444 Exploiting global viral immunity to develop a novel viro-immunotherapy using oncolytic viruses and CAR T-cells for hepatocellular carcinoma

Objectives/Goals: Hepatocellular carcinoma (HCC) is a therapeutic challenge due to poor tumor immunogenicity, low endogenous T cell response, and a complex tumor microenvironment (TME). We propose an immunotherapeutic strategy leveraging widespread antiviral immunity – particularly memory T cells against SARS-CoV-2 spike (SPIKE) – to redirect T cells into tumors. Methods/Study Population: By engineering oncolytic viruses (OV) to express SPIKE, the approach aims to recruit virus-specific T cells and re-activate them through viral boosting, enhancing tumor clearance. This has been successfully shown in a B-16 melanoma model, another solid tumor system. We will also develop a dual-specific CAR T cell platform against SPIKE and GPC3, the most common HCC tumor-associated antigen (TAA), enabling antitumor targeting which can also benefit from OV readministration. The experimental plan includes purification and titration of a single-cycle adenovirus expressing SPIKE (SC-Ad-SPIKE), infection of murine and human HCC cell lines to validate SPIKE expression and replication, and in vivo treatment of subcutaneous or orthotopic murine tumors in pre-immunized or naïve mice using OV. Results/Anticipated Results: This strategy offers a translatable platform to re-focus existing antiviral memory toward otherwise weakly immunogenic tumors like HCC, potentially enhancing clinical efficacy through oncolytic virotherapy and CAR T cell engineering. We should see better average tumor clearance and survival in the groups treated with the OV and CAR T against SPIKE than controls with only GPC3 given the lack of reliance on tumor-GPC3 expression. Discussion/Significance of Impact: Our approach could be crucial for patients given how varied current responses are to available therapies. The combination of a generalized OV therapy and a more targeted CAR T provides a promising new solution to the current unmet need of many HCC patients globally.