In Vitro: LDN-91946 is inactive against UCH-L3 at 20 μM. LDN-91946 demonstrates no activity against TGase 2, Papain, and Caspase-3 at 40 μM. There is no cytotoxicity when serum-starved Neuro 2A (N2A) cells are treated with LDN-91946 at concentrations as high as 0.1 mM.