In Vitro: Altiratinib also inhibits MET isoforms METD1228H, MET D1228N, METY1230C, METY1230D, METY1230H, METM1250T with IC50s of 3.6, 1.3, 1.2, 0.37, 1.5 and 6 nM, respectively. Altiratinib inhibits MET phosphorylation with IC50 values of 0.85 and 2.2 nM, respectively. In the U-87 glioblastoma cell line, MET and HGF are both expressed. Altiratinib blocks autocrine activation of MET phosphorylation in these cells (IC50=6.2 nM). Altiratinib potently inhibits cellular proliferation in MET-amplified EBC-1 and MKN-45 cells, as well as TPM3-TRKA fusion KM-12 cells. Activation of MET is known to increase the motility and invasiveness of cancer cells: Altiratinib inhibits HGF-induced A549 cell migration, with an IC50 of 13 nM. Altiratinib also inhibits FLT3-ITD mutant MV-4-11 cell proliferation with an IC50 of 12 nM.
In Vivo: A single oral dose of 30 mg/kg Altiratinib leads to >95% inhibition of MET phosphorylation for the entire 24-hour period. A single 10 mg/kg oral dose of Altiratinib exhibits complete inhibition of MET phosphorylation through 12 hours and 73% inhibition at 24 hours postdose. Altiratinib dosed at 10 mg/kg twice a day leads to a significant 90% decrease in BLI signal. Altiratinib exhibits properties amenable to oral administration and exhibits substantial blood–brain barrier penetration, an attribute of significance for eventual treatment of brain cancers and brain metastases.