphocyte (TIL) dynamics in the tumor microenvironment (TME) during preoperative chemoradiotherapy (CRT) on pathologic complete response (pCR) in microsatellite-stable (MSS) locally advanced rectal cancer (LARC).

3608 Background: Preoperative CRT followed by consolidation nivolumab before surgery showed a promising pCR rate in MSS LARC; both high PD-L1 expression and an elevated CD8+ T cell/effector regulatory T cell ratio analyzed by pre-CRT samples were independently related to high pCR rate (Bando H, Clin Cancer Res. 2022). Here, we applied AI-powered spatial TIL analysis to the VOLTAGE study to investigate whether dynamic change of TIL in TME may predict pCR in MSS LARC. Methods: The VOLTAGE study is a multicenter phase I/II study to evaluate the efficacy of CRT followed by 5 cycles of nivolumab and surgery in patients (pts) with LARC. In this study, tumor samples were obtained at multiple time points; pre-CRT (B1), post-CRT/pre-nivolumab (B2), post-3 cycles of nivolumab (B3), and surgery. In this analysis, a total of 86 H&amp;E whole-slide images (WSI) harvested at B1 and B2 time points from all the pts enrolled in the VOLTAGE study were included in the analysis. Lunit SCOPE IO (Lunit, Republic of Korea), AI-powered H&amp;E-WSI analyzer developed based on 16,443 WSI with pathologists' annotations, was applied to quantify TIL density in TME. Results: In a total of 43 pts, pCR rate of MSS and microsatellite instability-high (MSI-H) were 28.9% (11/38) and 60% (3/5), respectively. In MSS subgroup (n = 38), which has a higher unmet need for pCR prediction, tumor samples with pCR (n = 11) had increased TIL density in TME (tTIL) in post-CRT (B2, median [IQR] 726 [249-1607] /mm2) compared to pre-CRT (B1, 598 [366-905] /mm2), whereas those without pCR (n = 27) had decreased tTIL in post-CRT (405 [148-748] /mm2), compared to pre-CRT (B1, 748 [460-1153] /mm2). Intratumoral TIL density changes were more prominent than stromal TIL density changes in MSS tumor samples with pCR (mean fold change x17.7 vs. x1.5). MSS Pts with tTIL change from B1 to B2 (during CRT) more than x1.8 times achieved 75% (6/8) pCR rate, whereas those with tTIL change less than x1.8 had 16.7% (5/30) pCR rate (p = 0.0035). Conclusions: Change of TIL density in TME during CRT was significantly correlated with favorable clinical outcome of preoperative CRT and consolidation nivolumab, resulting in high pCR rate in MSS LARC.

Combining histological grade, TILs, and the PD-1/PD-L1 pathway to identify immunogenic tumors and de-escalate radiotherapy in early breast cancer: a secondary analysis of a randomized clinical trial

BackgroundThe implementation of immunological biomarkers for radiotherapy (RT) individualization in breast cancer requires consideration of tumor-intrinsic factors. This study aimed to investigate whether the integration of histological grade, tumor-infiltrating lymphocytes...

Abstract LB338: A novel class of T cell-activators targeting germline encoded TCRβ chains promotes antitumor activity in PD1-refractory models through expansion of a clonally enriched effector memory T cell subset

Abstract Background: Here we describe a new class of selective T cell activator molecule that combines antibody targeting of the variable (V) β regions of the T cell receptor (TCR) with a costimulatory cytokine. STAR0602, a molecule that selectively targets T cells expressing Vβ6 and Vβ10 TCRs and delivers IL-2R co-stimulation, activates and expands human Vβ6 and Vβ10 T cells that are enriched in tumor infiltrating lymphocytes (TIL) relative to other Vβ subsets. Using this molecular design, STAR0602 and molecules targeting other Vβ T cell subsets simultaneously engage a novel, non-clonal mode of TCR activation with cytokine co-stimulation. Methods: The effects of STAR0602 on activation and expansion of primary human T cells were assessed in vitro by flow cytometry, homogeneous time-resolved fluorescence, TCRseq, and NanoString. Several murine surrogate molecules targeting different Vβ T cell subsets with a range of baseline frequencies were tested in murine syngeneic tumor models. Tumors were excised for phenotyping of TILs including tetramer staining of antigen specific T cells using flow cytometry, and scRNAseq/TCRseq. Results: In vitro, STAR0602 induced TCR signaling and IL-2R pathway activation in human T cells that preceded expansion of Vβ6/Vβ10 T cells that acquired an atypical central memory T cell (TCM) phenotype. Across PD1-refractory syngeneic murine tumor models, monotherapy with fusion molecules targeting different Vβ TCR and delivering IL-2R co-stimulation induced potent anti-tumor activity that was associated with expansion and accumulation of targeted Vβ T cell subsets in blood and tumors. In vivo anti-tumor activity was dependent on the accumulation of effector memory T or TCM Vβ T cells expressing a novel effector gene signature. Additional analysis of TILs showed increased clonality in de novo expanded Vβ T cells compared to controls in addition to increased numbers of tumor-specific T cells. Conclusions: To our knowledge, the use of therapeutic antibodies to selectively target and expand Vβ T cell subsets and thereby modulate the germline TCR repertoire for therapeutic benefit is novel. Here we show that STAR0602 selectively binds and activates human Vβ6/Vβ10 T cells and promotes a novel TCM phenotype. Murine surrogate molecules targeting different Vβ T cell subsets demonstrated potent and durable single-agent anti-tumor activity even when targeting low frequency Vβ subsets. These expanded Vβ T cells appear to drive enhanced anti-tumor activity due to their increased effector potentials, novel memory phenotype, and a striking enrichment in clonal diversity. In summary, STAR0602 and similar Vβ TCR-targeting constructs have the potential to remodel the adaptive immune response to solid tumors that are refractory to anti-PD1 therapy. A Phase 1/2 clinical trial of STAR0602 is ongoing in patients with advanced metastatic cancers. Citation Format: Jacques Moisan, Madan Katraggada, Jonathan Hsu, Jessica Lowry, Wei Huang, Jian Tang, Roya Servattalab, Gurkan Guntas, Raj Chopra, Zhen Su, Andrew Bayliffe. A novel class of T cell-activators targeting germline encoded TCRβ chains promotes antitumor activity in PD1-refractory models through expansion of a clonally enriched effector memory T cell subset [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB338.

Abstract 1360: Spatial image analysis of tumor-infiltrating lymphocytes on gastric cancer to predict anti-PD1 inhibitor response

Abstract Background: The Tumor Immune microenvironment (TME) plays an important role in tumor development, progression, and treatment response. Recent studies show that spatial heterogeneity of Tumor-Infiltrating Lymphocytes (TILs), consisting of lymphocytic cell populations, is an important histopathologic feature and a powerful prognostic and predictive marker correlating with cancer progression and treatment response. Detecting and quantifying TIL density in Whole Slide Images (WSIs) is, however, labor-intensive, and it is difficult to assess differences in the composition of immune cells. Therefore, it remains a challenge to establish the analysis of TILs in the complex TME. We present an automated spatial image analysis of TILs on gastric cancer to address cancer immunotherapy. Method: 1,031WSIs of hematoxylin and eosin-stained (H&amp;E) formalin-fixed paraffin-embedded (FFPE) sections from four patient cohorts: TCGA-STAD (329), Yonsei-1 (620 patients), Yonsei-2 (45), and St. Mary (37), were analyzed. Two treatment groups in response were classified as CR + PR, while another two treatment groups in non-response were classified as PD + SD. H&amp;E stained WSIs were normalized using the Reinhard normalization method at 20X magnification for reducing the color variability of the stained tissue images. We used U-Net architecture to predict the normalized H&amp;E stained WSIs. Three U-Net models were trained for predicting tumor, TILs, and stroma, using Adam optimizer, 1e-4 learning rate, a binary loss function, L2 regularization, and 50 epochs. The normalized H&amp;E stained WSIs were predicted using the trained U-Net models. Spatial analysis of TILs was conducted on the predicted WSIs. Regional quantification of TILs was performed by two immune phenotype groups: immune-immersed (TILs enriched in tumor cells) and immune-excluded (TILs not enriched in tumor cells but in stromal cells). Kaplan-Meier with a log-rank test was used to evaluate the survival differences between the groups. Results: In TCGA-STAD, the proportion of immune-immersed composition is significantly different from the immune-excluded (p-value 0.05). In Yonsei-1, the immune-excluded composition is significantly different among the three risk groups (p-value 3e-05). In the Yonsei-2 and St. Mary cohorts, including anti-PD1 treated gastric cancer patients, the immune-immersed composition is significantly different between two response groups (p-value 0.007) and represented the diagnostic accuracy (AUROC: 0.78) on CR + PR groups. Conclusion: These findings suggest that the proposed TIL quantification in the complex TME is strongly associated with patient prognosis and anti-PD1 treatment response in gastric cancer. Citation Format: Sanghoon Lee, Sunho Park, Jae-Ho Cheong, Sam C. Wang, Matthew R. Porembka, In-Ho Kim, Sung Hak Lee, Tae Hyun Hwang. Spatial image analysis of tumor-infiltrating lymphocytes on gastric cancer to predict anti-PD1 inhibitor response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1360.