Ibrutinib is a first-in-class, potent, orally administered covalent inhibitor of Bruton's tyrosine kinase (BTK). Inhibition of BTK blocks downstream B-cell receptor (BCR) signaling pathways and thus prevents B-cell proliferation. In vitro, ibrutinib inhibits purified BTK and selected members of the kinase family with 10-fold specificity compared with non-BTK kinases. Phase 1 and 2 studies of ibrutinib in B-cell malignancies demonstrate modest toxicity and significant single agent activity in a variety of B-cell malignancies, including NHL.
