Antitumor Effects of Combination Therapy with Oncolytic Vaccinia Virus and Tepotinib on Lung Cancer Cells

Objectives: Despite advancements in molecular-targeted therapies and immune checkpoint inhibitors, the survival rate of patients with advanced lung cancer remains unsatisfactory. Therefore, new and effective treatment strategies are urgently needed. Both mesenchymal-epithelial transition (MET) inhibitors and oncolytic viruses exhibit immunomodulatory properties along with direct antitumor effects. Materials and Methods: The antitumor effects of a combination therapy using MDRVV, a modified vaccinia virus for oncolytic virus therapy, and tepotinib, a MET inhibitor, were evaluated in vitro and in vivo using lung cancer models. Results: The combination therapy demonstrated additive cytotoxic effects on various lung cancer cell lines in vitro and significantly suppressed tumor growth in an immunocompetent mouse model. MDRVV triggered immunogenic cell death, evidenced by the release of adenosine triphosphate (ATP) and high-mobility group box-1 (HMGB-1). Additionally, the combination therapy enhanced CD4+ and CD+ T-cell infiltration more effectively than either agent alone. MDRVV exhibited antitumor effects not only in the inoculated tumors but also in distant tumors, with the most pronounced effect observed when combined with tepotinib. Conclusions: These findings suggest that combining a MET inhibitor with oncolytic vaccinia virus represents a promising and effective strategy for improving lung cancer treatment by targeting both tumor cells and the tumor microenvironment.