RIP1 kinase inhibitor 1 strongly suppresses necroptotic cell death and phosphorylation of MLKL(pMLKL) in human colorectal adenocarcinoma HT-29 cells with IC50 of 2 nM and 1.3 nM for nectoptosis and pMLKL) as well as mouse L-cells NCTC 929 (nectoptosis, IC50=15 nM; pMLKL, IC50=2.7 nM).