Tirbanibulin (dihydrochloride) (KX2-391 (dihydrochloride)) is an inhibitor of Src that targets the peptide substrate site of Src, with GI₅₀ of 9-60 nM in cancer cell lines. IC50 & Target: GI50: 9 nM (Src HuH7), 13 nM (Src PLC/PRF/5), 26 nM (Src Hep3B), 60 nM (Src HepG2) In Vitro: Tirbanibulin (KX2-391) is a Src inhibitor that is directed to the Src substrate pocket. KX2-391 shows steep dose-response curves against Huh7 (GI₅₀=9 nM), PLC/PRF/5 (GI₅₀=13 nM), Hep3B (GI₅₀=26 nM), and HepG2 (GI₅₀=60 nM), four hepatic cell cancer (HCC) cell lines^[1]. Tirbanibulin (KX2-391) is found to inhibit certain leukemia cells that are resistant to current commercially available drugs, such as those derived from chronic leukemia cells with the T3151 mutation. Tirbanibulin (KX2-391) is evaluated in engineered Src driven cell growth assays inNIH3T3/c-Src527F and SYF/c-Src527F cells and exhibits GI₅₀ with 23 nM and 39 nM, respectively^[2]. In Vivo: Orally administered Tirbanibulin (KX2-391) is shown to inhibit primary tumor growth and to suppress metastasis, in pre-clinical animal models of cancer^[2].