Zeteletinib (BOS-172738; DS-5010) is an orally active, selective RET kinase inhibitor with nanomolar potency against RET and >300-fold selectivity against VEGFR2. Zeteletinib shows exquisite potency for the wild type RET, RETV804M/L gatekeeper mutants, and the most common oncogenic RET mutation M918T. Zeteletinib has potent antitumor activity[2].In Vitro: In biochemical assays of 106 kinases, RET and platelet-derived growth factor receptor (PDGFR) alpha/beta were inhibited more than 80% by 193 nM Zeteletinib (BOS-172738; DS-5010). The IC50 values of Zeteletinib against RET, RET-GKm (V804L) were single digit nano-molar even under a condition of high concentration of ATP; besides it against KDR was more than 1000 nM.In Vivo: In a Ba/F3-RET subcutaneous tumor model, Zeteletinib (BOS-172738; DS-5010) dosing at 10 mg/kg twice daily (bid) induces tumor regression.
In an LC2/ad NSCLC xenograft model, which has the RET-CCDC6 fusion gene, Zeteletinib dosing at 1 mg/kg thrice daily (tid) induced tumor regression.