1024P Baseline biomarkers associated with clinical benefit in patients with solid tumors refractory to immune checkpoint inhibitors (ICIs) treated with live biotherapeutic MRx0518 in combination with pembrolizumab

Abstract

MRx0518 is a novel, gut microbiome derived, single strain oral Live Biotherapeutic Product (LBP) with potent anti-tumour efficacy in multiple cancer models. MRx0518 has been shown to induce activation of CD8+ T-cells and suppress differentiation of Treg cells in vitro, and to increase the CD8/Treg cell ratio in murine models of cancer. In an ongoing phase I/II study (NCT03637803), preliminary antitumor activity has been observed in patient’s refractory to ICIs when MRx0518 is administered in combination with pembrolizumab.