Phase 3 Study of Dienogest for the Treatment of Endometriosis in Chinese Patients

Inclusion Criteria: * Women between 18 and 45 years of age, inclusive * Women with endometriosis confirmed by laparoscopy or laparotomy within ten years but no later than 2 weeks before the Screening Visit * A score of at least 30 on a 100 mm visual analog scale (VAS) for endometriosis-associated pelvic pain at Screening Visit and Baseline Visit * Good general health (except for findings related to endometriosis, with or without infertility), as evidenced by medical history and complete physical and gynecological examination * Willingness to use a barrier method of contraception is required Exclusion Criteria: * Pregnancy or lactation (less than three months since delivery, abortion, or lactation before start of treatment) * Wish for pregnancy within intended treatment period * Before menarche or after menopause * Amenorrhea (more than three consecutive months in the six months before screening) * Undiagnosed abnormal genital bleeding * Previous/use of hormonal agents * Any disease or condition that may worsen under hormonal treatment * Signs and/or symptoms of therapy-resistant endometriosis despite more than one prior attempt at drug treatment or surgical therapy * Need for primary surgical treatment of endometriosis * Regular use of pain medication due to other underlying diseases * Contra-indication for the supportive analgesic medication (ibuprofen)