Oritinib mesylate (SH-1028) is a highly selective, orally active, pyrimidine-based irreversible inhibitor of epidermal growth factor receptor (EGFR) with a low half maximal inhibitory concentration (IC50) of 18 nM. It demonstrates potent efficacy against both EGFR-sensitive and resistant (T790M) mutations. Furthermore, Oritinib mesylate effectively suppresses the proliferation of tumor cells harboring EGFR mutations, regardless of their sensitivity or resistance.

EGFR (L858R/T790M):0.1 nM (IC50), EGFR (WT):18 nM (IC50), EGFR (d746-750/T790M):0.89 nM (IC50), EGFR (d746-750):1.4 nM (IC50), EGFR (L861Q):4 nM (IC50), EGFR (L858R):0.7 nM (IC50)

Oritinib (SH-1028) (72 hours; 10 μmol/L and the 3-fold dilution; nine times) mesylate selectively inhibits EGFR-mutated NCI-H1975, H3255 and PC-9 cells, with IC 50 values of 3.93, 9.39 and 7.63 nM, respectively, which is more sensitive than the inhibition of wild-type EGFR in A431 cells[1]. Cell Proliferation Assay[1]Cell Line: A431 (EGFR WT ), H3255 (EGFR L858R ), PC-9 (EGFR d746-750 ) and NCI-H1975 (EGFR L858R/T790M ) cells Concentration: 0.001, 0.01, 0.1, 1, and 10 μM Incubation Time: 72 hours Result: Selectively inhibited EGFR-mutated NCI-H1975, H3255 and PC-9 cells, with IC 50 s of 3.93±1.12, 9.39±0.88 and 7.63±0.18 nmol/L, respectively, which were about 198-, 83- and 102-fold more sensitive than the inhibition of wild-type EGFR in A431 cells (IC 50 =778.89±134.74 nM).

Oritinib (SH-1028) (p.o.; once daily for consecutive 14 days; 2.5-15 mg/kg) mesylate inhibits EGFR-mutant tumor progression but not wild-type EGFR in vivo[1]. Oritinib (SH-1028) (p.o.; once daily for consecutive 14 days; 2.5-15 mg/kg) mesylate only induces a moderate tumor growth inhibition in A431 (wild-type EGFR) tumor xenografts, while causes profound and sustained tumor shrinkage in both NCI-H1975 and PC-9 xenograft models with EGFR mutations with 5 mg/kg/day[1]. Oritinib (SH-1028) (p.o.; once daily for consecutive 14 days; 2.5-15 mg/kg) mesylate shows good bioavailability, and is distributed extensively from the plasma to the tissues with T max of 1.5-2 h, and AUC 0–t values of SH-1028 in plasma are 118, 300 and 931 ng × h/ml on Day 1, while 272, 308 and 993 ng × h/ml on Day 14[1]. Animal Model: Nu/Nu female nude mice (6-8 weeks) bearing human lung cancer cell lines[1]Dosage: 2.5, 5, and 15 mg/kg (SH-1028) and control group (osimertinib, 5 mg/kg) Administration: p.o.; once daily for consecutive 14 days Result: Only induced a moderate tumor growth inhibition in A431 (wild-type EGFR) tumor xenografts, while caused profound and sustained tumor shrinkage in both NCI-H1975 and PC-9 xenograft models with EGFR mutations with 5 mg/kg/day.