GTx Receives FDA Clearance to Initiate Clinical Trial in Stress Urinary Incontinence

— Trial to evaluate an orally administered SARM in postmenopausal
women with stress urinary incontinence —

— Preclinical data demonstrates a SARM can increase pelvic floor
muscle mass and potentially improve outcomes in women with SUI —

MEMPHIS, Tenn.–(BUSINESS WIRE)–GTx, Inc. (Nasdaq:GTXI) today announced that the U.S. Food and Drug
Administration (FDA) has accepted the Company’s investigational new drug
(IND) application for a Phase 2 clinical trial to treat postmenopausal
women with stress urinary incontinence (SUI). The IND enables GTx to
initiate a Phase 2 proof-of-concept trial of enobosarm that will be the
first clinical trial to evaluate a selective androgen receptor modulator
(SARM) for SUI. The Company plans to initiate the trial by the first
quarter of 2016 and anticipates top-line data later in 2016.

The rationale for evaluating enobosarm (GTx-024) as a treatment for SUI
in the proof-of-concept trial is supported by preclinical in vivo
data demonstrating increases in pelvic floor muscle mass following
treatment with GTx’s SARM compounds, including enobosarm, as well as
human safety and efficacy data from enobosarm clinical trials involving
more than 1,500 subjects. Enobosarm has been found to be generally safe
and well tolerated. Following results from the proof-of-concept trial,
the company will determine which GTx SARM compound, including enobosarm,
may be further developed for this indication.

“SUI represents a unique opportunity for GTx, given the androgen
receptor rich environment of the pelvic floor muscles which are
potentially sensitive to relatively low doses of enobosarm,” said Robert
J. Wills, Ph.D., Executive Chairman of GTx. “With current treatment
options limited to pelvic floor physical therapy, injectable bulking
agents, implants or surgery, we hope to offer an orally administered
treatment option where none currently exists.”

About Stress Urinary Incontinence

Stress urinary incontinence (SUI) refers to the unintentional leakage of
urine during activities that increase abdominal pressure such as
coughing, sneezing or physical exercise. SUI, the most common type of incontinence
suffered by women, affects up to 35 percent of adult women. There are a
variety of treatments that are used to treat SUI in women, such as
behavioral modification and pelvic floor physical therapy, especially as
initial treatment options. As the condition worsens however, bulking
agents and surgical procedures are often the most widely used treatments.

About SARMS

Selective androgen receptor modulators (SARMS) are a class of drugs that
has been shown to stimulate the growth of skeletal muscle, similar to
traditional anabolic steroids, but without the undesirable side effects.
SARMS, such as enobosarm, are orally bioavailable and tissue-selective,
whereas testosterone and other anabolic steroids have limited oral
bioavailability and are only available in transdermal and intramuscular
formulations potentially leading to skin reactions and fluctuations in
serum concentrations of testosterone. GTx is developing a family of SARM
compounds to treat unmet medical needs.

About GTx

GTx, Inc., headquartered in Memphis, Tenn., is a biopharmaceutical
company dedicated to the discovery, development and commercialization of
small molecules for the treatment of cancer, including treatments for
breast and prostate cancer, and other serious medical conditions.

Forward-Looking Information is Subject to Risk and Uncertainty

This press release contains forward-looking statements based upon
GTx’s current expectations. Forward-looking statements involve risks and
uncertainties, and include, but are not limited to, statements relating
to GTx’s planned clinical trial for enobosarm (GTx-024) to treat
patients with stress urinary incontinence (SUI). 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 (i) that the
clinical trial that is planned to be conducted by GTx to treat SUI or
it’s Phase 2 clinical trials to treat advanced breast cancer may not be
initiated or completed on schedule, or at all, or may otherwise be
suspended or terminated; (ii) that any additional clinical development
of GTx’s product candidate, enobosarm, beyond the planned Phase 2
clinical trial in women with SUI and its ongoing Phase 2 clinical
studies to treat advanced breast cancer are contingent on GTx entering
into new collaborative arrangements with third parties for such
development or otherwise obtaining sufficient additional capital to
permit such development, which it may be unable to do; or (iii) that GTx
may not be able to obtain required regulatory approvals to commercialize
enobosarm or other product candidates in a timely manner or at all. In
addition, GTx will continue to need additional funding and may be unable
to raise capital when needed, which would force GTx to delay, reduce or
eliminate its product candidate development programs and potentially
cease operations. 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. 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 for the quarter ended June 30, 2015, filed August 10, 2015,
contains under the heading, “Risk Factors”, 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.

Contacts

GTx, Inc.
Investors:
Lauren Crosby, 901-271-8622
lcrosby@gtxinc.com
or
Red
House Consulting
Media:
Denise Powell, 510-703-9491
denise@redhousecomms.com