Discovery of 1,6-naphthyridinone-based MET kinase inhibitor bearing quinoline moiety as promising antitumor drug candidate.

A series of 1,6-naphthyridinone-based MET kinase inhibitors bearing quinoline moiety in block A were designed and synthesized based on the structures of Cabozantinib and our reported compound IV. Extensive SAR and DMPK studies led to the identification of 20j, a potent and orally bioavailable MET kinase inhibitor with favorable kinase selectivity. More importantly, 20j exhibited statistically significant tumor growth inhibition (Tumor growth inhibition/TGI of 131%, 4/6 partial regression/PR) in the U-87 MG xeograft model, which is superior to that of Cabozantinib (TGI of 97%, 2/6 PR), and significantly better than that of compound IV (TGI of 15%, 0/6 PR) at the same dose (12.5 mg/kg). Combined with favorable in vitro potency, kinase selectivity, pharmacokinetic profile and in vivo efficacy, the promising antitumor drug candidate 20j has subsequently advanced into preclinical research.