Abstract 4125: Rencofilstat exerts a dominant role in synergistic anti-PD1-combination effects in a fatty liver model of hepatocellular carcinoma

Abstract Rencofilstat is a clinical-phase drug candidate that inhibits multiple cyclophilin isomerases and affects many cellular processes. The objectives of this study were to characterize rencofilstat’s anti-tumor effects alone and in combination with anti-PD1 in a murine model of fatty liver-associated hepatocellular carcinoma (HCC). Murine Hep53.4 HCC cells were orthotopically implanted into livers of C57BL/6 mice fed either a normal diet or western diet. Treatments included rencofilstat and anti-PD1 IgG, alone or in combination, from Weeks 2-4 post-implantation. End-of-study analyses included tumor growth, survival, and tumor gene expression by bulk RNA sequencing. Hep53.4 tumors in fatty livers (“fatty tumors”) were more resistant to treatments compared to tumors in nonfatty livers (“nonfatty tumors”). On the normal liver background, rencofilstat and anti-PD1 IgG as monotherapies or in combination decreased tumor volumes by 76-83%. In contrast, only combination treatment consistently decreased tumor volumes (84%) in fatty livers. Rencofilstat plus anti-PD1 IgG also extended mouse survival in the fatty liver model. Tumor transcriptomic analyses revealed marked differences between treatments and tumor types. Rencofilstat altered the expression of 3-times more genes than anti-PD1 in fatty tumors (differentially expressed genes; DEGs), whereas the two treatments affected similar number of genes in nonfatty tumors. The same was true when analysis was restricted to only those genes whose expression correlated with tumor volume. The identities of the DEGs were very different between rencofilstat and anti-PD1 treatments in nonfatty tumors. In contrast, in fatty tumors, 40% of the anti-PD1 DEGs also occurred in rencofilstat-treated tumors, suggesting that rencofilstat can moderately mimic anti-PD1 in fatty tumors. Rencofilstat DEGs also overlapped significantly with combination-treatment DEGs (46%) in fatty tumors, whereas only 7% of the anti-PD1 DEGs were represented in the combination treatment tumors. DEG pathway mapping revealed that the biological pathways predicted to be affected by rencofilstat and anti-PD1 were highly dependent on the type of tumor. In nonfatty tumors both drug treatments predominantly affected cellular biology processes such as protein processing and metabolism, but in fatty tumors both drug treatments overwhelmingly affected immune-related processes such as T cell differentiation, natural killer cells, checkpoint pathways, and cytokine-chemokine signaling. These results highlight major differences in phenotype and treatment response of tumors in fatty livers compared to nonfatty livers. Furthermore, they suggest that a combination of a checkpoint inhibitor with rencofilstat may be especially efficacious for HCC in individuals with NAFLD or NASH, due in part to rencofilstat’s multi-pathway targeting. Citation Format: Daren Ure, Jack Leslie, Lacey Haddon, Claude Fu, Jelena Mann, Derek Mann. Rencofilstat exerts a dominant role in synergistic anti-PD1-combination effects in a fatty liver model of hepatocellular carcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4125.