Localized Pancreatic Ductal Adenocarcinoma Research Articles

In vivo bioluminescence tomography-guided system for pancreatic cancer radiotherapy research

Recent development of radiotherapy (RT) has heightened the use of radiation in managing pancreatic cancer. Thus, there is a need to investigate pancreatic cancer in a pre-clinical setting to advance our understanding of the role of RT. Widely-used cone-beam CT (CBCT) imaging cannot provide sufficient soft tissue contrast to guide irradiation. The pancreas is also prone to motion. Large collimation is unavoidably used for irradiation, costing normal tissue toxicity. We innovated a bioluminescence tomography (BLT)-guided system to address these needs. We established an orthotopic pancreatic ductal adenocarcinoma (PDAC) mouse model to access BLT. Mice underwent multi-projection and multi-spectral bioluminescence imaging (BLI), followed by CBCT imaging in an animal irradiator for BLT reconstruction and radiation planning. With optimized absorption coefficients, BLT localized PDAC at 1.25 ± 0.19 mm accuracy. To account for BLT localization uncertainties, we expanded the BLT-reconstructed volume with margin to form planning target volume(PTVBLT) for radiation planning, covering 98.7 ± 2.2% of PDAC. The BLT-guided conformal plan can cover 100% of tumors with limited normal tissue involvement across both inter-animal and inter-fraction cases, superior to the 2D BLI-guided conventional plan. BLT offers unique opportunities to localize PDAC for conformal irradiation, minimize normal tissue involvement, and support reproducibility in RT studies.

Nationwide trends over 10 years in epidemiology and management of pancreatic ductal adenocarcinoma: a real-world study from the French administrative database.

Significant progress has been made in the management of pancreatic ductal adenocarcinoma (PDAC) in recent years. In this population-based study, we aimed to compare incidence, therapeutic strategies, and survival outcomes of PDAC patients in France over a decade. This study was performed using a nationwide French database. All patients receiving care for PDAC during years 2009, 2014 and 2018 were included. Treatment modalities and survival outcomes were analyzed. A total of 8143/8771/10494 patients were considered in 2009/2014/2018, respectively. Incidence increased mainly among patients aged >60 years. In localized PDAC, the proportion of patients receiving best supportive care (BSC) only decreased at 43.6/36.4/32.4% and 27.8/29.1/34.3% received chemo(radio)therapy alone. The rate of upfront surgery remained stable while 3/8/18% of operated patients received neoadjuvant therapy. Median overall survival (OS) was 7.0/7.9/8.5 months in the overall population. Among treated patients, 1-year OS was 61.4/67.7/68.8% and 30.3/36.3/38.8% for localized and metastatic PDAC, respectively. This study confirms the rising incidence of PDAC. Improved outcomes were seen in localized PDAC, with a wider use of chemotherapy and neoadjuvant strategies, and in treated metastatic patients. A modest survival gain was seen overall, hindered by the still high rate of patients receiving BSC only.

Results of a Randomized Clinical Study of Gemcitabine Plus Nab-Paclitaxel Versus Gemcitabine Plus S-1 as Neoadjuvant Chemotherapy for Resectable and Borderline Resectable Pancreatic Ductal Adenocarcinoma (RCT, CSGO-HBP-015)

BackgroundThe optimal neoadjuvant chemotherapy (NAC) regimen for patients with localized pancreatic ductal adenocarcinoma (PDAC) remains uncertain. This trial aimed to evaluate the efficacy and safety of two neoadjuvant chemotherapy (NAC) regimens, gemcitabine plus nab-paclitaxel (GA) and gemcitabine plus S-1 (GS), in patients with resectable/borderline-resectable (R/BR) PDAC.Patients and MethodsTreatment-naïve patients with R/BR-PDAC were enrolled and randomly allocated. They received two cycles (2 months) of each standard protocol, followed by radical surgery for those without tumor progression in general hospitals belonging to our intergroup. The primary endpoint was to determine the superior regimen on the basis of achieving a 10% increase in the rate of patients with progression-free survival (PFS) at 2 years from allocation.ResultsA total of 100 patients were enrolled, with 94 patients randomly assigned to the GS arm (N = 46) or GA arm (N = 48). The 2-year PFS rates did not show the stipulated difference [GA, 31% (24–38%)/GS, 26% (18–33%)], but the Kaplan–Myer analysis showed significance (median PFS, GA/GS 14 months/9 months, P = 0.048; HR 0.71). Secondary endpoint comparisons yielded the following results (GA/GS arm, P-value): rates of severe adverse events during NAC, 73%/78%, P = 0.55; completion rates of the stipulated NAC, 92%/83%, P = 0.71; resection rates, 85%/72%, P = 0.10; average tumor marker (CA19-9) reduction rates, −50%/−21%, P = 0.01; average numbers of lymph node metastasis, 1.7/3.2, P = 0.04; and median overall survival times, 42/22 months, P = 0.26.ConclusionsThis study found that GA and GS are viable neoadjuvant treatment regimens in R/BR-PDAC. Although the GA group exhibited a favorable PFS outcome, the primary endpoint was not achieved.

Abstract 6313: Enhancing CAR T cell-based immunotherapy outcomes in PDAC: Evaluating iC9.B7-H3 CAR T cells in adjuvant, neoadjuvant, and monotherapy settings

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) is among the most aggressive and lethal cancers worldwide. Despite negative margin resections and subsequent systemic therapy, PDAC often recurs. Additionally, most patients present with locally advanced and unresectable tumors at the time of diagnosis. Cancer-associated fibroblasts (CAFs) contribute to the highly desmoplastic tumor microenvironment (TME) and form a biophysical barrier, limiting immune cell infiltration. Moreover, CAF-secreted factors suppress the anti-tumor activity of T cells and shift cancer cells toward invasive proliferative and mesenchymal phenotypes. Therefore, targeting CAFs can enhance T-cell infiltration and improve the efficacy of T-cell based immunotherapeutic strategies. B7-H3 is an immune checkpoint molecule highly expressed on PDAC cells and CAFs. In this study, we investigate the use of Chimeric Antigen Receptor (CAR) T cells targeting B7-H3 to eliminate metastatic PDAC in a preclinical mouse model in three different settings: I. Adjuvant II. Neoadjuvant III. CAR T cell monotherapy. Our CART-B7-H3 construct includes an inducible caspase 9 (iC9) suicide gene, which allows for the controlled elimination of the CAR T cells in the event of overwhelming cytokine release syndrome. Methods: To validate the therapeutic potential of iC9.B7-H3 CAR T cells in vivo, NSG mice were orthotopically engrafted with 1x105 patient-derived PDAC6 cells and 9x105 hCAF1 cells at a ratio of 1:9, reflecting a clinically relevant model. In the adjuvant group, mice underwent surgical resection of the primary tumor (distal pancreatectomy and splenectomy) after 25 days. On days 30 and 60, they received systemic iC9.B7-H3 CAR T cell treatment (5x106). In the neoadjuvant group, mice were systemically treated with iC9.B7-H3 CAR T cells on day 19 and underwent surgical resection of the primary tumor on day 25, following another systemic CAR T cell dose on day 60. In the CAR T monotherapy group, mice received systemic iC9.B7-H3 CAR T cells on days 19 and 60. Results: In vivo, iC9.B7-H3 CAR T cells in the neoadjuvant group effectively eradicated both local and distant PDAC metastases for the length of the experiment (180 days) and significantly increased the survival (P <0.0001), indicating long-term efficacy in the treatment of PDAC metastases with no adverse side effects. In the adjuvant and CAR T monotherapy groups, iC9.B7-H3 CAR T cells effectively control tumor growth, eliminate metastases, and significantly increase survival (P=0.0018 and P=0.0007, respectively). Conclusion: These data suggest that the neoadjuvant application of iC9.B7-H3 CAR T cells may demonstrate persistent efficacy in eradicating both local and distant PDAC metastases. iC9.B7-H3 CAR T cells adjuvantly and as monotherapy achieved significant tumor control. Citation Format: Shahrzad Arya, Seyed Amir Sanatkar, Marco Ventin, Giulia Cattaneo, Cristina Martin, Gabriella Lionetto, Jingyu Jia, Feng Chen, David T. Ting, Xinhui Wang, Sandra Ryeom, Cristina R. Ferrone, Soldano Ferrone. Enhancing CAR T cell-based immunotherapy outcomes in PDAC: Evaluating iC9.B7-H3 CAR T cells in adjuvant, neoadjuvant, and monotherapy settings [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 6313.

Abstract 3784: Methylated DNA markers for detection of peritoneal metastasis in pancreatic cancer

Abstract Introduction: Laparoscopy with peritoneal lavage enhances staging accuracy in patients with pancreatic ductal adenocarcinoma (PDAC). Occult intra-abdominal metastases are identified by staging laparoscopy in approximately 20% of patients with radiologically localized PDAC. Peritoneal fluid cytology has limited sensitivity in detecting occult intra-abdominal metastasis. Methylated DNA markers (MDMs) can accurately detect PDAC from tumor tissue, blood, and pancreatic secretions. This study aims to assess the feasibility of assaying MDMs in peritoneal lavage fluid obtained at the time of staging laparoscopy for patients with PDAC. Methods: Peritoneal lavage fluid (25-60 mL) obtained from patients with PDAC at the time of staging laparoscopy was centrifuged for 10 minutes at 1200 × g. The pellet was resuspended and aliquoted into 200µL tubes and frozen at -80°C. DNA extracted from one aliquot was assayed for mutant KRAS (G12A and G13D) and then bisulfite converted to measure 13 MDMs (GRIN2D, CD1D, ZNF781, FER1L4, RYR2, CLEC11A, AK055957, LRRC4, MAX.CHR5.4295, HOXA1, PRKCB, SHISA9, NTRK3) and a normalizing reference gene (B3GALT6) using quantitative methylation specific PCR. The association of KRAS and the average signal from the 13 MDMs (MDMscore) with intra-abdominal metastasis (Y/N) was assessed with the area under the receiver operator characteristic curve (AUC). Results: Among 48 PDAC patients, staging laparoscopy revealed intra-abdominal metastasis in 15 (31%). Of the 15 intra-abdominal metastases, 6 were found to have biopsy-confirmed intra-abdominal metastasis and positive peritoneal cytology, 4 were positive on peritoneal cytology alone, and 5 had biopsy-confirmed intra-abdominal metastasis alone. The sensitivity of the MDMscore for intra-abdominal metastasis was 87% (CI: 60-98%) at 90% (CI: 76-98%) specificity whereas the sensitivity for KRAS was 40% (CI: 16-68%) at 85% (CI: 68-95) specificity. The AUC for the MDMscore was 0.98 (CI: 0.94-1.00) compared to 0.62 (CI: 0.48-0.77) for that of KRAS (p<0.0001). Conclusion: MDMs assayed from peritoneal lavage fluid collected during staging laparoscopy is a novel tool for accurate molecular staging of PDAC. These early results warrant further study in a larger cohort to assess impact on peritoneal staging and its clinical utility in the neoadjuvant treatment paradigm of PDAC. Citation Format: Kalika Maheshwari, Calise K. Berger, William R. Taylor, Douglas W. Mahoney, Kelli N. Burger, Adriana M. Delgado, Karen A. Doering, Heather M. Streich, Patrick H. Foote, Sean P. Cleary, Travis E. Grotz, Micheal L. Kendrick, Rory L. Smoot, Patrick P. Starlinger, Cornelius A. Thiels, Mark J. Truty, Susanne G. Warner, John B. Kisiel, Shounak Majumder. Methylated DNA markers for detection of peritoneal metastasis in pancreatic cancer [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 3784.

Role of minimally invasive surgery in the management of localized pancreatic ductal adenocarcinoma: a review.

Pancreatic ductal adenocarcinoma (PDAC) remains a highly lethal malignancy with a minority of patients eligible for curative-intent surgical intervention. Pancreatic resections are technically demanding operations associated with considerable morbidity and mortality. Minimally invasive pancreatic resections (MIPRs), which include laparoscopic and robotic approaches, may enhance postoperative outcomes by lessening physiological impact of open surgery. A limited number of randomized-controlled trials as well as numerous retrospective reports have focused on MIPR outcomes and role in management of a variety of tumors, including PDAC. Today, MIPRs are generally considered acceptable alternatives to open surgery as a trend towards improved short-term metrics is observed. However, several questions remain regarding the oncological adequacy of MIPR's as long-term experience is less extensive compared to open techniques. This review aims to summarize existing evidence on MIPRs with a focus on PDAC.

Machine Learning Links T-cell Function and Spatial Localization to Neoadjuvant Immunotherapy and Clinical Outcome in Pancreatic Cancer.

Tumor molecular data sets are becoming increasingly complex, making it nearly impossible for humans alone to effectively analyze them. Here, we demonstrate the power of using machine learning (ML) to analyze a single-cell, spatial, and highly multiplexed proteomic data set from human pancreatic cancer and reveal underlying biological mechanisms that may contribute to clinical outcomes. We designed a multiplex immunohistochemistry antibody panel to compare T-cell functionality and spatial localization in resected tumors from treatment-naïve patients with localized pancreatic ductal adenocarcinoma (PDAC) with resected tumors from a second cohort of patients treated with neoadjuvant agonistic CD40 (anti-CD40) monoclonal antibody therapy. In total, nearly 2.5 million cells from 306 tissue regions collected from 29 patients across both cohorts were assayed, and over 1,000 tumor microenvironment (TME) features were quantified. We then trained ML models to accurately predict anti-CD40 treatment status and disease-free survival (DFS) following anti-CD40 therapy based on TME features. Through downstream interpretation of the ML models' predictions, we found anti-CD40 therapy reduced canonical aspects of T-cell exhaustion within the TME, as compared with treatment-naïve TMEs. Using automated clustering approaches, we found improved DFS following anti-CD40 therapy correlated with an increased presence of CD44+CD4+ Th1 cells located specifically within cellular neighborhoods characterized by increased T-cell proliferation, antigen experience, and cytotoxicity in immune aggregates. Overall, our results demonstrate the utility of ML in molecular cancer immunology applications, highlight the impact of anti-CD40 therapy on T cells within the TME, and identify potential candidate biomarkers of DFS for anti-CD40-treated patients with PDAC.

Improved Clinical Staging System for Localized Pancreatic Cancer Using the ABC Factors: A TAPS Consortium Study.

Previous studies suggest that besides anatomy (A: resectable, borderline resectable [BR], or locally advanced [LA]) also biologic (B: carbohydrate antigen 19-9 [CA 19-9]) and conditional (C: performance status) factors should be considered when staging patients with localized pancreatic ductal adenocarcinoma (PDAC). The prognostic value of the combined ABC factors has not been quantitatively validated. In this retrospective cohort study, we evaluated patients with localized PDAC treated with initial (modified) fluorouracil with leucovorin, irinotecan, and oxaliplatin ([m]FOLFIRINOX) at five high-volume pancreatic cancer centers in the United States and the Netherlands (2012-2019). Multivariable Cox proportional hazards analysis was used to investigate the impact of the ABC factors for overall survival (OS). Overall, 1,835 patients with localized PDAC were included. Tumor stage at diagnosis was potentially resectable in 346 (18.9%), BR in 531 (28.9%), and LA in 958 (52.2%) patients. The baseline CA 19-9 was >500 U/mL in 559 patients (32.5%). Performance status was ≥1 in 1,110 patients (60.7%). Independent poor prognostic factors for OS were BR disease (hazard ratio [HR], 1.26 [95% CI, 1.06 to 1.50]), LA disease (HR, 1.71 [95% CI, 1.45 to 2.02]), CA 19-9 >500 U/mL (HR, 1.36 [95% CI, 1.21 to 1.52]), and WHO performance status ≥1 (HR, 1.31 [95% CI, 1.16 to 1.47]). Patients were assigned 1 point for each poor ABC factor and 2 points for LA disease. The median OS for patients with score 0-4 was 49.7, 29.9, 22.0, 19.1, and 14.9 months with corresponding 5-year OS rates of 47.0%, 28.9%, 19.2%, 9.3%, and 4.8%, respectively. The ABC factors of tumor anatomy, CA 19-9, and performance status at diagnosis were independent prognostic factors for OS in patients with localized PDAC treated with initial (m)FOLFIRINOX. Staging of patients with localized PDAC at diagnosis should be based on anatomy, CA 19-9, and performance status.

Neoadjuvant therapy for localized pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive tumor with poor prognosis and rising incidence globally. Multimodal therapy that includes surgical resection and chemotherapy with or without radiation offers the best chance for optimal outcomes. The development of established criteria for anatomic staging of local primary tumors into potentially resectable (PR), borderline resectable (BR), and locally advanced (LA) has greatly clarified the optimal treatment strategies. While upfront surgical resection was traditionally the recommended approach for localized PDAC, increasingly neoadjuvant therapy (NT) is recommended prior to surgery. Whereas NT can lead to downstaging that facilitates surgical resection for BR/LA cancers, NT also enhances patient selection for surgery, improves margin-negative resection rates, and increases the odds of completing multimodality therapy for all patients with PDAC. Herein, we review the rationale for NT for localized PDAC and summarize existing and ongoing literature.

Prospective Evaluation of Circulating Tumor DNA using Next Generation Sequencing as a Biomarker during Neoadjuvant Chemotherapy in Localized Pancreatic Cancer.

In this prospective study, we aim to characterize the prognostic value of circulating tumor DNA (ctDNA) by next-generation-sequencing (NGS) in patients undergoing neoadjuvant chemotherapy (NAC) for pancreatic ductal adenocarcinoma (PDAC). Circulating tumor DNA is a promising blood-based biomarker that is prognostic in several malignancies. Detection of ctDNA by NGS may provide insights regarding the mutational profiles in PDAC to help guide clinical decisions for patients in a potentially curative setting. However, the utility of ctDNA as a biomarker in localized PDAC remains unclear. Patients with localized PDAC were enrolled in a prospective study at Northwestern Medicine between October 2020 and October 2022. Blood samples were collected to perform targeted tumor agnostic NGS utilizing the Tempus x|F 105 gene panel at three timepoints: pre-therapy (at diagnosis), post-NAC, and after local therapy, including surgery. The relationship between ctDNA detection and CA19-9, and the prognostic significance of ctDNA detection were analyzed. 56 patients were included in the analysis. ctDNA was detectable in 48% at diagnosis, 33% post-NAC, and 41% after local therapy. After completion of NAC, patients with detectable ctDNA had higher CA19-9 levels versus those without (78.4 vs. 30.0, P=0.02). The presence of baseline ctDNA was associated with a CA19-9 response; those without ctDNA had a significant CA19-9 response following NAC (109.0U/mL vs. 31.5U/mL; P=0.01), while those with ctDNA present at diagnosis did not (198.1U/mL vs. 113.8U/mL; P=0.77). In patients treated with NAC, the presence of KRAS ctDNA at diagnosis was associated with and independently predicted worse progression-free-survival. This report demonstrates the prognostic value of ctDNA analysis with NGS in localized PDAC. NGS ctDNA is a biomarker of treatment response to NAC. KRAS ctDNA at diagnosis independently predicts worse survival in patients treated with NAC.

Association of race and CA 19-9 nonproduction with limited pathologic response to neoadjuvant chemotherapy in patients with localized pancreatic cancer.

609 Background: Black patients with pancreatic ductal adenocarcinoma (PDAC) are less likely to have major pathologic response (MPR) following induction chemotherapy compared to non-Black patients. Rare reports have suggested that Black patients are more likely to be CA 19-9 non-producers. We aimed to determine if disproportionate rates of CA 19-9 nonproduction underlie racial differences in neoadjuvant chemotherapy response in patients with localized PDAC. We also explored differences in somatic mutations between CA 19-9 producers (CAprod) and non-producers (CAnonprod). Methods: Black and White patients with localized PDAC receiving ≥ 2 cycles of neoadjuvant chemotherapy followed by pancreatectomy (2010-2019) at 7 high-volume centers were reviewed. Patients were categorized as CAprod (CA 19-9 > 5 U/mL) or CAnonprod (CA 19-9 ≤ 5 U/mL). Uni- and multi-variable models evaluated differences in rates of CAnonprod by race, and the association of CAnonprod with MPR (CAP 0/1). The Pancreatic Cancer Action Network (PanCAN)’s SPARK health data platform which contains clinical and multi-omic data from the PanCAN Know Your Tumor program was queried to identify patients with CA 19-9 and genomic data. Fisher’s exact test was used to compare differentially mutated genes between CAprod and CAnonprod patients. Results: Our cohort included 385 (93.3%) CAprod and 30 (6.7%) CAnonprod. CAnonprod patients were more likely to be Black than CAprod (50.0% vs 12.5%, p<0.01). There were no other differences in demographic or clinical features between CAnonprod and CAprod. Most patients received FOLFIRINOX vs Gemcitabine based chemotherapy (60.3% CAprod vs. 56.7% CAnonprod, p=0.27) with a median number of 4.0 vs 5.0 cycles (p=0.83), respectively. Rate of MPR was significantly higher in patients with CAprod compared with CAnonprod patients (26.3% vs 7.7%, p=0.03). No CAnonprod patient had a complete pathologic response vs 28 (7.3%) of CAprod (p=0.12). CAnonprod was independently associated with decreased odds of MPR (OR 0.21, CI [0.04-0.99]). Black race was independently associated with increased odds of CAnonprod (OR 8.66, CI [3.81 – 19.7]). When stratified by production of CA 19-9, there was no significant difference between rate of MPR between Black and White patients. In the PanCAN KYT analysis, CAnonproduc had higher rates of SWI/SNF alterations (50.0% of CAnonprod vs 30.1% of CAprod, P<0.01;P-adj=ns; ARID1B was the most frequently mutated SWI/SNF gene in CAnonprod (31.0% vs 9.0% CApos, p<0.01; P-adj=ns). Conclusions: CAnonprod were more likely to be Black and have significantly worse rates of MPR following neoadjuvant chemotherapy in patients with localized PDAC. Moreover, CAnonprod was associated with higher rates of SWI/SNF alterations, noting a potential biologic basis for racial differences in chemotherapy response to curative-intent treatment for PDAC.

KRAS mutation status in the prediction of pancreatic tumor response after neoadjuvant systemic therapy and magnetic resonance-guided SBRT.

709 Background: Stereotactic body radiotherapy (SBRT) has been incorporated into multi-modality treatment of locally advanced and borderline resectable pancreatic ductal adenocarcinoma (PDAC). For non-metastatic inoperable PDAC patients (pts) who receive magnetic resonance-guided SBRT (MRgSBRT), baseline features that predict for treatment response remain unsettled. In localized PDAC, multiple studies have investigated the KRAS oncogene as a prognostic factor with mixed findings. In this single institution retrospective study of PDAC pts treated with MRgSBRT, we hypothesized that KRAS mutation status would be predictive of meaningful clinical outcomes. Methods: From an IRB approved dataset of PDAC pts treated with MRgSBRT between 2016 and 2022, 39 pts with non-metastatic inoperable pancreatic cancer, known KRAS mutation status, ≥ 3 months of neoadjuvant systemic therapy (NST), and at least 3 months post-RT follow up were extracted for analysis. Baseline demographics, tumor and treatment characteristics, and clinical endpoints including conversion to resectability, best imaging response per RECIST v1.1, pathologic response (PR) per TRG-CAP, and overall survival (OS) after MRgSBRT were collected. Objective response (ORR) on both imaging and pathology was defined as complete response (CR) + partial response (PR); disease control (DC) was defined as CR + PR + stable disease (SD). Logistic regression was used to assess correlation between baseline variables and ORR. Cox proportional hazard models were utilized to determine association with OS. Results: Out of 39 pts, 21 (53%) were KRAS-mutated (KRAS-mt) and 18 (47%) were KRAS wild-type (KRAS-wt). Median age was 62, 54% were male, only 1 pt had ECOG > 1, and CA 19-9 at diagnosis was 197. Median duration of NST was 9 cycles, and common agents included Gemcitabine and Abraxane (21%); FOLFIRINOX (28%); a combination of the two regimens (41%); or other NSTs (10%). Median MRgSBRT dose fractionation was 50 Gy (range 35 – 50) in 5 fractions; all fractions underwent adaptive optimization. Thirty pts (77%) experienced DC on imaging, 16 (43%) had ORR, and 12 (31%) were converted to resectable following MRgSBRT. Cohort median OS was 12.3 months, and pts who had surgery had a non-significant median OS advantage (18 vs 12 months; p=0.19). KRAS-mt was associated with worse ORR (p=0.04; AUC=0.73) and decreased OS (HR: 2.15; p=0.03). In a clinical model incorporating baseline characteristics (age, ECOG, radiographic staging, CA 19-9 level, and KRAS), only KRAS predicted OS (HR: 3.02 for KRAS-mt; p=0.01). KRAS-mt status was also predictive of OS among pts who underwent surgery (HR: 5.24 for KRAS-mt; p=0.04). Conclusions: For localized PDAC pts inoperable at diagnosis who received NST followed by MRgSBRT, KRAS was the only significant predictor of ORR and OS, highlighting the need for further treatment intensification in KRAS-mt pts.

Abstract A002: A phase II study of peri-operative modified FOLFIRINOX in localized pancreatic ductal adenocarcinoma (PDAC)

Abstract Introduction: Advances in adjuvant chemotherapy with 5-fluorouracil, irinotecan, and oxaliplatin (FFX) have improved survival for patients (pts) with resectable PDAC yet few are cured by the current standard of care. Neoadjuvant FFX may lead to early control of micrometastasis and enhance cure rates for this aggressive malignancy. Methods: We performed a single-arm phase-2 clinical trial for resectable PDAC evaluating 6 months of perioperative modified (m) FFX (NCT02047474). Patients underwent baseline pancreatic protocol CT and were reviewed for resectability by a multidisciplinary panel. Enrolled pts received 6 cycles of neoadjuvant mFFX followed by surgery and 6 cycles of adjuvant mFFX. The primary endpoint was a ≥ 66% 12-month progression-free survival (PFS). Additional endpoints included overall survival (OS), circulating tumor DNA (ctDNA), tumor molecular features and tumor Keratin 17 levels. Whole blood was prospectively collected and processed to stored plasma (median volume 5.4 mL, range: 2.6 – 10.2) for retrospective ctDNA analysis using a personalized, tumor-informed ctDNA assay (SignateraTM). Survival rates were estimated by Kaplan-Meier. Results: Forty-six pts enrolled with 63 months median follow up, median age of 65 [R 46–80], 36 (78%) were ECOG 0, 30 (65%) had an endobiliary stent and no pts had staging laparoscopy. All pts started mFFX, and 37 pts (80%) completed all 6 preop cycles. Thirty-three pts (72%) underwent surgery with 3 pts developing investigator-assessed progression during neoadjuvant mFFX. Six pts were unresectable intraoperatively, and 27 pts (59%) underwent resection per protocol (25 R0, 2 R1). Ten additional pts underwent surgery off protocol. The 12-month PFS was 78% (95% CI: 64.2–94.4), median PFS and OS were 36.5 months (95% CI: 16.6–74.5) and 37.2 months (95% CI 17.5–not reached), respectively. Two-year OS was 59% (95% CI: 45.8–74.7). Baseline ctDNA was detected in 16/22 (73%) pts, and after 6 cycles of mFFX ctDNA was detected in 3/17 (18%) of pts. Patients with a positive ctDNA test 4 weeks post-resection had worsened PFS (HR 34.0, 95% CI: 2.6-4758.6; P = 0.006) and OS (HR: 11.7, 95% CI: 1.5–129.9; P = 0.021) compared to ctDNA negative. Mutational signature analysis revealed predominant signatures to be COSMIC signatures SBS1 and SBS5 (age related), and SBS15 (mismatch repair deficiency associated) which was associated with improved OS. Using Keratin 17 as a biomarker of the basal molecular subtype, either in diagnostic needle aspirates or surgical specimens, we found that high K17 expression was associated with worse survival. Conclusion: The perioperative mFFX clinical trial for resectable PDAC met its primary endpoint with a promising survival rate, and R0 resection rate of 93%. These findings warrant further evaluation in a randomized clinical trial. Most pts with detectable ctDNA at baseline experience ctDNA clearance after 6 cycles of neoadjuvant mFFX. In the post-operative setting, ctDNA positivity was strongly associated with recurrence. Signature SBS15 and low K17 were associated with improved OS. Citation Format: Michael Cecchini, Ronald Salem, Marie Robert, Suzanne Czerniak, Moein Rajaei, Jeffrey Townsend, Ondrej Blaha, Daniel Zelterman, Jaykumar Thumar, Jeremy Kortmansky, Wajih Zaheer, Neal Fischbach, Justin Persico, Stacey Stein, Sajid Khan, Charles Cha, Kevin Billingsley, John Kunstman, Sumedha Chowdhury, Robert Tseng, Carlos Mauricio, Deanne Yugawa, Luisa Escobar-Hoyos, Kimberly Johung, Christina Wiess, Erik Spickard, Vasily N. Aushev, George Laliotis, Adham Jurdi, Minetta C. Liu, Jill Lacy. A phase II study of peri-operative modified FOLFIRINOX in localized pancreatic ductal adenocarcinoma (PDAC) [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A002.

Abstract B014: Immuno-modulation of the tumor microenvironment of pancreatic adenocarcinoma following isotoxic high-dose stereotactic body radiotherapy (iHD-SBRT)

Abstract INTRODUCTION: Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest tumors. Unlike other tumors, the progress of systemic therapies has been very slow, mainly due to the peculiar and resistant tumor microenvironment (TME) of PDAC. The addition of ablative stereotactic body radiation therapy (SBRT) in a total neoadjuvant strategy is promising for the treatment of localized PDAC and is currently being explored in several clinical trials. However, if radiation therapy possesses the ability to modulate the TME, the impact of high-dose SBRT is still poorly known in PDAC. Here, we aim to characterize by immunohistochemistry (IHC) and RNA sequencing (RNAseq) analysis the immuno-modulations of the TME following isotoxic high-dose stereotactic body radiotherapy (iHD-SBRT). MATERIAL: Paraffin-embedded residual tumoral tissues of 50 localized PDAC resected between 2011 and 2020 were used: seventeen patients had surgery first, seventeen received an induction chemotherapy with FOLFIRINOX (FFX) only and sixteen with FFX followed by an iHD-SBRT designed to individually maximize the dose prescribed to the tumor and vessels interfaces up to Dmax(0.5cc)<53Gy in 5 fractions. RESULTS: We found that although collagen deposition increases significantly after iHD-SBRT (COL1: 83.27 vs 78.60 vs 68.04%, p<0.001 for iHD-SBRT, FFX and treatment naïve cohort respectively), the intra-tumoral lymphocyte infiltration is globally not altered, including for cytotoxic CD8+ lymphocytes. Only the IHC expression of CD4+ T helper population is significantly decreased after iHD-SBRT. Using gene set enrichment analysis (GSEA) of the KEGG pathway, the IL-17 signaling pathway related to the T17 cells is particularly significantly increased after iHD-SBRT compared to FFX only. After iHD-SBRT, the IHC expression levels of FOXP3+ cells and PD-L1 are significantly increased. No difference is observed for CD68+ expression however, cell type enrichment analysis from our RNA-seq data using xCell algorithm shows that the M2-polarized CD68+ cells are increased after iHD-SBRT compared to FFX alone. PD-1 expression is significantly decreased after iHD-SBRT. Furthermore, RNAseq data revealed that iHD-SBRT is associated with significant enrichment in basaloid cells (p<0.0024), a subtype of basal–like cells associated with immunomodulatory stroma and better clinical outcomes. GSEA canonical pathway analysis further revealed metabolism-related pathways such as oxidative phosphorylation and gluthathione metabolism significantly enriched in iHD-SBRT treated group, suggesting the potential of mitochondrial inhibitors as candidates for combination therapy. CONCLUSIONS: iHD-SBRT is able to durably immuno-modulate the TME of PDAC. If the overall T-cell infiltration is preserved, we have identified some increased pro-tumoral cells and pathways after iHD-SBRT that could improve the development of better-oriented combination trials involving high-dose SBRT. Citation Format: Christelle Bouchart, Oier Azurmendi Senar, Julie Navez, Laurine Verset, Anaïs Boisson, Matthieu Hein, Nicky D’Haene, Dirk Van Gestel, Luigi Moretti, Pieter Demetter, Jean-Baptiste Bachet, Karen Willard-Gallo, Rémy Nicolle, Tatjana Arsenijevic, Jean-Luc Van Laethem. Immuno-modulation of the tumor microenvironment of pancreatic adenocarcinoma following isotoxic high-dose stereotactic body radiotherapy (iHD-SBRT) [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B014.

Abstract B022: A platform to characterize hepatic immunity reveals variation in hepatic infiltration of tumor expanded T cells in “localized” PDAC

Abstract Even in its earliest stages, pancreatic ductal adenocarcinoma (PDAC) is an essentially incurable disease due to the presence of disseminated, yet radiographically occult cancer cells in the setting of an otherwise “localized” primary tumor. The vast majority (~80%) of patients who undergo curative-intent surgery develop liver metastases, often within six months of surgery, and these hepatic metastases dominate survival outcomes, even in the presence of multisite recurrence. What drives hepatic organotropism remains unknown, in large part due to the exclusion of “normal” liver tissue from PDAC biobanking programs. While recent work in animal models suggests that suppression of the hepatic immune microenvironment may facilitate metastatic progression, confirmatory studies in human patients are lacking, due to a paucity of relevant model systems. To address this deficit, we developed an experimental pipeline to profile hepatic immunity at single-cell resolution vis-à-vis the peripheral and intratumoral immune compartments. We hypothesized that this platform could be leveraged to identify tissue- and patient-specific immunophenotypes associated with hepatic recurrence prior to the development of overt metastases. Patients with localized PDAC at Duke University were enrolled in an IRB-approved (Pro00108288) biobanking program to obtain multisegment liver biopsies, primary tumor specimen, and peripheral blood at the time of curative-intent resection. Immune (CD45+) cells were sorted following enzymatic digestion (tissues) or Ficoll separation (blood) and single-cell gene expression and T cell receptor libraries were created. Data was processed using CellRanger and aligned, filtered, and normalized using R. In total, we identified 32 unique immune cell populations conserved across patients, with both shared and site-specific cell types identified in the T cell, B cell, NK cell, and myeloid compartments. Additionally, we identified expanded T cell clones within the tumor microenvironment and traced a subset of these clonotypes to the premetastatic liver. These tumor-expanded T cells (TTE cells) presumably arise from recognition of a specific tumor antigen, which then instigates activation and proliferation of the clone. Notably, we identified a subset of our patients without known liver metastases who nonetheless demonstrated hepatic infiltration of TTE cells. While the significance of these hepatic TTE cells is still unclear, we hypothesize that this is evidence of a primed immune response to tumor antigens already present in the liver at the time of surgery. This experimental platform has now been implemented within an ongoing window-of-opportunity trial (NCT05634720) testing neoadjuvant hepatic artery chemotherapy in patients undergoing resection of localized PDAC. The correlative scientific objectives will focus on quantifying the variation of hepatic TTE infiltration across patients, determining the function and activation state of hepatic TTE cells, and testing the association between hepatic TTE cell infiltration and clinical outcomes. Citation Format: Elishama N. Kanu, Ashley A. Fletcher, Jiayin Bao, Austin M. Eckhoff, Karrie Comatas, Tao Wang, Bin-Jin Hwang, Michael E. Lidsky, Sabino Zani, Dan G. Blazer, Peter J. Allen, Zhicheng Ji, Daniel P. Nussbaum, Erika J. Crosby. A platform to characterize hepatic immunity reveals variation in hepatic infiltration of tumor expanded T cells in “localized” PDAC [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B022.

Abstract A035: Stromal composition, fibroblast heterogeneity and spatial organization in pancreatic adenocarcinoma

Abstract Background: The pancreatic ductal adenocarcinoma (PDAC) microenvironment is characterized by highly abundant stromal fibroblasts that are hypothesized to influence tumor behavior. While recent studies have identified multiple populations of stromal fibroblasts with divergent roles in PDAC biology, stromal composition remains incompletely characterized in human tumors, including the landscape of fibroblast subtypes and their spatial organization. Design: We designed multiplex immunofluorescence assays to quantify tumor cells (cytokeratin), immune cells (CD45), fibroblasts (αSMA, CD74, FAP, LaminA), other cells (CD31, CD56, CALD1, NG2), and collagen I in fixed tissue sections. Combinatorial fibroblast marker expression identified myofibroblasts (myCAF), inflammatory fibroblasts (iCAF), antigen-presenting fibroblasts (apCAF), and other hybrid fibroblast subtypes. We characterized fibroblast populations in up-front resected and neoadjuvant-treated cohorts of patients with localized PDAC and in patients with biopsies of metastatic lesions. Using digital imaging, supervised machine learning, and spatial proximity metrics, we quantified cell phenotypes, fibroblast subtype composition and spatial organization at the single-cell level and in the context of tumor clinicopathologic features and patient outcomes. Results: Across 301 up-front resected tumors, we cumulatively analyzed 1.7 million cells, including 611,000 fibroblasts. Stromal fibroblast density ranged from 632 to 4150 cells/mm2. Five main fibroblast subtypes constituted more than 85% of the fibroblast population in these tumors: αSMA+ (myCAF), FAP+αSMA+ (FAP+ myCAF), LaminA+ (iCAF), αSMA+ LaminA+ (myCAF/iCAF), and FAP+ αSMA+ LaminA+ (FAP+ myCAF/iCAF). Unexpectedly, 39% of fibroblasts showed co-expression of markers previously considered distinct for major fibroblast subtypes. By unsupervised clustering of fibroblast subtype proportions, we identified 3 fibroblast-defined tumor subgroups, including tumors rich in FAP+ fibroblasts, hybrid fibroblasts, and single positive fibroblasts (myCAFs, iCAFs, and apCAFs), which were associated with patient survival. Furthermore, fibroblast subtypes were spatially organized, with preferential localization of FAP+ myCAFs near tumor cells and iCAFs more distant from tumor cells yet closer to immune cells. FAP+ myCAFs were more abundant in basal-like tumors than in classical tumors, and FAP+ myCAFs were located closer to basal-like tumor cells than classical tumor cells within individual tumors. Compared to up-front resected primary tumors, neoadjuvant FOLFIRINOX treated tumors and metastatic lesions harbored distinct fibroblast profiles. Conclusion: Fibroblasts in the PDAC microenvironment are heterogeneous both in abundance and subtype composition, exhibit distinct spatial organization and are associated with patient outcomes. Treatment with FOLFIRINOX alters the composition of fibroblast subtypes in primary PDAC, and metastatic PDAC lesions have a different fibroblast composition compared to primary tumors. Citation Format: Dalia Elganainy, Andressa Dias Costa, Alexander Jordan, Suryun Kim, Sara A. Väyrynen, Hannah L. Williams, Chen Yuan, Douglas A. Rubinson, Kimberly Perez, Harshabad Singh, Richard F. Dunne, Thomas E. Clancy, David C. Linehan, Daniel T. Chang, Aram F. Hezel, Albert C. Koong, Andrew Aguirre, Brian M. Wolpin, Jonathan A. Nowak. Stromal composition, fibroblast heterogeneity and spatial organization in pancreatic adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A035.

Abstract A021: Adjuvant iC9.B7-H3 CAR T cell-based immunotherapy effectively eradicates local and distant metastases in pancreatic ductal adenocarcinoma

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis. Despite negative margin resections of the cancer and systemic therapy, PDAC often recurs. Pancreatic cancer-associated fibroblasts (CAFs) contribute to a highly desmoplastic tumor microenvironment (TME), preventing T cell infiltration. Moreover, CAF-secreted factors suppress the anti-tumor activity of T cells and shift tumor cells toward invasive proliferative and mesenchymal phenotypes. Therefore, targeting CAFs can enhance T-cell infiltration and improve treatment outcomes. In this study, we investigate using Chimeric Antigen Receptor (CAR) T cells targeting B7-H3 to eliminate PDAC metastatic disease in a preclinical mouse model. B7-H3, an immune checkpoint molecule, is highly expressed on PDAC cells and CAFs. Our CART-B7-H3 construct includes an inducible caspase 9 (iC9) suicide gene, which allows for the controlled elimination of the CAR T cells in the event of overwhelming cytokine release syndrome. Methods: The efficacy of iC9.B7-H3 CAR T cells was tested in vitro against human PDAC and fibroblast cell lines at various ratios. The antitumor activity of iC9.B7-H3 CAR T cells was assessed in PDAC cells after exposure to CAF-conditioned media, simulating TME with immunosuppressive cytokines. To validate the therapeutic potential of iC9.B7-H3 CAR T cells in vivo, NSG mice were orthotopically engrafted with patient-derived PDAC6 cells and hCAF1 cells at a ratio of 1:9, reflecting a clinically relevant model. After three weeks, the mice underwent surgical resection of the primary tumor (distal pancreatectomy and splenectomy) and were subsequently treated systemically with iC9.B7-H3 CAR T cells. Results: In vitro, at a high effector-to-target (E:T) ratio, iC9.B7-H3 CAR T cells effectively eliminated PDAC cells and CAFs. However, their anti-tumor activity was diminished when the E:T ratio was lowered (PDAC6 tumor cell killing (TCK): 92±5% at 1:1, hCAF1 TCK: 81.67±5% at 1:1, compared to PDAC6 TCK: 26±5% at 1:10, hCAF1 TCK: 0% at 1:10, P<0.0001). PDAC cells co-cultured with CAF cells demonstrated reduced susceptibility to elimination by iC9.B7-H3 CAR T cells compared to PDAC cells alone (PDAC3 TCK: 92±5% at 1:1, PDAC3+hCAF1 (1:9 ratio) TCK: 81±5% at 1:1, P=0.002). However, incubation with CAF-conditioned media did not significantly affect the elimination of PDAC cells by iC9.B7-H3 CAR T cells, which may suggest that CAFs may require direct cell-cell contact to exert their effects. In vivo, iC9.B7-H3 CAR T cells effectively eradicated both local and distant PDAC metastases for the length of the experiment (160 days), indicating long-term efficacy in the treatment of PDAC metastases with no adverse side effects. Conclusion: These data suggest that iC9.B7-H3 CAR T cells may be an effective adjuvant treatment for the eradication of micro-metastases and the prevention of disease recurrence in PDAC patients. Citation Format: Shahrzad Arya, Seyed Amir Sanatkar, Cristina Martin, Marco Ventin, Jingyu Jia, Giulia Cattaneo, Gabriella Lionetto, David T. Ting, Xinhui Wang, Sandra Ryeom, Cristina R. Ferrone, Soldano Ferrone. Adjuvant iC9.B7-H3 CAR T cell-based immunotherapy effectively eradicates local and distant metastases in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A021.

AMIGO2 is a pivotal therapeutic target related to M2 polarization of macrophages in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is a common kind of lethal cancer, with low early diagnostic rate and poor prognosis. In this study, we identified and verified the AMIGO2 with significant diagnostic and prognostic value in PDAC through LASSO regression combined with multiple machines learning methods, including RVM-RFE and Random Forest in TCGA and GEO datasets. The relevance between the expression of AMIGO2 and M2 polarization of macrophages was identified through pancancer, normal tissue, and cell lines data in TCGA, GTEx and CCLE datasets. The relevance between AMIGO2 and M2 polarization was then further identified in our local PDAC cohort. Finally, the role of AMIGO2 as cancer promoter and pivotal factor enrolled in M2 polarization was verified through siRNA transfection and M2 macrophages induction. These findings could facilitate diagnosis and treatment of PDAC. In addition, further research was deemed necessary on the deep mechanism between AMIGO2 and M2 polarization of macrophages in PDAC.

Patterns and characteristics of survival scenarios in patients with localized pancreatic ductal adenocarcinoma: a population-based study

Patterns and characteristics of survival scenarios in patients with localized pancreatic ductal adenocarcinoma: a population-based study

Impact of Recombinant Granulocyte Colony-Stimulating Factor During Neoadjuvant Therapy on Outcomes of Resected Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease characterized by chronic inflammation and a tolerogenic immune response. The granulocyte colony-stimulating factor (G-CSF)-neutrophil axis promotes oncogenesis and progression of PDAC. Despite frequent use of recombinant G-CSF in the management and prevention of chemotherapy-induced neutropenia, its impact on oncologic outcomes of patients with resected PDAC is unclear. This cohort study assessing the impact of G-CSF administration was conducted on 351 patients with PDAC treated with neoadjuvant therapy (NAT) and pancreatic resection at a high-volume tertiary care academic center from 2014 to 2019. Participants were identified from a prospectively maintained database and had a median follow-up of 45.8 months. Patients receiving G-CSF (n=138; 39.3%) were younger (64.0 vs 66.7 years; P=.008), had lower body mass index (26.5 vs 27.9; P=.021), and were more likely to receive 5-FU-based chemotherapy (42.0% vs 28.2%; P<.0001). No differences were observed in baseline or clinical tumor staging. Patients receiving G-CSF were more likely to have an elevated (>5.53) post-NAT neutrophil-to-lymphocyte ratio (45.0% vs 29.6%; P=.004). G-CSF recipients also demonstrated higher circulating levels of neutrophil extracellular traps (+709 vs -619 pg/mL; P=.006). On multivariate analysis, G-CSF treatment was associated with perineural invasion (hazard ratio [HR], 2.65; 95% CI, 1.16-6.03; P=.021) and margin-positive resection (HR, 1.67; 95% CI, 1.01-2.77; P=.046). Patients receiving G-CSF had decreased overall survival (OS) compared with nonrecipients (median OS, 29.2 vs 38.7 months; P=.001). G-CSF administration was a negative independent predictor of OS (HR, 2.02; 95% CI, 1.45-2.79; P<.0001). In the inverse probability weighted analysis of 301 matched patients, neoadjuvant G-CSF administration was associated with reduced OS. In patients with localized PDAC receiving NAT prior to surgical extirpation, G-CSF administration may be associated with worse oncologic outcomes and should be further evaluated.