Abstract 3238: Integrative biomarker analysis of regorafenib plus nivolumab (RegoNivo) in unresectable hepatocellular carcinoma (uHCC): A multicenter phase 2 RENOBATE trial
Authors: Kim Hyung-Don , Jung Seyoung , Ryoo Baek-Yeol , Ryu Min-Hee , Kang Beodeul , Chon Hong Jae , Hong Jung Yong , Lim Ho Yeong , Lee Jeong Seok , Koh June-Young , Yoo Changhoon 
Published: April 2023

Abstract
RegoNivo combination has shown promising anti-cancer activity in multiple cancer types. REBNOBATE is a single-arm multicenter phase 2 trial of first-line RegoNivo in patients (pts) with uHCC (NCT04310709). In this study, we present the final clinical outcomes of RENOBATE and integrative biomarker analysis. Pts with &gt;19 years, ECOG PS 0 or 1, BCLC stage B or C, and no prior systemic therapy were eligible. Pts received Nivo 480 mg iv, every 4 wks, and Rego 80 mg daily po, 3 wks on/1 wk off, every 4 wks. Tumor response was assessed according to RECIST v1.1 every 8 wks. ctDNA analysis was performed using the Guardant 360 CDx platform (n=42). scRNA-seq was performed using peripheral blood mononuclear cells (PBMCs) at baseline (e.g., C1D1, n=28) and C1D15 (n=19) from early progression (EP) group (pts with PD or tumor burden increases towards PD on the first evaluation) and long-term response (LR) group (pts with PR or SD &gt; 6 months). A total of 42 pts was enrolled. Response rates were 31.0% and median progression-free survival (PFS) was 7.4 mo (95% CI, 4.2-13.0) and 1-year OS rate was 80.5% (95% CI, 63.0-90.3%). Aberrations of Wnt/β-Catenin and PI3K/mTOR pathways identified in ctDNA were not associated with efficacy outcomes. scRNA-seq revealed that genes upregulated in immune cells on C1D15 (vs. baseline) were associated with immune activation and regulation of angiogenesis. Unsupervised clustering identified 13 immune subets; among them, classical monocyte showed most prominent changes in their proportion and gene expression profiles. After RegoNivo treatment, CD8 T cell clusters had enhanced expressions of genes related to cytoxicity, tissue homing (i.e., CXCR6, CX3CR1, and CXCR3) and proliferation (MKI67), and monophaghocyte clusters showed an enrichment of the gene signatures representing polarization towards M1-related features. Importantly, enrichment of cytotoxic features of the T cell clusters and M1-polarizing features of monophagocyte clusters were more pronounced in LR group than in EP group. From the analysis of differentially expressed genes monophagocyte clusters between the EP and LR groups, a surface molecule ‘X’ was identified as a potential biomarker involved in resistance to RegoNivo. RegoNivo showed promising efficacy outcomes in pts with uHCC. Through scRNA-seq of serial PBMCs, we identified enhanced cellular immune responses induced by RegoNivo and found a potential predictive marker for immunotherapy in pts with uHCC. Our study highlighted that Rego, a multikinase inhibitor, might synergize with anti-PD-1 in pts with uHCC. Association between differential features of T cell and monophagocyte clusters induced by this combination and distinct clinical outcomes highlights the importance of immune-modulation in HCC pts and suggests a potential to further harness these signals.
Citation Format: Hyung-Don Kim, Seyoung Jung, Baek-Yeol Ryoo, Min-Hee Ryu, Beodeul Kang, Hong Jae Chon, Jung Yong Hong, Ho Yeong Lim, Jeong Seok Lee, June-Young Koh, Changhoon Yoo. Integrative biomarker analysis of regorafenib plus nivolumab (RegoNivo) in unresectable hepatocellular carcinoma (uHCC): A multicenter phase 2 RENOBATE trial [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 3238.