X-376

X-376 is a potent and highly specific ALK tyrosine kinase inhibitor (TKI) (IC₅₀=0.61 nM). X-376 is a less potent inhibitor of MET (IC₅₀=0.69 nM). X-376 displays potent anti-tumor activity^[1]. IC50 & Target: IC50: 0.61 nM (ALK), 0.69 nM (MET)^[1] In Vitro: The ability of X-376 to inhibit the growth of different cancer cell lines harboring ALK fusions or point mutations is tested. X-376 is potent in H3122 lung cancer cells harboring EML4-ALK E13;A20 (IC₅₀: 77 nM). X-376 is also potent in H2228 lung cancer cells harboring EML4-ALK E6a/b; A20 (IC₅₀: 57 nM). Furthermore, X-376 is potent in SUDHL-1 lymphoma cells harboring NPM-ALK (IC₅₀: 32 nM). X-376 also inhibits SY5Y neuroblastoma cells harboring ALK F1174L, MKN-45 gastric carcinoma cells harboring MET dependent, HepG2 cells and PC-9 lung cancer cell lines harboring EGFR exon 19 del with IC₅₀s of 142 nM, 150 nM, 15.137 μM and 3.062 μM, respectively^[1]. In Vivo: The effects of X-376 in vivo against H3122 xenografts are examined. A pharmacokinetic study reveals that X-376 shows substantial bioavailability and moderate half-lives in vivo. Nude mice harboring H3122 xenografts are treated with X-376 at 50 mg/kg bid. X-376 significantly delays the growth of tumors compared to vehicle alone. In the xenograft experiments, X-376 appears well-tolerated in vivo. Mouse weight is unaffected by X-376 treatment. Drug-treated mice appear healthy and do not display any signs of compound related toxicity. To further assess potential side effects of X-376, additional systemic toxicity and toxico-kinetic studies are performed in Sprague Dawley (SD) rats. Following 10 days of repeated oral administration of X-376 at 25, 50, 100 mg/kg in SD rats, all animals survive to study termination. The no significant toxicity (NST) levels are determined to be 50 mg/kg for X-376. At NST levels, X-376 achieves an AUC of 41 μM×hr and a C_max of 5.04 μM^[1].