GTx, Inc. (Nasdaq: GTXI) today announced results of its two Phase 3
enobosarm clinical trials, the POWER trials, in patients with non-small
cell lung cancer (NSCLC) receiving chemotherapy. The Company announced
that the clinical trials failed to meet the overall criteria for the
co-primary responder endpoints of lean body mass and physical function
as agreed upon with the United States Food and Drug Administration
(FDA); the responder endpoints showed mixed results (for POWER1 and
POWER2, p values at Day 84 for LBM were 0.036 and 0.113, respectively; p
values at Day 84 for SCP were 0.315 and 0.289, respectively).
Initial exploratory quantitative (continuous variable) analysis
demonstrated that enobosarm had a consistent effect on LBM relative to
placebo in both studies at all assessment times (p values were 0.0003
and 0.0227 at Day 84 for POWER1 and POWER2, respectively). Corresponding
analyses for SCP were inconsistent between trials (p values were 0.0336
and 0.7923, respectively). Missing data were well balanced between the
arms in both trials for both endpoints.
Across both clinical trials, enobosarm was generally well tolerated,
with the occurrence of serious adverse events and overall incidence of
adverse events similar across placebo and treatment groups. In POWER1,
the four most common adverse events reported (in decreasing order of
incidence) were nausea, alopecia, anemia and vomiting. In POWER2, the
four most common adverse events reported were anemia, nausea,
neutropenia and vomiting. In the safety analysis of survival, there was
no evidence of a difference between patients treated with enobosarm and
placebo in either clinical trial.
“While we are disappointed that both studies did not meet the
pre-specified responder analyses, we are encouraged by the unambiguous
effect of enobosarm on muscle and we are confident that it will
translate to clinical benefit and potentially increase survival in
patients with non-small cell lung cancer,” said Mitchell Steiner, M.D.,
CEO of GTx. “We look forward to sharing our clinical data from these and
previous trials with FDA and European authorities to discuss the path
forward. I would like to personally thank all the employees at GTx for
their tremendous effort in conducting two high quality Phase 3 clinical
studies and the principal investigators and their staff at over 80
clinical sites in 8 countries for their help recruiting and managing
these studies. Most of all, I want to thank the patients with non-small
cell lung cancer who participated in the POWER1 and POWER2 clinical
trials in order to make it possible for future patients to potentially
have access to important therapies.”
Published observational data suggest that LBM is related to survival
outcome. This observational finding has been replicated based on
exploratory analysis of current survival data from the POWER studies
using landmark analysis and time-dependent covariate Cox regression
modeling that includes LBM response and arm as covariates. The effect
size and direction were similar in both trials.
GTx plans to initiate discussions with both the FDA and European
regulatory authorities to determine the path forward.
“Muscle wasting in patients with non-small cell lung cancer is
devastating and unfortunately it affects hundreds of thousands of
patients worldwide,” said Jeffrey Crawford, M.D., Chief, Division of
Medical Oncology at Duke University School of Medicine, and principal
investigator for the POWER1 and POWER2 trials. “While some of the
pre-specified primary endpoints were not met, I am encouraged by the
substantial and consistent effect of enobosarm on muscle in these
patients with lung cancer receiving chemotherapy.”
“Data from the POWER trials provide compelling evidence that enobosarm
maintains or increases muscle,” said Carla Prado, Ph.D., Assistant
Professor, Nutrition, Food and Exercise Sciences at Florida State
University. “Loss of muscle, independent of weight loss, is a common and
often occult feature of cancer, and is acknowledged as a remarkable and
powerful prognostic indicator of shorter survival.”
About The POWER Trials
A 3 mg dose of enobosarm was studied in two Phase 3 clinical trials to
prevent and treat muscle wasting in patients with NSCLC. In each of
these placebo controlled, double blind clinical trials, approximately
325 patients with stage III or IV NSCLC were randomized to oral daily
doses of placebo or enobosarm 3 mg at the time they began first-line
standard platinum doublet chemotherapy. The POWER trials were designed
to assess the response rates of enobosarm versus placebo for the
co-primary endpoints at 3 months of treatment on maintenance or
improvement of total lean body mass (muscle) assessed by Dual-energy
X-ray Absorptiometry (DXA) and improvement in physical function measured
by the stair climb test (power). Durability of enobosarm treatment was
assessed at five months. Secondary endpoints included an assessment of
whether enobosarm-treated patients had an improved quality of life and
reduced healthcare resource utilization compared to placebo. Overall
survival is being assessed as an additional safety endpoint. GTx
announced early this year that the FDA has designated enobosarm for the
prevention and treatment of muscle wasting in patients with NSCLC as a Fast
Track development program.
About Cancer-Induced Muscle Wasting
Cancer-induced muscle wasting begins early in the disease process,
resulting in decreased physical function and other detrimental
consequences, such as fatigue and weight loss, which can contribute to
disability, reduced quality of life and shorter overall survival,
compared with patients without muscle loss. There are currently no drugs
approved for the prevention and treatment of muscle wasting in patients
with cancer.
About Non-Small Cell Lung Cancer
The American Cancer Society estimates about 228,190 new cases of lung
cancer will be diagnosed in the United States in 2013, and approximately
85 to 90 percent of these are non-small cell lung cancer. Approximately
159,480 Americans are expected to die from lung cancer this year.
Conference Call Details
The GTx management team will host a conference call and webcast to
discuss this announcement. The event will be held today at 9:00 a.m.
Eastern Time (ET). The live event will be available from the GTx website
at http://www.gtxinc.com
under the Investors section, or by calling (866) 700-5192 (domestic) or
(617) 213-8833 (international). The access code is 35408233. A replay of
the discussion will be available beginning at approximately 11:00 a.m.
ET today from the GTx website or by calling (888) 286-8010 (domestic) or
(617) 801-6888 (international), using access code 18733881. The
telephone and website replays will be available until 11:59 p.m. ET on
September 2, 2013.
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, cancer supportive care,
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 clinical trials for enobosarm (also known as Ostarine®
or GTx-024). 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 GTx will not be able to commercialize its
product candidates if clinical trials do not demonstrate safety and
efficacy in humans; (ii) that GTx may not be able to obtain required
regulatory approvals to commercialize its product candidates in a timely
manner or at all; (iii) that clinical trials being conducted by GTx may
not be completed on schedule, or at all, or may otherwise be suspended
or terminated; or (iv) that 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 candidate 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 Securities and Exchange Commission on
July 22, 2013 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.
Copyright Business Wire 2013