GTx, Inc. Collaborates with Tessera, Inc. to Develop a Diagnostic Test to Detect High Grade PIN

Memphis, Tenn.—July 27, 2004— GTx, Inc., (Nasdaq: GTXI) a biopharmaceutical company dedicated to the discovery, development and commercialization of therapeutics primarily related to the treatment of serious men's health conditions, announced today that it has entered into a collaboration with Tessera, Inc. Under the terms of the agreement GTx will provide clinical samples from its completed Phase IIb clinical trial program which evaluated ACAPODENE™ (toremifene citrate) for the reduction in the incidence of prostate cancer in men with high grade prostatic intraepithelial neoplasia (PIN), a premalignant lesion that has the potential to progress to prostate cancer. ACAPODENE™ is a nonsteroidal SERM (selective estrogen receptor modulator) that appears to block the estrogen's unwanted actions on the prostate.

The collaboration will focus on the development of a commercial blood or urine test which could detect high grade PIN in the millions of men who unknowingly harbor this precancerous lesion of the prostate or who may develop prostate cancer.

"Currently, there is an estimated 9.4 million men in the U.S. alone that unknowingly harbor high grade PIN, but on average, only 115,000 of these men will be diagnosed each year," says Mitchell Steiner, M.D., CEO of GTx. "When a blood or serum test to detect PIN is discovered, we believe ACAPODENE can provide this large number of men who are at high risk for developing prostate cancer the opportunity to reduce the risk that they will develop this disease."

Dr. Robert Masterson, President/CEO of Tessera, states, "The partnership with GTx is to evaluate the use of Tessera's ProstaMark» EPCA (Early Prostate Cancer Antigen) to identify patients with PIN lesions and/or early stage prostate cancer. Theranostics, which is the use of a diagnostic with a disease therapy, is the wave of the future in healthcare and specifically in cancer treatment." Dr. Masterson also comments, "Tessera is very excited with the opportunity to work closely with Dr. Steiner and the extremely qualified and talented group of scientists at GTx, Inc."

About high grade PIN
High grade PIN has been established as a premalignant lesion of the prostate that has a high potential to progress to invasive prostate cancer. Men who harbor PIN are thought to be at greater risk for developing prostate cancer within ten years. Unfortunately, today high grade PIN diagnosis is only detected when men are biopsied. GTx sees a great need for a diagnostic blood or urine marker that will provide a simple, but effective way of detecting PIN and/or prostate cancer. This year in the United States, approximately 1,300,000 prostate biopsies will be performed to detect over 230,000 new cases of prostate cancer. High grade PIN is found in an average of 9% of prostate biopsies which represents an estimated 115,000 new cases of high grade PIN diagnosed each year. Patients who are found to have high grade PIN are at high risk of prostate cancer with up to 37% of patients being later diagnosed with prostate cancer within 1 year.

High grade PIN clinical development overview
On June 4, 2004, GTx announced positive Phase IIb clinical trial results for its lead program ACAPODENE™. The ACAPODENE™ Phase IIb study was a double-blind, placebo-controlled, one-year clinical trial in 514 men with high grade PIN who are at high risk for prostate cancer. The primary endpoint was the incidence of prostate cancer. This is the largest prospective study to determine the natural history of patients with high grade PIN and supports the premise that high grade PIN patients have a high risk for developing prostate cancer. The study also suggests that ACAPODENE™ may be a highly effective agent in preventing prostate cancer. Specifically, the trial demonstrated that ACAPODENE™ 20mg can produce a clinically significant reduction of prostate cancer cumulative risk over one year. Patients treated with ACAPODENE™ 20mg had a lower incidence of prostate cancer compared to placebo, 24.4% vs. 31.2% respectively. Furthermore, the data appears to suggest that the longer men with high grade PIN are treated with ACAPODENE™, the greater the likelihood that their risk of prostate cancer is reduced. The study revealed that patients who were treated with ACAPODENE™ for the entire 12 months had a 48% reduction in prostate cancer incidence. The study also demonstrated that ACAPODENE™ was well tolerated by patients compared to placebo. Following discussions with the Food and Drug Administration (FDA), GTx plans to initiate a pivotal Phase III clinical trial to confirm these positive findings.

About ACAPODENE™
Toremifene is a nonsteroidal SERM, a small molecule that binds and selectively modulates the estrogen receptor. SERMs have been shown to block estrogen receptors in the prostate. GTx has licensed the right to develop, market and distribute toremifene citrate, the active ingredient of ACAPODENE™ tablets, worldwide in the field of prevention and treatment of prostate cancer from Orion Corporation, Finland.

About GTx
GTx, Inc. is a biopharmaceutical company dedicated to the discovery, development and commercialization of therapeutics primarily related to the treatment of serious men's health conditions. GTx's drug discovery and development programs are focused on small molecules that selectively modulate the effects of estrogens and androgens. GTx has two clinical programs: In the first clinical program, GTx is developing ACAPODENE™, its most advanced product candidate for two separate indications: (1) a pivotal Phase III clinical trial for the treatment of serious side effects of advanced prostate cancer therapy and (2) its completed Phase IIb clinical trial for the reduction in the incidence of prostate cancer in high risk men with precancerous prostate lesions. In the second clinical program, GTx is developing andarine, and other specified backup compounds, with its partner, Ortho Biotech Products, L.P., a subsidiary of Johnson & Johnson. Andarine will be entering a planned Phase II clinical trial this year. GTx retains all rights to the discovery, development, and commercialization of the rest of its SARM program including its other specific product candidates ostarine, prostarine and andromustine.

About Tessera, Inc.
Tessera, Inc. (Seattle, WA) was incorporated in 2000 by Dr. Robert Masterson and H. Raymond Cairncross as a biomedical company committed to the discovery and commercialization of effective products for the early detection of prostate and colon (or colorectal) cancer. Through its exclusive, worldwide licensing arrangements with both Johns Hopkins University School of Medicine and the University of Pittsburgh Department of Urology, Tessera has obtained rights to the use and development to date of more than 60 protein markers not only for the early diagnosis of these often lethal cancers but also for drug screening and "in vivo" imaging. ProstaMark™ EPCA is the first of potentially many early detection products to be developed and commercialized.

Forward Looking Statements
This press release contains forward-looking statements, including, without limitation, statements related to GTx's current and anticipated clinical trials of ACAPODENE™ and its other research and development programs. These forward-looking statements are based upon GTx's current expectations. Forward-looking statements involve risks and uncertainties. GTx's actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation, risks that neither GTx nor its collaboration partners will not be able to commercialize its product candidates if preclinical studies do not produce successful results or clinical trials do not demonstrate safety and efficacy in humans; if third parties do not manufacture the Company's product candidates in sufficient quantities and at an acceptable cost, clinical development and commercialization of its product candidates would be delayed; use of third-party manufacturers may increase the risk that the Company will not have adequate supplies of its product candidates; if third parties on whom the Company relies do not perform as contractually required or expected, the Company may not be able to obtain regulatory approval for or commercialize its product candidates; the Company is dependent upon collaborative arrangements to complete the development and commercialization of some of its product candidates, and these collaborative arrangements may place the development of its product candidates outside its control, may require it to relinquish important rights or may otherwise be on terms unfavorable to the Company; and if the Company is not able to obtain required regulatory approvals, the Company will not be able to commercialize its product candidates. You should not place undue reliance on these forward looking statements, which apply only as of the date of the press release. The annual report filed on Form 10-K with the U.S. Securities and Exchange Commission on March 26, 2004 contains under the heading "Additional Factors That Might Affect Future Results" a more comprehensive description of these and other risks to which GTx is subject. GTx expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in its expectations with regard thereto or any change in events, conditions or circumstances on which any such statements are based.