Necroptosis is a regulated caspase-independent cell death mechanism that results in morphological features resembling necrosis. Serine/threonine kinase activity of the death domain receptor-associated molecule RIP1 is thought to be essential for Fas ligand-induced and tumor necrosis factor-α (TNF-α) induced necrosis. Necrostatin-5 is a selective allosteric inhibitor of RIP1 kinase that prevents the death of TNF-α-treated FADD-deficient Jurkat cells with an EC50 value of 240 nM.