Mubritinib, also known as TAK-165, is a protein kinase inhibitor which was under development by Takeda for the treatment of cancer. It completed phase I clinical trials (may be discontinued since 2008). Mubritinib(TAK 165) is a potent EGFR, HER2 and p34cdc2 inhibitor with IC50 of 6 nM and 0.2 ÂM, respectively. Mubritinib(TAK 165) also inhibits p33cdk2 and p33cdk5. Mubritinib(TAK 165) displays > 4000-fold selectivity over EGFR, FGFR, PDGFR, JAK1 and Src. Mubritinib(TAK 165) exhibits potent antiproliferative effects in ErbB2-overexpressing cancer cell lines (IC50 = 5 nM in BT474 breast cancer cells) and significantly inhibits bladder, breast and prostate cancer xenograft growth in vivo.