Opexa Therapeutics, Inc. (OPXA) Reports Additional Favorable Data with Tovaxin(R)

Sep. 8, 2009 (Business Wire) — Opexa Therapeutics, Inc. (NASDAQ:OPXA), a company developing Tovaxin^®, a personalized T-cell immunotherapy for multiple sclerosis (MS), today announced results from further analysis of the double-blind, placebo-controlled, 52-week Phase IIb TERMS clinical study of 150 patients with Relapsing Remitting MS (RRMS). This analysis evaluated patients with an annualized relapse rate of one or greater at study entry (ARR≥1). More than 83% of the Tovaxin-treated group (n=85) remained relapse free at one year and the annualized relapse rate after treatment decreased to 0.20, a 42% reduction compared to placebo.

The results of this expanded analysis confirm those found in the previously-reported per-protocol analysis of patients in the TERMS study with ARR>1. This post-hoc analysis which represents 86% of the total patient population in the TERMS study was conducted to evaluate Tovaxin treatment among study patients with the same baseline disease activity that is being targeted for inclusion in the forthcoming Phase IIb study. Along with a marked reduction in relapses, 73% of the Tovaxin-treated patients with ARR≥1 showed stabilization or improvement in MS disability, including 16.5% with a sustained improvement in the Expanded Disability Status Scale (EDSS) of at least one full point. On MRI, the Tovaxin-treated group also demonstrated a reduction in brain atrophy and fewer inflammatory brain lesions that progressed to “black holes,” as compared to the placebo-treated group. Treatment with Tovaxin was well tolerated, with no serious adverse events reported in any Tovaxin-treated patient.

“The expanded analysis represents the MS patient population with active relapsing-remitting disease planned for recruitment into the next Phase IIb trial of Tovaxin,” stated Dawn McGuire, MD, a board certified neurologist and a member of Opexa’s Clinical Advisory Board. “Clinical benefits include not only reduction in relapses, but a surprising reversal of disability in over 16% of Tovaxin-treated patients. Along with MRI data suggesting a reduction in neuronal cell loss, these results raise the possibility that Tovaxin-treatment may have neuroprotective as well as disease-modifying effects. Tovaxin’s favorable safety profile and these early efficacy signals strongly support moving forward with a confirmatory Phase IIb trial.”

Tovaxin is a personalized T-cell vaccine based on a patient’s individual immunologic profile. Detailed immunology data analysis from the TERMS trial indicate that Tovaxin can successfully induce changes in T-cell reactivity to all three targeted myelin antigens implicated in the autoimmune attacks causing neurologic damage in MS. These changes appear epitope-specific, are sustained for 6 months or more, and match each patient’s Tovaxin formulation. Tovaxin is not broadly immunosuppressive, an important feature of its favorable safety profile.

“From an immunology perspective, the data generated thus far from the TERMS trial, from thousands of patient samples, appear to correlate nicely with the putative mechanism of action for Tovaxin. While additional analyses are still in progress, we are also seeing early associations between depletion of myelin reactive T-cells and favorable clinical outcomes,” commented Dr. McGuire.

About Opexa

Opexa Therapeutics, Inc. is dedicated to the development of patient-specific cellular therapies for the treatment of autoimmune diseases. The Company’s leading therapy, Tovaxin^®, is an individualized cellular immunotherapy treatment in Phase IIb clinical development for multiple sclerosis (MS). Tovaxin is derived from T-cells isolated from peripheral blood, expanded ex vivo, and reintroduced into the patients via subcutaneous injections. This process triggers a potent immune response against specific subsets of autoreactive T-cells known to attack myelin, believed to be a primary cause of MS attacks and nervous system damage.

For more information visit the Opexa Therapeutics website at www.opexatherapeutics.com.

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