“…C-C chemokine receptor type 4 (CCR4), the cognate receptor of the secreted proteins C-C motif chemokine ligand 17 (CCL17), and 22 (CCL22), is the predominant chemokine receptor on human T reg and is responsible for migration and accumulation of T reg in the TME. 1,2,3 FLX475 is an orally available and selective small-molecule antagonist of CCR4 which demonstrated potent inhibition of CCL17-and CCL22-induced CCR4-mediated chemotaxis, an increase in the intratumoral T eff /T reg ratio, and anti-tumor efficacy as a single agent and in combination with checkpoint inhibitors. 4 Given the proposed mechanism of action, a Phase 2 study investigating the safety, efficacy of FLX475 in combination with pembrolizumab in patients with advanced or metastatic gastric cancer is being conducted.…”