Varlitinib (Alternative Names: ARRY-334543; ARRY-543; ASLAN-001; Varlitinib tosylate) is a small molecule based reversible pan-HER inhibitor of EGFR, HER2 and HER4. In response to the binding of various ligands, these kinases undergo heterodimerisation and homodimerization, resulting in activation of numerous growth factor signaling pathways, by inhibiting the activation of the HER receptors via drug, effects such as shrinkage of the tumor and longer survival can be anticipated. In a large variety of cancers, the overexpression and/or constitutive activation of EGFR and HER2 are often observed and frequently correlate with poor clinical prognosis. Licensed from Array BioPharma with global rights for all indications, varlitinib is being developed as first-in-class drug for cholangiocarcinoma, gastric and colorectal cancer, and as best-in-class drug for breast cancer.

PD-153035 is a potent and selective ATP-competitive inhibitor of the epidermal growth factor receptor tyrosine kinase EGFR. PD 153035 shows a potent and selective inhibitory effect on tyrosine phosphorylation induced by EGF in Swiss 3T3 fibroblast and A-431 human epidermoid carcinoma cells. PD153035 shows dose-dependent growth inhibitory effects in cultures of EGF receptor-overexpressing human cancer cell lines (A431, Difi, DU145, MDA-MB-468, and ME180) and in nasopharyngeal carcinoma (NPC) cell lines (NPC-TW01, NPC-TW04, and HONE1). Pretreatment of EGFR inhibitors by 24 hours significantly enhances the cytotoxic effect of doxorubicin, paclitaxel, cisplatin, and 5-fluorouracil in NPCTW04 cells. PD153035 abolishes COX-2 expression induced by the PAR(2)-activating peptide 2-furoyl-LIGRLO-NH(2) (2fLI) in Caco-2 colon cancer cells. In A431 human epidermoid tumors grown as xenografts in immunodeficient nude mice, PD153035 at 80 mg/kg i.p. inhibit EGF receptor tyrosine kinase activity. PD153035 improves glucose tolerance, insulin sensitivity, and signaling and reduces subclinical inflammation in HFD-fed mice.