The invention provides compounds for use as medicaments, which act by inhibiting CYP17A1 and CYP19A1 enzymes. The compounds have particular application in the treatment of cancer especially prostate cancer and breast cancer. The compounds have the formula: [Chem. 1] wherein: R is independently selected from the group consisting of optionally substituted arylamide; optionally substituted alkylarylamide; optionally substituted aryl carboxamide; optionally substituted cyanopiperidine; optionally substituted oxopiperidine; optionally substituted N-(pyridin-3-yl); optionally substituted pyridin-3-yl; optionally substituted pyrazole-4-carboxamide; optionally substituted pyrimidin-4-ylcarboxamide; optionally substituted pyrimidin-4-ylcarboxamide; optionally substituted 1H-pyrrol-2-ylcarboxamide; optionally substituted morpholin carboxamide; optionally substituted 1H-indazol-3-ylcarboxamide; optionally substituted 5-cyanopiperidin-3-ylcarboxamide; optionally substituted quinolin-7-yl; optionally substituted pyrazin-2-ylcarboxamide; optionally substituted 1H-1,3-benzodiazole-6-carboxamide; and optionally substituted 3-oxo-3,4-dihydro-2H-1,4-benzoxazin-7-ylcarboxamide; Each R1, R2, R3, R4, R5 is independently selected from the group consisting of H; OH; a halogen atom; OCH3; and NH2; and X is independently selected from the group consisting of O, H and OH. Some of the compounds are claimed per se and the invention also encompasses pharmaceutically acceptable salts, solvates, hydrates, primary metabolites and prodrugs thereof.