Metastatic Pancreatic Cancers Research Articles

Abstract PR-21: Temporal stability and chemotherapy responsiveness of classical and basal transcriptional subtypes of pancreatic cancer

Abstract Background: Transcriptional profiling of pancreatic cancers (PC) has defined classical and basal subtypes; basal tumors have worse outcomes. Initial data suggest worse outcomes to FOLFIRINOX (FFX) compared with gemcitabine nab-paclitaxel (GnP) in basal tumors. In addition, it is hypothesized that classical to basal conversion may lead to chemotherapy resistance, although clinical evidence for subtype conversion and subtype specific chemotherapy sensitivity are sparse. Here, we examined the temporal stability and clinical implications of PC transcriptional subtypes in a large, real-world dataset. Methods: We examined patients with metastatic PC, who had outcomes data and RNA sequencing (n=5,335) performed at Caris Life Sciences (Phoenix, AZ). Classical and basal subtypes were identified along a six subtype continuum from strong classical (SC) to strong basal (SB) on either pole using PurIST algorithm. Overall survival (OS) was defined from date of biopsy of metastatic site to date of death or last known contact and estimated using Kaplan-Meier method. Survival was compared between groups using log-rank test and cox proportional hazards regression. Predictors of subtype discordance were assessed in patients who underwent RNA-sequencing of two tumor biopsies using multivariable logistic regression. Results: In patients with metastatic PC, SB tumors (n = 1,579) had significantly worse OS compared to SC tumors (n = 2,118), with a median OS of 5.7 vs. 10.0 months, respectively (hazard ratio [HR] 1.49, 95% confidence interval [CI], 1.39-1.60, p = 2.77e-27) independent of impact of age, gender and mutations in KRAS, TP53, CDKN2A or SMAD4 in cox proportional hazard models. OS was worse in patients with SB tumors who received either 1L GnP [SB (n = 112) vs. SC (n = 178), median OS: 6.0 vs. 10.4 months (HR 1.35 [95% CI, 1.05-1.75], p = 0.02)], or 1L FFX [SB (n = 155) vs. SC (n = 215), median OS: 8.9 vs. 12.5 months (HR 1.35 (95% CI, 1.06-1.72), p = 0.013)]. The prognostic impact of transcriptional subtype within different KRAS-mutant alleles is not well defined. OS was short and not significantly different between the three most frequent KRAS alleles (G12 V/D/R) in SB tumors (median OS, KRAS G12R/V/D: 5.4 vs. 5.4 vs. 5.5 months). In SC tumors, KRAS G12D was associated with a significantly worse OS compared to KRAS G12R (median OS: 8.6 vs. 11.9 months, HR 1.23 (95% CI, 1.04-1.47), p = 0.018). KRAS G12V had a numerically worse survival compared with KRAS G12R in SC tumors (median OS: 9.4 vs. 11.9 months, HR 1.15 (95% CI, 0.96-1.37), p = 0.12). Sixty of 77 cases (78%) maintained their transcriptional subtype between two temporally &/or spatially disparate lesions. The likelihood of transcriptional subtype change was independent of the duration between (p = 0.79) or site of (p = 0.37) the two biopsies. Conclusions: SB subtype is a strong independent predictor of worse outcomes, irrespective of mutant KRAS allele or upfront chemotherapy regimen, and tends to remain stable between biopsies in individual patients Citation Format: Harshabad Singh, Joanne Xiu, Kevin Kapner, Chen Yuan, Raja R Narayan, Matthew Oberley, Alex Farrell, Rishi Surana, Brandon M Huffmann, Kimberly J Perez, James M Cleary, Alexander C Jordan, Andressa Dias Costa, Hannah L Williams, Srivatsan Raghavan, Benjamin Weinberg, Michael J Pishvaian, Rachna T Shroff, Sanjay Goel, Stephanie K Dougan, Jonathan Nowak, David Spetzler, George Sledge, Brian M Wolpin, Andrew J Aguirre. Temporal stability and chemotherapy responsiveness of classical and basal transcriptional subtypes of pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr PR-21.

Outcomes Analysis of Yttrium-90 Radioembolization for Tumors Other Than Metastatic Colorectal Cancer from the Radiation-Emitting SIR-Spheres in Nonresectable (RESiN) Registry

PurposeTo characterize the response and survival outcomes of yttrium-90 (90Y) transarterial radioembolization (TARE) for unresectable, liver-dominant metastases from primary neoplasms other than colorectal carcinoma. Materials and MethodsThis study included 1,474 patients enrolled in the Radiation-Emitting Society of Interventional Radiology (SIR)–Spheres in Nonresectable Liver Tumor registry who received resin 90Y-TARE as part of their oncologic management for unresectable primary or secondary liver tumors (NCT 02685631). Of these patients, 33% (481/1,474) were treated for liver metastases of noncolorectal origin (m-non-CRC) compared with 34% (497/1,474) treated for metastatic colorectal cancer (mCRC) and 34% (496/1,474) treated for hepatocellular carcinoma. Treatment response and cancer survival probabilities were computed and compared for each primary cancer type. The Kaplan-Meier method and log-rank test were used to compare survival outcomes. ResultsRadiological responses were observed in 12 unique cancer types, mostly heavily pretreated malignancies refractory to multiple lines of systemic therapies. The overall use of resin 90Y-TARE in m-non-CRC resulted in better treatment outcomes in terms of duration of response, progression-free survival, time to progression, and overall survival (P = .04, P = .02, P = .01, and P = .04, respectively). Analyses of cancer cell types revealed that metastatic neuroendocrine tumor, sarcoma, and ovarian, renal, prostate, and breast cancers were associated with superior treatment outcomes, whereas worse treatment outcomes were observed in metastatic lung, gastric, pancreatic, and esophageal cancers. ConclusionsReal-world data demonstrate the use of resin 90Y-TARE in m-non-CRC refractory to standard chemotherapy. For some cell types, this expanded use achieved superior treatment outcomes relative to the reference standard of mCRC, suggesting the need for inquiry into broadened indications for 90Y-TARE.

Altering the gut microbiome and TME in advanced liver cancers: A phase II study of nivolumab, tadalafil, and oral vancomycin in refractory HCC or liver-dominant metastatic CRC or PDAC.

e14642 Background: The gut-liver axis shapes the environment that promotes liver disease. In murine models of liver cancer, our group showed that altering gut microbiome with oral vancomycin can induce an antitumor effect by modifying bile acids (BA) that then recruit natural killer T cells (NKTC). However, these NKTC were met by an immunosuppressive counter-regulatory response where myeloid-derived suppressor cells (MDSC) accumulated, impairing their cytotoxicity. Tadalafil, a PDE5 inhibitor, can suppress these MDSC in the TME. The aim of this study was to examine if the immunomodulatory effects of oral vancomycin and tadalafil can enhance nivolumab activity in advanced primary liver cancer or liver metastases. Methods: This is a phase II study of adult patients (pts) with refractory hepatocellular carcinoma (HCC) or liver-dominant metastatic colorectal (mCRC) or pancreatic (mPDAC) cancers. Pts received IV nivolumab 480mg on D1, oral vancomycin 125mg every 6 hours on D1-21, and tadalafil 10mg once daily in 28d cycles until disease progression or unacceptable toxicity. Primary endpoint was best overall response (BOR) according to RECIST v1.1. Secondary endpoints included safety/tolerability and mOS. Correlative studies were performed on paired stool, blood, and tumor biopsies. Results: From 6/2019 - 7/2021, 22 heavily pretreated pts were enrolled: 6 HCC, 9 PDAC, 7 CRC. Median age was 63y (41-82), and 27% were female. Molecular testing showed MSS, TMB low to intermediate (1.57-13.35), and frequent mutations in KRAS and TP53. The BOR was SD (3pts, 18.75%), followed by PD (13pts, 81.25%); there were no PR or CR (ORR = 0%). Six pts had symptomatic deterioration prior to restaging scans. At a median follow-up of 4m (0.9-23.0m), all 22 pts had died of progressive disease with mOS of 4m. When stratified by site of origin, mOS was 9.5m (95%CI: 1.3-21.9m) in HCC and 3.6m (95%CI: 1.9-6.6m) in liver metastases (log-rank test, p=0.27). The most common grade 3-4 trAEs were electrolyte disturbances and anemia. The stool microbiome composition of Bacteroides species did not change with treatment as detected by shotgun sequencing. Plasma secondary BA, measured by the mixed meal test, decreased with treatment (p<0.05, n=18, two-way ANOVA). The classical to non-classical monocytes ratio increased with treatment in flow cytometry analysis of PBMC immune cells (p<0.05, n=14, one-way ANOVA). Transcriptomic analysis of treated liver tumor biopsies showed an increase in BA metabolism. Conclusions: Although well tolerated, the combination of oral vancomycin and tadalafil with nivolumab did not produce any meaningful clinical responses. Correlative studies suggested enhanced activation of BA metabolization, but TME immune profiling did not reveal substantial changes in regulatory suppressor cells or NKTC activity. Clinical trial information: NCT03785210 .

Abstract PO3-25-07: Characterization of tertiary lymphoid structures and its association with response to immune checkpoint inhibitors in triple negative breast cancer using spatial transcriptomics

Abstract Background Tertiary lymphoid structures (TLS) are ectopic lymphoid organs playing a role in adaptive antitumor immune response. They were shown to be associated with favorable outcome and appears to be a promising biomarker for response to immune checkpoint inhibitors (ICI). Yet, there is no consensus for their detection and quantification. Here we aimed to derive a specific TLS signature using high resolution spatial transcriptomics data from a large series of triple negative breast cancer (TNBC) samples and to assess its clinical relevance including response to ICI. Methods Spatial transcriptomics (ST) was performed on a series of 94 early-stage TNBC surgical samples with detailed clinicopathological and outcome data. TLS and tumor infiltrating lymphocytes (TILs) were scored using hematoxylin and eosin and double immunohistochemistry (CD3/CD20) stained slides by a dedicated breast pathologist. Regression based on morphological annotations and deconvolution methods estimated the fraction of gene expression related to TLS in each ST spot allowing to derive specific TLS signature. Its prognostic and predictive value of response to ICI was assessed using publicly available breast cancer (METABRIC, SCAN-B, and I-SPY2) and other tumor type datasets treated with ICI (Bareche et al. Ann Oncol, 2022) from bulk gene expression data. Results Deconvolution of the TLS compartments using the ST gene expression data showed that TLS are enriched in all B cell subsets, CD4+ (central) memory and naïve T cells, as well as mast cells. A functional analysis showed an enrichment of ‘vascular endothelial cell proliferation’, ‘mitotic G2/M transition checkpoint’, ‘V/D/J recombination’ and ‘regulation of cell chemotaxis to fibroblast growth factor’ suggesting that TLS aggregates are associated with angiogenesis, immune cell proliferation, adaptative humoral response and tissue remodeling. A comparison of gene expression data between TLS and non-aggregated TILs led to the development of a specific TLS gene signature comprising B and T cell-specific genes, immunoglobulin genes as well as genes associated with TLS initiation. Its projection on tumor slides overlapped with the regions annotated as TLS by the pathologist, demonstrating its specificity for TLS detection. As expected, the highest levels of the TLS signature were observed in the immunomodulatory TNBC molecular subtype and fully inflamed tumors, whereas the lowest levels were observed in the mesenchymal molecular subtype and immune desert tumors (p< 0.05). Of note, high levels of the TLS signature were associated with better prognosis in TNBC patients from METABRIC (p=6.5 10−5) and SCAN-B datasets (p=1.6 10−3) as well as with higher pathological complete response rates in all breast cancer patients treated with neoadjuvant pembrolizumab in the I-SPY2 study (p=0.026). Similar results were found in other tumor types treated with immunotherapy in the metastatic setting including metastatic melanoma, pancreatic and bladder cancers (PFS, p=6 10−6). Of interest, the TLS signature outperformed the predictive value of other immune-related signatures including TILs suggesting a key role of TLS in obtaining a sustainable, adaptive antitumor immune response in the vicinity of the tumor area. Conclusion By leveraging the potential of spatial transcriptomics, we have successfully developed a unique TLS gene signature that demonstrates a strong correlation with the response to ICI in breast cancer and various other tumor types. This TLS gene signature outperforms other immune biomarkers, underscoring the pivotal role of TLS in eliciting a robust antitumor immune response. The universality of this TLS signature makes it a potent biomarker capable of identifying patients who would benefit from immunotherapy, pending further validation. Citation Format: Xiaoxiao Wang, David Venet, Frédéric Lifrange, Denis Larsimont, Mattia Rediti, Linnea Stenbeck, Floriane Dupont, Ghizlane Rouas, Andrea Joaquin Garcia, David Gacquer, Ligia Craciun, Laurence Buisseret, Nayanika Bhalla, Yuvarani Masarapu, Kim Thrane, Eva Gracia Villacampa, Lovisa Franzén, Sami Saarenpää, Linda Kvastad, Joakim Lundeberg, Françoise Rothé, Christos Sotiriou. Characterization of tertiary lymphoid structures and its association with response to immune checkpoint inhibitors in triple negative breast cancer using spatial transcriptomics [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-25-07.

Abstract CT082: Phase I study of autologous CD8+ and CD4+ transgenic T cells expressing high-affinity KRAS G12V mutation-specific T cell receptors (FH-A11KRASG12V-TCR) in patients with metastatic pancreatic, colorectal and non-small cell lung cancers with KRAS G12V mutations

Abstract Background: KRAS, the most common driver oncogene in human malignancies, has predictable mutations. 85% of RAS mutations occur at the Glycine (G) 12 position with G12V being amongst the most common. Cancers driven by mutant KRAS include pancreatic (PDAC), colorectal (CRC), and non-small cell lung (NSCLC) malignancies. The prognosis of patients with activating KRAS mutations remains poor. Preliminary anti-tumor activity has been observed in the clinic with T cell receptor (TCR) T cell therapies targeting KRAS mutations, but durable clinical benefit is lacking. Rationale: FH-A11KRASG12V-TCR is an autologous CD8+ and CD4+ transgenic T cell product expressing (1) an HLA-A11-restricted, high affinity KRASG12V mutation-specific T cell receptor (TCR) and (2) the wildtype CD8α/β coreceptor enabling CD4+ T cell recognition of KRAS G12V presented on an MHC class I allele mediating helper T cell activity and cytotoxicity. The TCR sequence is derived from the peripheral blood of a healthy HLA-A11+ adult based on a strong pre-clinical dataset. Methods: This is an ongoing, investigator-initiated, Phase 1, first-in-human, single-center, open-label dose escalation study of FH-A11KRASG12V-TCR. The aims are to evaluate the safety, tolerability, maximum tolerated dose (MTD), and preliminary anti-tumor activity of FH-A11KRASG12V-TCR in patients with advanced PDAC, CRC, and NSCLC who express the HLA-A11-restricted KRAS G12V mutation. Dose modification will be guided by the Bayesian Optimal Interval design (BOIN). Patients will initially be treated in cohorts of 3 at each dose level (DL). BOIN will be used to identify the recommended dose for subsequent patients. The planned target doses are 5 x 109 transgenic TCR T cells in DL 1 with dose escalation up to 15 x 109 transgenic TCR T cells in DL 3. This study enrolls patients who are 18 years or older, HLA-A*11:01-positive, with KRAS G12V mutated metastatic PDAC, CRC, or NSCLC. Patients must have progressed on or be intolerant of at least two lines of prior therapies including any targeted therapies indicated for their current malignancy. Patients undergo leukapheresis prior to treatment and receive lymphodepleting chemotherapy with either cyclophosphamide intravenously (IV) and fludarabine IV on days -6, -5, -4, and -3 or bendamustine IV on days -4 and -3. FHA11KRASG12V-TCR is administered IV on day 0. The dose-limiting toxicity observation period is 28 days. Patients may receive an additional FHA11KRASG12V-TCR IV infusion at the same or lower dose as soon as 28 days or up to 1 year after the first infusion. One patient enrolled to date and the study is actively recruiting (NCT06043713). Citation Format: Elena Gabriela Chiorean, Andrew Coveler, Rachael Safyan, Stacey Cohen, Sylvia Lee, Cecilia Yeung, Mary Redman, Thomas Schmitt, Aude Chapuis, Philip D. Greenberg. Phase I study of autologous CD8+ and CD4+ transgenic T cells expressing high-affinity KRAS G12V mutation-specific T cell receptors (FH-A11KRASG12V-TCR) in patients with metastatic pancreatic, colorectal and non-small cell lung cancers with KRAS G12V mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT082.

Tackling Challenges in Assessing the Economic Value of Tumor-Agnostic Therapies: A Cost-Effectiveness Analysis of Pembrolizumab as a Case Study

ObjectivesAssessing the value of tumor-agnostic drugs (TAD) is challenging given the potential variability in treatment effects, trials with small sample sizes, different standards of care (SoC), and lack of comparative data from single-arm basket trials. Our study developed and applied novel methods to assess the value of pembrolizumab compared with SoC to inform coverage decisions. MethodsWe developed a partitioned survival model to evaluate the cost-utility of pembrolizumab for previously treated patients with 8 advanced or metastatic microsatellite instability-high or mismatch repair-deficient cancers from a US commercial payer perspective. Efficacy of pembrolizumab was based on data from trials directly or with adjustment using Bayesian hierarchical models. Eight chemotherapy-based external control arms were constructed from the TriNetX electronic health record databases. Tumor-specific health-state utility values were applied. All costs were adjusted to 2022 US dollars. ResultsAt a lifetime horizon, pembrolizumab was associated with increased effectiveness compared with chemotherapies in colorectal (quality-adjusted life years [QALYs]: +0.64, life years [LYs]: +0.64), endometrial (QALYs: +3.79, LYs: +5.47), and small intestine cancers (QALYs: +1.73, LYs: +2.48), but not for patients with metastatic gastric, cholangiocarcinoma, pancreatic, ovarian, and brain cancers. Incremental cost-effectiveness ratios varied substantially across tumor types. Pembrolizumab was found to be cost-effective in treating colorectal and endometrial cancers (incremental cost-effectiveness ratios: $121 967 and $139 257, respectively), and not cost-effective for other assessed cancers at a $150 000 willingness-to-pay/QALY threshold, compared with SoC chemotherapies. ConclusionsThe cost-effectiveness of TADs can vary by cancers. Using analytic tools such as external controls and Bayesian hierarchical models can tackle several challenges in assessing the value of TADs and uncertainties from basket trials.

Abstract 5128: Circulating H3K27me3 modified nucleosomes as a biomarker to monitor anti EZH2-based treatment in advanced solid tumour patients: Translational analyses from CAIRE trial

Abstract CAIRE is a phase 2 umbrella study which assessed activity of combined anti-EZH2 tazemetostat and anti-PDL1 durvalumab (T+D) in advanced pretreated pancreatic, colorectal and sarcoma cancer patients. The are currently no plasma biomarkers for anti-EZH2 treatment monitoring or outcome. EZH2 catalyzes tri-methylation of Lysine 27 (K27me3) on nucleosomal histone 3 (H3, H3K27me3). Circulating, cell free H3K27me3 modified nucleosomes are thus a potential biomarker for tazemetostat activity. We evaluated the concentration of circulating H3K27me3 modified nucleosomes normalized to H3.1 nucleosomes (the most common isoform of H3) in T+D treated patients, irrespective of the tumor primary site, to determine target engagement during anti-EZH2 treatment. Plasma from patients receiving T+D was collected before the first cycle administration (C1D1), on the following two cycles administration (C2D1, C3D1) and at end of treatment (EOT). H3.1 and H3K27me3 containing nucleosomes were quantified by Nu.Q®-H3.1 and Nu.Q®-H3K27me3 Chemiluminescent Immunoassays. Concentrations are reported as ng/ml and the comparison of their median values at the different timepoints were tested with Kruskal-Wallis and Mann Whitney (independent samples) or Wilcoxon tests (paired samples), with SciPy.stat package (1.6.2). Bonferroni correction was applied to multiple comparisons. Of 197 total samples, 191 were evaluable for both biomarkers (6 higher than top standard after 5x dilution): 69 at C1D1, 63 at C2D1, 50 at C3D1 and 9 at EOT. For 58 patients paired C1D1 and C1D2 levels were available, 46 from C1D1 to C3D1 and 8 from C1D1 to EOT. The normalized Nu.Q®-H3K27me3 C1D1 median value (0.56) was significantly higher than C2D1 (0.31, p: e-12), C3D1 (0.31, p: e-12) and EOT ones (0.28, p: 0.001). Conversely, Nu.Q®-H3.1 levels were similar from C1D1 to C3D1 (range of the medians: 122.16-133.25 ng/ml) and increased at EOT (290.09 ng/ml), but with no significant difference between pairwise timepoints. Regarding paired-samples comparison, the normalized Nu.Q®-H3K27me3 was significantly higher at C1D1 than at C2D1 (p: e-8) and C3D1 (p: e-9) and at EOT (p: 0.02). Conversely, H3.1 concentration was significantly higher at EOT than at C1D1 (p: 0.02), at C2D1 (p: 0.02) and C3D1 (p: 0.05).In conclusion, we described for the first time that normalized circulating nucleosomal H3K27me3 values significantly decrease during T-based treatment in metastatic solid tumor patients, irrespective of the primary disease site, supporting its potential role as a pharmacodynamic biomarker for EZH2 inhibition. Moreover, total nucleosomal H3.1 seems to represent a surrogate of disease burden in metastatic pancreatic, colorectal and sarcoma cancers, as suggested previously in other hematological malignancies. Citation Format: Francesca Salani, Mark Eccleston, Lola-Jade Palmieri, Simon Pernot, Sophie Cousin, Gianluca Masi, Francesco Crea, Antoine Italiano. Circulating H3K27me3 modified nucleosomes as a biomarker to monitor anti EZH2-based treatment in advanced solid tumour patients: Translational analyses from CAIRE trial [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 5128.

Efficacy and safety of autologous tumor-infiltrating lymphocytes in recurrent or refractory ovarian cancer, colorectal cancer, and pancreatic ductal adenocarcinoma

BackgroundTumor-infiltrating lymphocyte (TIL) therapy has shown efficacy in metastatic melanoma, non-small cell lung cancer, and other solid tumors. Our preclinical work demonstrated more robust CD8 predominant TIL production when agonistic...

Cohort expansion from the phase 1 JEWEL-101 study investigating the tissue factor-targeting antibody-drug conjugate XB002 in patients with advanced solid tumors: Pancreatic and esophageal cancer cohorts.

TPS421 Background: Patients (pts) with metastatic pancreatic and esophageal cancers have poor prognosis, with 5-year survival rates of 3% and 6%, respectively (SEER 22). Tissue factor (TF), a factor VIIa receptor involved in initiation of the extrinsic coagulation cascade, is overexpressed in these tumors and has been associated with poor outcomes. XB002 is a novel antibody-drug conjugate (ADC) composed of a high-affinity TF-directed human monoclonal antibody conjugated to the linker-payload zovodotin. Zovodotin consists of an auristatin-based payload with a stable protease-cleavable linker; it is designed to have lower off-target payload deconjugation and improved tolerability versus other auristatin-based ADCs. In preclinical studies, XB002 showed encouraging safety and antitumor activity without affecting coagulation. JEWEL-101 (NCT04925284) is a phase 1, dose-escalation and multi-cohort expansion study evaluating XB002 alone and in combination with nivolumab or bevacizumab in pts with advanced solid tumors. Preliminary results from the dose-escalation stage showed XB002 was well tolerated at multiple dose levels, with low-grade ocular toxicity and no bleeding events or treatment-related peripheral neuropathy (PN).1 Presented here is the design of the expansion cohorts for pancreatic and esophageal cancers. Methods: Eligible pts must have an inoperable, locally advanced, metastatic, or recurrent solid tumor. Pts with pancreatic adenocarcinoma will receive XB002 single agent. Pts enrolled with esophageal squamous cell carcinoma (ESCC) will be randomized between 2 cohorts to receive either XB002 single agent or XB002 plus nivolumab. All pts in the pancreatic cancer and ESCC cohorts must have ECOG performance status of 0–1, measurable disease per RECIST v1.1, and have received 1–2 prior lines of systemic anticancer therapy, and radiographically progressed during or after their last therapy. Prior immunotherapy is allowed for pancreatic cancer and required for ESCC if locally considered standard of care and pts are eligible. Key exclusion criteria include prior treatment with TF-targeting or auristatin-based ADCs, and significant ocular disorders. Concomitant anticoagulants are permitted, and pts with PN are eligible, provided it is not impacting activities of daily living. The primary objective is objective response rate per RECIST v1.1 by investigator. Secondary objectives include safety, pharmacokinetics, immunogenicity, progression-free survival, duration of response, and overall survival. Enrollment is ongoing in the United States, Europe, and the Asia-Pacific region. 1. Ulahannan et al. ENA 2022. Clinical trial information: NCT04925284 .

Segmentation of cellular ultrastructures on sparsely labeled 3D electron microscopy images using deep learning.

Focused ion beam-scanning electron microscopy (FIB-SEM) images can provide a detailed view of the cellular ultrastructure of tumor cells. A deeper understanding of their organization and interactions can shed light on cancer mechanisms and progression. However, the bottleneck in the analysis is the delineation of the cellular structures to enable quantitative measurements and analysis. We mitigated this limitation using deep learning to segment cells and subcellular ultrastructure in 3D FIB-SEM images of tumor biopsies obtained from patients with metastatic breast and pancreatic cancers. The ultrastructures, such as nuclei, nucleoli, mitochondria, endosomes, and lysosomes, are relatively better defined than their surroundings and can be segmented with high accuracy using a neural network trained with sparse manual labels. Cell segmentation, on the other hand, is much more challenging due to the lack of clear boundaries separating cells in the tissue. We adopted a multi-pronged approach combining detection, boundary propagation, and tracking for cell segmentation. Specifically, a neural network was employed to detect the intracellular space; optical flow was used to propagate cell boundaries across the z-stack from the nearest ground truth image in order to facilitate the separation of individual cells; finally, the filopodium-like protrusions were tracked to the main cells by calculating the intersection over union measure for all regions detected in consecutive images along z-stack and connecting regions with maximum overlap. The proposed cell segmentation methodology resulted in an average Dice score of 0.93. For nuclei, nucleoli, and mitochondria, the segmentation achieved Dice scores of 0.99, 0.98, and 0.86, respectively. The segmentation of FIB-SEM images will enable interpretative rendering and provide quantitative image features to be associated with relevant clinical variables.

Propagated Circulating Tumor Cells Uncover the Potential Role of NFκB, EMT, and TGFβ Signaling Pathways and COP1 in Metastasis.

Circulating tumor cells (CTCs), a population of cancer cells that represent the seeds of metastatic nodules, are a promising model system for studying metastasis. However, the expansion of patient-derived CTCs ex vivo is challenging and dependent on the collection of high numbers of CTCs, which are ultra-rare. Here we report the development of a combined CTC and cultured CTC-derived xenograft (CDX) platform for expanding and studying patient-derived CTCs from metastatic colon, lung, and pancreatic cancers. The propagated CTCs yielded a highly aggressive population of cells that could be used to routinely and robustly establish primary tumors and metastatic lesions in CDXs. Differential gene analysis of the resultant CTC models emphasized a role for NF-κB, EMT, and TGFβ signaling as pan-cancer signaling pathways involved in metastasis. Furthermore, metastatic CTCs were identified through a prospective five-gene signature (BCAR1, COL1A1, IGSF3, RRAD, and TFPI2). Whole-exome sequencing of CDX models and metastases further identified mutations in constitutive photomorphogenesis protein 1 (COP1) as a potential driver of metastasis. These findings illustrate the utility of the combined patient-derived CTC model and provide a glimpse of the promise of CTCs in identifying drivers of cancer metastasis.

Prospective BASECAMP-1 experience in patients with gastrointestinal (GI) cancer: Identifying patients with human leukocyte antigen (HLA) loss of heterozygosity (LOH) for a future therapeutic trial exploiting LOH as a tumor vulnerability.

209 Background: Metastatic colorectal (CRC), pancreatic (PANC), and gastroesophageal cancers are the leading causes of GI cancer–related mortality (5-y survival: 15%, 3%, and 5%-6%, respectively) (ACS 2022). HLA LOH is a recurrent mechanism of immune escape observed in 15%-20% of GI cancers (Hecht R., ASCO GI 2022). The Tmod platform is a logic-gated chimeric antigen receptor (CAR) T-cell modular system, comprising a carcinoembryonic antigen (CEA)- or mesothelin (MSLN)-targeting CAR activator and a separate HLA-A*02-targeting blocker receptor. Both in vitro/in vivo, Tmod CAR T therapy kills cells with HLA-A*02 LOH (tumor) without harming cells with retained HLA-A*02 expression (normal). However, HLA-A*02 LOH can only be therapeutically exploited if patients are identifiable through a feasible and timely clinical workflow. Methods: We established a biobanking protocol (BASECAMP-1, NCT04981119) to determine whether HLA-A*02 LOH patients can be prospectively identified. Patients with CRC, PANC, or non-small cell lung cancer (NSCLC), and a high risk for incurable relapse, were screened first using a standard HLA assay. Heterozygous HLA-A*02 positive tumor samples were then assessed for LOH using a bioinformatic algorithm applied via the Tempus xT platform. Results: As of Sep 1, 2022, 83 patients were consented at 4 institutions. HLA status was obtained from 70 patients and 28 were identified as HLA-A*02:01 heterozygous (40%; expected frequency based on USA NMDP data, 27.6%). LOH results were available for 16 patients; 4 LOH-positive patients were identified (25%, 2 PANC, 2 NSCLC). The LOH assay sensitivity declines below a tumor purity of 40% (Hecht R., ASCO GI 2022). Six patients had a tumor purity of 20% (all with PANC, a tumor known for high stromal content), limiting possible LOH detection. The impact of tumor purity on LOH sensitivity was highlighted in a patient with a low initial sample tumor purity (30%) that resulted in a 41% probability of HLA-A*02:01 LOH (below positive threshold). A second sample with a higher tumor purity (70%), obtained from formalin-fixed, paraffin-embedded sections, resulted in a 92% probability of HLA-A*02:01 LOH (positive). Conclusions: BASECAMP-1 prospective identification of HLA-A*02 LOH is feasible in the real-world setting. The frequencies of the HLA-A*02 allele and of HLA-A*02 LOH in this cohort mirrored expected population frequencies. LOH results can be obtained within a clinically feasible workflow and timeframe, although samples with a < 40% tumor purity have a reduced sensitivity for LOH detection, an issue recurrently observed in patients with PANC. The BASECAMP-1 strategy enables prospective identification of appropriate patients for future therapeutic clinical trials using Tmod CEA and MSLN logic-gated CAR T cells. Clinical trial information: NCT04981119 .

Different effects of NK cells and NK-derived soluble factors on cell lines derived from primary or metastatic pancreatic cancers

Natural killer (NK) cells are cytotoxic lymphoid cells that play a key role in defenses against tumors. However, their function may be severely impaired in patients with pancreatic adenocarcinoma (PA). Indeed, PA cells release soluble factors, thereby generating an immunosuppressive environment that dysregulates NK-cell cytolytic function and favors tumor immune evasion. Here, we analyzed the interactions between NK and PA cells using the PANC-1 and CAPAN-1 cell lines derived from a ductal PA and metastatic lesion, respectively. Metastatic and nonmetastatic cell lines were both able to impair NK cytolytic activity. An analysis of the effect of NK cells and NK-cell-derived exosomes revealed substantial differences between the two cell lines. Thus, NK cells displayed higher cytotoxicity against nonmetastatic PA cells than metastatic PA cells in both 2D cultures and in a 3D extracellular matrix cell system. In addition, NK-derived exosomes could penetrate only PANC-1 spheroids and induce cell killing. Remarkably, when PANC-1 cells were exposed to NK-derived soluble factors, they displayed substantial changes in the expression of genes involved in epithelial-to-mesenchymal transition (EMT) and acquired resistance to NK-mediated cytolysis. These results, together with their correlation with poor clinical outcomes in PA patients, suggest that the induction of resistance to cytolysis upon exposure to NK-derived soluble factors could reflect the occurrence of EMT in tumor cells. Our data indicate that a deeper investigation of the interaction between NK cells and tumor cells may be crucial for immunotherapy, possibly improving the outcome of PA treatment by targeting critical steps of NK-tumor cell crosstalk.

Abstract A016: Phase 1 study of hypofractionated radiation in combination with tremelimumab and durvalumab in refractory metastatic pancreatic adenocarcinoma

Abstract Immune checkpoint inhibitors have limited clinical activity in pancreatic cancer. Based on preclinical data, we hypothesized that hypofractionated radiation may cooperate with dual checkpoint inhibition in patients (Rech AJ, et al, Cancer Research, 2018). We therefore designed a phase 1 study to evaluate the safety and feasibility of two schedules of hypofractionated radiation with durvalumab (anti-PDL1) and tremelimumab (anti-CTLA-4) in patients with metastatic pancreatic, lung, and breast cancers and melanoma. Here, we present the data for pancreatic adenocarcinoma. Methods: Patients with metastatic pancreatic cancer treated with at least one prior line of therapy with measurable disease by RECIST in addition to an index lesion amenable to hypofractionated radiation were enrolled sequentially to two cohorts – cohort A evaluating 3 fractions of 8 Gy or cohort B evaluating 1 fraction of 17 Gy. Patients received 4 cycles of tremelimumab 1 mg/kg IV and durvalumab 20 mg/kg IV every 4 weeks for 4 doses followed by durvalumab 10 mg/kg IV every 2 weeks until progression. Radiation was given in week 2 of treatment. Patients were replaced if they did not receive week 5 of therapy on trial, but were included in safety/feasibility analysis. Blood and, when feasible, baseline and on-treatment biopsies were obtained for exploratory biomarker evaluation. Results: 10 patients were treated in cohort A and 21 patients in cohort B. All patients were included in the safety and feasibility assessment. Overall, treatment was well tolerated in both cohorts. The most common adverse events were grade 1 or 2 fatigue (A 30%, B 23.8%), diarrhea (A 10%, B 14.3%), pruritis (A 10%, B 14.3%), AST/ALT elevation and constipation (each A 10%, B 9.5%). Grade 3 diarrhea, elevated bilirubin, pneumonitis, and syncope were noted in 1 patient each, all in cohort B. Grade 5 pneumothorax occurred after baseline biopsy in 1 patient. Grade 2 hyperthyroidism (A) and pneumonitis (B) were noted each in 1 patient. 8 patients in cohort A and 13 patients in cohort B were evaluable for response. In cohort A, 50% of patients had stable disease as best response, and median overall survival was 4.9 months. In cohort B, 23.1% had PR and 30.8% had SD as best response and mOS was 5.2 months. Responses occurred more frequently when metastatic lung nodules were radiated – SD in 3/5 (60%) patients in cohort A, PR in 3/10 (30%) and SD in 4/10 (40%) patients in cohort B, compared to SD in 1/3 (33%) patients in cohort A and 0/3 (0%) patients in cohort B who underwent radiation to a liver lesion. Biomarker analysis will be presented. Conclusions: The combination of durvalumab, tremelimumab with hypofractionated radiation is safe and feasible in a refractory pancreatic adenocarcinoma patient population. Encouraging clinical activity warrants further evaluation, especially when hypofractionated radiation is delivered to lung nodules. Citation Format: Mark H. O'Hara, Adham S. Bear, Max M. Wattenberg, Ursina R. Teitelbaum, Kim A. Reiss, Thomas B. Karasic, Charles J. Schneider, Peter J. O'Dwyer, Edgar H. Ben-Josef, Andrzej P. Wojcieszynski, Amit H. Maity, Rosemarie H. Mick, Robert H. Vonderheide. Phase 1 study of hypofractionated radiation in combination with tremelimumab and durvalumab in refractory metastatic pancreatic adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr A016.

Abstract A004: Repetitive elements and viral mimicry co-evolve in pancreatic cancer

Abstract Overexpression of repetitive DNA is an emerging hallmark of human cancers and several repeats, such as SINE elements and satellite, transcribe immunostimulatory RNA that mimic features associated with viral infection. However, the extent to which specific repeat families affect tumor evolution and the immune microenvironment in a pro-or anti-tumorigenic manner remains poorly understood. We present an integrated, evolutionary multi-omic analysis pf repeat evolution in multiregion-sampled human metastatic and primary pancreatic cancers for the first time. We found that LINE-1 (L1) somatic insertion location coincides with tumor evolution. Moreover, we found L1 activity is negatively correlated with immunogenic SINE element expression. Two orthogonal metrics were used in quantifying immunogenicity of SINE elements: IFN signature and capability of forming dsRNA, where both methods revealed that evolutionary young SINE elements have stronger correlation with IFN signatures and are more likely to form dsRNAs. Moreover, the anti-correlation between L1 activity and SINE expression is validated through both immunohistological analysis of human samples and pancreatic cancer cell lines. In the end, we proposed that the model of hypoactive L1 is beneficial for tumors by suppression of immunogenic SINE elements through either their direct reverse transcription or accelerating their degradation. Our analysis therefore sheds light on the evolutionary role of dark matter repeats in a tumor’s adaptation to immunogenic vulnerabilities. Citation Format: Siyu Sun. Repetitive elements and viral mimicry co-evolve in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr A004.

Next generation sequencing (NGS) to identify relapsed gastrointestinal (GI) solid tumor patients with human leukocyte antigen (HLA) loss of heterozygosity (LOH) for future logic-gated CAR T therapy to reduce on target off tumor toxicity.

190 Background: Metastatic colorectal (CRC), pancreatic (PANC), and gastroesophageal (GE) cancers are the leading causes of GI cancer–related mortality (5-yr survival rate, 14%, 3% and ̃5-6%, respectively). T-cell immunotherapy targeting GI-associated tumor antigens has been attempted, but efficacy has been constrained by on-target off-tumor toxicity, limiting the therapeutic window. The Tmod (TM) platform is an AND-NOT logic-gated CAR T modular system, versions of which have a CEA- or MSLN-targeting CAR activator and a separate HLA-A*02-targeting blocker receptor to protect normal cells. Tmod CAR T exploits HLA LOH, common in GI malignancies (10-33% in primary solid tumors [TCGA]) and can kill tumor cells without harming healthy cells in vitro and in vivo. However, the prevalence of HLA LOH across GI tumors is unknown in the real-world setting. We utilized the Tempus xT oncology NGS database of patients with multiple GI tumors. From a standard-of-care NGS assay, GI cancer patients can be readily identified for HLA LOH and future treatment with Tmod CAR T therapy. Methods: The occurrence of HLA LOH in GI tumors of 1439 patients was assessed using paired germline and somatic DNA sequencing using a research assay [6]. CRC, PANC and GE patients with ≥ stage 3 were then extracted, and rates of HLA LOH were identified (ie, whether loss occurred across high-frequency HLA-A alleles). In addition, mutations in KRAS and BRAF, as well as MSI status were stratified to determine any association with HLA-A LOH. Results: HLA-A LOH was detected in 830 (17.3%) of all solid tumor records, and a similar proportion when all GI cancer records were analyzed (17.0%). For GI subtypes, these values ranged from 13.5% to 23.1% (Table). No high-frequency HLA-A allele (A*01, A*02, A*03, A*11) was more likely to be lost. Clinical biomarkers ( KRAS, BRAF and MSI status) were not associated with HLA-LOH. Conclusions: The frequency of HLA LOH among advanced solid tumor cancers in this dataset is 17.3%, with a range of 13.5-23% between CRC, PANC and GE. The HLA LOH frequency observed in these GI tumors is consistent with that in primary tumors from TCGA, which also used germline-matched and tumor samples. Clinical biomarkers were not associated with HLA LOH. Tempus NGS was able to identify HLA LOH, which can be used for Tmod CAR T therapy to an enhanced therapeutic window. Identification of these patients in BASECAMP-1 (NCT04981119) will enable novel Tmod CAR T therapy. [Table: see text]

Aminopyridine analogs selectively target metastatic pancreatic cancer.

Metastatic outgrowth is supported by metabolic adaptations that may differ from the primary tumor of origin. However, it is unknown if such adaptations are therapeutically actionable. Here we report a novel aminopyridine compound that targets a unique Phosphogluconate Dehydrogenase (PGD)-dependent metabolic adaptation in distant metastases from pancreatic cancer patients. Compared to structurally similar analogs, 6-aminopicolamine (6AP) potently and selectively reversed PGD-dependent metastatic properties, including intrinsic tumorigenic capacity, excess glucose consumption, and global histone hyperacetylation. 6AP acted as a water-soluble prodrug that was converted into intracellular bioactive metabolites that inhibited PGD in vitro, and 6AP monotherapy demonstrated anti-metastatic efficacy with minimal toxicity in vivo. Collectively, these studies identify 6AP and possibly other 6-aminopyridines as well-tolerated prodrugs with selectivity for metastatic pancreatic cancers. If unique metabolic adaptations are a common feature of metastatic or otherwise aggressive human malignancies, then such dependencies could provide a largely untapped pool of druggable targets for patients with advanced cancers.

Use of Palliative Care Among Commercially Insured Patients With Metastatic Cancer Between 2001 and 2016.

Early palliative care, concomitant with disease-directed treatments, is recommended for all patients with advanced cancer. This study assesses population-level trends in palliative care use among a large cohort of commercially insured patients with metastatic cancer, applying an expanded definition of palliative care services based on claims data. Using nationally representative commercial insurance claims data, we identified patients with metastatic breast, colorectal, lung, bronchus, trachea, ovarian, esophageal, pancreatic, and liver cancers and melanoma between 2001 and 2016. We assessed the annual proportions of these patients who received services specified as, or indicative of, palliative care. Using Cox proportional hazard models, we assessed whether the time from diagnosis of metastatic cancer to first encounter of palliative care differed by demographic characteristics, socioeconomic factors, or region. In 2016, 36% of patients with very poor prognosis cancers received a service specified as, or indicative of, palliative care versus 18% of those with poor prognosis cancers. Being diagnosed in more recent years (2009-2016 v 2001-2008: hazard ratio [HR], 1.8; P < .001); a diagnosis of metastatic esophagus, liver, lung, or pancreatic cancer, or melanoma (v breast cancer, eg, esophagus HR, 1.89; P < .001); a greater number of comorbidities (American Hospital Formulary Service classes > 10 v 0: HR, 1.71; P < .001); and living in the Northeast (HR, 1.43; P < .001) or Midwest (v South: HR, 1.39; P < .001) were the strongest predictors of shorter time from diagnosis to palliative care. Use of palliative care among commercially insured patients with advanced cancers has increased since 2001. However, even with an expanded definition of services specified as, or indicative of, palliative care, < 40% of patients with advanced cancers received palliative care in 2016.

ImmunoPET of Ovarian and Pancreatic Cancer with AR9.6, a Novel MUC16-Targeted Therapeutic Antibody.

Advances in our understanding of the contribution of aberrant glycosylation to the pro-oncogenic signaling and metastasis of tumor cells have reinvigorated the development of mucin-targeted therapies. Here, we validate the tumor-targeting ability of a novel monoclonal antibody (mAb), AR9.6, that binds MUC16 and abrogates downstream oncogenic signaling to confer a therapeutic response. The in vitro and ex vivo validation of the binding of AR9.6 to MUC16 was achieved via flow cytometry, radioligand binding assay (RBA), and immunohistochemistry (IHC). The in vivo MUC16 targeting of AR9.6 was validated by creating a 89Zr-labeled radioimmunoconjugate of the mAb and utilizing immunoPET and ex vivo biodistribution studies in xenograft models of human ovarian and pancreatic cancer. Flow cytometry, RBA, and IHC revealed that AR9.6 binds to ovarian and pancreatic cancer cells in an MUC16-dependent manner. The in vivo radiopharmacologic profile of 89Zr-labeled AR9.6 in mice bearing ovarian and pancreatic cancer xenografts confirmed the MUC16-dependent tumor targeting by the radioimmunoconjugate. Radioactivity uptake was also observed in the distant lymph nodes (LNs) of mice bearing xenografts with high levels of MUC16 expression (i.e., OVCAR3 and Capan-2). IHC analyses of these PET-positive LNs highlighted the presence of shed antigen as well as necrotic, phagocytized, and actively infiltrating neoplastic cells. The humanization of AR9.6 did not compromise its ability to target MUC16-expressing tumors. The unique therapeutic mechanism of AR9.6 combined with its excellent in vivo tumor targeting makes it a highly promising theranostic agent. huAR9.6 is poised for clinical translation to impact the management of metastatic ovarian and pancreatic cancers.

Randomized Phase II Study of PARP Inhibitor ABT-888 (Veliparib) with Modified FOLFIRI versus FOLFIRI as Second-line Treatment of Metastatic Pancreatic Cancer: SWOG S1513.

PARP inhibitors synergize with topoisomerase inhibitors, and veliparib plus modified (m) FOLFIRI (no 5-FU bolus) had preliminary activity in metastatic pancreatic cancers. This study evaluated the safety and efficacy of second-line treatment with veliparib and mFOLFIRI versus FOLFIRI (control) for metastatic pancreatic cancer. This randomized phase II clinical trial led by the SWOG Cancer Research Network enrolled patients between September 1, 2016 and December 13, 2017. The median follow-up was 9 months (IQR 1-27). BRCA1/2 and homologous recombination DNA damage repair (HR-DDR) genetic defects were tested in blood and tumor biopsies. Patients received veliparib 200 mg twice daily, days 1-7 with mFOLFIRI days 3-5, or FOLFIRI in 14-day cycles. After 123 of planned 143 patients were accrued, an interim futility analysis indicated that the veliparib arm was unlikely to be superior to control, and the study was halted. Median overall survival (OS) was 5.4 versus 6.5 months (HR, 1.23; P = 0.28), and median progression-free survival (PFS) was 2.1 versus 2.9 months (HR, 1.39; P = 0.09) with veliparib versus control. Grade 3/4 toxicities were more common with veliparib (69% vs. 58%, P = 0.23). For cancers with HR-DDR defects versus wild-type, median PFS and OS were 7.3 versus 2.5 months (P = 0.05) and 10.1 versus 5.9 months (P = 0.17), respectively, with FOLFIRI, and 2.0 versus 2.1 months (P = 0.62) and 7.4 versus 5.1 months (P = 0.10), respectively, with veliparib plus mFOLFIRI. Veliparib plus mFOLFIRI did not improve survival for metastatic pancreatic cancer. FOLFIRI should be further studied in pancreatic cancers with HR-DDR defects.