September 11, 2008

Top-Line Data From Opexa’s Phase IIb Tovaxin(R) Study to Be Presented at World Congress on Treatment and Research in Multiple Sclerosis

Opexa Therapeutics, Inc. (NASDAQ:OPXA), a company dedicated to the development of patient-specific cellular therapies for the treatment of autoimmune diseases such as multiple sclerosis (MS) and diabetes, today announced that top-line data from the company's Phase IIb study of Tovaxin(R) will be presented at the World Congress on Treatment and Research in Multiple Sclerosis in Montreal, Canada, on September 19, 2008. Tovaxin, Opexa's lead product candidate, is a novel T-cell vaccine for the treatment of MS that is specifically tailored to each patient's disease profile. Clinical results to date have demonstrated that Tovaxin may offer enhanced efficacy, safety and tolerability as compared to other MS therapies currently on the market or in development.

Dr. Edward J. Fox, M.D., Ph.D., director of the Multiple Sclerosis Clinic of Central Texas and the study's principal investigator, will present top-line results from Opexa's TERMS (Tovaxin for Early Relapsing Multiple Sclerosis) study. The details of Dr. Fox's presentation are as follows:

 Title:     TERMS (Tovaxin for Early Relapsing MS) Phase IIb Placebo- Controlled Trial of Autologous T-cell Vaccination in Patients with Clinically Isolated Syndrome or Relapsing- Remitting Multiple Sclerosis  Session:   Parallel Session 07 - Emerging Therapies  Date:      Friday, September 19, 2008  Time:      2:55 - 3:10 p.m. (EST)  Location:  Palais des congres de Montreal Room 517ab 

Investigator Q&A Session

Opexa will host an investigator Q&A session following the conclusion of the day's programs on September 19, 2008. The Q&A session will be webcast. For details regarding the Q&A session, please contact Stephanie Diaz of Vida Communication at 415-675-7401 or [email protected]

The World Congress on Treatment and Research in Multiple Sclerosis, the first joint meeting of ACTRIMS (the Americas Committee on Treatment and Research in Multiple Sclerosis) and its counterparts in Europe and Latin America: ECTRIMS and LACTRIMS, will take place September 17-20, 2008, in Montreal, Canada.

About the TERMS Study

The TERMS study is a Phase IIb multi-center, randomized, double blind, placebo-controlled trial in 150 patients with Relapsing-Remitting Multiple Sclerosis (RRMS) or high risk Clinically Isolated Syndrome (CIS). The study involves 2:1 randomization with 100 patients receiving Tovaxin and 50 receiving placebo. According to the study protocol, patients received a total of five subcutaneous injections at weeks 0, 4, 8, 12 and 24. The primary efficacy endpoint of the TERMS trial is the cumulative number of gadolinium (Gd)-enhanced brain lesions (CELs) using MRI scans summed over weeks 28, 36, 44 and 52. The trial's secondary efficacy endpoints include annualized relapse rate (ARR) and additional MRI measurements.

About Tovaxin

Tovaxin is developed using Opexa's proprietary method for the production of patient-specific T-cell vaccines. To produce the Tovaxin vaccine, Opexa isolates disease-causing T-cells from blood taken from an MS patient and expands them in the laboratory to create an appropriate therapeutic dose. The attenuated T-cells, which comprise the Tovaxin vaccine, are reintroduced into the patient via subcutaneous injection to trigger a therapeutic immune system response. Tovaxin is manufactured in Opexa's in-house cGMP facility.

Opexa recently announced two-year follow-up data from its Phase I/II clinical studies. Data from 22 patients demonstrated that 73 percent of patients on Tovaxin remained relapse free after two years with 86 percent experiencing no disease progression.

Opexa believes that Tovaxin may possess the following competitive advantages:

-- Efficacy - Clinical trials conducted to date demonstrate that Tovaxin may result in a clinically significant reduction in ARR (a key measure of MS treatment effectiveness) for Relapsing-Remitting MS (RRMS) and Secondary-Progressive MS (SPMS) patients comparable to, or greater than, currently available MS therapeutics.

-- Safety and Tolerability - Tovaxin treatment selectively targets and depletes the pathogenic T-cell population. It is not a general immune suppressant and accordingly, is not associated with the serious side effects seen with those MS treatments that function by systemically suppressing the immune system. In clinical trials conducted to date, there have been no serious adverse events associated with Tovaxin treatment.

-- Improved Compliance - In clinical trials, Tovaxin is administered only five times per year. This patient-friendly treatment regimen may provide significant compliance benefits compared to currently available MS treatments (at least once per month and, in some cases, as frequently as every day).

-- Customized Therapy - Using the company's proprietary Epitope Analysis Assay (EAA) to profile an individual's disease profile, Opexa can continually customize treatments to specifically target an individual's disease progression and/or modification.

About Opexa Therapeutics

Opexa Therapuetics is a biotechnology company dedicated to the development of patient-specific cellular therapies for the treatment of autoimmune diseases. The company's leading therapies currently in development have the potential to address significant unmet medical needs in several large patient populations including multiple sclerosis (MS) and diabetes. The company's lead product is Tovaxin, a T-cell therapy for MS which is in Phase IIb trials. The company also holds an exclusive worldwide license for adult multi-potent stem cells derived from mononuclear cells of peripheral blood. The technology provides means to differentiate these stem cells into other tissue types such as pancreatic islets. By using an individual's own cells, this approach may minimize threat of treatment rejection. This technology serves as the basis for Opexa's preclinical diabetes program, which is focused on the generation of insulin-secreting pancreatic-like cells. For more information visit the Opexa Therapeutics website at

Cautionary Statement Relating to Forward - Looking Information for the Purpose of "Safe Harbor" Provisions of the Private Securities Litigation Reform Act of 1995

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, obtain FDA approval for its therapeutic products, 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.