Opexa Presents Tovaxin Data at the American Academy of Neurology 2010 Annual Meeting

April 14, 2022 08:30 AM Eastern Daylight Time

Poster Presentation Ties New Immunology Data to Clinical Outcome Data From TERMS Phase 2b Study in Multiple Sclerosis

THE WOODLANDS, Texas--(April 14, 2022)--Opexa Therapeutics, Inc. (NASDAQ: OPXA), a company developing a novel T-cell therapy for multiple sclerosis (MS), announced today that the Company presented key efficacy data at the American Academy of Neurology (AAN) 62nd Annual Meeting held in Toronto, Canada. Dawn McGuire, M.D., Chair of Opexas Clinical Advisory Board and the Companys acting-Chief Medical Officer, presented data from the Phase 2b TERMS clinical trial which demonstrated promising efficacy and safety results in patients treated with Tovaxin, the Companys lead therapy for MS. The presentation highlighted previously communicated efficacy data as well as new immunology data that appear to link Tovaxins mechanism of action with observed clinical benefits.

The data show an increasing level of FoxP3+ T-Regulatory cells in patients treated with Tovaxin (a 23.4% increase from baseline to week 52) compared with a 6.3% increase among patients receiving placebo. The levels were statistically significantly larger (p<0.02) from baseline at each interval measured in the efficacy period (weeks 24-52) within the Tovaxin group, Additionally, the Tovaxin-treated patients who appeared to benefit the most clinically, as defined by an improvement or stabilization in disability (EDSS), also demonstrated the largest increase in the percentage of FoxP3+ cells. This correlation with clinical outcome is potentially quite relevant. FoxP3 is a marker identifying a subset of T-cells that regulate the immune system to prevent attacks against the bodys own tissues. A reduction in these specific T-cells may contribute to the development of autoimmune diseases such as MS. It has been demonstrated in prior published studies that T-Regulatory cell function and FoxP3 expression are notably reduced in Relapsing Remitting MS patients as compared to healthy donors. The trend towards a sustained increase of FoxP3+ cells suggests that Tovaxin may elicit regulatory T-cell-mediated effects in patients. The potential ability of Tovaxin to restore the percentage of FoxP3+ T-Regulatory cells supports the existing mechanism of action hypothesis whereby Tovaxin works, in part, by physically depleting and/or functionally inactivating pathogenic auto-reactive T-cells in MS patients.

"We are pleased to have again been invited by the AAN to present key data on Tovaxin. The comprehensive data analyses of the TERMS Phase 2b trial have been progressing well and continue to provide strong evidence to support the further clinical development of Tovaxin," stated Neil K. Warma, Opexa President and Chief Executive Officer. To summarize our data analyses to this point, we have observed that among MS patients with active disease, defined as having at least one relapse per year at baseline, Tovaxin treatment has resulted in a post-treatment Annualized Relapse Rate (ARR) of approximately 0.20, which is at least as good as that observed with the best drug on the market. The associated reduction in ARR was 42% as compared to placebo, with 83% of Tovaxin treated patients remaining relapse free at the end of the 52 week study. Further, more than 16% of Tovaxin-treated patients in this group actually had sustained improvements in disability scores. Brain atrophy was substantially decreased in Tovaxin patients versus placebo patients, and fewer of their inflammatory lesions progressed to black holes, suggestive of less irreversible tissue loss. The additional new immunological data added to our previously-communicated clinical data provide a compelling case for linking Tovaxins mechanism of action as we understand it thus far to clinical outcomes in MS patients. We will continue to evaluate the immunological data, its correlation to clinical benefit and continue to refine our understanding of Tovaxins mechanism of action in our efforts to advance Tovaxin through clinical development, added Mr. Warma.

About Opexa

Opexa Therapeutics, Inc. is dedicated to the development of patient-specific cellular therapies for the treatment of autoimmune diseases. The Companys leading therapy, Tovaxin, is a personalized cellular immunotherapy treatment that is in 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 and, thereby, reduces the risk of relapse over time.

Opexa completed its 150 patient Tovaxin for Early Relapsing Multiple Sclerosis (TERMS) Phase 2b clinical study in late 2008 which was one of the first clinical studies investigating an autologous T-cell therapy in MS patients. Data from this clinical study show evidence that Relapsing Remitting MS (RRMS) patients treated with Tovaxin saw overall clinical, MRI, and immunological benefits over the placebo group, including statistical significance for decrease in the Annualized Relapse Rate (ARR), improvement in disability score (EDSS), and improvement in quality of life measures (MSQLI), as well as an excellent safety profile with no serious adverse events related to Tovaxin treatment.

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

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 which are made pursuant to the safe harbor provisions of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. The forward-looking statements in this release do not constitute guarantees of future performance. Investors are cautioned that statements in this press release which are not strictly historical statements, including, without limitation, statements regarding current or future financial payments, returns, royalties, performance and position, management's strategy, plans and objectives for future operations, plans and objectives for product development, plans and objectives for present and future clinical trials and results of such trials, plans and objectives for regulatory approval, litigation, intellectual property, product development, manufacturing plans and performance, constitute forward-looking statements. Such forward-looking statements are subject to a number of risks and uncertainties that could cause actual results to differ materially from those anticipated, including, without limitation, risks associated with: market conditions, our capital position, the success of third party development and commercialization efforts with respect to products covered by intellectual property rights transferred by the Company, the success of third party patent prosecution efforts with respect to such products, the ability of the Company to enter into and benefit from a partnering arrangement for the Company's product candidate, Tovaxin, on reasonably satisfactory terms (if at all), and our dependence (if partnered) on the resources and abilities of any partner for the further development of Tovaxin, our ability to compete with larger, better financed pharmaceutical and biotechnology companies, new approaches to the treatment of our targeted diseases, our expectation of incurring continued losses, our uncertainty of developing a marketable product, our ability to raise additional capital to continue our treatment development programs, the success of our clinical trials, our ability to develop and commercialize products, our ability to obtain required regulatory approvals, our compliance with all Food and Drug Administration regulations, our ability to obtain, maintain and protect intellectual property rights for our products, the risk of litigation regarding our intellectual property rights, our limited manufacturing capabilities, our dependence on third-party manufacturers and value added resellers, our ability to hire and retain skilled personnel, our volatile stock price, and other risks detailed in our filings with the Securities and Exchange Commission. We assume no obligation to update any forward-looking information contained in this press release or with respect to the announcements described herein.