Definition

An orally bioavailable inhibitor and specific dimer breaker of the serine/threonine-protein kinase B-raf (BRAF) protein, with potential antineoplastic activity. Upon oral administration, plixorafenib selectively binds to and inhibits the activity of dimeric BRAF mutants, including BRAF fusions and splice variants, and BRAFV600 monomers, while sparing RAF function in normal cells. This inhibits the proliferation of tumor cells which express these mutated forms of BRAF. BRAF, a member of the raf family of serine/threonine protein kinases, plays a role in the regulation of mitogen-activated protein kinase (MAPK) and extracellular signal-regulated kinase (ERK) signaling pathways, which may be constitutively activated due to BRAF gene mutations. Mutated forms and fusions of BRAF are associated with a number of neoplastic diseases.