GTx Incorporated

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GTx, Inc.
FoundedSeptember 24, 1997
HeadquartersMemphis, Tennessee, United States
ProductsEnobosarm Edit this on Wikidata

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 modulator 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]


  1. ^ a b c "GTX, INC. - FORM S-1/A". Gtx via SEC Edgar. 22 December 2003.
  2. ^ Pritchard, Carolyn (2 February 2004). "GTX prices IPO of 5.4 mln shares at $14.50 each". MarketWatch.
  3. ^ Hennessey, Raymond (4 February 2004). "With a Busy IPO Week Ahead, Mixed Reviews for 3 Offerings". Wall Street Journal.
  4. ^ Carroll, John (2 November 2009). "GTx shares blitzed by FDA's toremifene rejection". FierceBiotech.
  5. ^ Carroll, John (2 March 2011). "Ipsen bows out of troubled toremifene pact with GTx". FierceBiotech.
  6. ^ "Press release: GTx Announces Sale of Fareston". GTx via FierceBiotech. 2 October 2012.
  7. ^ Nagle, Mike (7 November 2007). "Merck flexes muscle with GTx deal". Outsourcing Pharma.
  8. ^ Swanekamp, Kelsey (15 March 2010). "Merck And GTx Go Their Separate Ways". Forbes.
  9. ^ "Enobosarm fails endpoints in Ph III study". The Pharma Letter. 20 August 2013.
  10. ^ Carroll, John (2 October 2013). "Struggling GTx axes 53 staffers in restructuring after PhIII failures". FierceBiotech.
  11. ^ a b Sheffield, Michael (April 4, 2014). "Steiner resigns from GTx". Memphis Business Journal.
  12. ^ Garde, Damian (4 April 2014). "GTx's CEO finds the door as the company moves on from a PhIII failure". FierceBiotech.
  13. ^ "GTx begins Phase II trial of enobosarm to treat women with stress urinary incontinence - Drug Development Technology". Drug Development Technology. 14 January 2016.
  14. ^ Therapeutics, Oncternal (2019-06-10). "Oncternal Therapeutics Completes Reverse Merger with GTx, Inc". GlobeNewswire News Room. Retrieved 2020-03-19.