An orally bioavailable and selective inhibitor of the receptor tyrosine kinase AXL (UFO), with potential immunostimulating and antineoplastic activities. Upon oral administration, SLC-391 targets, binds to and prevents the activation of AXL. This blocks AXL-mediated signal transduction pathways, and inhibits both AXL-mediated tumor cell growth, proliferation and migration and AXL-mediated immunosuppression. AXL, a member of the Tyro3, AXL and Mer (TAM) family of receptor tyrosine kinases, is overexpressed by many tumor cell types and also expressed in a variety of immune cells including macrophages, natural killer (NK) cells, and regulatory T-cells (Tregs). It plays a key role in tumor cell proliferation, survival, invasion and metastasis, and is a mediator of immunosuppression. Its expression is associated with drug resistance and poor prognosis.