Elliott, Natalie

Abstract The paradigm in the field of oncolytic virotherapy proposes that tumor cell killing by an oncolytic virus (OV) culminates in the priming of antitumor CD8+ T cells. However, this ignores the impact a highly immunodominant antiviral response against the OV has on the subdominant antitumor response, particularly with regard to the naturally low affinity of tumor antigens to their cognate T-cell receptors. To investigate this experimentally, we first studied the interaction between the two responses in B16 and MC38 tumor models, both expressing ovalbumin (OVA). Contrary to the accepted paradigm, the inflammatory vesicular stomatitis virus (VSV) failed to expand OVA-specific T cells in vivo unless armed with tumor-associated antigen (TAA). In fact, treatment with the control VSV led to the ablation of antitumor T cells and a shift toward dysfunction as determined by the upregulation of markers, including LAG3 and CD39, correlating with lower rates of survival. Combination with anti–PD-1 immune checkpoint blockade therapy significantly improved survival only when VSV expressed TAA. VSV-expressing altered peptide ligand variants of tumor antigens, which evade mechanisms of central tolerance, expanded near self-antigen–specific T cells with the ability to cross-react with tolerized tumor antigens, thus providing an antitumor effector population capable of proliferating in the presence of a potent antiviral response. Taken together, these findings offer a rational approach to OV design which preserves acute antitumor therapy provided by antiviral innate and T-cell responses while promoting the induction of tumor-specific T cells. Significance: Oncolytic viruses can induce an antiviral T-cell response that occludes an antitumor response, challenging the paradigm in the field and elucidating strategies to optimize the efficacy of oncolytic viroimmunotherapy.

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.

PURPOSE Hepatopancreatobiliary (HPB) cancers—including hepatocellular carcinoma (HCC), cholangiocarcinoma (CCA), pancreatic ductal adenocarcinoma (PDAC), and gallbladder cancer—are aggressive malignancies with limited treatment options and poor prognosis. The emergence of personalized liquid biopsy technologies, particularly bespoke circulating tumor DNA (ctDNA), offers new opportunities for improving clinical management. Traditional methods like imaging and tumor markers may miss early recurrence or evolving disease. This study explores the real-world application of ctDNA in HPB cancers, focusing on its use for surveillance, diagnostic clarification, treatment monitoring, and recurrence detection. Methods We retrospectively analyzed the use of a personalized ctDNA assay (Signatera, Natera) in 54 patients with HPB cancers at a single academic cancer center. The cohort included PDAC (22/54), HCC (11/54), and CCA (21/54). ctDNA was assessed longitudinally for surveillance, treatment monitoring, or diagnostic clarification. Concordance with imaging and tumor markers, as well as lead time to recurrence detection, was descriptively analyzed. RESULTS ctDNA was evaluable in 37/54 patients (84.6%), with ctDNA positivity in 22/37 (59.5%). Success rates by tumor type were 16/22 (72.7%) in PDAC, 10/11 (90.9%) in HCC, and 11/21 (52.4%) in CCA. ctDNA concordance with imaging was observed in 69/85 assessments (72.6%) and with tumor markers (carbohydrate antigen 19-9 or alpha fetoprotein) in 39/95 (41%). Clinical applications included disease surveillance (21/54, 38.9%), treatment monitoring (24/54, 44.4%), and diagnostic clarification (16/54, 29.6%). In patients with recurrence, ctDNA detected disease before imaging in several cases, with a median lead time of 28 days (range, 1 month to 7 months). CONCLUSION Personalized ctDNA testing demonstrated meaningful utility across HPB cancers, enabling early recurrence detection and guiding clinical decision making as a complementary tool in multidisciplinary care.

PURPOSE For patients with advanced biliary tract cancer (BTC), cancer-related time spent in health care systems, time toxicity, represents a critical but understudied burden affecting quality of life. This study aimed to quantify time toxicity in patients receiving first-line systemic therapy and evaluate whether the addition of durvalumab to gemcitabine plus cisplatin (GC) increases health care contact time. METHODS This international, multicenter, retrospective cohort study included patients with advanced BTC seen between January 2019 and April 2024 at Mayo Clinic Enterprise (US), and between January 2021 and April 2024 at Kyorin University Hospital (Japan), and Hospital Israelita Albert Einstein (Brazil). Patients received GC plus durvalumab (GCD) or GC. Time toxicity was recorded from treatment initiation until discontinuation or last follow-up during first-line systemic therapy. Multiple regression analysis identified factors associated with high time toxicity. RESULTS Among 193 patients (102 GCD, 91 GC; median age 65 years; 50% male; 49% Eastern Cooperative Oncology Group performance status [PS] 0), median time on treatment (TOT) was 156 days (95% CI, 122 to 190). The median proportion of total time toxicity was 14.4% (IQR, 10.9-20.6). Planned visits accounted for 11.9%, while unplanned visits were infrequent (1.8%). Time toxicity strongly correlated with TOT ( r = 0.824) and progression-free survival ( r = 0.827). Despite longer treatment in the GCD group than the GC group (212 v 134 days; P = .027), total time toxicity was similar (27 v 18 days; P = .19). Younger age and poor PS were independent factors of higher time toxicity. CONCLUSION Time toxicity represents a meaningful metric that allows for more comprehensive integration of the net benefit in patients with advanced BTC with a limited lifespan.

Abstract The paradigm in the field of oncolytic virotherapy proposes that tumor cell killing by an oncolytic virus (OV) culminates in the priming of antitumor CD8 T cells. However, this ignores the impact a highly immunodominant antiviral response against the OV has on the antitumor response which has been weakened by mechanisms of central tolerance. Here, we show that inflammatory Vesicular Stomatitis Virus (VSV) failed to prime an adoptively transferred, or pre-existing, population of tumor-reactive T cells.Combination with αPD1 immune checkpoint blockade therapy improved survival only when VSV expressed tumor associated antigens (TAA). These data show that, in this model, the highly inflammatory OV VSV alone actively outcompetes antitumor immunity. However, we also show that viral expression of a mutant near-self TAA can break central tolerance expanding heteroclitic self-reactive and near-self-reactive T cells, thus overcoming viral immunodominance by promoting tumor-specific T cell proliferation in parallel with expanding antiviral T cells.

Background: Morreton virus (MORV) is an oncolytic Vesiculovirus , genetically distinct from vesicular stomatitis virus (VSV). Aim: To report that MORV induced potent cytopathic effects (CPEs) in cholangiocarcinoma (CCA) and hepatocellular carcinoma (HCC) in vitro models. Approach and Results: In preliminary safety analyses, high intranasal doses (up to 10 10 50% tissue culture infectious dose [TCID 50 ]) of MORV were not associated with significant adverse effects in immune competent, non–tumor‐bearing mice. MORV was shown to be efficacious in a Hep3B hepatocellular cancer xenograft model but not in a CCA xenograft HuCCT1 model. In an immune competent, syngeneic murine CCA model, single intratumoral treatments with MORV (1 × 10 7 TCID 50 ) triggered a robust antitumor immune response leading to substantial tumor regression and disease control at a dose 10‐fold lower than VSV (1 × 10 8 TCID 50 ). MORV led to increased CD8 + cytotoxic T cells without compensatory increases in tumor‐associated macrophages and granulocytic or monocytic myeloid‐derived suppressor cells. Conclusions: Our findings indicate that wild‐type MORV is safe and can induce potent tumor regression via immune‐mediated and immune‐independent mechanisms in HCC and CCA animal models without dose limiting adverse events. These data warrant further development and clinical translation of MORV as an oncolytic virotherapy platform.

PURPOSE This investigation sought to evaluate the prognostic value of pretreatment of circulating tumor DNA (ctDNA) in metastatic biliary tract cancers (BTCs) treated with platinum-based first-line chemotherapy treatment. MATERIALS AND METHODS We performed a retrospective analysis of 67 patients who underwent ctDNA testing before platinum-based chemotherapy for first-line treatment for metastatic BTC. For analysis, we considered the detected gene with highest variant allele frequency as the dominant clone allele frequency (DCAF). Results of ctDNA analysis were correlated with patients' demographics, progression-free survival (PFS), and overall survival (OS). RESULTS The median age of patients was 67 (27-90) years. Fifty-four (80.6%) of 67 patients evaluated had intrahepatic cholangiocarcinoma; seven had extrahepatic cholangiocarcinoma, and six gallbladder cancers. Forty-six (68.6%) of the patients were treated with cisplatin plus gemcitabine, and 16.4% of patients received gemcitabine and other platinum (carboplatin or oxaliplatin) combinations, whereas 15% of patients were treated on a clinical trial with gemcitabine and cisplatin plus additional agents (CX4945, PEGPH20, or nab-paclitaxel). TP53, KRAS, FGFR2, ARID1A, STK11, and IDH1 were the genes with highest frequency as DCAF. The median DCAF was 3% (0%-97%). DCAF > 3% was associated with worse OS (median OS: 10.8 v 18.8 months, P = .032). Stratifying DCAF in quartiles, DCAF > 10% was significantly related to worse PFS (median PFS: 3 months, P = .014) and worse OS (median OS: 7.0 months, P = .001). Each 1% increase in ctDNA was associated with a hazard ratio of 13.1 in OS when adjusting for subtypes, metastatic sites, size of largest tumor, age, sex, and CA19-9. CONCLUSION DCAF at diagnosis of advanced BTC can stratify patients who have worse outcomes when treated with upfront platinum-based chemotherapy. Each increase in %ctDNA decreases survival probabilities.