The present invention relates to the compound of formula (I), <;IMAGE>; (I) also known as 17 beta -N-(2,5-bis(Trifluoromethyl))phenylcarbamoyl-4-aza-5 alpha -androst-1-en-3-one, solvates thereof, its preparation, intermediates used in its preparation, pharmaceutical formulations thereof and its use in the treatment of androgen responsive and mediated diseases.