Taletrectinib (DS-6051b) is a potent, orally active, and next-generation selective ROS1/NTRK inhibitor. Taletrectinib potently inhibits recombinant ROS1, NTRK1, NTRK2, and NTRK3 with IC50s of 0.207, 0.622, 2.28, and 0.98 nM, respectively. Taletrectinib also inhibits ROS1 G2032R and other Crizotinib-resistant ROS1 mutants[2].In Vitro: The IC50 of Taletrectinib (1-1000 nM; 72 hours) against Ba/F3-TPM3-NTRK1, Ba/F3-ETV6-NTRK1, -NTRK2, -NTRK3, or KM12 cells is ~3-20?nM.
Taletrectinib (0.001-1000 nM; 2 hours) dose dependently inhibited autophosphorylation of ROS1 in U-118-MG cells in vitro.
Taletrectinib potently inhibits autophosphorylation of ROS1 in JFCR-165, JFCR-168, and MGH193-1B cells.
Taletrectinib partially suppresses phospho-NTRK1 at 10?nM, and completely suppresses by 100?nM. Taletrectinib free base potently inhibits recombinant ROS1, NTRK1, and NTRK3 in sub-nanomolar concentration in an ATP-competitive manner. Taletrectinib almost completely inhibits ACK, ALK, DDR1, and LTK at 0.2?μM among 160 kinases in the presence of 1 mM ATP, but did not inhibit other 152 kinases strongly.
Taletrectinib effectively inhibits Crizotinib-resistant ROS1 secondary mutations, including G2032R solvent front mutation.In Vivo: Taletrectinib (DS-6051b) (25-200 mg/kg; p.o.; once daily for 18 days) shows antitumor activity.
Taletrectinib (6.25-200?mg/kg; p.o.; once daily for 8 days) inhibits NTRK-rearranged cancer in Balb-c nu/nu mice bearing KM12 cells.
Taletrectinib (3-100 mg/kg; p.o.; once daily for 4 days) shows rapid tumor regression in the wild-type (WT) and the G2032R-mutant Ba/F3-bearing mice without severe body weight loss.