Colony stimulating factor 1 (CSF1) is a cytokine that is involved in the recruitment and activation of tissue macrophages. It exerts these effects by binding to its corresponding receptor tyrosine kinase, the cFMS/CSF1 receptor (CSF1R). Pexidartinib is a brain-penetrant inhibitor of CSF1R, as well as c-Kit and FLT3 (IC50s = 20, 10, and 160 nM in vitro, respectively).1 It has been used in combination with paclitaxel to block macrophage recruitment in mammary tumor-bearing mice, thus slowing primary tumor development and metastasis.1 Pexidartinib has also been used to block microglial stimulation of glioblastoma invasion in both cell culture and a mouse model of glioblastoma multiforme.2
1.DeNardo, D.G., Brennan, D.J., Rexhepaj, E., et al.Leukocyte complexity predicts breast cancer survival and functionally regulates response to chemotherapyCancer Discov.1(1)54-67(2011) 2.Coniglio, S.H., Eugenin, E., Dobrenis, K., et al.Microglial stimulation of glioblastoma invasion involves epidermal growth factor receptor (EGFR) and colony stimulating factor 1 receptor (CSF-1R) signalingMol. Med.18(1)519-527(2012)