Tovaxin®
Opexa's lead product candidate is Tovaxin, a personalized T-cell vaccine for the treatment of multiple sclerosis (MS) that is specifically tailored to each patient's disease profile. Opexa believes the potential combination of efficacy, superior safety, improved tolerability and patient-friendly administration schedule may position Tovaxin as the MS treatment of choice as compared to existing therapeutic options.
Tovaxin is designed to reduce the number of specific subsets of autoreactive T-cells known to attack myelin. Tovaxin is manufactured using Opexa Therapeutics’ proprietary method for the production of patient-specific T-cell vaccines, which comprises the collection of blood from the MS patient, the harvest and expansion of disease-causing T-cells from the blood, and the return of these expanded, irradiated T-cells back to the patient. These 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 being developed as a first line treatment for MS. The treatment will consist of donating blood and creating a vaccine using the patient’s own cells. The vaccine cells will be irradiated to render them unable to divide, but able to evoke an immune response. The vaccines will be administered in the doctor’s office as a subcutaneous injection in the arm given five times a year. The first four injections are administered a month apart with the fifth and final injection being administered two months after the fourth. While many other MS treatments have constant side effects such as flu symptoms, injection site problems, and serious adverse events, Tovaxin has not had any treatment related serious adverse events (SAEs). The most common side effect reported form clinical studies has been mild to moderate injection site reaction that usually resolves without treatment within 24 hours. Tovaxin therapy is specific for the immune response against myelin destroying T cells and does not cause a general immunosuppression. Tovaxin may be a strong alternative for subjects who do not want to start hospital infusions or weekly injections, or have not been able to tolerate the side effects or infections of immunosuppressant drugs on the market. Tovaxin could represent a viable alternative for patients who:
- Have chosen to stop or not start treatments;
- Are newly diagnosed with MS;
- Are dissatisfied with currently marketed drugs.
Personalized Therapy
Tovaxin is a personalized autologous immunotherapy that is manufactured for every individual patient and is also tailored annually to match each patient’s evolving disease profile. The T-cell technology producing Tovaxin is similar to that of traditional microbial vaccine technology, where the pathogen (or the attenuated derivative) is used to derive the protective T-cells necessary to induce protective immune responses. Tovaxin consists of attenuated, patient-specific myelin reactive T-cells (MRTCs) against peptides of the three primary myelin proteins [Myelin basic protein (MBP), Myelin oligodendrocyte glycoprotein (MOG) and Proteolipid protein (PLP)] that have been implicated in T-cell pathogenesis of MS. In preparing Tovaxin for a patient, the patient-specific MRTCs causing the disease are isolated from the blood and expanded in culture with specific peptides identified by assaying peripheral blood mononuclear cell (PBMC) reactivity against 109 peptides derived from MBP, MOG and PLP in the presence of antigen-presenting cells and growth factors. Myelin-peptide reactive T-cells are grown to therapeutic levels and cryopreserved. Prior to use, the MRTCs are expanded, formulated, and attenuated (by irradiation) to render them unable to replicate but viable for therapy. These attenuated T-cells are administered in a defined schedule of five subcutaneous injections. Patients will be treated with a new vaccine series (5 sc injections) each year based on their altered disease profile or epitope shift.
Competitive Advantages
Tovaxin's perceived mechanism of action and observed clinical effects to date have resulted in the following key advantages:
Efficacy – Clinical trials conducted to date demonstrate that Tovaxin may result in a reduction in Annualized Relapse Rate (ARR) to a level that is at least as good as the most effective treatment currently available on the market.
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 by those MS treatments that function by systemically suppressing the immune system. In clinical trials conducted to date, including the 150-patient Phase 2b study, there have been no serious adverse events associated with Tovaxin treatment.
Customized Therapy – Using Opexa's proprietary epitope analysis assay, the company customizes Tovaxin treatments to specifically target an individual's disease progression and/or modification.
Improved Compliance – Tovaxin's treatment regimen of five subcutaneous injections per year may provide significant compliance benefits to both patients and physicians.
Opexa believes the potential combination of comparable/enhanced efficacy and superior safety, tolerability and administration may position Tovaxin as the MS therapy of choice when compared to existing therapeutic options.