Ponatinib

Ponatinib is a multi-target kinase inhibitor. Its primary cellular target is the Bcr-Abl tyrosine kinase protein which is constitutively active and promotes the progression of CML. This protein arises from the fused Bcr and Abl gene- what is commonly known as the Philadelphia chromosome. Ponatinib is unique in that it is especially useful in the treatment of resistant CML because it inhibits the tyrosine kinase activity of Abl and T315I mutant kinases. The T315I mutation confers resistance in cells as it prevents other Bcr-Abl inhibitors from binding to the Abl kinase. Other targets that ponatinib inhibits are members of the VEGFR, PDGFR, FGFR, EPH receptors and SRC families of kinases, and KIT, RET, TIE2, and FLT3. A decrease in tumour size expressing native or T315I mutant BCR-ABL have been observed in rats.