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Background: Inflammatory breast cancer (IBC) is a rare but aggressive tumor type accounting for up to 10% of breast cancer deaths. One-third of IBCs express high PD-L1 that can be targeted by atezolizumab (Az). MEK inhibitor cobimetinib (Co) not only inhibits the RAS-MAPK pathway but can further enhance immune-mediated killing. Thus, we hypothesize that Az+Co may enhance the efficacy of chemotherapy in metastatic IBC (mIBC). We opened a trial to test this hypothesis with a comprehensive multi-omics biomarker assessment. Patients and Methods: In a single-center, open-label phase II study, cohort 1 received one cycle of Az+ Co, followed by four cycles of Az+Co+eribulin (E) to induce a maximum clinical response, followed by Az+Co maintenance. Pre and Post one cycle of Az+Co tumors were collected for immunohistochemistry (IHC), multiplex immunofluorescence (mIF), whole-exome sequencing (WES), and RNA sequencing (RNAseq). Blood was collected for circulating tumor DNA (ctDNA). Results: Seventeen patients were enrolled in cohort 1. Seven had PR, and three had SD as the best responses. Fourteen had pre, and six had pre/post tumors. The levels of PD-L1 expression at pre/post were not associated with responses. WES revealed the median tumor mutation burden at pre- was 9mt/Mb. More than 50% had TP53 and PI3K pathway mutations at pre. RTK-RAS and Notch pathways were altered in 4/9 cases. PRDM9 and DPY19L2 single-gene mutations were commonly noted in pre. No cancer-associated gene aberration, including potential biomarkers of anti-PDL1 agent response was associated with clinical outcomes. Transcriptomic gene set enrichment analysis demonstrated a greater degree of TNFa and TGFb signaling, Oxphos, angiogenesis, and epithelial-to-mesenchymal transition (EMT) processes in tumors from patients with poor response. Immune profiling by RNAseq revealed two responders to have elevated effector memory T cells, NK T cells, myeloid dendritic cells, and M1 macrophage signatures in pre-samples, but post-samples were not available. mIF confirmed a higher frequency of NK-T cells. The ctDNA analysis from serially collected blood samples is ongoing. Discussion: In this comprehensive multi-omics analysis of pre-and-post-Az+Co, we observed several novel findings, while conventional biomarkers for Az and Co did not correlate with clinical responses. EMT, Oxphos, Notch, and chronic inflammation pathways, which are not previously well reported, were observed in this IBC cohort. These markers warrant further validation to see if they carry significance as therapeutic targets in IBC. Citation Format: Bora Lim, Angela Alexander, Jie S. Willey, Huiming Sun, Suyu Liu, Anisha B. Patel, Edwin Roger Parra, Cara Haymaker, Luisa Solis Soto, Alejandra Serrano, Baohua Sun, Cibelle Freitas Pinto Lima, Auriole Tamegnon, Renganayaki K. Pandurengan, Dzifa Douse, Jessica Lan, Luthra Raja, Randy Chu, Mark Knafl, Scott E. Woodman, Haifeng Zhu, Katja Shulze, Katherine Fedenko, Walter Darbonne, Naoto T. Ueno, Vicente Valero. Biomarker analysis: Multi-omics elucidation of Cohort 1 from a phase II study of a triple combination of Atezolizumab + cobimetinib + eribulin in patients with metastatic inflammatory breast cancer. [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-08-19.

Background: Preclinical CRC models reveal KRAS mutations activate the CXCR2 axis promoting an immunosuppressive tumor microenvironment (TME). This occurs via KRAS repression of interferon regulatory factor 2 (IRF2) resulting in upregulation of CXCL3 chemokines, which bind CXCR2 and recruit myeloid-derived suppressor cells (MDSC; Liao et al, Cancer Cell 2019). MDSCs also accelerate metastases by ‘priming’ the premetastatic niche via promoting egress of tumors cells into the circulation, inhibiting killing by immune cells and promoting extravasation into the tissues (Veglia et al. Nature 2021). SX-682 is a novel oral small-molecule inhibitor of CXCR1/2 chemokine receptors involved in MDSC-recruitment to TME. This proof-of-concept study investigates whether a CXCR1/2 antagonist in combination with anti-PD-1 therapy can overcome de novo immunotherapy resistance in MSS RAS mutated mCRC and eradicate micrometastatic disease in ctDNA positive CRC post definitive therapy. Methods: STOPTRAFFIC-1 is a phase I/II, open-label, dose-escalation/dose expansion study of SX-682 plus nivolumab for patients (pts) with RAS mutated MSS mCRC or ctDNA positive CRC. Key eligibility criteria - Arm A: pts with MSS mCRC with progression or intolerance to 2 prior lines of therapy, ECOG 0/1; Arm B: ctDNA positive post completion of definitive therapy (adjuvant chemotherapy for stage III or metastasectomy for stage IV CRC). Pts will receive SX-682 (5 dose levels: 25 mg, 50 mg, 100mg, 200mg, or 400 mg PO twice daily) in an 8-week cycle with intravenous nivolumab (480 mg) on days 1 and 29. Adverse events per CTCAE v5.0. RECIST assessments every 8 weeks. In dose escalation, pts enter a 3-week monotherapy safety run-in of SX-682 followed by 3-week combination with nivolumab for a six-week dose-limiting toxicity (DLT) period. Cohorts 1-4 have been completed without DLT. Enrollment to Cohort 5 is completed with expansion arms to open February 2023. Dose expansion is a Simon's optimal two-stage design for Arm A. Efficacy will be assessed in the first 15 pts with a requirement of 2 responses in order to enroll 14 additional pts (N=29). Pre- and on-treatment tissue biopsies will be collected. Arm B will enroll 15 pts with positive ctDNA post definitive therapy. Pts will be screened with CLIA certified ctDNA test for minimal residual disease (MRD) and if positive, enrolled for treatment for up to 6 months (m). Pts will undergo radiographic evaluation at 3 and 6m and then every 3-6m for at least 3 years. The primary objectives are to determine safety profile, recommended phase 2 dose, clinical activity & 6m ctDNA clearance rate in CRC pts with MRD following 6m of SX-682 + Nivolumab on Arm B. Translational analyses include correlations of clinical outcomes with genomic and immune biomarkers from paired tissue and plasma samples. Clinical trial information: NCT04599140. Citation Format: Benny Johnson, Cara Haymaker, Van K. Morris, Arvind Dasari, Victoria Serpas Higbie, John Paul Shen, Christine Parseghian, Maria Pia Morelli, Ryan Huey, Michael S. Lee, Jason Willis, Kanwal P. Raghav, Ying Yuan, John Zebala, Ronald A. DePinho, Scott Kopetz, Michael Overman. A phase I/II trial of a CXCR1/2 inhibitor in combination with anti-PD-1 for circulating tumor DNA (ctDNA) positive & refractoryRAS-mutated microsatellite stable (MSS) colorectal cancer [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 CT118.

Immune checkpoint inhibitors (ICI) have demonstrated limited success in patients with metastatic uveal melanoma (MUM) with liver involvement due to an immunosuppressive tumor microenvironment (TME) driven in part by myeloid-derived suppressor cells (MDSCs). Toll-like receptor-9 agonists (TLR-9A) have improved ICI response rates in cutaneous melanoma, but delivery challenges have limited their application for MUM. Hepatic arterial infusion (HAI) of TLR-9A using a pressure-enabled drug deliveryTM (PEDDTM) device has the potential to enhance responsiveness to ICI by optimizing delivery to intrahepatic tumors and reprogramming the TME, including elimination of MDSCs.PERIO-01 is an open-label first-in-human Phase 1 trial of SD-101 given by HAI using a PEDDTM in MUM (NCT04935229). The study consists of dose-escalation cohorts of single agent SD-101 alone and with ICI. SD-101 is delivered over 2 cycles, with 3 weekly doses per cycle. Research blood, tumor and normal liver biopsies are collected serially for correlative studies. At data cutoff, a total of 20 patients were enrolled, with 13 in the single agent dose escalation cohort (2, 4, and 8 mg) and 7 patients with SD-101 (2 mg) + nivolumab. The median age was 65.5 years with an equal gender distribution. Only 2 patients were treatment-naïve and the median number of liver metastases was 5.1. The average number of SD-101 infusions was 5.2. One patient in the combination cohort experienced a serious adverse event related to treatment - asymptomatic Grade 3 increase in liver enzymes. PEDDTM resulted in high drug levels in the liver (up to 2,340 ng/ml at 8mg) with only transient exposure in the periphery ( Citation Format: Sapna P. Patel, Cara Haymaker, Rahul A. Sheth, Joshua D. Kuban, Joshua Weintraub, Eric Wehrenberg-Klee, Paula Novelli, Carin Gonsalves, Robert Adamo, Virgina Honaker, Laura Timciuc, Tarin Hennegan, Juan C. Amador Molina, Dzifa Duose, Edwin R. Parras Cuenta, Anthony Lucci, Salyna Meas, Vanessa Sarli, Victor G. Prieto, Jason LaPorte, Ann-Marie Hulstine, Ashley Moody, Bryan Cox, David Geller, Diwakar Davar, Kamaneh Montazeri, Marlana Orloff, Steven C. Katz, Richard Carvajal. PERIO-01: Initial safety experience and immunologic effects of a Class C TLR9 agonist using pressure- enabled drug delivery in a phase 1 trial of hepatic arterial infusion of SD-101 +/- checkpoint inhibition in metastatic uveal melanoma [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 5881.

Background: Recently, neoadjuvant immunotherapy plus chemotherapy has been approved for treatment of resectable non-small cell lung carcinoma (NSCLC). Defining the immune landscape of these tumors and its spatial distribution will help to understand lung cancer biology. Here, we analyzed the distribution of immune-related biomarkers in tumor-defined regions and its associations with clinicopathological variables in resected lung adenocarcinomas using high-plex profiling approaches. Methodology: Thirty-three FFPE tumor tissues from surgically resected treatment-naïve lung adenocarcinoma stage I/II were used to construct a tissue microarray from the MD Anderson ICON cohort. We used three 1-mm core per patient [2 from central tumor (CT), and 1 from invasive margin (IM)] and performed the GeoMx Digital Spatial Profiling protein protocol to assess 49 immune biomarkers. Pancytokeratin (panCK; epithelial), CD45 (immune) and SYTO 13 (nuclear) were utilized as morphology biomarkers. Regions of interests were placed in cores containing tumor, and segmented in ‘”Tumor (Tu)” (PanCK+) and the “tumor microenvironment (TME)” (PanCK-). Digital counts were normalized using background correction. Statistical analysis was performed using linear mixed model. A p value equal or less than 0.05 was considered significant. Results: We first compared the relative counts of immune biomarkers in the TME in CT and IM. IM had higher CD3, CD8, CD45RO, as well as CD163 and STING (P ranges 0.006 to 0.035), while CT had higher PD1 (P 0.025). Then we analyzed differential biomarker expression by sex and smoking status. Females had higher counts of Immune related biomarkers: CD45, CD3, CD20, immune checkpoints: PD-L1, VISTA, CTLA4, LAG3, and ICOS, and myeloid: CD68, CD11c, CD163, and B2M (P ranges 0.0005 to 0.046). Smokers had higher counts of CD66b (P 0.007) and B2M (P 0.039) while never smokers had higher counts of HLA-DR, CD34, FoxP3, OX40L, Tim-3, and B7-H3 (P ranges 0.001 to 0.049). Finally, we analyzed Tu segments. IM had higher CD66b, VISTA, CD163, OX40L, HLA-DR, GZMB, STING, and CD8 (P ranges 0.007 to 0.045) than CT. Female patients had higher CD45, CD68, CD11c and CD163 (P ranges 0.008 to 0.045), and males had higher SMA (P 0.005). Smokers had higher CD66b (P 0.007), B2-microglobulin (P 0.043), and never smokers had higher HLA-DR, STING, CD34, CD44, FoxP3 and CD25 (P ranges 0.006 to 0.043). Conclusions: In this study, biomarker analysis of treatment-naïve adenocarcinoma in CT areas and IM indicates a higher immune response in the IM and presence of inhibitory signaling inside the tumor. Our data also showed that tumors from females have higher immune response than tumors from males, which is concordant with previous studies. Distinct profiling by smoking status was also observed. Further analysis of gene expression analysis of this set is ongoing. Citation Format: Sharia D. Hernandez, Wei Lu, Alejandra G. Serrano, Claudio J. Arrechedera, Beatriz Sanchez-Espiridion, Nejla Ozirmak, Max Molina, Larisa Kostousov, Sean Barnes, Khaja Khan, Ximing Tang, Junya Fujimoto, Edwin R. Parra, Gabriela Raso, Stephanie T. Schmidt, Carmen Behrens, John Heymach, Jianjun Zhang, Ken Chen, Boris Sepesi, Tina Cascone, Don Gibbons, Ignacio I. Wistuba, Cara Haymaker, Luisa M. Solis. Spatial profiling of immune biomarkers in resected treatment-naïve early stage lung adenocarcinoma. [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 4460.

Introduction: HER2 protein expression by immunohistochemistry (IHC) has been the main testing method for breast and gastric cancers. Much remains unknown about the frequency of HER2-low (IHC 1+ or 2+) expression and the change of HER2 status from primary to metastatic tumor samples. There is limited data available about the HER2-low frequency in solid tumors beyond breast and gastric/gastroesophageal (GEJ) cancer. Methods: HER2 IHC was performed in 923 patients (pts) with metastatic breast and 51 pts with gastric/GEJ cancers in CLIA-certified labs. We evaluated the HER2 IHC in paired primary and metastatic samples in breast cancer. We also assessed the HER2 status in non-breast, non-gastric/GEJ histologies. In available cases, concurrent HER2 genomic alterations were evaluated. Results: A total of 867 pts with breast cancer had a definitive HER2 IHC score for their metastatic sample: 101 pts (11.6%) were 3+, 171 pts (19.7%) were 2+, 252 pts (29%) were 1+ and 343 (39.6%) had no HER2 expression. The HER2 IHC scores in metastatic samples as compared to primary was in concordance in 54.9% of cases, while HER2 3+ remained unchanged in 87.2%, kappa=0.85 with a 95% CI = (0.79, 0.91). In 48 cases with metastatic gastric/GEJ cancer, HER2 was: 3+ in 2 pts (4.2%), 2+ in 5 pts (10.4%), 1+ in 9 pts (18.8%) and 32 (66.7%) had no HER2 expression. In non-breast and non-gastric/GEJ cancers, HER2-low was found in 631 pts (33.5%) as shown in the table below. A total of 1,552 pts who had HER2 IHC also had genomic testing: 36 had HER2 activating mutations, 48 had HER2 amplification (amp) and 3 had HER2 amp and mutations. 22 of 33 pts with HER2 mutations (without amp) had HER2 IHC expression: 10 pts (30%) were 1+, 10 (30%) were 2+ and 2 (6%) were 3+. Conclusion: Our results show that HER2-low expression is frequently found across tumor types and HER2 activating mutations are enriched in cancers where HER2 is expressed. These findings suggest that a high number of pts with solid tumors with HER2-low expression could potentially benefit from HER2 directed therapies. HER2 expression in solid tumors Cancer Types HER2 expression levels (IHC) Total* 3+(N pts) 3+(%) 2+(N pts) 2+(%) 1+(N pts) 1+(%) 0 (N pts) 0 (%) Appendiceal 0 0 3 6 8 16 39 78 50 Cancer of Unknown Primary 2 4 8 15 15 28 29 54 54 Cholangiocarcinoma 5 4 15 12 35 29 67 55 122 Colorectal 19 3 46 8 118 20 394 68 577 Endometrial 16 13 49 39 10 8 52 41 127 Gallbladder 3 9 8 24 7 21 15 45 33 HNSCC 2 9 1 4 4 17 16 70 23 Salivary 6 13 10 21 14 29 18 38 48 Hepatocellular Carcinoma 0 0 8 25 6 19 18 56 32 Non-small cell lung cancer 6 3 31 15 68 33 100 49 205 Ovarian/Fallopian Tube 4 5 17 20 11 13 53 62 85 Pancreas 1 1 5 7 16 24 45 67 67 Prostate 0 0 0 0 4 13 27 87 31 Renal Cell Carcinoma 0 0 0 0 1 5 18 95 19 Sarcoma 0 0 1 3 1 3 35 95 37 Small Bowel Cancer 2 9 2 9 1 4 18 78 23 Thyroid 0 0 0 0 2 4 54 96 56 Urothelial Carcinoma 38 22 48 27 32 18 57 33 175 *more than 15 samples available; HNSCC=head and neck squamous cell carcinoma Citation Format: Burak Uzunparmak, Cara Haymaker, Gabriela Raso, Chen Zhu, Serena Masciari, Lei Wang, Bryce Kirby, Heather Lin, Aysegul Gorur, Ann-Marie Cimo, Amber Kennon, Qingqing Ding, Andrea Palmieri, Gabriele Elizabeth Urschel, Ying Yuan, Guoxin Feng, Yasmeen Rizvi, Aisha Hussain, Vivek Subbiah, Timothy Anthony Yap, Jordi Rodon-Ahnert, Sarina Anne Piha-Paul, David S. Hong, Funda Meric-Bernstam, Ecaterina E. Dumbrava. HER2-low expression in patients with advanced or metastatic solid tumors [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 961.

Pancreatic ductal adenocarcinoma (PDAC) is a highly fatal tumor-type with very few effective treatment strategies. Attempts to improve outcomes using immune checkpoint blockade therapy have also failed, likely because the overall Tcell infiltration in this tumor-type is low. Despite this, the presence of CD3+CD8+ tumor-infiltrating lymphocytes (TIL) in PDAC is associated with improved survival outcomes, suggesting that other immune-based strategies could be more successful. Here, we examine ex vivo tumor-infiltrating Tcell expansion for adoptive Tcell therapy (ACT) as a potential strategy for treating PDAC. The focus of this study is to understand the transcriptional states of Tcells in the pancreas and PDACs and how they change with ex vivo expansion and re-infusion into patients as treatment strategy. We have performed both single cell transcriptome and TCR sequencing (scRNA-TCRseq) on 54,579 Tcells from 8 human PDAC samples and the ex vivo grown TIL from a subset of 6 patients and found 13 purported substates. Through TCR tracking of the Tcell clonotypes, we find that the expansion protocol is able to expand Tcells found in many different Tcell states in the primary tumor. Furthermore, we compared our thirteen tumor-infiltrating substates with 41,935 Tcells from two other independent single cell studies across 71 samples, and confirmed our substates to be present across all datasets. Citation Format: Aislyn Schalck, Donastas Sakellariou-Thompson, Marie-Andrée Forget, Emi Sei, Tara Hughes, Shanshan Bai, Min Hu, Tapsi Kumar, Mark Hurd, Matthew Katz, Chine-Wei Tzeng, Shubham Pant, Milind Javle, Anirban Maitra, Cara Haymaker, Michael Kim, Nicholas Navin, Chantale Bernatchez. Simultaneous TCR and transcriptomic sequencing of single Tcells defines biological subtypes in pancreatic cancer for adoptive Tcell therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2847.

Background: In the Phase III randomized trial (SWOG Lung-MAP S1400I non match trial), adding ipilimumab (I) to nivolumab (N) did not improve survival of patients with advanced, pretreated, immune checkpoint inhibitor naive lung squamous cell carcinoma (SCC). The I+N combination demonstrated superiority in patients with a tumor mutation burden (TMB) ≥10 mt/MB and PD-L1 expression Methods: RNA extracted from baseline FFPE samples from 66/252 patients enrolled in the S1400I trial was received from the SWOG bank with 28 samples considered inadequate due to low input RNA. 38 samples were run on the ncounter platform using the PanCancer Immune Profiling panel using the manufacturer’s instructions with the addition of Human Reference RNA control. Data were processed and normalized using nSolver. All samples passed the post run QC with no batch effect. Using a log-rank test on dichotomized normalized data, we performed time to event analysis to identify genes that correlated with overall survival (OS) and PFS (Progression Free Survival) for all 38 samples and for each arm (23 N and 15 I+N). We ran a Cox model using significant genes identified independently and in association with TMB≥10 and PD-L1 ≥5 thresholds identified in the clinical studies. TIMER and nSolver advanced analysis were used to infer immune cells that correlated to clinical outcomes. Results: We observed that BLNK, CD163, FCGR2A associated with increased OS (p Conclusion: Despite a small dataset, this analysis shows a potential advantage in PFS and OS with increased presence of immune cells including exhausted CD8+ T cells and genes associated with myeloid cells. Validation of these findings is warranted and may refine patient populations that would benefit from this combination strategy. Acknowledgments: Scientific and financial support: U10CA180888, U10CA180819, U24CA224285, U24CA224316, PACT, PPP and FNIH Citation Format: Dzifa Y. Duose, Jiexin Zhang, Mary Redman, Baili Zhang, Ethan Cerami, James Lindsay, Joyce Yu, Roshni Biswas, Stephen Van Nostrand, Radim Moravec, Rajyalakshmi Luthra, Gheath Al-Atrash, Karen Kelly, Roy Herbst, Ignacio Wistuba, Scott Gettinger, Lyudmila Bazhenova, J. Jack Lee, Jianjun Zhang, Cara Haymaker. Immune gene expression signatures associated clinical benefit from nivolumab and ipilimumab for previously treated patients with stage IV squamous cell lung cancer: An immune biomarker analysis of phase III SWOG LungMAP S1400I trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1974.

Background: Lung squamous cell carcinoma (SCC) is the second most common type of non-small cell lung cancer. Immunotherapy is a promising treatment for SCC. However, only a small proportion of unselected SCC patients are able to achieve durable clinical benefit. We leveraged the precious specimens from S1400I trial and sought to explore whether the levels and spatial distributions of tumor-associated immune cells (TAICs) in screening samples are associated with PFS, and OS. Methods: We utilized paraffin tumor tissue provided by the SWOG bank from screening on LungMAP. 82/252 eligible SCC sample from patients treated with nivolumab plus ipilimumab (nivo+ipi; n = 35) or with nivolumab alone (nivo; n = 47) were studied. Image analysis tissue immunoprofiling was conducted using 9 markers in 2 multiplex immunofluorescence panels against cytokeratin, CD3, CD8, granzyme B, CD45RO, and FOXP3, PD1, PD-L1, and CD68. Densities of cells phenotypes (cells/mm2) were assessed and dichotomized as being high (> median) or low (≤ median) in tumor, stroma, and total compartments. Distances from malignant cells (MCs) to cell populations were measured and dichotomized as close from MCs (≤ median) and faraway from MCs (> median) and associated with clinical variables. Clinicopathologic features and data on PFS, and OS were retrieved from the CIDC portal as provided by the LungMap team. Non-parametric tests where utilized to assessment associations of cell phenotypes versus continue or categorical variables and log-rank test for survival analysis. Results: Univariate analysis showed that higher densities of memory T cells in total compartment (HR:0.63, CI:0.40-1.00, P=0.041), antigen-experienced T cells in the stroma (HR:0.60, CI:0.37-0.96, P=0.024) and total compartment (HR:0.60, CI:0.38-0.95, P=0.023) and activated cytotoxic T cells in the tumor compartment (HR:0.55, CI:0.35-0.87, P=0.011) were associated with significative better PFS. In the nivo+ipi arm, higher ratios of cytotoxic T cells to regulatory T cells in the stroma were associated with better PFS. The spatial analysis of these TAICs showed that the presence of activated cytotoxic T cells close to the MCs (median, ≤19.27 µm) was associated with better PFS (P=0.037). Conclusions: Our findings suggest that patients who have a detectable immunosuppressive tumor axis (PD-L1/PD1) with adequate activated cytotoxic T cells close to the tumor cells are the ideal patients for immune therapy to be targetable with these types of treatments. Acknowledgments: Scientific and financial support for: U10CA180888, U10CA180819U24CA224285, U24CA224316, PACT, PPP and FNIH. Citation Format: Edwin Roger Parra, Jiexin Zhang, Mary Redman, Rossana Lazcano, Piubelli Mario, Caddie Laberiano Fernandez, Renganayaki K. Krishna, Shanyu Zhang, Hong Chen, Ganiraju Manyam, Radim Moravec, Ethan Cerami, James Lindsay, Joyce Yu, Roshni Biswas, Stephen Van Nostrand, Dzifa Y. Duose, Jianjun Zhang, Roy Herbst, Gheath Al-Atrash, Kasthuri Kannan, Ignacio I. Wistuba, Scott Gettinger, Lyudmila Bazhenova, Jack Lee, Jianhua Zhang, Cara Haymaker. Infiltration and spatial distribution of immune cells are associated clinical benefit from Nivolumab and Ipilimumab for previously treated patients with stage IV squamous cell lung cancer: an immune biomarker analysis of Phase III SWOG LungMAP S1400I trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2580.

Background: Our understanding of the immunopathology of early-stage NSCLC is still limited. While neoadjuvant immunotherapeutic strategies have recently shown anti-tumor effects in resectable NSCLC, their mechanisms remain inadequately understood. Here, we explore immune programs that inform of tumor immunity and response to neoadjuvant chemotherapy and chemoimmunotherapy in localized NSCLC. Methods: Targeted immune gene sequencing using the HTG Precision Immuno-Oncology panel was performed in localized NSCLCs from three cohorts based on treatment: naïve (n=190), neoadjuvant chemotherapy (n=38) and neoadjuvant chemoimmunotherapy (n=21). Three tumor immune microenvironment (TIME) phenotypes (inflamed, cold, excluded) were derived based on CD8+ T cell infiltration. Signatures of immune cell abundance and immune genes were statistically compared based on tumoral PD-L1 expression, immune phenotypes, associated with pathological response, and were cross-compared across the three cohorts. Results: PD-L1 positive tumors exhibited increased signature scores for various lymphoid and myeloid cell subsets (both, p Conclusions: Our findings highlight immune gene programs that may underlie host tumor immunity and response to neoadjuvant chemotherapy and chemoimmunotherapy in early-stage NSCLC. Citation Format: Pedro Rocha, Jiexin Zhang, Raquel Laza-Briviesca, Alberto Cruz-Bermúdez, Katsuhiro Yoshimura, Carmen Behrens, Apar Pataer, Edwin Parra-Cuentas, Cara Haymaker, Junya Fujimoto, Stephen Swisher, John Heymach, Don L. Gibbons, J Jack Lee, Boris Sepesi, Tina Cascone, Luisa M. Solis, Mariano Provencio, Ignacio I. Wistuba, Humam Kadara. Distinct immune gene programs associated with host tumor immunity, neoadjuvant chemotherapy and chemoimmunotherapy in resectable NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6152.

The use of immune-checkpoint inhibitors (CPI) has become an important modality in the treatment of metastatic melanoma (MM). However, most patients (pts) do not experience durable responses and new treatment options are needed to improve clinical outcomes. Our pre-clinical studies have demonstrated that intratumoral CD40 activation synergizes with anti-PD-1 based therapy and induces systemic and distant anti-tumor effects. In this ongoing phase I/II study, we assessed intratumoral sotigalimab (APX005M), a CD40 agonist antibody, in combination with systemic pembrolizumab in CPI treatment naïve, unresectable stage III or IV MM. A total of 40 participants will be enrolled. As of December 15, 2021, 30 pts were enrolled. Pts received sotigalimab every 3 weeks for a total of 4 doses. The dose escalation portion of the trial has been completed, with 14 pts enrolled in 5 dosing cohorts of sotigalimab at 0.1, 0.5, 1, 3 and 10 mg. The primary objectives include safety and tolerability, determination of the recommended phase 2 dose (RP2D), and assessment of the overall response rate (ORR) by RECIST v1.1. Biomarker analyses of blood and tumor samples were performed to measure immune activation using immunophenotyping including imaging mass cytometry, TCR sequencing, and a cross-cohort comparison of gene expression data (sotigalimab plus pembrolizumab versus anti-PD1 monotherapy). The combination therapy has been well-tolerated, and there were no study discontinuations or death due to treatment-related adverse events (TRAEs). Most common TRAEs were injection-site reactions; six pts experienced grade-3 immune-related adverse events. Efficacy analysis of 30 pts with post-baseline disease evaluations demonstrated an ORR of 50% (5 CR and 10 PR) in distant lesions and a disease control rate of 67%. The ORR at the RP2D of 10 mg is 55% (12/22). Responses were observed in PD-L1 negative pts and those with elevated LDH. Comprehensive transcriptome and immune cell profiling of peripheral blood mononuclear cells and tumor biopsies obtained from local lesions at baseline and 24 hours post sotigalimab injection demonstrate that sotigalimab effectively engaged CD40 pathway. In comparison to anti-PD1 monotherapy, the combination therapy significantly increased expression of genes associated with antigen presentation and effector T cells in local lesions accompanied by an increase in T cell activation genes at distant lesions. Additionally, T cell repertoire analysis demonstrated a significant increase in T cell clonality with expansion of new clones shared between local and distant tumors. Importantly, these immunologic changes were correlated with clinical response. Collectively, this combination therapy is well tolerated and has a notable clinical response rate, accompanied by broad innate and adaptive immune activation at both local and distant lesions. Citation Format: Salah-Eddine Bentebibel, Daniel Johnson, Rodabe Amariae, Daniel McGrail, Srisuda Lecagoonporn, Cara Haymaker, Dzifa Duose, Khalida Wani, Houssein Safa, Isabella Claudia Glitza, Sapna Pradyuman Patel, Michael K. Wong, Hussein Tawbi, Jared Burks, Xiaodong Yang, Patrick Hwu, Cassian Yee, Michael A. Davies, Ravi Murthy, Chantale Bernatchez, Suhendan Ekmekcioglu, Adi Diab, Gregory Lizée. Intratumoral CD40 agonist sotigalimab with pembrolizumab induces broad innate and adaptive immune activation in local and distant tumors in metastatic melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT039.

Introduction: Differences in the host immune environment are thought to mediate heterogeneous treatment responses in non-small cell lung cancer (NSCLC). Unlike individual platform analyses, integrative analysis of multi-platform profiling allows for the discovery of novel interactions that expand our understanding of the disease. Utilizing the ImmunogenomiC prOfiling of NSCLC patient cohort (ICON), a prospective multi-omics protocol of operable early-stage NSCLC tumors with integrated immune, genomic, and clinical data, we hypothesized that multi-platform analyses would identify differences in the immune-genomic landscape that are associated with disease recurrence. Methods: Tumor and tumor-adjacent uninvolved lung was collected at resection; blood was collected before and after surgery. Tissue samples underwent WES, RNAseq, TCR sequencing (TCRseq), multiplex immunofluorescence (mIF), and RPPA profiling; tissue and blood (PBMC) samples were analyzed by flow cytometry. An integrated, inter-modality network was built using Spearman correlations between measurement pairs from different data modalities. Multivariate analysis was performed to adjust for stage and histology. Results: A total of 89 treatment-naïve patients with Stage 1-3 resected NSCLC (Squamous: 19; Non-squamous: 70) and 24 months of follow-up were analyzed (recurrence N = 24; no recurrence N = 65). The data network includes over 4,000 measurements linked by over 50,000 correlations. InfoMap, a community detection approach, was used to extract sub-network modules, which were used to contextualize the results of multivariate analysis. Tumors from patients with recurrence demonstrated decreased immune cell infiltration and activation including decreased cytotoxic CD8 T-cells (CD8+PD1+; fold-change (FC) = 0.898, p = 0.018; flow cytometry), decreased T-cell clonality (FC = 0.954, p = 0.017; TCRseq), and decreased tumor-associated macrophages (CD68+PD-L1+; FC = 0.426, p = 0.011; mIF). Furthermore, circulating CD8+ICOS+ activated T cells were decreased in patients with recurrence suggesting an impaired systemic anti-tumor immune response (FC = 0.552, p = 0.042; PBMC Flow). Finally, tumor-adjacent uninvolved lungs showed distinct T-cell phenotypes with accumulation of inactive CD8 T-cells (CD8+PD1-TIM3-) in patients with recurrence and increased populations of activated CD8 T-cells (CD8+PD1+) in patients without recurrence. Conclusion: Integrative multi-omic analysis suggests preserved anti-tumor immune surveillance in patients who are disease-free after 2 years from surgical resection with curative intent for treatment of NSCLC relative to patients with disease recurrence. Further analysis is ongoing to interrogate genomic and immune variables that are associated with disease recurrence. Citation Format: Neal Akhave, Stephanie Schmidt, Alexandre Reuben, Tina Cascone, Jianhua Zhang, Jun Li, Junya Fujimoto, Lauren A. Byers, Beatriz Sanchez-Espiridion, Lixia Diao, Jing Wang, Lorenzo Federico, Marie-Andree Forget, Daniel J. McGrail, Annikka Weissferdt, Shiaw-Yih Lin, Younghee Lee, Carmen Behrens, Ignacio I. Wistuba, Andrew Futreal, Ara Vaporciyan, Boris Sepesi, John V. Heymach, Chantale Bernatchez, Cara Haymaker, Jianjun Zhang, Christopher A. Bristow, Marcelo V. Negrao, Don L. Gibbons. Integrated multi-platform profiling of early-stage non-small cell lung cancer identifies relationship between disease recurrence and decreased native immune response in treatment-naïve resected NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 619.

Sarcomas encompass a rare but highly diverse set of tumor malignancies, contributing disproportionately to years of life lost. Immune checkpoint blockade (ICB) has been successful across various tumor types; however, their efficacy and predictability in sarcomas remain unknown. We conducted a translational study using pre- and on-treatment tumor biopsies collected prospectively on a Phase II clinical trial (NCT02815995) evaluating the role of combination anti-PD-L1 and anti-CTLA-4 in 57 patients, enrolled across multiple histologies of metastatic sarcoma. We obtained tumor biopsies at baseline and after 6 weeks of treatment and performed whole-exome, T-cell repertoire (TCR) and RNA-sequencing, along with multiplexed-immunofluorescence (mIF).We deconvoluted substantial variability present in the tumor microenvironment (TME) within sarcomas and found instances of relatively inflamed tumors which failed to respond to ICB. However, amongst those potential molecular correlates of response analyzed, elevated levels of B-cells both at the transcriptome and through validation staining (p = 0.047 and p = 0.022) were most significantly correlated with response. In order to gain more insight into the phenotype and function of B-cells in contributing to response, we inferred BCR-templates and found higher levels of both IGH and IGL diversity (p = 0.0276 and p = 0. 0889 respectively) in responders to ICB. Additionally, we detected increased levels of hyperexpanded IGH clones at the on-treatment time point in patients that responded to therapy (p = 0.048). This B-cell enrichment was validated and found to be predictive of response (p = 0.043) in an independent sarcoma anti-PD-1 treated cohort with matched molecular data. Responsive tumors were also associated with higher levels of TCR richness indicating a strong association of diversity in the TCR of responders (p = 0.047). This work demonstrates the potential for multi-lineage immune cell enrichment and frames the potential molecular features of the TME that may influence response in ICB treated sarcomas. Citation Format: Akash Mitra, Neeta Somaiah, Anthony P. Conley, Behrang Amini, Heather Lin, Beatriz E. Sanchez, Celia Garcia-Prieto, Grace Mathew, Chantale Bernatchez, Vinod Ravi, Dejka Araujo, Maria A. Zarzour, John A. Livingston, Christina L. Roland, Najat Daw, Joshua Baguley, Wei-Lien Wang, Hannah Beird, Taylor Tate, Cara Haymaker, Latasha D. Little, Curtis Gumbs, Xingshi Song, Emily Z. Keung, Shaojun Zhang, Swati Gite, Jianhua Zhang, Luisa Solis, Hussein Tawbi, Linghua Wang, Shreyaskumar Patel, Robert S. Benjamin, Alexander J. Lazar, Ignacio I. Wistuba, Andrew Futreal. Immunogenomic correlates of response to combination immune checkpoint blockade in advanced sarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 518.

Background: We have previously demonstrated that the presence of a proinflammatory peripheral cytokine milieu correlates with high levels of circulating neutrophils at the time of surgery and reduced overall survival and recurrence-free survival. In this study, we hypothesized that functional immune features or states in circulation may indicate early tumor recurrence when assessed longitudinally. We also investigated whether potential deficiencies in peripheral immune functionality at the time of lung cancer resection could identify correlates with subsequent outcome. Methods: We performed flow cytometry and luminex profiling of blood samples collected from patients with stage I-IIIA resected NSCLC (n=150) and enrolled on the Immunogenomic profiling of NSCLC (ICON) prospective protocol. Patient characteristics include 75 adenocarcinomas, 30 squamous and 12 mixed or other histologies. Only patients who underwent primary cancer resection without neoadjuvant therapy were included. At a median follow up of 18.2 months, 37 patients had disease recurrence. Blood was collected at the time of primary lung cancer resection, at 4 weeks, and 4 months thereafter with PBMCs utilized for flow cytometry and plasma for cytokine assessment. Changes in cytokines were assessed by normalizing to baseline levels. Results: Larger tumors as well as advanced clinical and pathological stages were associated with higher frequencies of proliferating Ki67+CD4+ and Ki67+CD8+ T cells in circulation at time of resection, suggesting an activated circulating immune response. We identified novel strong correlations in the plasma between soluble BTLA and Tim3 (r= 0.87, p=1.74e-140), PD1 and CD80 (r=0.72, p=6.41e-74) and moderate correlations between soluble PD1 and PDL1 (r=0.39, p=8.41e-18). Efforts are ongoing to determine the association of specific circulating immune states with the presence of these soluble receptors. CD8+Tim3+ T cells (FC=5.2%, p=0.028) and CTLA4+NK cells (FC=47.7%, p=0.002) as well as CTLA4+Tregs (FC=25.2%, p=0.05) were found to be increased in circulation at pre-recurrence time points (either 4 weeks or 4 months) relative to resection. This suggests the emergence of a suppressive cell type as well as induction of specific checkpoint receptors on effector cells that correlate with tumor recurrence. Finally, we identified a cytokine signature associated with recurrence by testing three sets within the ICON cohort with a training set AUC = 0.76 and the test set AUC=0.72, which was validated in a third set of patients yielding an AUC = 0.76. Conclusions: We identified circulating immune features associated with initial tumor size and overall stage as well as unique associations among soluble proteins. Increased presence of potentially inhibited or suppressed CD8+ T cells and NK cells as well as Tregs are suggestive of mechanisms of immune suppression relative to tumor recurrence. Citation Format: Younghee Lee, Daniel McGrail, Hai Tran, Mayra E. Vasquez, Carlos Ramos, Alexandre Reuben, Ara A. Vaporciyan, Annikka Weissferdt, Chantale Bernatchez, Tina Cascone, Ignacio I. Wistuba, Jianjun Zhang, John Heymach, Marcelo V. Negrao, Don L. Gibbons, Boris Sepesi, Cara L. Haymaker. Circulating biomarkers are associated with recurrence following complete resection of non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1670.

The purpose of this study was to determine the role of BAP1 levels in cutaneous melanoma (CM). BAP1 is a tumor suppressor in which loss of heterozygosity (LOH) from mutation and copy number alteration is well described in germline and somatic cancers. Although BAP1 genomic alterations in CM are extremely rare (2% of 665 samples from 5 datasets), marked variability in BAP1 expression is observed in CM. We show that low nuclear BAP1 levels portend a significantly worse clinical outcome in stage III CM (n=37, log rank p ≤0.01 for both overall survival and progression-free survival). Gene Set Enrichment Analysis (GSEA) revealed low BAP1 expression to be most highly ranked with an increased epithelial–mesenchymal transition (EMT) gene expression profile in CM tumors (n=379, FDR q = 1.34E-26) and cell lines (n=53, FDR q = 2.86E-116). We identify the expression of ZEB1, a master regulator of EMT, to be significantly associated with low BAP1 expression in CM tumors and cell lines (p= 1.5E-04 and 3.3E-05, respectively). Analysis of the BAP1 promoter indicates three canonical ZEB1 binding sites. Functional experiments show ZEB1 to bind to the BAP1 promoter, and luciferase activity assays indicate that ZEB1 acts as a transcriptional suppressor of BAP1 expression with differential utilization of the promoter binding sites. Targeted reduction of endogenous ZEB1 caused increased BAP1 levels, while targeted reduction of BAP1 did not modulate ZEB1 levels, consistent with ZEB1 having a suppressive effect on BAP1. Phenotypically, targeted reduction of BAP1 in CM cells resulted in a switch from a more differentiated, melanocytic state, to a less differentiated, more migratory and invasive phenotype. Extinguishing melanocyte-specific BAP1 in mice with a BRAF V600E mutant genetic background resulted in the emergence of primary melanoma tumors, with a marked EMT gene expression profile, and resultant metastases. Given the phenotypic changes associated with BAP1 levels in our mouse and human studies, we then tested the effect of modulating BAP1 on BRAF targeted therapy. Exogenous expression of BAP1 sensitized BRAF inhibitor (vemurafenib)-resistant melanoma cells, while the targeted reduction of BAP1 desensitized BRAF inhibitor-sensitive melanoma cells. BRAF mutant/BAP1 loss mice failed to exhibit a marked response to vemurafenib treatment compared to control mice. These data implicate regulation of BAP1 to be a major mechanism that characterizes a highly malignant and treatment-resistant subset of tumors. Our study indicates that nongenomic reduction in BAP1 through ZEB1 transcriptional modulation may be a key factor in aggressive CM. This abstract is also being presented as Poster A30. Citation Format: Haifeng Zhu, Junna Oba, Xiaoxing Yu, Caitlin A. Creasy, Marie-Andrée Forget, Fernando Carapeto, Cara L. Haymaker, Chang-Jiun Wu, Tatiana V. Karpinets, Wei-Lien Wang, Michael T. Tetzlaff, Alexander J. Lazar, Gordon B. Mills, Amanda R. Moore, Yu Chen, Jianhua Zhang, Jeffrey E. Gershenwald, Jennifer A. Wargo, Chantale Bernatchez, Patrick Hwu, P. Andrew Futreal, Scott E. Woodman. Nongenomic BAP1 aberrancy drives highly aggressive cutaneous melanoma phenotype [abstract]. In: Proceedings of the AACR Special Conference on Melanoma: From Biology to Target; 2019 Jan 15-18; Houston, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(19 Suppl):Abstract nr PR03.

Background: Tilsotolimod, an investigational Toll-like receptor 9 (TLR9) agonist, modulates the tumor immune microenvironment and has single-agent antitumor activity in preclinical models. The ILLUMINATE-101 phase 1b study (NCT03052205) explored the safety, efficacy, and immune effects of intratumoral tilsotolimod in multiple solid tumors. Methods: Adults with a histologically- or cytologically-confirmed diagnosis of cancer not amenable to curative therapies received intratumoral tilsotolimod 8, 16, 23, or 32 mg into a single lesion on Days 1, 8, and 15 of Cycle 1 and Day 1 of each subsequent 3-week cycle, for up to 17 cycles. Additionally, patients with advanced melanoma were enrolled into an expansion cohort at the recommended phase 2 dose of 8 mg. The primary objective was to characterize safety (dose escalation cohort) and efficacy (expansion cohort). Secondary objectives included pharmacokinetics of tilsotolimod. Immunological assessment of injected and non-injected tumors was an exploratory objective. Blood samples and tumor biopsies of injected lesions were obtained at baseline and 24 hours post treatment for immune analyses. Results: A total of 54 patients were enrolled. Of the 38 patients in the dose escalation cohort, 35 had metastatic disease. Patients in this cohort had a median of 7 prior lines of treatment, and the most common cancer types were pancreatic (12 patients) and colorectal (7 patients). All 16 patients in the melanoma cohort had metastatic disease with a median of 3 lines of prior therapy, and 10 patients had elevated LDH. Injected lesions were deep and required interventional radiology in 52 of 54 patients. No dose-limiting toxicities were observed. The most common treatment-related adverse events were pyrexia, fatigue, chills, nausea, and vomiting. Compared to pretreatment, biopsies of injected tumors at 24 hours showed increased activation of the Type-I IFN pathway, upregulation of MHC class I/II, IFNγ expression, and expression of multiple immune checkpoints (i.e. PD-1, LAG3). Of the 35 evaluable patients in the dose escalation cohort, 12 (34%) achieved a best overall response of stable disease (SD). Of the 16 evaluable patients in the melanoma cohort, 3 had SD, 1 who had a 35% tumor reduction with no confirmatory scan. Conclusions: Tilsotolimod was generally well tolerated and induced alterations in the tumor microenvironment, including immune checkpoint upregulation, activation of dendritic cells, and induction of Type-I IFN signaling. Additional clinical studies of tilsotolimod in combination with checkpoint inhibitors are underway (NCT03445533, NCT03865082, and NCT02644967). Citation Format: Hani M. Babiker, Vivek Subbiah, Asim Ali, Alain Algazi, Jacob Schachter, Michal Lotem, Corinne Maurice-Dror, Daniel Hendler, Shah Rahimian, Hans Minderman, Cara Haymaker, Chantale Bernatchez, Ravi Murthy, Rolf Hultsch, Nadia Caplan, Gregory Woodhead, Charles Hennemeyer, Sri Chunduru, Peter Anderson, Adi Diab, Erkut Borazanci, Igor Puzanov. Tilsotolimod engages the TLR9 pathway to promote antigen presentation and Type-I IFN signaling in solid tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT134.

While checkpoint inhibitor therapy has transformed treatment of multiple tumor types, many patients remain refractory. Tilsotolimod, a toll-like receptor 9 agonist, has been shown in preclinical models to activate plasmacytoid dendritic cells and increase T cell infiltration to the tumor microenvironment. Preliminary results of a phase 1/2 study suggested that intratumoral injection of tilsotolimod in combination with ipilimumab may revive an immune response in patients with immune checkpoint inhibitor-resistant metastatic melanoma. To further explore the role of tilsotolimod in modulating the tumor immune microenvironment, we conducted a Phase Ib monotherapy trial (ILLUMINATE-101). Adults with histologically or cytologically confirmed diagnosis of cancer not amenable to curative therapies received intratumoral tilsotolimod in doses escalating from 8 mg to 32 mg into a single lesion at weeks 1, 2, 3, 5, 8, and 11. Objectives of the dose evaluation portion included characterizing safety and pharmacokinetics, and evaluating alterations in the tumor microenvironment. Blood samples and tumor biopsies of injected and distal lesions were obtained at baseline and on treatment. Immune analyses included evaluation using Nanostring and/or flow cytometry of activation of the type 1 interferon (IFN) pathway, IFN gamma levels, activation of dendritic cell subsets, and changes in T cell status. As of November 7, 2018, 41 patients have been enrolled, including 38 patients into the dose evaluation portion and 3 patients into a melanoma expansion cohort. No dose-limiting toxicities or treatment-related adverse events have been observed. Within 24 hours, fresh tumor biopsies showed significant increases in IFN gamma levels, activation of the type 1 IFN pathway, induction of an antigen processing gene signature (a measure of the MHC class I antigen presentation pathway), and maturation of dendritic cells as measured by expression of HLA-DR (MHC class II), compared to pretreatment biopsies. Of 25 evaluable patients who received at least 1 dose of tilsotolimod and had at least 1 post-baseline disease assessment, 12 (48%) had a RECIST v1.1 disease assessment of stable disease. For patients with at least one disease assessment following documentation of stable disease (n=8), duration of stable disease ranged from 0.53 to 4.2+ months, with 3 patients ongoing. These results demonstrate that single agent tilsotolimod was well tolerated and induced robust alterations in the tumor microenvironment. Citation Format: Hani M. Babiker, Vivek Subbiah, Orla Maguire, Shah Rahimian, Hans Minderman, Cara L. Haymaker, Chantale Bernatchez, Erkut Borazanci, James Geib, Srinivas K. Chunduru, Peter M. Anderson, Igor Puzanov, Adi Diab. Activation of innate and adaptive immunity using intratumoral tilsotolimod (IMO-2125) as monotherapy in patients with refractory solid tumors: a phase Ib study (ILLUMINATE-101) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4062.

Background: Although immune checkpoint blockade has been successfully utilized in treating patients with non-small cell lung cancer (NSCLC), the benefit of immunotherapy for patients with advanced EGFR-mutant (EGFRm) NSCLC has been limited. Data from IMpower150 trial’s subgroup analysis suggests modulation of the tumor immune microenvironment (TME) with antiangiogenic agents and chemotherapy might enhance response to anti-PD-1/PD-L1 blockade in EGFRm lung cancers. We aim to gain a deep understanding of EGFRm NSCLC TME as the first step to make EGFRm amenable to immune therapy. Methods: We queried two cohorts of resected stage I-III lung adenocarcinomas: PROSPECT (94 tumors) and Immune Genomic Profiling of NSCLC (ICON, 76 tumors). In the PROSPECT cohort (14 EGFRm vs 80 WT), we compared 10 immune markers by IHC (PD-L1, PD-1, CD3, CD4, CD8, CD45RO, CD57, CD68, FoxP3 and Granzyme B) and 44 immune regulator genes’ expression levels and pathway signatures from microarray data. We subsequently validated the observation of differentially expressed genes in the ICON cohort (15 EGFRm vs 61 WT) using IF, RNAseq and WES. Results: In the PROSPECT cohort, lower PD-L1 (2.2 vs 10.4 H-score, p Conclusion: Our analysis showed that EGFR-mutant NSCLCs demonstrate a PD-L1 low, GzmB low, IFN-gamma low immune phenotype, suggesting a suppressive tumor microenvironment. We found that the CD8+ T cells were present in the tumor, but likely suppressed functionally by the negative regulators in the TME. These results direct future analysis of suppressive immune cell populations (CD4+ subpopulation, macrophages and dendritic cells) in EGFRm lung cancers, and represent an initial step for rationale combination of immune therapy to modulate the suppressed TME, which might lead to enhanced treatment efficacy to benefit patients with EGFR-mutant lung cancers. Citation Format: Xiuning Le, Marcelo V. Negrao, Alexandre Reuben, Won-Chul Lee, Edwin Parra, Jun Li, Tatiana Karpinets, Carmen Behrens, Boris Sepesi, Ara Vaporiciyan, Jack Roth, Cara Haymaker, Emily Roarty, Jianhua Zhang, Chantale Bernatchez, Jianjun Zhang, Ignacio Wistuba, Don Gibbons, John Heymach. Characterization of the tumor immune microenvironment in treatment-naïve EGFR-mutant NSCLC uncovers a low IFN-gamma suppressive immune phenotype [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5028.

Introduction: immune checkpoint inhibitors have revolutionized the treatment of non-small cell lung cancer (NSCLC), but only ~15% of patients will achieve durable clinical benefit. Our group and others have focused on characterizing the interaction between tumor genomic characteristics and immune microenvironment. Genes such as PTEN, CTNNB1, STK11 and KEAP1 have been associated with intra-tumor immune depletion, but a broader understanding of other key driver genes of NSCLC and their interplay with the immune microenvironment is currently lacking. To prospectively delineate the genomic and immune landscape of NSCLC, we launched the ICON Project (Immunogenomic Profiling of NSCLC). Methods: we prospectively collected tissue specimens from patients with stage I-IIIA NSCLC undergoing surgical resection. Samples were subjected to extensive immune-genomic profiling, including whole-exome and RNA sequencing, multiplex immunofluorescence (mIF), and flow cytometry. Results: from 2016-2018, 150 patients were accrued, with 78 samples having undergone genomic profiling. Most patients had stage I-II disease (74%) and non-squamous histology (70%). Most commonly mutated genes were TP53, EGFR, KRAS, CDKN2A, STK11, and mean TMB was 7.6 mut/Mb, which is comparable to TCGA (6.9mut/Mb, p=ns). Unsupervised clustering according to expression of CD8+ T cell related genes segregated tumors into immune-enriched (clusters 1 and 3) and immune-depleted (clusters 2 and 4) subgroups. We validated these findings through flow cytometry (CD8+GzB+ T cells) and mIF (CD8), with both methods showing CD8+ T cell infiltration to be enriched in clusters 1 and 3. Cluster 1 included squamous and non-squamous histology, tumors with epithelial and mesenchymal signatures, and high TMB. Cluster 2 included exclusively squamous histology with predominant mesenchymal tumor signature, high TMB, and was enriched for TP53 mutations. Cluster 3 had predominantly non-squamous histology, epithelial signature, and low TMB. Cluster 4 had exclusively non-squamous histology, predominant epithelial signature, low TMB, and was enriched for KEAP1 mutations. In addition, PD-L1 expression (by mIF) was negatively correlated with TGF-beta and WNT/Beta-catenin signaling pathway, as well as high EGFR and FGFR2 expression on malignant cells. Conclusion: CD8+ T-cell gene signature identifies immunosuppressed subgroups of lung cancer, especially among squamous cell carcinomas with a mesenchymal signature, that may be associated with resistance to immune-based therapies. TGF-beta and Wnt/beta-catenin pathways are associated with an immunosuppressed tumor microenvironment, and may be potential novel targets to restore anti-tumor immunity in lung cancers with low PD-L1 expression. Citation Format: Marcelo V. Negrao, Tatiana Karpinets, Jun Li, Alexandre Reuben, Cara Haymaker, Kyle G. Mitchell, Junya Fujimoto, Chi-Wan Chow, Edwin R. Parra, Lorenzo Federico, Jianhua Zhang, Ara A. Vaporciyan, Chantale Bernatchez, Tina Cascone, Boris Sepesi, Ignacio I. Wistuba, John V. Heymach, Jianjun Zhang, Don L. Gibbons, ICON Team. Immunogenomic profiling identifies a subgroup of squamous cell lung cancers with immunosuppressed tumor microenvironment and correlates TGF-beta and Wnt/beta-catenin signaling as predictive of low PD-L1 expression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1176.

Purpose Brain metastases can induce life-threatening events and their immune microenvironment is still unrevealed. To elucidate the probability of immune-oncology therapy for brain metastases, we utilized immune profiling of resected brain metastases and paired non-small cell lung cancer (NSCLC). Methods To compare pure tumor-infiltrating lymphocytes (TILs) or tumor tissues between NSCLC and brain metastases, macro-dissection was performed before extracting DNA and RNA from 39 patients who received surgical resection of local NSCLC tumor lesions and brain metastases from matched patients. We applied gene expression analysis of mRNA by using a 770 gene panel related with cancer immune cells. Targeted sequencing of 50 cancer hotspot genes on extracted DNA was performed for genotyping. TCRß sequencing of extracted DNA was utilized for profiling of TCR repertoire. Results We identified 161 differentially expressed genes, which reflected inhibition of dendritic cell maturation pathway, Th1 pathway, and leukocyte extravasation signaling pathway in brain metastases (p < 0.01). VCAM1 was one of highly inter-connected network genes with low expression level in brain metastases. Immune cell profiling analysis illustrated low T-cell infiltration and higher ratio of macrophages against TILs in the brain metastases (p < 0.001). The detected mutations in genotyping analysis were completely shared in 28 patients (71%). TCR sequencing analysis revealed that T-cell clones were expanded in 64% of patients with brain metastases. The majority of TCR repertoire in brain metastases were principally shared with the paired NSCLC, while the density of T cells was sparse in the brain metastases. Conclusion The microenvironment in brain metastases from NSCLC was revealed to be immunosuppressive, with the majority of T-cell clones in brain metastases being shared with the primary lesion. Citation Format: Yujin Kudo, Cara Haymaker, Jiexin Zhang, Alexandre Reuben, Dzifa Yawa Duose, Junya Fujimoto, Sinchita Roy-Chowdhuri, Luisa Maren Solis, Hitoshi Dejima, Edwin Roger Cuentas, Barbara Mino, Ronald Abraham, Norihiko Ikeda, Rajyalakshmi Luthra, Jack J. Lee, Humam Kadara, Jason T. Huse, Ignacio I. Wistuba. Characterization of the immune microenvironment in brain metastasis from non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2790.

Background: The immunocheckpoint represents a group of membrane proteins expressing on immune cells, composed of multiple co-inhibitory and co-stimulatory pathways. They are involved in eliminating unwanted substances while maintaining self-tolerance, which play a crucial role in immunomodulation. Malignant cells (MCs), on the other hand, often tends to take advantage of immunocheckpoints, for instance, by activating inhibitory checkpoint pathways in situ, to evade immune responses. Therefore, cancer immunotherapies, which target key immune checkpoints to restore effective anti-tumor immune function, emerge as a revolutionary strategy during recent years. The aim of this study was analyze a full range of checkpoint available to investigate their role in the microenvironment and their frequent co-expression in MCs and tumor infiltrated lymphocytes (TILs) in non-small cell lung carcinomas. Material and Methods: 4 µm-thick histology sections obtained from formalin-fixed paraffin-embedded (FFPE) tissues from a TMA containing 256 NSCLCs (adenocarcinomas, ADC=156; squamous cell carcinomas, SCC=100); were used for multiplex immunofluorescence (mIF) analyses. Nine immune markers including PD-L1, B7-H3, B7-H4, IDO-1, ICOS, OX-40, LAG3, TIM3, VISTA, CD3 and CD20 was optimized for immunofluorescence. Two mIF immunocheckpoints panels were composed included seven antibodies as follows: Panel 1: AE1/AE3, PD-L1, B7-H3, B7-H4, IDO1, VISTA, and CD3; and Panel 2: AE1/AE3, ICOS, LAG3, TIM3, OX40, CD3, and CD20. For quantitative image analysis of mIF markers, the stained TMA slides were scanned using the Polaris™ multispectral microscope (Perkin Elmer) and analyzed using the inForm™ 2.3.1 software. Results: In this preliminary report using the median density in MCs and TILs expressing those markers, we identified overall higher expression of immunocheckpoints in SCC than ADC. The higher density co-expression by MCs (AE/AE3+) was B7-H3 + IDO-1+ following by B7-H3+PD-L1+ expression when compared with the other markers (P~0.001) in the panel 1. Furthermore, we observed higher densities of TILs (CD3+) expressing IDO-1+ as well as B7-H3+ and high densities of TILs (CD3+) co-expressing B7-H3+PD-L1+ when compared the other (P~0.001) markers in the same panel. In panel 2, we observed higher densities of TILs (CD3+) expression ICOS+ than the other markers (P~0.001). Conclusions: Here, we describe a mIF platform with computational image processing workflows, enabling simultaneous evaluation of 12 biomarkers to FFPE tissue section. These data highlight digital image processing pipelines to the community for examining immune complexity of immunocheckpoints expression in MCs and TILs to improve biomarker discovery and assessment. Citation Format: Edwin Roger Parra, Mei Jiang, Jiexin Zhang, Carmen Behrens, Jack Lee, John Victor Heymach, Marie-Andrée Forget, Cara Haymaker, Chantale Bernatchez, Cesar Moran, Jianjun Zhang, Don Gibbons, Ignacio Wistuba. Immunofluorescence profiling of co-expression of multiple immune checkpoints in malignant and tumor infiltrated lymphocytes in non-small cell lung carcinomas using image analysis system [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3633.

Background: While checkpoint inhibitor (CPI) therapy has transformed metastatic melanoma (MM) treatment, many patients remain refractory. We reasoned that combining CPI with an agent that activates antigen presenting cells and improves T-cell priming may result in improved response. Our approach is to modulate the tumor microenvironment through image-guided intratumoral (i.t.) injection of the TLR9 agonist, IMO-2125, in combination with either ipilimumab (ipi) or pembrolizumab (pembro). We hypothesize that this will result in dendritic cell (DC) activation and induction of tumor-specific CD8+T-cells which will synergize with ipilimumab or pembrolizumab to overcome immune-escape. Based on this rationale we initiated a phase I/II clinical trial. Study Design/Methods: Adults with refractory MM that have had prior PD-1 blockade therapy (with or without a BRAF inhibitor) are eligible. IMO-2125, in doses escalating from 4mg to 32mg, is given i.t. weeks 1, 2, 3, 5, 8, and 11 along with standard doses of ipilimumab or pembrolizumab. Primary endpoints are safety, tumor response, and PK. Multiple biopsies are obtained in both the injected and distant tumor pre- and on-treatment. Immune analyses include DC subsets and their activation status as well as T cell activation, function and proliferation. T-cell repertoire diversity is evaluated by high-throughput CDR3 sequencing and changes in gene expression signatures are assessed by nanoString. Changes in circulating cytokines are also being assessed during therapy. Results: Enrollment is proceeding on both the IMO-ipilimumab and IMO-pembrolizumab dose-escalation arms of the trial. Safety is acceptable with no DLT recorded to date. Durable clinical responses (including 1 CR) have been observed with IMO-ipilimumab in patients who were refractory to PD-1 inhibitor. Fresh tumor biopsies show maturation (upregulation of HLA-DR) of the myeloid DC1 subset (CD1c+CD303-), upregulation of PD-L1 by malignant cells, as well as an IFNα response gene signature in the IMO-2125 injected tumor lesion 24 hrs post-treatment compared to pre-treatment biopsy. On-treatment biopsy results show a higher expression of CD56+ and Ki67+ effector CD8+ T-cells in responding patients. Initial CDR3 sequencing demonstrates increased diversity in the injected lesions of all patients assessed and expansion of top clones present in the distant lesion in a responding patient. Plasma analysis showed an increase in IFNγ levels in the plasma of responding patients. Conclusions: These results demonstrate that IMO-2125 with a checkpoint inhibitor is a viable strategy to revive the immune response in tumors that are refractory to PD-1 inhibitors. Further clinical evaluation of both the IMO-ipilimumab and IMO-pembrolizumab combination is planned in a Phase 2 expansion of the current trial. Citation Format: Cara Haymaker, Marc Uemura, Ravi Murthy, Marihella James, Daqing Wang, Julie Brevard, Suzanne Swann, James Geib, Mark Cornfeld, Srinivas Chunduru, Sudhir Agrawal, Cassian Yee, Jennifer Wargo, Rodabe Amaria, Sapna Patel, Hussein Tawbi, Isabella Glitza, Scott Woodman, Wen-Jen Hwu, Michael A. Davies, Patrick Hwu, Willem Overwjik, Chantale Bernatchez, Adi Diab. Translational evidence of reactivated innate and adaptive immunity with intratumoral IMO-2125 in combination with systemic checkpoint inhibitors from a Phase I/II study in patients with anti-PD-1 refractory metastatic melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5652. doi:10.1158/1538-7445.AM2017-5652

There have been significant advances in the treatment of metastatic melanoma through targeted and immunotherapy, however a significant proportion of patients still progress on these regimens with many experiencing mixed responses. Intense research efforts to better understand resistance are underway, and multiple molecular resistance mechanisms to targeted therapy have been identified. The appreciation of genetic heterogeneity as a contributor to resistance to therapy has grown, though immune heterogeneity has been poorly characterized. The goal of the present study is to better understand the molecular and immune heterogeneity in synchronous melanoma metastases at the time of disease progression. In this study, we prospectively evaluated 32 tumors from 15 patients who were treatment-naïve (n = 4), or had received prior targeted (n = 4) or immunotherapy (n = 7). Whole exome sequencing demonstrated between 4-41% of non-synonymous exonic mutations (NSEM) were restricted to individual tumors within a patient. Deep profiling of infiltrating immune cell subsets by flow cytometry and immunohistochemistry analyses confirmed the immune infiltrate between synchronous metastases to be highly heterogeneous, specifically in regards to CD4 and CD8 T lymphocytes. In aggregate, 92% of these T cell clones were unique to distinct tumors within the same patient, with limited overlap with clones detected in the blood. NetMHC3.4 neoantigen prediction demonstrated a large fraction of predicted neoantigens were restricted to individual tumors, with over 10% of these presenting extremely high predicted affinity. Importantly, analysis of RECIST measurements of individual lesions within the same patient suggested this molecular and immune heterogeneity could contribute to differential tumor growth and response to therapy within the same patient. This has important clinical implications, and suggests a single tumor biopsy may not be sufficiently representative of the molecular and immune landscape of multiple tumors within the same individual. Citation Format: Alexandre Reuben, Christine N. Spencer, Peter A. Prieto, John P. Miller, Xizeng Mao, Wei-Shen Chen, Hannah Cheung, Hong Jiang, Cara Haymaker, Mariana Petaccia De Macedo, Haven R. Garber, Pei-Ling Chen, Vancheswaran Gopalakrishnan, Jacob Austin-Breneman, Courtney W. Hudgens, Jason Roszik, Patrick Hwu, Scott E. Woodman, Lynda Chin, Michael A. Davies, Rodabe N. Amaria, Sapna P. Patel, Alexander J. Lazar, Michael T. Tetzlaff, Karen C. Dwyer, Ignacio I. Wistuba, Padmanee Sharma, James P. Allison, Jianhua Zhang, Andrew Futreal, Zachary A. Cooper, Jennifer A. Wargo. Genomic and immune heterogeneity in synchronous melanoma metastases is associated with differential tumor growth and response to therapy. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2392.

T cell-mediated immunotherapies are promising cancer treatments. However, most patients still fail to respond to these therapies. The molecular determinants of immune resistance are poorly understood. Here, we interrogated the role of loss of expression of the tumor suppressor, PTEN, in immune resistance. In preclinical studies, we found that silencing PTEN in tumor cells inhibited T cell-mediated tumor killing and decreased T cell trafficking into tumors. In clinical studies, we observed that tumors with loss of PTEN had significantly less CD8+ T cell infiltration than PTEN-present tumors. In addition, 26% of melanomas that did not yield successful TIL growth demonstrated PTEN loss, which was more frequent than was observed in tumors that yielded successful TIL growth (11%). We further validated the association between reduced number and impaired function of TIL with PTEN loss using another independent cohort, TCGA dataset for SKCM. More importantly, we analyzed clinical outcomes of metastatic melanoma patients treated with the FDA-approved anti-PD-1 antibodies. Our analysis demonstrates that a greater reduction in tumor burden was achieved by PD-1 blockade in PTEN present patients, when compared with PTEN absent patients. To decipher the factors mediating the immunosuppressive effects of PTEN loss, we determined the expression profiles of tumor cells with or without PTEN expression. Our results indicated that PTEN loss increased the production of immunosuppressive factors, including CCL2 and VEGF. Anti-VEGF blocking antibody improved anti-tumor activity of transferred tumor-reactive T cells and enhanced tumor infiltration of transferred T cells in PTEN-silenced tumors. These results suggest that loss of PTEN can facilitate the resistance of T cell-mediated immune responses by increasing the expression of immunosuppressive factors. Given that PTEN loss results in activation of the PI3K pathway, we evaluated the efficacy of immunotherapy in combination with a selective PI3Kβinhibitor to treat spontaneously developed BRAF mutant, PTEN null melanomas in genetically engineered mouse models. Our result showed that the combination of PI3Kβ inhibitor and anti-PD-1 significantly delayed tumor growth in tumor-bearing mice. Mice treated with this combination had a median survival time of 28 days, which is longer than the survival time of mice treated with either therapy. Increased numbers of T cells at tumor sites were found in mice receiving the combination therapy compared with mice receiving either agent alone. Taken together, our results demonstrate that PTEN loss contributes to the generation of immunosuppressive tumor microenvironment. Notably, this study provides the first direct clinical evidence to support the association between PTEN loss and poor clinical outcome in immunotherapy treated patients. In addition, our study indicates that inhibition of the PI3K-AKT pathway can improve the efficacy of immunotherapy in cancer. Citation Format: Weiyi Peng, Jie Qing Chen, Chengwen Liu, Shruti Malu, Caitlin Creasy, Michael Tetzlaff, Chunyu Xu, Jodi McKenzie, Chunlei Zhang, Xiaoxuan Liang, Leila Williams, Wanleng Deng, Guo Chen, Rina Mbofung, Alexander Lazar, Carlos Torres-Cabala, Zachary Cooper, Pei-Ling Chen, Trang Tieu, Stefani Spranger, Xiaoxing Yu, Chantale Bernatchez, Marie-Andree Forget, Cara Haymaker, Rodabe Amaria, Jennifer McQuade, Isabella Glitza, Tina Cascone, Haiyan Li, Lawrence Kwong, Timothy Heffernan, Jianhua Hu, Roland Bassett, Marcus Bosenberg, Scott Woodman, Willem Overwijk, Gregory Lizée, Jason Roszik, Thomas Gajewski, Jennifer Wargo, Jeffrey Gershenwald, Laszlo Radvanyi, Michael Davies, Patrick Hwu. Loss of PTEN promotes resistance to T cell-mediated immunotherapy. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4363.