PURPOSE Deficient mismatch repair/microsatellite instability (dMMR, MSI-H) in biliary tract cancers (BTCs) is observed in 1%-5% of tumors. MSI-H across solid tumors has demonstrated durable response to immune checkpoint inhibitors (ICIs) regardless of the anatomic location. Here, we describe clinical outcomes and surgical conversion of MSI-H BTC treated with ICIs. Patients and Methods We conducted a multicenter, retrospective analysis of BTC patients with dMMR/MSI-H between 2017 and 2024 at Mayo Clinic, University of Michigan, and University Hospitals Seidman Cancer Center. Outcomes of interest were surgical resection rate, rate of pathologic response, 2-year overall survival (OS; time from initiation of treatment to death/last follow-up), and time to treatment discontinuation (TTD; time from initiation of treatment to cessation because of any cause). Analyses were descriptive. RESULTS Thirty patients with MSI-H BTC were identified: 19 with cholangiocarcinoma, three with gallbladder cancer, and 8 with BTC undefined. The median age at diagnosis was 61.5 years (range, 26-86). Twenty-six (86.7%) patients had advanced stage at diagnosis. Twenty-seven patients (90%) received first-line systemic therapy, and 13 (48.1%) continued onto second line. Six patients (23.1%) were restaged to resectable from advanced disease after ICI therapy and underwent resection; all remained recurrence-free at last follow-up. Of these six patients, 3 (50%) achieved a pathologic complete response. Among those receiving first-line therapy, the median TTD was 9.9 months (95% CI, 5.7 to 14.5 months) and the 2-year OS was 73% (95% CI, 56% to 94%). CONCLUSION ICI therapy in patients with MSI-H BTC demonstrated durable response and downstaged some BTC to a resectable stage. dMMR/MSI-H should be performed up-front to guide treatment decisions.

PURPOSE:Gastroesophageal carcinoma (GEC) is increasingly managed using biomarker-guided therapies. Although both tissue DNA (tDNA) and circulating tumor DNA (ctDNA) testing are used clinically, the concordance of genomic alterations between primary tumors, metastatic sites, and liquid biopsy remains incompletely understood. METHODS:We retrospectively analyzed 345 patients with GEC who underwent ctDNA testing at Mayo Clinic. tDNA next-generation sequencing and immunohistochemistry (IHC) for human epidermal growth factor receptor 2 (HER2)/erb-b2 receptor tyrosine kinase 2 (ERBB2) and mismatch repair (MMR) were collected. Concordance was evaluated between ctDNA and tDNA, ctDNA and IHC, and across all three modalities, using 60-day and 30-day intervals. RESULTS:Among 345 patients with ctDNA testing, 186 had tDNA testing, and 310 underwent IHC. ctDNA testing showed a shorter turnaround time than tDNA (median 6 v 13 days). The most frequent alteration in ctDNA, primary tDNA, and metastatic tDNA was TP53. Concordance between ctDNA and primary tDNA was ≥78.8% for key genes; between ctDNA and metastatic tDNA, it was ≥84.8%. IHC-ctDNA concordance was higher in metastatic tumors, with 91.1% for HER2/ERBB2 and 97.7% for mismatch repair (MMR)/microsatellite instability (MSI) compared with 81.1% and 95.8%, respectively, in primary tumors. Triplet concordance for MSI/MMR was 97.6% in primary tumors and 100% in metastatic tumors, while ERBB2/HER2 showed 84.4% and 93.9% concordance, respectively. ctDNA temporal heterogeneity analysis revealed 14 patients with fluctuating ERBB2 status and 3 with fluctuating MSI-H status. CONCLUSION:ctDNA testing demonstrates high concordance with tDNA and IHC and offers faster turnaround. Given its minimally invasive nature and strong concordance with tissue-based testing, ctDNA is a reliable tool for genomic profiling and longitudinal monitoring in GEC.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with a 5-year survival rate of 13.3%. This study investigates the treatment efficacy of VMG, a chimeric oncolytic vesiculovirus, against PDAC, focusing on its mechanism and therapeutic potential. VMG is engineered to replace the Vesicular Stomatitis Virus (VSV) glycoprotein (G) gene with the Morreton virus (MorV) glycoprotein, enhancing its safety, efficacy, and immune infiltration compared to wild-type VSV. We conducted an in-depth proteomic analysis of VMG treatment and evaluated its in vitro and in vivo efficacy. Our findings indicate that VMG treatment not only induces apoptosis and reduces tumor cell viability in PDAC cell lines, but also significantly slows tumor growth and enhances survival in PDAC mouse models. We then explored whether proteomic analysis could help uncover the mechanistic underpinnings of this efficacy. This approach allowed us to investigate the biological pathways involved in VMG's action. To understand these mechanisms, proteomic data were integrated with information from Ingenuity Pathway Analysis (IPA), the Kyoto Encyclopedia of Genes and Genomes (KEGG), and The Cancer Genome Atlas (TCGA). This analysis aimed to identify the key signaling pathways modulated by VMG. By integrating efficacy testing with proteomic and pathway analyses, we sought to clarify how VMG exerts its molecular effects. This approach offers a strong framework for uncovering the biological processes influenced by VMG. The study reveals that VMG treatment leads to a substantial overlap between virus-induced proteomic changes and prognostic markers found in the TCGA PDAC cohort. Specifically, VMG downregulates proteins associated with unfavorable prognosis, including those involved in altered mitochondrial function, genome DNA synthesis and repair, RNA modification, ribosome biogenesis, intracellular trafficking, cell cycle control, cytoskeletal dynamics, and palmitoylation. This multifaceted oncolytic mechanism disrupts fundamental processes driving PDAC progression, survival, and chemoresistance, providing a robust foundation for identifying novel therapeutic targets and biomarkers.

Background: Biliary tract cancers (BTC) are aggressive malignancies with limited treatment options. Homologous recombination deficiency (HRD) may confer increased immunogenicity and potentially augment responsiveness to immune checkpoint inhibitor-based chemoimmunotherapy (CIO), but its predictive value for immunotherapy benefit in BTC remains poorly characterized.Methods: This multicenter retrospective study included 998 patients with advanced BTC treated between 2012 and 2024. HRD status was determined via genomic sequencing of tumor tissue or circulating tumor DNA. Patients were stratified by HRD status and first-line treatment ( Chemotherapy (CT) alone vs. CIO). Primary endpoints were progression-free survival (PFS) and overall survival (OS) analyzed by Kaplan-Meier estimates while predictors were assessed through univariate and multivariate Cox regression.Results: Of 998 patients, 179 (17.9%) were HRD-positive, of whom 15.1% received CIO. The most commonly HRR alterations were ATM (38.5%), BRCA2 (23.5%) and BRCA1 (16.2%). ORR was higher with CIO vs. CT in both HRD- (35.2% vs. 22.5%; p=0.008) and HRD+ patients (51.9% vs. 25.8%; p=0.01), but this did not translate into survival benefit. In HRD+ patients, CIO was associated with worse OS than CT (13.4 vs. 22.5 months; HR 2.07, 95% CI 1.22–3.54; p=0.006). Among BRCA1/2-mutant patients, CT alone yielded better OS than CIO (33.6 vs. 24.8 months; HR 2.90; p=0.045). Multivariable analysis revealed HRD status did not independently predict OS while CIO use (HR 1.58, 95% CI 1.07–2.32; p=0.020) was associated with decreased OS.Conclusions: Adding immunotherapy to chemotherapy did not improve survival in HRD+ BTC patients. These findings are hypothesis-generating and raise the possibility that HRD+ status is associated with a lack of added benefit from IO to CT, underscoring the need for prospective biomarker-driven trials to refine treatment strategies in BTC.

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal cancers, driven by KRAS mutations long deemed "undruggable". We conducted a meta-analysis of seven early phase cohorts (n = 695) that evaluated KRAS-targeted therapies in patients with PDAC. The pooled objective response rate was 29% (95% CI 24-35%), indicating promising activity in refractory PDAC, with consistent estimates across studies (I2 = 5.7%). Gastrointestinal toxicities were among the most common adverse events, with pooled incidences of 40% for diarrhea and 41% for nausea in all patients treated with KRAS-targeted agents. These findings validate direct KRAS inhibition as a breakthrough concept in PDAC but are tempered by modest durability, risk of bias, and limitations of early phase designs, underscoring the need for biomarker-guided, rigorously designed clinical trials.

The limited efficacy of current therapies against cholangiocarcinoma (CCA) necessitates the development of novel treatment strategies. Src family kinases (SFKs) contribute significantly to tumor progression and resistance in CCA. Therefore, we investigated the novel, first-in-class SFK 'OFF' inhibitor NXP900 in diverse preclinical CCA models, including those with acquired resistance. This study evaluated the therapeutic effects of NXP900 and detailed adaptive molecular responses to SFK inhibitor therapy. We also aimed to identify biomarkers predictive of drug sensitivity using integrated multiomic profiling and develop strategies to overcome resistance. NXP900 inhibited YAP activity through direct inhibition of tyrosine phosphorylation and indirect activation of the Hippo pathway via LATS. These effects were associated with decreased tumor cell viability in CCA cell lines and several in vivo models. Notably, IDH -mutant patient-derived xenograft CCA models were particularly sensitive to NXP900. NXP900 also synergized with gemcitabine/cisplatin chemotherapy, enhancing antitumor efficacy in both in vitro and in vivo models. Multiomic analyses combining transcriptomics, global proteomics, and phosphoproteomics identified molecular features associated with primary response and acquired resistance. IL13RA-AKT signaling was upregulated in resistant models; NXP900 sensitivity could be restored with AKT or IL13RA2 inhibition. Together, these findings demonstrate the therapeutic potential of NXP900 as a novel YAP inhibitor in CCA and support further investigation in a clinical trial.

Adoptive cellular immunotherapy (ACT) has revolutionized hematologic malignancies, yet translation to solid tumors has historically been limited. This landscape shifted significantly in 2024 with US Food and Drug Administration approvals of lifileucel, a tumor-infiltrating lymphocyte (TIL) therapy for advanced melanoma, and afamitresgene autoleucel, an engineered T-cell receptor (TCR) therapy for synovial sarcoma. These approvals mark the clinical arrival of ACT for solid tumors and highlight a rapidly expanding therapeutic landscape. Beyond these indications, multiple ACT platforms including TIL, TCR, chimeric antigen receptor (CAR) T-cell, CAR-natural killer, and CAR-macrophage therapies are under active clinical investigation across diverse solid tumor indications. Clinical experience to date has defined key barriers to efficacy, including impaired tumor trafficking, antigen heterogeneity, immunosuppressive tumor microenvironment, and limited cellular persistence. In parallel, rapid advances in cellular engineering are reshaping the field, with the development of armored constructs, logic-gated and multiantigen targeting strategies, innate immune-based platforms, and novel manufacturing approaches including allogeneic and in vivo cell engineering. As ACT enters clinical practice for select solid tumors, distinct toxicity profiles and logistical requirements necessitate careful patient selection and multidisciplinary coordination. Early biomarker testing, timely referral to specialized centers, and familiarity with evolving toxicity management frameworks are increasingly critical. Here, we seek to provide a practice-oriented framework for understanding emerging ACT platforms, clinical data, toxicity considerations, and implementation strategies relevant to contemporary solid tumor oncology care.

837 Background: A recent randomized trial suggested that CR may influence ICI activity in patients with lung cancer. However, the same has not been established in GI cancers, where reports have shown mixed results with variable definitions of 'early' vs 'late' IT. We evaluated multiple approaches to assess the impact of CR on first-line ICI in GI malignancies. Methods: This retrospective study included patients from three Mayo Clinic sites (N=455). Both previously reported IT cutoffs and a new cutoff derived from ROC analysis were evaluated. Patients were categorized by the median of all ITs, the median of the first four ITs, and whether ≥20% of ITs occurred before the identified cutoff. Univariate and multivariate Cox regression (adjusting for age, MSI status, type of cancer, metastasis status, number of cycles, and receipt of chemotherapy with ICI) assessed associations with OS. KM analyses were performed to illustrate survival differences. The primary endpoint was OS. Results: When patients were categorized based on whether ≥20% of infusions occurred before 14:00 (ROC-derived cutoff), a significant association with OS was observed. On univariate analysis, early infusion timing was associated with improved survival (HR 2.30, 95% CI 1.58–3.32, p <0.001). This remained significant after multivariable adjustment (HR 2.11, 95% CI 1.41–3.16, p < 0.001). Median OS was 14.2 months in the early group vs 3.8 months in the late group (log-rank p < 0.001). Using previously defined cutoffs, categorization by the median IT of all infusions or the median of the first four infusions did not demonstrate a significant association with OS in either univariate or multivariate Cox regression analyses. Conclusions: These findings highlight the potential role of infusion timing as a chronotherapy factor in GI cancers. Given the retrospective design and heterogeneous population, prospective studies are warranted to validate this signal and clarify its clinical relevance. Baseline demographics of patients by infusion timing (early vs late). Variables Early N=412 (%) LateN=43(%) Total N=455(%) p-value Age <70 249(60.4) 21(48.8) 270 (59.3) 0.1 >70 163(39.6) 22(51.2) 185 (40.7) Gender F 118(28.6) 16(37.2) 134 (29.5) 0.3 M 294(71.4) 27(62.8) 321 (70.5) Cancer Type Gastroesophageal 109 (26.5) 8 (18.6) 117 (25.7) 0.1 Hepatocellular 159 (38.6) 24 (55.8) 183 (40.2) Biliary 86 (20.9) 4 (9.3) 90 (19.8) MSI-H 58 (14.1) 7 (16.3) 65 (14.3) Metastasis No 150 (36.4) 22 (51.2) 172 (37.8) 0.1 Yes 262 (63.6) 21 (48.8) 283 (62.2) Immunotherapy Cycle Number <6 189 (45.9) 33 (76.7) 222 (48.8) <0.001 >6 223 (54.1) 10 (23.3) 233 (51.2)

Background Pancreatic ductal adenocarcinoma (PDAC), the most common malignant type of pancreatic cancer, is characterized by a dense desmoplastic stroma, low neoantigen burden, and a highly immunosuppressive tumor microenvironment (TME). Methods We present a novel strategy harnessing acute transplant rejection mechanisms by employing a recombinant oncolytic rVMG vector engineered to express murine alloantigens H-2Kb (rVMG-H-2Kb) or H-2Kk (rVMG-H-2Kk), thereby inducing tumor-specific antigenic mismatch responses. Results In vitro, rVMG-H-2Kb and rVMG-H-2Kk exhibited strong replication and cytolytic activity while inducing cell surface expression of both H-2Kk and endogenous H-2Kb, in addition to upregulation of antigen presentation genes (β2-microglobulin, Tap1, and Tapbp). In two immunocompetent PDAC models, intratumoral and systemic delivery of rVMG-H-2Kb and rVMG-H-2Kk delayed tumor progression, with rVMG-H-2Kk conferring a survival advantage. Multiplex immunohistochemistry and immunophenotyping revealed substantial TME remodeling, marked by increased effector T-cell infiltration, regulatory T-cell depletion, and reduced fibrosis. Spatial transcriptomics further showed compartment-specific immune activation and epithelial metabolic reprogramming, corroborating with enhanced tumor immunogenicity. Despite these effects, rVMG-H-2Kk also induced compensatory immunosuppressive pathways, including upregulation of antiviral response genes and immune checkpoint receptors such as programmed death-ligand-2. Importantly, combination therapy with rVMG-H-2Kk and murine checkpoint blockade (anti-programmed cell death protein-1 and anti-cytotoxic T-lymphocyte-associated protein 4) drastically improved survival compared to checkpoint blockade alone. Strikingly, surviving mice resisted tumor rechallenge, indicating the establishment of durable antitumor memory. Conclusion These findings establish rVMG-mediated alloantigen delivery as a novel immunotherapeutic platform capable of converting immune-cold tumors into immune-hot, sensitizing tumors to immune checkpoint inhibitors, and establishing durable antitumor immunity in PDAC.

The global burden of hepatocellular carcinoma (HCC) continues to rise, driven by increasing metabolic risk factors such as nonalcoholic fatty liver disease, obesity, and type II diabetes. Patients with advanced HCC have limited therapeutic options and a dismal prognosis. While recent advancements in combination therapies—including immune checkpoint blockade (ICB) with anti-PD-1/PD-L1 and anti-CTLA-4 agents and anti-angiogenics—have improved survival for some, up to 80% of patients fail to respond, underscoring an unmet need for new strategies. Emerging data indicate a strong association between increased tumor-infiltrating lymphocytes (TILs) and better responses in ICB-treated HCC, suggesting TIL enhancement as a promising approach. However, HCC’s inherent low immunogenicity and immunosuppressive tumor microenvironment (TME) limit the efficacy of current TIL-promoting strategies. Here, we demonstrate that low-dose intratumoral immunotherapy using the trivalent MMR vaccine—composed of live attenuated measles, mumps, and rubella viruses—modulates TME immune infiltration, increases cytotoxic T cell frequency, and delays tumor growth in multiple murine HCC models. Importantly, intratumoral or systemic MMR administration in combination with dual ICB (anti-mPD-1/anti-mCTLA-4) significantly prolongs survival, promoting tumor-specific and memory immune responses in both subcutaneous and orthotopic HCC models. These findings reveal a unique mechanism of vaccine-induced anti-tumor activity, highlighting MMR as a viable, globally accessible option for enhancing immune responses in advanced HCC therapy. Mulu Z. Tesfay,Aleksandra Cios,Khandoker U. Randal S. Shelton,Bahaa Mustafa,Camila C. Simoes,Steven Post,Thomas Kelly,Moaven Moaven,Lewis R. Roberts,Mitesh J. Borad,Martin J. Cannon,Alexei Basnakian,Nagalo Bolni. Live attenuated MMR vaccines modulate tumor immune cell infiltration and synergize with standard of care to prolong survival in preclinical HCC models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 945.

Pancreatic ductal adenocarcinoma (PDA) is a disease with guarded prognosis with a 5-year overall survival (OS) of 3.1% in patients with metastatic disease. The need for innovative treatments for this lethal disease is paramount. TTFields is a novel treatment modality that employs low intensity, alternating, and intermediate frequency electrical fields that abrogates cancer cell proliferation through different mechanisms. These include inhibition of mitosis, disruption of cancer cell membranes, metabolomic dysregulation of cancer cells, and immunogenic activation of the tumor microenvironment (TME). TTFields are approved in glioblastoma multiforme, non-small cell lung cancer and malignant mesothelioma. The PANOVA trial demonstrated promising efficacy for TTFields plus chemotherapy in patients with PDA. A trial of GCN in patients with PDA demonstrated exceptional efficacy in patients with metastatic disease. Here in, we present our ongoing clinical trial investigating the safety and efficacy of TTFields plus GCN in patients with PDA (NCT04605913). This a phase I/II trial with an initial safety run-in phase followed by the phase II portion. The primary objective of the trial is to determine the safety (CTCAE v 5.0) of GCN plus TTFields. Secondary objectives include determining the 6-month progression free survival (PFS) rate, overall response rate (ORR, RECIST v1.1), 12-month survival rate, OS, and QOL (EORTC QLQ-C30, version 3.0.2.3). Inclusion criteria include PDA with liver metastasis (patients can have additional sites of metastasis), ECOG 0-1, measurable disease, and ability to operate the Novo TTF-100L (P)/Novo TTF-200T system. Treatment consisted of TTFields (150 kHz 18 hours/day) and GCN (G: 1000 mg/m2, C 30 mg/m2, and N: 150 mg/m2 every 2 weeks, 28 days cycle), followed by a maintenance phase after 6 months (G: 1000 mg/m2 every 2 weeks) plus TTFields until progression. Six patients were to be enrolled in the phase I portion and if ≤1/6 patients experienced a dose limiting toxicity (DLT, treatment emergent adverse event, or skin toxicity of Gr4), the plan would be to move to a phase II trial enrolling 34 more patients. If 2/6 patients experienced a DLT, 6 patients would be enrolled in dose level -1 (GCN plus TTFields for 9 hours/day followed by the maintenance treatment) and if tolerated the phase II portion would start with dose level -1 regimen. The phase I portion was completed without any DLTs and the trial is currently enrolling to the phase II portion. The total number of patients (40) was powered to the 6-months PFS rate and ORR (estimated using the lower bound of exact one-sided 90% confidence intervals). The goal is to "reject" a 6-month PFS rate of 66% and an ORR of 71% (based on previous GCN trial). Time-to-event endpoints will be assessed using the Kaplan-Meier method. Hani M. Babiker, Jason Starr, Jeremy Jones, Conor O’Donnell, Robert Jones, Jacqueline Boni, Lashundra Stewart, Josh Cameron, Oudom Kour, Kabir Mody, Robert R. McWilliams, Daniel H. Ahn, Tanios Bekaii-Saab, Mitesh J. Borad, Umair Majeed. A phase I/II pilot trial, single arm, open label, of gemcitabine, cisplatin, protein-bound paclitaxel (GCN) combined with Tumor Treatment Fields (TTFields) in patient with metastatic pancreatic adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_2):Abstract nr CT190.

The clinical efficacy of systemic oncolytic virotherapy (OV) is constrained by the rapid development of neutralizing antibodies (nAbs), which prevent repeat systemic administration, a critical barrier to sustained anti-tumor immunity. Vesiculoviruses offer potent oncolytic and immunogenic potential. However, leveraging their serological diversity for repeat dosing remains unexplored. We generated a library of chimeric vesiculovirus vectors incorporating glycoproteins from less well characterized vesiculovirus species. We evaluated vector replication, infectivity, interferon (IFN) responses, and oncolysis in vitro, alongside assessments of neutralization resistance using patient sera, monoclonal antibodies, and in silico structural modeling. In vivo studies assessed tumor delivery, immune activation, and therapeutic efficacy following intravenous administration. The vesiculovirus library exhibited broad tumor infectivity, distinct IFN-stimulatory profiles, and variable oncolytic activity. Neutralization assays and computational modeling identified serological distinctness across vectors, driven by hypervariable glycoprotein epitopes, enabling evasion of cross-neutralizing antibodies. Tumor delivery and anti-tumor immunity were preserved despite humoral barriers. Incorporating tumor-associated antigens (TAAs) further amplified anti-tumor responses, even in the context of anti-viral memory. Sequential administration of distinct vesiculovirus vectors induced robust immune activation and improved survival in a B16-OVA-IFNAR-/- model. Our findings establish a glycoprotein-diverse vesiculovirus platform capable of overcoming humoral immunity, enabling repeat intravenous dosing and sustained engagement of the tumor microenvironment. This strategy advances the field of oncolytic virotherapy by addressing a major translational barrier and lays the groundwork for future clinical studies integrating multi-vector, multi-dose immunovirotherapy with immune checkpoint blockade.

e16265 Background: The pivotal TOPAZ-1 trial established durvalumab plus gemcitabine and cisplatin (GC) as a new first-line standard of care for advanced biliary tract cancer (ABTC). However, weekly administration of GC can lead to significant toxicity limiting its tolerability in clinical practice. Based on previous studies, we implemented biweekly regimen of GC on days 1 and 15 together with durvalumab on day 1 of each 28-day cycle to optimize the treatment delivery and improve tolerability. Here, we report the Mayo Clinic experience with biweekly GC with monthly durvalumab in patients with ABTC. Methods: At our three-site institution, we retrospectively identified patients with ABTC between January 2021 and August 2024, who received biweekly GC with monthly durvalumab. Patient demographics, tumor characteristics, treatment details - treatment related adverse events (trAEs) graded according to the NCTCAE V5.0 were collected. Outcomes included median progression-free survival (mPFS), median overall survival (mOS) and clinically assessed overall response rate (ORR) and disease control rate (DCR). Results: 57 patients were included in our analysis, median age was 68 years (range 35-90), and 57.9% were females. 91.2% of patients had ECOG performance status of 0-1. 71.9% had intrahepatic cholangiocarcinoma, 19.3% extrahepatic cholangiocarcinoma and 8.7% gallbladder carcinoma. 70.2% had metastatic disease, 21 % locally advanced unresectable disease and 8.7% recurrent metastatic disease. Patients were followed for a median of 9.1 months (2.3-28.5). 91.2% of the patients received biweekly GC plus monthly durvalumab while 8.8% switched from weekly to biweekly GC plus monthly durvalumab due to treatment toxicities. Median number of treatment cycles was 5. Maintenance regimens included durvalumab (19.3%), gemcitabine/durvalumab (8.8%) and GC/durvalumab (8.8%). Median duration of follow up was 9.1 months (range 2.3 – 28.5). ORR was 36.9% and DCR was 72% (complete response 5.3%, partial response 31.6% and stable disease 35.1%). mPFS was 7.2 months, while mOS was 16 months. Grade(G) 3 or 4 trAEs included abnormal liver function tests (15.7%), infections (11.5%), anemia (8.7%), thrombocytopenia (5.2%), peripheral neuropathy (1.7%), acute kidney injury (1.7%). Immune-related AEs were noted in 6 patients (10.5%) including colitis, gastritis, hepatitis, myocarditis and hypothyroidism. There was no patient with severe neutropenia or febrile neutropenia. Only 5 patients (8.8%) stopped treatment due to trAEs. Conclusions: Biweekly GC on days 1 and 15 plus durvalumab on day 1 of each 28-day cycle is associated with a more favorable toxicity profile while maintaining efficacy similar to that observed in the TOPAZ-1 trial indicating that a de-escalation strategy is feasible with improvement in patient centered outcomes.

Intrahepatic cholangiocarcinoma (ICC) is a rare but aggressive cancer with limited curative options outside of surgical resection. Trans-arterial radioembolization (TARE) with yttrium-90 is a promising treatment with retrospective data showing an overall survival (OS) of up to 30 months. The single arm prospective MISHPEC trial combined TARE with gemcitabine and cisplatin showed an overall response rate (ORR) of 39% at 3 months along with a median OS of 22 months. PDL1 inhibitor (Durvalumab) has shown modest benefit in addition to chemotherapy in unresectable cholangiocarcinoma with three-year OS of 15% based on the TOPAZ-1 trial. ICC is a biologically cold tumor; preclinical data indicates that Yttrium-90 TARE can alter tumor microenvironment making it conducive to effector T cell recruitment and function leading to enhanced efficacy of immunotherapy. This provides the biological rationale of combining yittrium-90 TARE with systemic immunotherapy involving dual PDL1 and CTLA-4 inhibitors. Here in, we present our ongoing clinical trial investigating the safety and efficacy of yttrium-90 TARE combined with Durvalumab and Tremelimumab in patients with ICC (NCT06058663). In this phase 1 study, yittrium-90 TARE will be combined with Durvalumab and Tremelimumab in 16 patients with unresectable or oligometastatic ICC. Eligible patients with histologically confirmed measurable disease must not have received any prior local therapies and any immunotherapy with ECOG PS of 0 or 1, adequate liver (Child Class A, ALBI 1 or 2) and renal function. Patients should also have a favorable mapping angiography based on an angiosomal analysis. Ablative radioembolization would be performed at least a dose of greater than 205 Gy MIRD to >75% of tumor. Study treatment with Tremelimumab (x 1 dose of 300mg total) + Durvalumab 1500mg monthly will continue until unacceptable toxicities, or disease progression for up to 24 months. Durvalumab and Tremelimumab will be infused in two alternate schedules after yittrium-90 TARE. In cohort 1 (3 patients) immunotherapy will be delivered within 24 hours of TARE. In cohort 2 (3 patients) immunotherapy will be delivered 2 weeks after TARE. Subsequent patients will be enrolled in either cohort 1 or 2 based on the safety signal from the first 6 patients. Primary goal of the study is to determine safety of this combination. Secondary goals include ORR per RECIST 1.1, progression-free survival, overall survival, infield and out of field response rate and downstaging to resection. Correlative studies include ctDNA at baseline along with evolution through treatment, pre and post treatment biopsies to look at tumor microenvironment and post treatment dose volume histograms. Three patients have been accrued in the study thus far. Umair Majeed, Jason Starr, Conor O'Donnell, Robert Jones, Jacqueline Boni, Josh Cameron, Oudom Kour, Mitesh Borad, Hani Babiker, Kabir Mody, Beau Toskich. Yttrium-90 radioembolization in combination with tremelimumab and durvalumab for treating patients with locally advanced, unresectable or oligo-metastatic intrahepatic cholangiocarcinoma who are not candidates for curative therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_2):Abstract nr CT189.

Oncolytic virotherapy (OVT) has emerged as a promising and innovative cancer treatment strategy that harnesses engineered viruses to selectively infect, replicate within, and destroys malignant cells while sparing healthy tissues. Beyond direct oncolysis, oncolytic viruses (OVs) exploit tumor-specific metabolic, antiviral, and immunological vulnerabilities to reshape the tumor microenvironment (TME) and initiate systemic antitumor immunity. Despite promising results from preclinical and clinical studies, several barriers, including inefficient intratumoral virus delivery, immune clearance, and tumor heterogeneity, continue to limit the therapeutic advantages of OVT as a standalone modality and hindered its clinical success. Recent advances in OV engineering have enhanced viral tropism, immune evasion, and transgene delivery, enabling better tumor targeting and penetration and sustained immune activation in malignant tumors. Moreover, rational combination strategies with immune checkpoint inhibitors (ICIs), chemotherapeutics, and immunometabolic modulators are reshaping OVT into a versatile strategy for precision oncology. This review highlights the mechanistic innovations driving next-generation OV engineering, explores emerging combination regimens, and discusses future directions to overcome resistance and maximize clinical efficacy.

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal cancers, driven by KRAS mutations long deemed “undruggable”. We conducted a meta-analysis of five early phase cohorts (n=301) that evaluated KRAS-targeted therapies in patients with PDAC. The pooled objective response rate was 28% (95% CI 22–35%), indicating promising activity in refractory PDAC, with consistent estimates across the studies (I 2 =0%). Gastrointestinal toxicities were common (diarrhea, 47%; nausea, 43%). These findings validate direct KRAS inhibition as a breakthrough concept in PDAC but are tempered by modest durability, risk of bias, and limitations of early phase designs, underscoring the need for biomarker-guided, rigorously designed clinical trials.

TPS3171 Background: Genetic alterations in fibroblast growth factor receptors 2 and 3 ( FGFR2/3 ) occur in nearly all cancer types. FGFR2 fusions and rearrangements occur in up to 10-15% of intrahepatic cholangiocarcinomas (iCCA) and alterations in FGFR3 occur in 15-30% of urothelial cancers. The clinical benefit from currently approved FGFR inhibitors (FGFRi) is often curtailed by development of acquired resistance, which may arise through on-target mutations in the FGFR2/3 kinase domain. Additionally, off-tumor effects on FGFR1 by pan-FGFRi can lead to hyperphosphatemia and consequently to dose reductions or dose holds. Thus, there is an unmet clinical need for a selective FGFR2/3 inhibitor that has clinical efficacy against activating alterations and resistance mutations without causing FGFR1-mediated hyperphosphatemia. CGT4859 is an orally bioavailable, ATP-competitive, reversible inhibitor of FGFR2/3, with potency against clinically relevant FGFR2/3 kinase domain mutations. In addition, CGT4859 demonstrates >140 fold selectivity over FGFR1, and shows robust efficacy in target altered in vivo tumor models without increases in serum phosphorus. Nonclinical pharmacokinetics (PK) and safety data support evaluating CGT4859 in a first-in-human, open-label, dose-escalation and signal-seeking Phase I/II study (NCT06777316). Safety, tolerability, PK, pharmacodynamics, and antitumor activity of CGT4859 will be assessed in adults with histologically confirmed unresectable or metastatic iCCA or other solid tumors with FGFR2/3 alterations. Methods: CGT4859 will be administered orally continuously in 28-day cycles to patients (N=~50) at a starting dose of 1 mg QD, and dose escalation will not exceed 40 mg QD as determined using a Bayesian optimal interval design with backfill (BF-BOIN). This approach will be used to guide dose escalation and establish the maximum tolerated dose (MTD) and recommended Phase 2 Dose (RP2D). BF-BOIN enables backfilling of participants to doses that are cleared for safety during the dose escalation, generating additional data on safety and tolerability below the MTD. Objective response rate (ORR) and disease control rate will be determined based on investigator assessment using RECIST v1.1. Phase II will enroll up to 4 cohorts, each enrolling ~15 patients. Proposed cohorts will include participants who have iCCA and are either FGFRi-naïve or FGFRi-exposed. Two additional cohorts with other advanced solid tumors harboring FGFR2/3 alterations may be included based on signals detected in dose escalation. The primary efficacy endpoint for Phase II is ORR per RECIST v1.1. The preclinical data support the study of CGT4859 in this patient population with solid tumors harboring FGFR2 and/or FGFR3 genetic alterations. The phase I dose escalation study is currently enrolling at sites in the United States. Clinical trial information: NCT06777316 .

PURPOSE:Neoadjuvant immune checkpoint inhibitors (nICIs) have demonstrated high response rates in deficient mismatch repair/microsatellite instability-high (dMMR/MSI-H) gastroesophageal adenocarcinoma (GEA). The NEONIPIGA and INFINITY trials demonstrated high rates of pathologic complete response (pCR) in this patient population. Furthermore, the INFINITY trial explored the feasibility of managing these patients nonoperatively, demonstrating promising results. This study aimed to evaluate clinical outcomes of nICIs in resectable dMMR/MSI-H GEA, with a focus on the feasibility of nonoperative management (NOM). MATERIALS AND METHODS:This retrospective cohort study included patients with resectable dMMR/MSI-H GEA and treated with nICIs ± surgery at the Mayo Clinic. Patients were identified from institutional records, and clinical data were retrospectively reviewed. Primary outcomes were clinical complete response (cCR) and pCR. Secondary outcomes included event-free survival (EFS), radiologic complete response (rCR), and immune-related adverse events (irAEs). RESULTS:A total of 26 patients treated between April 1, 2017, and July 30, 2025, were identified. Nine patients (34.6%) underwent surgery, of whom six (66.7%) achieved pCR. Seventeen patients (65.4%) pursued NOM, with 10 (71.4%) of 14 evaluable patients achieving cCR and 14 (82.4%) of 17 evaluable achieving rCR. One patient who initially achieved cCR had a local recurrence on surveillance endoscopy and underwent salvage endoscopic resection. At a median follow-up of 19.3 months, 15 (88.2%) of 17 patients in the NOM cohort were alive and metastasis-free, with EFS rates of 87.3% at 12 and 24 months for all patients. irAEs occurred in nine patients (34.6%), with no grade ≥3 toxicities. CONCLUSION:In this retrospective cohort study, nICIs led to high cCR and pCR rates in resectable dMMR/MSI-H GEA, supporting the use of immune checkpoint inhibitors in this setting and the feasibility of NOM in select patients.

Purpose: TRK-950 is a first-in-class humanized antibody targeting cytoplasmic activation/proliferation-associated protein-1, which is strongly expressed on the cell membrane surface in or on most solid tumors but not in or on normal tissues. This first-in-human study investigated the safety profile, pharmacokinetics (PK), and preliminary antitumor activity.Patients and Methods: Patients with treatment-refractory, locally advanced, or metastatic solid tumors were enrolled in a dose escalation/expansion study. TRK-950 was administered intravenously weekly for 3 weeks in a 28-day cycle, with doses ranging from 3 to 30 mg/kg. Dose expansion included 10 mg/kg weekly and 30 mg/kg biweekly for colorectal cancer and 10 mg/kg weekly for cholangiocarcinoma. The primary objective of this study was to determine its safety, tolerability, and maximum tolerated dose. The secondary objectives were PK, preliminary antitumor activity, and identification of potential biomarkers.Results: Thirty-six patients received at least one dose of TRK-950. In the dose escalation cohort, the maximum tolerated dose was not reached, and no dose-limiting toxicities were observed up to 30 mg/kg. Common adverse events included abdominal pain, fatigue, constipation, back pain, nausea, and decreased appetite. TRK-950 exhibited a PK profile similar to that of other IgG subclass 1 therapeutic antibodies, with linear PK parameters over the 3 to 30 mg/kg dose range. The best response was stable disease. Notably, one patient with cholangiocarcinoma showed signs of cavitation after approximately 8 months, suggesting potential antitumor activity.Conclusions: TRK-950 is safe and well tolerated, has a favorable PK profile, and should be further investigated as a monotherapy and in combination with standard treatment for various types of solid tumors.Significance: TRK-950, a humanized antibody targeting CAPRIN-1, demonstrated good tolerability, no dose-limiting toxicities, a favorable PK profile, and potential antitumor activity in this first-in-human study. Currently, TRK-950 is undergoing Phase Ib and II trials for various cancers, showing promising development potential.