A pharmaceutically acceptable salt comprising 3-[3-tert-butylsulfanyl-1-[4-(6-ethoxy-pyridin-3-yl)-benzyl]-5-(5-methyl-pyridin-2-ylmethoxy)-1H-indol-2-yl]-2,2-dimethyl-propionate as the anion and a cation selected from Na+, K+, Li+, Ca2+, NH4+, the protonated form of dicyclohexylamine, the protonated form of N-methyl-D-glucamine, the protonated form of tris(hydroxymethyl)methylamine, the protonated form of arginine, and the protonated form of lysine is disclosed, along with formulations and methods of using the same.