A Randomized, Double-blind, Placebo-controlled, Phase 2 Study to Assess the Efficacy, Safety, and Dose-Response Relationship of ASP1707 in Subjects with Endometriosis Associated Pelvic Pain for 12 Weeks, Followed by a 12-Week Double-blind Extension without Placebo Control, Including a 24-Week Open-Label Leuprorelin Acetate Treatment Group for Bone Mineral Density Assessment |