Exhibit 99.1
Opexa Therapeutics Reports Positive
Top-line Data in Phase I/II Extension Trial with Tovaxin(TM) for
Multiple Sclerosis
Effectiveness Shown in Relapsing Remitting Subjects Across Both
Phase I/II Dose Escalation and Extension Trials
THE WOODLANDS, Texas--(BUSINESS WIRE)--June 21, 2007--Opexa
Therapeutics, Inc. (NASDAQ:OPXA), a company involved in the
development and commercialization of cell therapies, today announced
positive top-line data in an open-label Phase I/II extension clinical
trial of the investigational T-cell vaccine, Tovaxin(TM), for multiple
sclerosis (MS). In this one-year, 8-subject extension clinical trial
of relapsing remitting (RRMS) and secondary progressive (SPMS)
subjects, Tovaxin therapy was shown to be safe and effective. The
"per-protocol" analysis of Tovaxin therapy achieved a 92% reduction in
annualized relapse rate (ARR) in subjects who received two treatment
doses of 30 - 45 x 10(6) attenuated T-cells eight weeks apart and were
monitored for an additional 44 weeks. Subjects in the extension study
had previously been treated an average of 5.2+/-1.8 (1, 8; median 5.4)
years earlier at Baylor College of Medicine under the direction of
Jingwu Zhang, M.D., Ph.D with a T-cell vaccine developed from myelin
basic protein (MBP) reactive T-cells. The safety profile revealed only
injection site mild reactions and no severe adverse reactions related
to T-cell vaccination.
Both Phase I/II clinical studies have demonstrated that T-cell
vaccination depletes myelin reactive T-cells in peripheral blood. In
the extension study patient population, the myelin reactive T-cell
frequencies were reduced by 84% and 72% at 6 and 12 months on study,
respectively. Reductions in myelin reactive T-cell frequencies in the
dose escalation study were 76.7% and 64.8% at 6 and 12 months on
study, respectively.
All subjects currently are enrolled in a retreatment extension
study to collect longitudinal safety and effectiveness data.
Effectiveness data for the 13 RRMS subjects across the two Phase
I/II trials showed an 80% reduction in ARR. The Expanded Disability
Scoring Scale (EDSS) for the RRMS subjects for a 0.5 point effect was
improved, unchanged and worsened by 64.3%, 21.4% and 14.3%,
respectively. The EDSS for a 0.5 point sustained (no change over 3
months) effect was improved, unchanged and worsened by 42.9%, 42.9%
and 14.2%, respectively. The EDSS for a 1.0 sustained effect was
improved, unchanged and worsened by 28.6%, 57.1% and 14.3%,
respectively.
Brian Loftus, M.D. of Bellaire Neurology, the Principal
Investigator of these Tovaxin studies, commented, "This data, combined
with prior data presented on myelin reactive T-cell frequencies and
ARR reductions, laid the ground work for the placebo-controlled
Tovaxin IIb clinical trial (TERMS). We have shown that myelin reactive
T-cells can be identified and used to produce T-cell vaccine which
effectively induces the depletion of an individual's autoreactive
T-cells and results in positive clinical outcomes. I anticipate
Tovaxin will usher in the age of personalized therapy for MS."
David McWilliams, president and chief executive officer of Opexa,
said, "We are particularly encouraged by the data from this extension
trial which indicates that subjects previously treated with T-cell
vaccine can be safely and effectively retreated with Tovaxin. This
outcome is important to our planned extension trial for subjects
currently enrolled in our TERMS trial following the one year core
study time period." In addition, the effectiveness data in RRMS
subjects across the two Phase I/II trials indicate strongly positive
outcomes in both ARR and EDSS improvements following Tovaxin therapy."
About TERMS
The Tovaxin Phase IIb clinical study will include 150 patients in
a multicenter, randomized, double blind, placebo-controlled trial
designed primarily to evaluate the efficacy, safety and tolerability
of the Tovaxin T-cell vaccination with clinically isolated syndrome
(CIS) and relapsing-remitting MS (RR-MS) patients. A total of 100
patients will receive Tovaxin, while 50 will receive placebo. The
study is designed as a two-arm, 52-week, parallel-group study, whereby
patients will be given five subcutaneous injections at 0, 4, 8, 12 and
24 weeks. The analyses will be performed at the end of the 52-week
study to assess the safety and efficacy of Tovaxin. The primary
efficacy variable is the cumulative number of gadolinium-enhancing
lesions on T1-weighted MRI scans summed over the Week 28, 36, 44, and
52 MRIs. The secondary efficacy variables are the cumulative number of
new gadolinium-enhancing lesions at Weeks 28-52, the change in
T2-weighted lesion volume, and the annualized relapse rate. As of May
17, 2007, Opexa announced the completion of patient enrollment in a
150-patient Phase IIb safety and efficacy study (TERMS). All patients
who complete the trial will be eligible to participate in an optional
one-year extension study, in which they will receive Tovaxin under an
open-label protocol. The open-label study is being planned under a
different protocol that will be submitted to the FDA.
The TERMS study is being conducted at 36 U.S. sites to evaluate
the safety and effectiveness of Tovaxin. The TERMS study is registered
on the U.S. National Institutes of Health-sponsored website,
www.clinicaltrials.gov, where pharmaceutical companies are required to
register trials for medicines that will treat serious or
life-threatening diseases or conditions. For more information, visit
the TERMS website at www.tovaxin.com.
About T-cell Vaccination
For a T-cell vaccine to be effective, it should be able to induce
T-cell cytotoxic and/or regulatory immune responses against the
pathogenic T-cells. Studies of T-cell vaccine have indicated that
T-cell vaccination with peripheral blood-derived autologous
myelin-peptide selected T-cells in multiple sclerosis patients
resulted in the in vivo induction of CD8+ cytotoxic T-cells and
CD4+CD25+FoxP3 Tregs specific for T-cell vaccine. The induction of
anti-idiotypic cytotoxic CD8+ effector T-cells and anti-ergotypic
CD4+CD25+FoxP3 positive Tregs is believed to provide a therapeutically
effective dual mechanism of protection to patients treated with
Tovaxin(TM). The observed regulatory immune responses have been shown
to collectively correlate with clinical improvement in treated
patients.
About Opexa Therapeutics
Opexa Therapeutics develops and commercializes cell therapies to
treat autoimmune diseases such as MS, rheumatoid arthritis, and
diabetes. The Company is focused on autologous cellular therapy
applications of its proprietary T-cell and stem cell therapies. The
Company's lead product, Tovaxin(TM), a T-cell therapy for multiple
sclerosis is in a Phase IIb trial. The Company holds the exclusive
worldwide license for adult multipotent stem cells derived from
mononuclear cells of peripheral blood. The technology allows large
quantities of monocyte derived stem cells to be produced efficiently
for use in autologous therapy, thus circumventing the threat of
rejection. The Company is in preclinical development for diabetes
mellitus. For more information, visit the Opexa Therapeutics website
at www.opexatherapeutics.com.
Safe Harbor Statement
This press release contains "forward-looking statements,"
including statements about Opexa Therapeutics' growth and future
operating results, discovery and development of products, strategic
alliances and intellectual property, as well as other matters that are
not historical facts or information. These forward-looking statements
are based on management's current assumptions and expectations and
involve risks, uncertainties and other important factors, specifically
including those relating to Opexa Therapeutics' ability to obtain
additional funding, develop its stem cell technologies, achieve its
operational objectives, and obtain patent protection for its
discoveries, that may cause Opexa Therapeutics' actual results to be
materially different from any future results expressed or implied by
such forward-looking statements. Opexa Therapeutics undertakes no
obligation to update or revise any such forward-looking statements,
whether as a result of new information, future events or otherwise.
CONTACT: Company Contact:
Opexa Therapeutics, Inc.
Lynne Hohlfeld, 281-719-3421
lhohlfeld@opexatherapeutics.com
or
Investor Relations Contacts:
Lippert/Heilshorn & Associates
Kim Sutton Golodetz, 212-838-3777
kgolodetz@lhai.com
Bruce Voss, 310-691-7100
bvoss@lhai.com