Lyc-55716: A novel small-molecule RORγ agonist immuno-oncology agent: Rationale for tumor selection and clinical evaluation of gastric and esophageal carcinoma in phase 2a expansion.

Abstract

67 Background: Type 17 effector T cell differentiation and function are regulated by the master transcription factor retinoic acid receptor–related orphan receptor γt (RORγ). Synthetic RORγ agonists, which modulate immune cell gene expression to enhance effector functions and decrease Treg and checkpoint pathways, have shown promise as mono- and combination therapy in syngeneic tumor models. Translational and bioinformatics assessments were performed during Phase 1 testing of the investigational RORγ agonist LYC-55716 to support inclusion of patients with gastric carcinoma (GC) and esophageal carcinoma (EC) in a Phase 2a expansion of clinical trial LYC-55716-1001 (NCT02929862). Methods: Transcriptional profiling of murine and human T cells treated ± RORγ agonists identified a gene signature. Using The Cancer Genome Atlas (TCGA), and other public datasets, data on GC and EC patients were evaluated to determine: (a) RORγ and RORγ-inducing cytokine expression; (b) signature genes associated with RORγ biology, surrogate biomarkers for endogenous RORγ ligands, and correlations with prognosis; (c) tumor microenvironment (TME) immune profiles. Results: Expression: In TCGA RNA sequencing data analysis, 50%-70% of GC and EC samples expressed moderate to high levels of RORγ, indicating infiltration of Type 17 T cells into the tumors. Furthermore, genes that support expression of RORγ were highly expressed in ~75% of GC and EC tumors. Biology: TCGA data showed that GC and EC tumors express low levels of sterol efflux genes, suggesting low levels of endogenous agonists in the TME. In analysis of public datasets, expression of the RORγ target gene IL17A correlated with a favorable prognosis for EC. In addition, some of the other RORγ signature genes also correlated with good prognosis in GC and EC. Immune profile: TCGA showed infiltration of T cells and a high mutational burden in GC and EC, which are positively associated with efficacy of immunotherapy. Conclusions: Bioinformatics assessments of RORγ expression, biology, and tumor immune profiles support the inclusion of GC and EC patients in an ongoing Phase 2 clinical trial of LYC-55716.