Described herein is the DP2 antagonist [2′-(3-benzyl-1-ethyl-ureidomethyl)-6-methoxy-4′-trifluoromethyl-biphenyl-3-yl]-acetic acid, or a pharmaceutically acceptable salt thereof. Also described are methods of preparing the DP2 antagonist, or a pharmaceutically acceptable salt thereof. Also described herein are pharmaceutical compositions suitable for administration to a mammal that include the DP2 antagonist, or a pharmaceutically acceptable salt thereof, and methods of using such pharmaceutical compositions for treating respiratory diseases or conditions, allergic diseases or conditions, inflammatory diseases or conditions, as well as other prostaglandin D2-dependent or prostaglandin D2-mediated diseases or conditions.