RIPA-56 shows efficient inhibition of RIP1 kinase activity, with an IC50 of 13 nM. It showed no inhibition of RIP3 kinase activity at a 10 µM concentration. RIPA-56 does not inhibit IDO activity at a concentration of 200 µM, which represents an estimated 10,000-fold selectivity window based on the RIP1 ADP-Glo activity of 13 nM.
