The present invention relates to metal salts of 2-[3-[(3R)-3-[[2-chloro-3-(trifluoromethyl)phenyl]methyl-(2,2-diphenylethyl)amino]butoxy]phenyl]acetic acid which exhibit improved physical properties and stability. The invention also relates to pharmaceutical compositions including an effective amount of the metal salts, as well as methods of treating cancer including administration of a pharmaceutical composition including a salt of the invention to a subject in need thereof.