The present invention relates to (2S)-2-({3'-Chloro-4'-[(2,2-dimethylpyrrolidin-1-yl) carbonyl]-5-fluorobiphenyl-2-yl}oxy)propanoic acid and (2R)-2-({3'-chloro-4'-[(2,2-dimethylpyrrolidin-1-yl) carbonyl]-5-fluorobiphenyl-2-yl}oxy)propanoic acid of formula (I), and crystalline forms and pharmaceutically acceptable salts thereof useful as pharmaceuticals.