Thiazolidinediones as therapy for endometriosis: A case series

Background: Current medical therapies for endometriosis result in delayed conception and have not been shown to provide any fertile benefit subsequent to treatment. Thiazolidinediones (TZDs) do not impede conception and have been shown to reduce endometriotic lesions in animal models; however, no studies have been performed in humans. The aim of this study was to provide preliminary data about the effectiveness of a TZD in treating endometriosis-related pain. Methods: Case series of women with endometriosis recruited from the University of Michigan as part of an open-label prospective phase 2a clinical trial. Participants were given rosiglitazone, 4 mg daily, for 6 months. Subjective endometriosis symptoms were assessed using a modified Biberoglu and Behrman symptom severity scale and the McGill pain questionnaire. Results: Two of the 3 patients exhibited improvement in severity of symptoms and pain levels with a concurrent decrease in pain medication, while 1 experienced no change. Rosiglitazone was well tolerated by all patients. Conclusions: Combined with data gathered from studies in rats and nonhuman primates, the results from this study offer positive justification for using TZDs as a well-tolerated treatment for endometriosis that can address pain without impeding ovulation and without the need for add-back therapy.