Varlitinib (ARRY-334543; ASLAN001) is a potent, reversible, small molecule pan-EGFR inhibitor with IC50s of 7, 2, 4 nM for HER1, HER2 and HER4, respectively.
In cell-based assays using tumor cells that over-express EGFR (A431) or ErbB-2 (BT474), Varlitinib (ARRY-334543) potently inhibits substrate phosphorylation. Varlitinib is shown to be highly selective for EGFR/ErbB-2, and does not show any significant activity when screened against a panel of 104 kinases[2].
Varlitinib treatment potently inhibits tumor growth with complete tumor regression observed at dosing of 100 mg/kg twice a day. After five days of Varlitinib treatment, phosphorylation of HER1-3, RAS/RAF/MEK/MAPK, p70S6K, S6 ribosomal, 4EBP1, Cdk-2, Cdc-2 and retinoblastoma are strongly inhibited. Varlitinib treatment results in a significant reduction in survivin and a concomittant increase in Caspase 3 cleavage products[1]. In murine xenograft models, Varlitinib (ARRY-334543) demonstrates significant dose-related (25, 50, 100 mg/kg) tumor growth inhibition in A431-derived tumors when administered orally, twice a day, for 21 days[2].
References:
[1]. Hsieh C, et al. Varlitinib to demonstrate anti-tumour efficacy in patient-derived hepatocellular carcinoma xenograft models. Journal of Clinical Oncology 34, no. 15_suppl
[2]. Miknis G, et al. ARRY-334543, A potent, orally active small molecule inhibitor of EGFR and ErbB-2.Proc Amer Assoc Cancer Res, Volume 46, 2005