The invention is directed to a pharmaceutical composition comprising a progesterone receptor antagonist namely (11β,17β)-17-Hydroxy-11-[4-(methylsulphonyl)phenyl]-17-(pentafluoroethyl)estra-4,9-dien-3-one at the dosage of about 0.5 to 5 mg and more particularly 2 mg. Additionally, the invention is directed to the use of the novel pharmaceutical composition for treatment of and/or prophylaxis of gynaecological diseases, such as fibroids of the uterus (myomas, uterine leiomyoma), endometriosis or excessive menstrual bleeds, and method for obtaining such composition and oral dosage form.