Turning pancreatic cancer from cold to hot: the promise of a p53-expressing oncolytic adenovirus (OBP-702)

Pancreatic cancer remains one of the most lethal malignancies, with limited therapeutic options and poor responsiveness to immune checkpoint inhibitors (ICIs). This resistance is largely attributed to its profoundly immunosuppressive and desmoplastic tumor microenvironment (TME), characterized by low tumor mutational burden, dense stroma, and abundant immunosuppressive cell populations. Therefore, strategies capable of enhancing tumor immunogenicity and overcoming immune evasion are urgently needed. Oncolytic virotherapy is a promising approach, offering not only tumor-selective cytotoxicity, but also potent immunomodulatory effects. Of these agents, Telomelysin (OBP-301, Suratadenoturev), a telomerase-specific oncolytic adenovirus, demonstrated clinical safety but limited efficacy in refractory tumors. To address this challenge, we developed OBP-702, a next-generation, p53-armed, oncolytic adenovirus designed to augment antitumor activity. Preclinical studies have shown that OBP-702 exerts robust cytotoxicity through multiple mechanisms, including p53-mediated apoptosis and autophagy, E1A-E2F1-mediated p21 suppression, and inhibition of oncogenic KRAS pathways. Importantly, OBP-702 induces strong immunogenic cell death, activates dendritic cells, and promotes tumor-specific T-cell responses, effectively converting immunologically "cold" pancreatic tumors into "hot" tumors. OBP-702 also remodels the immunosuppressive TME by reducing granulocyte-macrophage colony-stimulating factor (GM-CSF) secretion, suppressing myeloid-derived suppressor cells (MDSCs), and targeting stromal components, such as cancer-associated fibroblasts (CAFs). These effects contribute to enhanced responses to ICIs and standard chemotherapies. Given its multifaceted antitumor functions and ability to overcome key barriers in pancreatic cancer, OBP-702 represents a highly promising therapeutic candidate. A first-in-human clinical trial evaluating endoscopic ultrasonography-guided intratumoral injection of OBP-702 is currently in preparation, expected to advance clinical translation of this novel virotherapeutic strategy.