Small Molecule Kinase Inhibitors for the Treatment of Brain Cancer.

In addition to each of the factors that govern the identification of a successful oncology drug candidate, drug discovery aimed at treating neurological cancer must also consider the presence of the blood-brain barrier (BBB). The high level of expression of efflux transporters (e.g., P-glycoprotein (P-gp) and breast cancer resistance protein (Bcrp)) at the BBB limits many small molecules from freely reaching the brain, where neurooncologic malignancies reside. Furthermore, many of the targets identified for the potential treatment of central nervous system (CNS) malignancies suggest that kinase inhibitors, capable of penetrating the BBB to reach their target, would be desirable. This Perspective discusses the unmet need for neurooncology treatments, the appeal of kinase targets in this space, and a summary of what is known about free brain penetration of clinical inhibitors of kinases that are of interest for the treatment of brain cancer.