The present invention relates to a substantially a solid form of 3-(6-(1-(2,2-difluorobenzo[d][1,3]dioxol-5-yl)cyclopropanecarboxamido)-3-methylpyridin-2-yl)benzoic acid (Compound 1, Solvate Form A and Compound 1, HCl Salt Form A), processes for making such forms, pharmaceutical compositions thereof, and methods of treatment therewith.