GTx Announces That Ostarine Achieved Primary Endpoint Of Lean Body Mass And A Secondary Endpoint Of Improved Functional Performance

GTx, Inc. (Nasdaq:
GTXI), the Men's Health Biotech Company, today announced that ostarine, a
first-in-class selective androgen receptor modulator (SARM), met its
primary endpoint in a Phase II proof of concept double blind, randomized,
placebo controlled clinical trial in 120 subjects (60 elderly men and 60
postmenopausal women). Without a prescribed diet or exercise regimen, all
subjects treated with ostarine had a dose dependent increase in total lean
body mass (muscle), with the 3 mg cohort achieving an increase of 1.3 kg
compared to baseline and 1.4 kg compared to placebo (p







Secondary endpoints: performance, fat mass, bone mineral density, and
bone turnover markers


-- In a stair climb functional performance test that measured speed
(time to completion) and power exerted (watts), subjects treated with
a 3 mg dose of ostarine demonstrated on average a 15.5% faster time
to completion (p=0.006) and exerted on average 25.5% more power
(p=0.005) than subjects receiving placebo.


-- Total tissue percent fat decreased compared to placebo in a dose
dependent fashion and achieved statistical significance at the 1 mg
dose (p=0.02) and 3 mg dose (p=0.006) of ostarine. Total fat mass was
lower in subjects receiving either the 3 mg or 1 mg ostarine dose,
although not at a statistically significant level (p = 0.08 for both
doses). For subjects receiving the 3 mg ostarine dose, total fat on
average declined 0.6 kg compared to placebo. The site of fat loss
differed among male and female subjects, with males losing fat
primarily from the trunk and abdomen, and females losing fat
primarily from the thighs and legs.


-- In this short trial, ostarine had no apparent effect on bone mineral
density, and bone turnover markers results were mixed. In preclinical
in vitro and in vivo models, ostarine demonstrated both anabolic and
antiresorptive activity on bone. A longer clinical study is necessary
to demonstrate the actual effects of ostarine on bone.



Safety


-- Ostarine continued to demonstrate a favorable safety profile, with no
serious adverse events reported.


-- At the end of three months, no subject had clinically meaningful
levels in liver enzyme tests. However, one female discontinued the
study per protocol due to elevated liver enzymes which returned to
baseline.


-- Ostarine treatment resulted in a dose dependent decrease in both LDL
and HDL cholesterol levels, with the average LDL/HDL ratio for all
doses tested remaining in the low cardiovascular risk category.



Selectivity


-- Ostarine treatment resulted in no apparent effect on serum PSA
(prostate), sebum production (skin and hair), or serum LH
(pituitary).



"The use of anabolic agents has previously been limited because of
concerns over unwanted androgenic and steroidal side effects and oral
bioavailability," said Mitchell S. Steiner, MD, CEO of GTx. "Ostarine's
safety, tissue selectivity profile, and efficacy results demonstrated in
our Phase II clinical trial, combined with oral dosing, distinguish this
drug candidate from existing anabolic steroids and testosterone analogues.
This opens the door for its potential use in both males and females in a
multitude of diseases, including cancer cachexia, end stage renal disease
muscle wasting, frailty and osteoporosis."



GTx recently conducted discussions with various divisions of the United
States Food & Drug Administration to investigate the required regulatory
pathways for several indications under consideration for ostarine's ongoing
clinical development. With more clarity regarding the required regulatory
pathway and with proof of concept Phase II clinical data, GTx has selected
cancer cachexia as the initial acute indication for ostarine development.
GTx plans to initiate a Phase IIb ostarine clinical trial for cancer
cachexia by the summer of 2007.



Cachexia, or muscle wasting, is a serious result of many cancers,
causing selective muscle loss, fatigue, and deteriorating quality of life
which adversely impacts response to treatment and overall survival. Cancer
cachexia has been identified as one of the two most frequent and
devastating problems affecting individuals with advanced malignancies. It
has been estimated that a third of the approximately 1.3 million patients
diagnosed with cancer in the United States each year will suffer from
cancer cachexia. A drug with the ability to increase lean body mass and
improve functional performance would address significant unmet needs for
the millions of patients living with cancer.



GTx also intends to evaluate the ability of ostarine to treat chronic
disease indications including end stage renal disease muscle wasting,
frailty and osteoporosis.



Collaboration with Ortho Biotech for andarine



GTx has reacquired full rights to develop and commercialize andarine
and all backup compounds previously licensed to Ortho Biotech Products,
L.P., a subsidiary of Johnson & Johnson (Ortho Biotech), through a Joint
Collaboration and License Agreement executed between GTx and Ortho Biotech
in March 2004, which has been terminated by mutual agreement of the
parties. GTx now has full ownership and control of its SARM portfolio.



"With GTx's reacquisition of all rights to andarine, we are now free to
pursue any indication for ostarine, including cancer cachexia, without a
concern that andarine could become a potential competitor," said Dr.
Steiner. "Having positive ostarine proof of concept data and the full
rights to all of our SARMs, we are now in position to maximize the value of
our SARM program through clinical development and potential partnerships."



In the fourth quarter 2006, GTx expects to recognize collaboration
revenue of approximately $3.3 million, which represents the unamortized
balance of the upfront licensing fee paid by Ortho Biotech to GTx in April
2004.



Conference Call



GTx will host a conference call and webcast this morning at 9:00 a.m.
EST. To listen to the conference call, please dial:



-- 866-202-4367 from the United States and Canada or



-- 617-213-8845 (International)



The access code for the call is 32056343.



A playback of the call will be available beginning today at 11:00 a.m.,
Eastern Time through December 22, and may be accessed by dialing:



-- 888-286-8010 from the United States and Canada or



-- 617-801-6888 (International)



The reservation number for the replay is 89704161.



Additionally, you may access the live and subsequently archived webcast
of the conference call from the Investor Relations section of the company's
website at gtxinc.



About GTx



GTx, headquartered in Memphis, Tenn., is a biopharmaceutical company
dedicated to the discovery, development and commercialization of
therapeutics for cancer and serious conditions related to men's health.
GTx's lead drug discovery and development programs are focused on small
molecules that selectively modulate the effects of estrogens and androgens.
GTx is developing ACAPODENE(R) (toremifene citrate), a selective estrogen
receptor modulator, or SERM, in two separate clinical programs in men:
first, a pivotal Phase III clinical trial for the treatment of serious side
effects of androgen deprivation therapy for advanced prostate cancer, and
second, a pivotal Phase III clinical trial for the prevention of prostate
cancer in high risk men with high grade prostatic intraepithelial
neoplasia, or PIN. GTx has licensed to Ipsen Limited exclusive rights in
Europe to develop and commercialize ACAPODENE(R). GTx also is developing
ostarine, a first-in-class selective androgen receptor modulator, or SARM.
GTx believes that ostarine has the potential to treat a variety of
indications, including cancer cachexia, end stage renal disease muscle
wasting, frailty and osteoporosis. GTx plans to initiate a Phase IIb
ostarine clinical trial for cancer cachexia by the summer of 2007.



Forward-Looking Information is Subject to Risk and Uncertainty



This press release contains forward-looking statements based upon GTx's
current expectations, including, without limitation, the statements related
to future clinical and other development of, and potential applications
for, ostarine and expected collaboration revenue to be recognized in the
fourth quarter 2006. 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,
the risks that (i) GTx will not be able to commercialize its product
candidates, including ostarine, if clinical trials do not demonstrate
safety and efficacy in humans; (ii) GTx may not be able to obtain required
regulatory approvals to commercialize its product candidates; (iii) GTx's
clinical trials may not be completed on schedule, or at all, or may
otherwise be suspended or terminated; and (iv) GTx could utilize its
available cash resources sooner than it currently expects and may be unable
to raise capital when needed, which would force GTx to delay, reduce or
eliminate its product development programs or commercialization efforts.
You should not place undue reliance on these forward-looking statements,
which apply only as of the date of this press release. GTx's Quarterly
Report on Form 10-Q filed with the U.S. Securities and Exchange Commission
on November 3, 2006 contains 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.


GTx, Inc.

gtxinc