Compositions and methods for suppressing endometrial proliferation

A method for treating endometriosis according to an intermittent administration regimen comprising administering to a human female in need of such treatment 2 to 80 mg of a selective progesterone receptor modulator (SPRM) selected from CDB-4124 (21-methoxy-17α-acetoxy-11β-(4-N,N-dimethylaminophenyl)-19-norpregna-4,9-diene-3,20-dione) and 17α-acetoxy-11β-(4-N,N-dimethylaminophenyl)-19-norpregna-4,9-dien-3,20-dione for an administration period during which the SPRM is administered daily consecutively over a period of two to four months, then discontinuing said administration for a period of time sufficient for the female to undergo menstruation, said period of time being at least 32 days and equal to or less than the number of days during which the SPRM was previously administered, then administering 2 to 80 mg of the SPRM daily consecutively over a period of two to four months, then discontinuing said administration for a period of time sufficient for the female to undergo menstruation, said period of time being at least 32 days and equal to or less than the number of days during which the SPRM was previously administered, and repeating this pattern of administration and discontinuation of administration for a sufficient duration to treat the endometriosis, wherein the female is administered a progestin in an amount effective to induce menstruation during each discontinuance period.