Letrozole in the Treatment of Severe and Recurrent Endometriosis

Inclusion Criteria Premenopausal women > 18 years of age. Laparoscopic and Histologically confirmed diagnosis of moderate or severe endometriosis according rASRM-Score III and IV BMI less than 40 kg/m². Patient is sexually abstinent or using mechanical (condoms, diaphragms) or sterilization methods of contraception and is willing to continue using them throughout the study. Patient is willing and able to comply with study requirements. Written informed consent. Exclusion Criteria Endometriosis stage I-II acc. according to rASRM Women with other causes of chronic pelvic pain including infectious, gastrointestinal, musculoskeletal, neurologic or psychiatric. Significant abnormalities in the physical or laboratory examination including renal and liver function more than twice the normal range. Patient desires pregnancy for the duration of the study, is pregnant or breast feeding. GnRH therapy during the last 6 months Use of hormonal contraception, selective estrogen receptor modulators, progestins, estrogens, steroids, or ovulation induction in the 4 weeks prior to inclusion into the study. Untreated abnormal pap smear or other gynecologic condition. History of venous thrombosis events including deep vein thrombosis, pulmonary embolism, or retinal vein thrombosis. History of stroke, complicated migraine, or documented transient ischemic attack. Known hypersensitivity to any ingredient of the study medication. Treatment with other aromatase inhibitors Other investigational drugs within the past 30 days and the concomitant use of investigational drugs. History of non-compliance to medical regimens, and patients who are considered potentially unreliable. Additional protocol-defined inclusion / exclusion criteria may apply