3-SUBSTITUTED-D-HOMO-1,3,5,(10)-ESTRATRIENE DERIVATIVES

Estratriene derivatives of the following formula have a powerful inhibitory effect on estrone sulfatase and are hence useful for the prophylaxis or treatment of diseases caused by estrogens, such as breast cancer, uterine cancer, ovarian cancer, endometriosis, adenomyosis uteri and mastopathy. Wherein one of A and B represents C=O or CH2 and the other represents O or NH; and R represents -SO2NR1R2 or -PO(OM)2 in which R1 and R2 each independently represent a hydrogen atom or a lower alkyl group and M represents a hydrogen atom or an alkali metal; provided that, when one of A and B represents NH, the other represents C=O.