The pharmacodynamic endpoint of percentage of subjects with suppressed estradiol level (less than 20 pg/mL) on cycle day 29 is the primary endpoint of the study.

Objectives of this study: 1. To determine efficacy and pharmacodynamic effects of various dosing regimens of Ovarest® (within the 60-mg - 120 mg daily dosing range) in women with endometriosis. 2. To determine a minimally effective daily dosing regimen of Ovarest® with pharmacodynamic effects at least comparable to the historical data for marketed Lupron Depot formulations and for GnRH antagonists indicated for the treatment of endometriosis. 3. To evaluate safety and tolerability of the long-term administration of leuprolide within the targeted daily dosing range in women with endometriosis. The most important goal of this study is to provide adequate dose-response data for the suppression of estradiol (E2) levels below the menopausal threshold of 20 pg/mL. Results of this study in conjunction of Enteris proprietary PK data will support further development of Leuprolide Acetate Oral Tablet for the treatment of reproductive disorders, particularly endometriosis. Another reason for this trial is to support a comparative evaluation of the PD effects across the QD and BID regimens delivering the same overall dose of Ovarest