MedKoo product information:

GTX-758

Description of GTX-758: GTx-758 is an orally available, nonsteroidal selective estrogen receptor (ER) alpha agonist with potential antineoplastic activity. Upon administration of GTx-758, this agent suppresses the secretion of the gonadotropins follicle-stimulating hormone (FSH) and luteinizing hormone (LH) by the pituitary gland through feedback inhibition. In males, the inhibition of LH secretion prevents the synthesis of androgens, including testosterone, by the testes. This may result in suppressed total serum testosterone to the levels observed in castration. Check for active clinical trials or closed clinical trials using this agent. (NCI Thesaurus).

Current developer:    GTx, Inc.

GTx is developing Capesaris (GTx-758), a selective estrogen receptor (ER) alpha agonist, for the first-line treatment of men with advanced prostate cancer. GTx-758 rapidly suppresses secretion of luteinizing hormone by feedback inhibition on the pituitary, thereby inhibiting the production of androgens by the testes. Capesaris has the potential to achieve medical castration to control the prostate cancer and to prevent bone loss and hot flashes (source: http://www.gtxinc.com/Pipeline/GTx758.aspx?Sid=5)

Clinical trials halted (2/21/2012: According news release on 2/21/2012,  GTx Inc. (GTXI) said the U.S. Food and Drug Administration has halted its clinical trials for Capesaris, a potential advanced prostate cancer and hormonal treatment, due to an increased risk of blood clots.  The biopharmaceutical company said the FDA's clinical hold notification affects its Phase II loading-dose finding clinical trial, Phase IIb maintenance-dose finding clinical trial, and its Phase II clinical trial in men with castration-resistant prostate cancer.  GTx said it found an increased risk of venous thromboembolic events, or blood clots, in subjects treated with 1000 milligrams or more of Capesaris, and it asked the FDA to discuss changes in its clinical development program.  The company has suspended further enrollment and has notified clinical sites to discontinue treatment of subjects.  The company believes it may be able to develop Capesaris at lower doses to treat men with metastatic hormone sensitive prostate cancer or castration-resistant prostate cancer.