Citations

Background Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal cancer with a 5-year survival rate of 12%. It has two major molecular subtypes: classical and basal, regulated by the master transcription factors (MTFs) GATA6 and ΔNp63, respectively. Objective This study sought to uncover the transcriptional regulatory mechanisms controlling PDAC subtype identity. Design We integrated primary tumour single-cell RNA-seq, patient-derived xenograft RNA-seq and multispectral imaging to identify MTF-dependent, subtype-specific markers. We created subtype-specific fluorescent reporter systems and conducted drug screenings to find actionable targets. We analysed chromatin accessibility (ATAC-seq), genome-wide occupancy (ChIP-seq) for epigenetic status (H3K27ac), MTFs (GATA6, ΔNp63), RNA polymerase II (Pol II), H3K4me3-anchored chromatin topology (HiChIP) and nascent RNA capture sequencing (PRO-seq). Additionally, we used nuclease-dead Cas9 (dCas9) to manipulate transcriptional regulatory mechanisms. Results Our approach identified glucocorticoid receptor (GR) agonists as agents that suppress the classical transcriptional programme by interacting with GATA6. GATA6 regulates classical-specific transcription through promoter-proximal pause release. Depletion of GATA6 increased Pol II occupancy at GATA6-bound enhancers and transcriptional start sites, stabilising enhancer–promoter interactions. Artificially inducing pausing at GATA6-bound enhancers with dCas9 abrogated target gene expression and induced pausing at both the enhancer and target gene promoter. Conversely, in basal PDAC ΔNp63 promotes Pol II recruitment and stabilises enhancer–promoter interactions. Conclusion This study provides new insights into the transcriptional control and role of GR agonists in controlling PDAC molecular subtype identity.

Abstract Background Characterization of transplant transmitted infections associated with drowned organ donors and the recipients is not well delineated, posing challenges for optimal management and prophylaxis strategies. Broader organ sharing may pose additional considerations due to pathogen variation. Methods We reviewed 22 potential donor disease transmission events (PDDTEs) from drowned donors reported to the Organ Procurement and Transplantation Network (OPTN) ad hoc Disease Transmission Advisory Committee (DTAC) from 2017-2022 to estimate the incidence of PDDTEs among all US drowned organ donors and identify the most common pathogens in this setting. We also characterized donor/recipient epidemiology, infection timing and risk factors, and recipient survival. Results From 2017-2022, drowning was the mechanism of death in 777/74,232 (1.0%) of all US organ donors, from whom 2500 organs were transplanted. Among the 22 PDDTEs, there were 70 organ recipients. The median donor age was 17.5 years (range 1-70 years) and lung recipients accounted for 5/70 organ recipients. All PDDTE reports were submitted due to recipient disease, and index cases occurred 2-19 days post-transplant. 7/22 (7/777 drowned donors, 0.9%) PDDTEs were associated with pathogens consistent with plausible waterborne transmission, of which 4 were due to invasive molds (Zygomycetes and Scedosporium) and 3 were due to bacteria (Pseudomonas and Legionella). Of the 21 organ recipients from these 7 donors, 8 had proven or probable infections. 6/8 recipients had severe infection with 3 deaths, all from invasive mold infections. There were no identifiable infection risk factors related to drowning water source, donor immersion time, or geographic region. However, donor/recipient regional discordance occurred in 5/21 recipients, demonstrating the trend in broader organ sharing. Conclusion Though rare, organ recipients are at risk for transplant transmitted infection from drowned donors, particularly invasive mold infections. All infections occurred within the first month after transplant with high associated mortality. Though optimal management and prophylaxis strategies in these scenarios remain uncertain, post-transplant vigilance for early infection is paramount. Disclosures Helen S. Te, MD, CVS Caremark: Advisor/Consultant Lara A. Danziger-Isakov, MD, MPH, Aicuris: clinical research contract, paid to institutio|Ansun BioPharma: clinical research contract, paid to institution|Astellas: Advisor/Consultant|Astellas: clinical research contract, paid to institutio|Merck: clinical research contract, paid to institutio|Pfizer: Grant/Research Support|Takeda: clinical research contract, paid to institutio Anil J. Trindade, MD, CareDx, Inc.: Advisor/Consultant|CareDx, Inc.: Grant/Research Support|TFF Pharmaceuticals: Advisor/Consultant|Veloxis Pharmaceuticals, Inc.: Grant/Research Support

566 Background: Immune checkpoint inhibitors (ICIs) have become the preferred treatment for unresectable hepatocellular carcinoma (HCC). Conflicting data exist regarding the prognostic value of immune-related adverse events (irAEs) in these patients. We aimed to explore potential the association between irAEs and prognosis in HCC patients treated with ICIs. Methods: We searched PubMed, Scopus, Web of Science, and CENTRAL databases for articles published from inception to June 2024 using keywords including ICI, HCC, and irAEs. Two reviewers independently screened studies for eligibility and relevant data. A random effects model was used for statistical analysis, and subgroup analysis was performed by the grade of irAEs. Results: Of 3,028 studies, 25 (n=4,116 patients) met criteria for inclusion. Atezolizumab plus bevacizumab was the most common treatment regimen (n=10 studies). About half (49.5%) of patients experienced irAEs. irAEs were associated with increased objective response rate (ORR) (pooled OR: 1.72; 95% CI: 1.36 – 2.19, I 2 =39%), higher complete response rate (pooled OR: 1.45; 95% CI: 1.21-1.74, I 2 =74%), and longer progression-free survival (PFS) (pooled HR: 0.66; 95% CI: 0.52-0.84, I 2 =71%). Although irAEs were associated with longer overall survival, this difference was not statistically significant (pooled HR: 0.83; 95% CI: 0.62 – 1.11, I 2 =73%). Subgroup analysis showed a survival benefit for patients with grade 1-2 irAEs (pooled HR: 0.50; 95% CI: 0.36-0.67, I 2 =0%) but not for those with grade 3-4 irAEs (pooled HR: 0.95; 95% CI: 0.24-3.72, I 2 =84%). Conclusions: The development of irAEs is associated with a favorable prognosis in HCC, including improved PFS and higher ORR. A survival benefit was noted in patients with mild irAEs, but not in those with severe irAEs. Future studies are needed to determine if a differential survival benefit relates to the continuation vs. discontinuation of ICI therapy.

532 Background: HCC accounts for 80% of primary liver cancers, and worldwide, is the third common cause of cancer-related death. Two FDA approved 1st line systemic treatment options include atezo/bev and durva ± treme. Herein we report outcomes of these regimens in the 1st line setting via a real-world, multi-institutional retrospective cohort study. Methods: We reviewed clinical outcomes of patients (pts) who initiated 1st line atezo/bev or durva ± treme for unresectable HCC between March 2017 and February 2024, across 5 institutions (Mayo Clinic, University of Alabama, Cedars-Sinai Medical Center, University Hospitals Seidman Cancer Center and University of Michigan). Time to treatment failure (TTF) and overall survival (OS) were analyzed using the Kaplan-Meier method. Best (objective) response was tabulated. Multivariable analyses were performed using Cox models and logistic regression for time-to-event and binary outcomes, respectively, while adjusting for age, sex, race, HCC etiology, Child-Pugh class, and ALBI grade. Results: A total of 433 HCC pts were included; atezo/bev (336), durva ± treme (97). Median age at the start of therapy was 68 years; 77% were male, 82% were Caucasian. Etiologies of HCC were viral hepatitis (38%), MASLD (20%), alcohol (10%), non-viral multifactorial (10%), or unknown (22%). Pts receiving durva ± treme were less likely to have cirrhosis (11% vs. 28%, p<0.01) but similar in terms of macrovascular invasion (63% vs. 58%, p=0.35) compared to pts receiving atezo/bev. Reasons for treatment discontinuation were similar between the two groups, with the most common being disease progression - atezo/bev (56%) and durva ± treme (47%). The differences in clinical outcomes were not statistically significantly and remained consistent after multivariable adjustment. (Table, atezo/bev as the reference group). Outcomes were significantly different between Child-Pugh classes (CP: A,B,C) respectively, OS: 19.0 m, 6.4 m, 1.9 m (p<0.001); TTF: 6.1 m, 2.7 m, 1.3 m (p<0.001). Conclusions: In this real-world retrospective cohort study of unresectable HCC, the differences in overall survival, objective response, and time to treatment failure were not statistically significant between atezo/bev and durva ± treme in the 1st line setting. Outcome Atezo/bev Durva±treme Univariate p-value Multivariable adjusted hazard ratio (95% CI) Multivariable adjusted odds ratio (95% CI) Overall Survival, Median (month) 14.0 14.6 0.77 0.78 (0.54-1.14) --- Time to Treatment Failure, Median (month) 4.9 4.1 0.71 0.95 (0.72-1.26) --- Objective response, % 26.3% 21.1% 0.31 --- 0.78 (0.43-1.39)

573 Background: Immunotherapy has shown great efficacy in hepatocellular carcinoma (HCC). No clear consensus exists on when to stop the immune checkpoint inhibitor (ICI) after complete response (CR), and clinical course after stopping ICI remains unknown. Methods: We identified 138 HCC patients who received ICI at Cedars-Sinai Medical Center and Mayo Clinic Rochester from 2016-2023. Modified Response Evaluation Criteria In Solid Tumors (mRECIST) was used to assess treatment response. We further described the clinical course of patients who achieved CR after ICI discontinuation, including cancer recurrence, subsequent treatment, liver transplantation (LT) listing and outcomes. Results: The median age at ICI initiation was 68 years; 79% were male; 55.9% were white; 51.5% were BCLC stage C. 9.4% CRs, 25.4% partial responses, 39.9% stable diseases, and 25.4% progressive disease. Hepatitis C etiology was associated with higher likelihood of CR (P=0.005). Among 13 patients who achieved CR, 10 stopped ICI (60% for LT evaluation, 40% for toxicity). After stopping ICI, 40% had recurrence (Table). 3 patients underwent local therapy for recurrent HCC within Milan criteria and 1 patient restarted ICI for recurrence beyond Milan criteria. Among CR patients, 9 patients underwent LT evaluation after stopping ICI and 7 patients were waitlisted. After listing, 3 dropouts were observed, due to recurrent HCC beyond Milan criteria, sepsis leading to death, and personal preference. 4 patients underwent LT. 2 patients underwent local therapy before LT for recurrent HCC (Table). All transplanted patients had the last dose of ICI more than 1 year before LT (12, 21, 24, and 29 months). On explanted livers, 2 patients had no residual viable tumor and 2 patients had residual HCC within Milan criteria. 1 patient developed acute cellular rejection and was treated with immunosuppressants and maintained stable graft function. None had graft loss or evidence of HCC recurrence in the follow-up period at 8, 20, 28, and 51 months. Conclusions: Immunotherapy demonstrated excellent effects on a subset of HCC patients, including 9.4% who achieved CR. After stopping ICI, 40% had cancer recurrence but 3 out of 4 were within Milan criteria. 4 underwent successful LTs (2.9%) with excellent post LT outcome. Larger prospective data is needed to establish a protocol for ICI use, especially to determine the optimal timing for ICI discontinuation after CR. BCLC at ICI initiation ICI cycles before stopping, ICI Recurrence after last ICI (days) Within Milan at recurrence Treatment(s) received after recurrence and outcomes OS (days) Patient 1 B 7, Nivolumab 730 No Nivolumab. Died from GI bleeding 1065 Patient 2 B 64, Atezo/Bev 149 Yes TACE with CR, followed by LT without recurrence. 1203 Patient 3 A 8, Nivolumab 1393 Yes Y90 with CR. No recurrence. 1984 Patient 4 C NA, Pembrolizumab 407 Yes TACE and MWA with CR, followed by LT without recurrence. 1722

142 Background: Fruquintinib (F) is a highly selective, oral tyrosine kinase inhibitor of all 3 vascular endothelial growth factor receptors (VEGFRs -1, -2, -3) that is approved by the US FDA and in the EU, UK, and Japan for previously treated metastatic colorectal cancer (mCRC), regardless of biomarker status. FRESCO-2 (NCT04322539) met its primary endpoint demonstrating significantly improved overall survival (OS) with F + best supportive care (BSC) vs placebo (P) + BSC. This subgroup analysis assessed landmark survival of all FRESCO-2 patients (pts), and baseline (BL) characteristics and safety data of pts treated with F who had OS ≥10 months (mos) compared with the intent-to-treat (ITT) population (pop). Methods: Pts were randomized 2:1 to receive F 5 mg or matching P, by mouth, once daily, 3 weeks on, 1 week off, + BSC. Pts had received prior chemotherapy, anti-VEGF therapy and, if RAS wild type, anti-EGFR therapy; and had prior exposure to trifluridine/tipiracil (TAS-102) and/or regorafenib. The hazard ratio (HR) between the two treatment arms was calculated from a stratified Cox proportional hazard model with treatment group as the only covariate in the model. Results: In the ITT pop, OS was improved with F vs P (HR 0.66); OS rates (95% confidence intervals [CIs]) at 6 and 9 mos were 60.4% (55.9–64.9) vs 41.5% (35.0–48.0) and 41.1% (36.4–45.8) vs 28.2% (22.1–34.3), respectively. Progression-free survival (PFS) rates (95% CIs) at 6 and 9 mos were 23.8% (19.7–28.0) vs 1.1% (0–2.6) and 11.3% (8.1–14.6) vs 0.5% (0–1.6), respectively. Of 461 pts who received F, 113 (24.5%) had OS ≥10 mos (range 10.0–18.9) with a median duration of F treatment of 6.3 mos (range 0.7–19.1). Among pts receiving F, a higher proportion (≥10% difference) of pts with OS ≥10 mos had no liver metastases (mets) and an Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 at BL compared with the ITT pop (Table). In pts with OS ≥10 mos, 61.9% experienced a grade ≥3 treatment-emergent adverse event compared with 62.7% in the ITT pop. Conclusions: Longer-term OS and PFS rates at 6 and 9 mos were higher with F vs P in the FRESCO-2 ITT pop. The data show a higher proportion of pts with OS ≥10 mos had an absence of liver mets and ECOG PS 0 at BL than the ITT pop. The safety profile of F in pts with OS ≥10 mos was consistent with the ITT pop. Clinical trial information: NCT04322539 . BL characteristics of pts treated with F with OS ≥10 mos vs ITT pop. BL characteristic Pts with OS ≥10 mos (n=113) ITT pop(n=461) ECOG PS (0 / 1), % 54.0 / 46.0 42.5 / 57.5 Median time since 1 st CRC diagnosis, mos 52.0 47.2 Primary tumor location at 1 st diagnosis (colon / rectum / both), % 51.3 / 35.4 / 13.3 60.5 / 31.0 / 8.5 Primary site at 1 st diagnosis (colon left / colon right), % 42.5 / 15.9 41.6 / 21.0 Liver mets, % 58.4 73.5 Median duration of mCRC, mos 42.7 37.9 Prior lines of therapy for mCRC (≤3 / >3), % 26.5 / 73.5 27.1 / 72.9 Prior TAS-102, % 46.9 52.1 Prior regorafenib, % 12.4 8.7

ABSTRACT Understanding clinical trajectories of sepsis patients is crucial for prognostication, resource planning, and to inform digital twin models of critical illness. This study aims to identify common clinical trajectories based on dynamic assessment of cardiorespiratory support using a validated electronic health record data that covers retrospective cohort of 19,177 patients with sepsis admitted to intensive care units (ICUs) of Mayo Clinic Hospitals over 8-year period. Patient trajectories were modeled from ICU admission up to 14 days using an unsupervised machine learning two-stage clustering method based on cardiorespiratory support in ICU and hospital discharge status. Of 19,177 patients, 42% were female with a median age of 65 (interquartile range [IQR], 55–76) years, The Acute Physiology, Age, and Chronic Health Evaluation III score of 70 (IQR, 56–87), hospital length of stay (LOS) of 7 (IQR, 4–12) days, and ICU LOS of 2 (IQR, 1–4) days. Four distinct trajectories were identified: fast recovery (27% with a mortality rate of 3.5% and median hospital LOS of 3 (IQR, 2–15) days), slow recovery (62% with a mortality rate of 3.6% and hospital LOS of 8 (IQR, 6–13) days), fast decline (4% with a mortality rate of 99.7% and hospital LOS of 1 (IQR, 0–1) day), and delayed decline (7% with a mortality rate of 97.9% and hospital LOS of 5 (IQR, 3–8) days). Distinct trajectories remained robust and were distinguished by Charlson Comorbidity Index, The Acute Physiology, Age, and Chronic Health Evaluation III scores, as well as day 1 and day 3 SOFA ( P < 0.001 ANOVA). These findings provide a foundation for developing prediction models and digital twin decision support tools, improving both shared decision making and resource planning.