Abstract LB306: PD-L1-targeted radioimmunethrapeutics combined with oncolytic virus for treatment of pancreatic cancer

Abstract

Abstract Pancreatic cancer is difficult to treat, and the first line treatment provide only modest survival benefits to patients due to its highly desmoplastic and immune-desert phenotype. To overcome these hurdles, PD-L1-targeted radioimmunotherapy (RIT) using lutetium-177-labelled atezolizumab (177Lu-aPD-L1) combined with an oncolytic virus, named HY-oAd, that co-expresses three therapeutic genes (interleukin-12, granulocyte-macrophage colony-stimulating factor and relaxin) was investigated. HY-oAd treatment was shown to elevate PD-L1 expression level and promoted degradation of extracellular matrix (ECM) of pancreatic tumors, resulting in increased aPD-L1 or 64Cu-aPD-L1 accumulation in tumor tissues. Moreover, HY-oAd in combination with either aPD-L1 or 177Lu-aPD-L1 elicited more potent antitumor effect against the pancreatic tumors than respective monotherapy in pancreatic tumor models. The potent antitumor effect of HY-oAd+aPD-L1 combination therapy can lead to superior intratumoral infiltration and activation of dendritic cells and CD4+ or CD8+ T cells over the respective monotherapy. Collectively, our findings demonstrate that HY-oAd can potentiate PD-L1-targeted RIT through PD-L1 upregulation and ECM degradation, thus resulting in synergistic antitumor efficacy and antitumor immune response. Citation Format: Arum Yoon, Chae-Ok Yun, Jin Su Kim. PD-L1-targeted radioimmunethrapeutics combined with oncolytic virus for treatment of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB306.