Ibrutinib (Ibr)

Ibrutinib is an anticancer drug targeting B-cell malignancies.  In preclinical studies on chronic lymphocytic leukemia (CLL) cells, ibrutinib has been reported to promote apoptosis, inhibit proliferation, and also prevent CLL cells from responding to survival stimuli provided by the microenvironment. Additionally, ibrutinib inhibited proliferation of CLL cells in vitro, effectively blocking survival signals provided externally to CLL cells from the microenvironment including soluble factors (CD40L, BAFF, IL-6, IL-4, and TNF-α), fibronectin engagement and stromal cell contact. Ibrutinib has been reported to reduce CLL cell chemotaxis towards the chemokines CXCL12 and CXCL13, and inhibit cellular adhesion following stimulation at the B cell receptor. Together, these data are consistent with a mechanistic model whereby ibrutinib blocks BCR signaling.