343 (PB123) - HX301, a potent CSF1R inhibitor, suppresses tumor associated M2 macrophage (TAM), enhancing tumor immunity and causing transit tumor inhibition in syngeneic EMT-6 tumors

Abstract

Background. Tumor associated macrophage (TAM) plays important immunosuppression role within the tumor microenvironment (TME). CSF1R is a receptor tyrosine kinase (RTK) responsible for the growth, survival and polarization (toward M2) of macrophages, thus implicated in pathogenesis of immunological disorders, as well as immuno-oncology (IO). High CSF1R expression is reported to be correlated to poorer prognosis of cancers CSF1R inhibitors (CSF1Ri), both TKIs or antibodies, have been proposed as potential cancer treatment strategy, although yet to be proven in the clinics.