GTx Incorporated

GTx, Inc. is a pharmaceutical company that is working on drugs in the selective estrogen receptor modulator (SERM) and selective androgen receptor modulator (SARM) classes. Its drugs in development include enobosarm (ostarine) and GTx-758.

The company was founded in Memphis in 1997 by Mitch Steiner and Marc S. Hanover.[1] The company was originally called Genotherapeutics, changed its name to GTx, Inc. in 2001, and reincorporated in Delaware in 2003.[1] The company licensed toremifene from Orion Corporation, and licensed andarine, enobosarm and prostarine from the University of Tennessee Research Foundation; the SARM compounds from Tennessee had been invented by Karen Veverka and Michael Whitt and each later joined the company.[1] The company held its IPO in February 2004.[2][3]

In 2006 GTx signed a partnership with Ipsen to develop toremifene, a selective estrogen receptor modulatorm to prevent prostate cancer and to prevent bone loss in men with prostate cancer; the FDA rejected the application to market the drug for this use in 2009, and Ipsen terminated the arrangement in 2011.[4][5] In 2012 GTx sold its rights to toremifene to ProStrakan, a subsidiary of Kyowa Hakko Kirin, for around $19 million, and terminated its agreement with Orion.[6]

By 2007 enobosarm was in a Phase II trial, and that year Gtx signed an exclusive license agreement for its SARM program with Merck; Merck bought $30M in GtX stock, paid an upfront fee of $40M, and agreed to fund $15M in research over the next three years. The agreement also included royalties on any product brought to market and around $400M in biodollars.[7] The companies ended the deal in 2010.[8]

In August 2013 GTx announced that enobosarm had failed in two Phase III clinical trials to treat wasting in people with lung cancer.[9] In October 2013 the company laid off around 60% of its 88-person workforce,[10] and Steiner resigned 6 months later.[11] The company had invested around $35 million in the development of the drug.[11] The company said at that time that is planned to pursue approval of enobosarm in Europe; the company was also still developing GTx-758 for castration-resistant prostate cancer.[12]

In 2016 GTx began Phase II trials, to see if enosobarm might be effective to treat stress urinary incontinence in women.[13]

In June 2019, GTx combined with Oncternal Therapeutics in a reverse merger. The combined company will operate under the name Oncternal Therapeutics, Inc.[14]