An orally bioavailable, small-molecule focal adhesion kinase (FAK) inhibitor with potential antiangiogenic and antineoplastic activities. Defactinib inhibits FAK, which may prevent the integrin-mediated activation of several downstream signal transduction pathways, including those involving RAS/MEK/ERK and PI3K/Akt, thus inhibiting tumor cell migration, proliferation, survival, and tumor angiogenesis. The tyrosine kinase FAK, a signal transducer for integrins, is normally activated by binding to integrins in the extracellular matrix (ECM) but may be upregulated and constitutively activated in various tumor cell types. Check for active clinical trials using this agent. (NCI Thesaurus)