Described herein are amorphous and crystalline forms of the androgen receptor modulator 4-[7-(6-cyano-5-trifluoromethylpyridin-3-yl)-8-oxo-6-thioxo-5,7-diazaspiro[3.4]oct-5-yl]-2-fluoro-N-methylbenzamide. Also described are pharmaceutical compositions suitable for administration to a mammal that include the androgen receptor modulator, and methods of using the androgen receptor modulator, alone and in combination with other compounds, for treating diseases or conditions that are associated with androgen receptor activity.本發明闡述非晶型及晶型雄性激素受體調節劑4-[7-(6-氰基-5-三氟甲基吡啶-3-基)-8-側氧基-6-硫酮基-5,7-二氮雜螺[3.4]辛-5-基]-2-氟-N-甲基苯甲醯胺。本發明亦闡述包括該雄性激素受體調節劑且適於投與哺乳動物之醫藥組合物,以及單獨或與其他化合物組合使用該雄性激素受體調節劑治療與雄性激素受體活性相關之疾病或病況之方法。