Editor’s Choice

Model-Based Dose Selection for Intravaginal Ring Formulations Releasing Anastrozole and Levonorgestrel Intended for the Treatment of Endometriosis Symptoms

Endometriosis affects many young women, causing pain, dysmenorrhea, and other symptoms that affect the quality of life. Traditional therapy has attempted to reduce estrogen effects through suppression of systemic endogenous production. However, estrogens place an important role in the body including improving bone mineral density reducing fracture risk. Newer therapies have targeted the production of estrogens locally at the site of endometriosis to reduce systemic adverse effects. This month’s Editor’s Choice article examines the use of an intravaginal ring containing the aromatase inhibitor anastrozole (to reduce local estrogen production) and the progestin, levonogestrel (for treatment), combined with model-based dose selection to minimize follicle production and thus, reduce the risk of treatment induced ovarian cysts. It is estimated that the overall lifetime risk of endometriosis in women could be as high as 2.2%. Thus, more effective and less toxic treatments are needed.

-- Isabel Reinecke, Marcus-Hillert Schultze-Mosgau, et al.,