T-cell platform

Opexa's initial disease targets are autoimmune diseases amenable to T-cell based therapies, such as Multiple Sclerosis (MS). Opexa has developed a proprietary T-cell technology platform that allows for the production of patient-specific T-cell therapies that induce therapeutic immune responses to combat a variety of autoimmune diseases. Tcelna, Opexa's lead therapeutic candidate for the treatment of MS is based on this platform. Tcelna is a personalized autologous immunotherapy that is not only manufactured for every individual patient but also is tailored to match each patient's evolving disease profile. Tcelna 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.

Tcelna is manufactured for a patient by the ImmPath^® process, Opexa's proprietary manufacturing process. In the initial step, 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 are expected be treated with a new series of Tcelna (5 doses) each year based on their altered disease profile or epitope shift.

ImmPath^® Manufacturing Process

Tcelna is manufactured using Opexa Therapeutics' proprietary method for the production of an autologous T-cell product, ImmPath^®, which encompasses the collection of blood from the MS subject, isolation of peripheral blood mononuclear cells (PBMC), generation of an autologous pool of myelin-reactive T-cells (MRTC) raised against selected peptides, and the return of these expanded, irradiated T-cells back to the subject. These attenuated T-cells are reintroduced into the subject via subcutaneous injection to trigger a therapeutic immune response consisting of anti-idiotypic cytotoxic and regulatory T-cells, to limit the frequency and function of T-cell dependent autoimmunity directed against myelin.

Tcelna® is administered in an annual course defined as five subcutaneous injections over 6 months. Subjects will be treated with a new, personalized treatment course each year based on their altered disease profile or epitope shift to myelin antigens, and the re-manufacture of a new Tcelna product representing the emerging immunodominant T-cells.