Abstract 720: Combining zelasudil, a small molecule ROCK2 inhibitor, with chemotherapy or immunotherapy improves response in preclinical models of pancreatic cancer

Abstract Zelasudil (RXC007) is an orally available, highly selective small molecule inhibitor of Rho-associated coiled-coil containing protein kinase 2 (ROCK2), which has demonstrated pre-clinical anti-fibrotic efficacy and is currently being tested in a Phase 2a clinical trial for the treatment of idiopathic pulmonary fibrosis (IPF) (NCT05570058). Pancreatic ductal adenocarcinoma (PDAC) is an aggressive and therapeutically challenging disease with a dense and highly fibrotic tumor microenvironment which may limit efficacy of conventional therapies. Here, we investigate the benefit of combining an anti-fibrotic, RXC007, with either standard of care chemotherapy or immunotherapy in mouse models of PDAC. In a fibrotic patient-derived metastatic PDAC orthotopic model, RXC007 (10mg/kg, 50mg/kg and 100mg/kg BID 5d on/2d off PO) in combination with SoC chemotherapy Gemcitabine (100mg/kg IP QW) /Abraxane (30 mg/kg IP QW) improved survival in a dose-dependent manner (all P0. 0001) compared to Gemcitabine/Abraxane alone. In the immunocompetent orthotopic LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx1-Cre (KPC) model of metastatic PDAC, survival was significantly increased (P0. 0001) upon treatment with a combination of RXC007 (50 mg/kg BID 5d on/2d off PO) and anti-PD1 (200 ug BIW) compared to anti-PD1 alone. ROCK2 inhibition elicited positive immunomodulatory effects in KPC pancreatic tumors, with increase of CD8+ (P=0. 0031) and CD4+ (P=0. 008) T cell infiltrate into the tumor cortex and reduction in immunosuppressive FOXP3+ regulatory T cells at the tumor border. Furthermore, RXC007 monotherapy exhibited anti-fibrotic effects, via a decrease in collagen content and organization, effects associated with CAF reprogramming and reduced intra-tumoral aSMA+ PDPN+ myofibroblast-like CAFs (myCAFs; P=0. 0406). This data highlights the potential for treating highly fibrotic tumours with RXC007 in combination with SoC chemotherapy or immunotherapy in order to improve patient outcomes in this aggressive and treatment-refractory cancer. Citation Format: Marina Pajic, Benjamin McLean, Diego Chacon Fajardo, Sean Porazinski, Dannielle H. Upton, Diana Schuhmacher, Aji Istadi, Thomas Cox, Paul Timpson, Daniel J. Wilcock, Katie J. Anderson, Helen Mason, Nicolas E. Guisot, Clifford D. Jones, Caroline Phillips, Richard Armer. Combining zelasudil, a small molecule ROCK2 inhibitor, with chemotherapy or immunotherapy improves response in preclinical models of pancreatic cancer abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 720.