Tcelna


Tcelna (formerly known as "Tovaxin") is a novel anti-T cell therapeutic vaccine with potential use in treating multiple sclerosis (MS),[1] being developed by Opexa Therapeutics (formerly known as PharmaFrontiers) in The Woodlands, Texas.

Mechanism of Action

The proposed mechanism parallels that of autologous cancer vaccines, but instead of modifying cancerous cells, Tcelna consists of attenuated autoreactive T cells.

The production of the vaccine takes a patient's own T cells from a blood sample; attenuation of the cells during the vaccine production process renders the cells non-replicating but viable. They will elicit an immune response when injected subcutaneously into the patient, with the immune response directed against those T cells within the patient that are self-reactive with myelin, the sheath that covers the neurons affected in multiple sclerosis. It is hoped that this immune response directed against a specific subset of autoreactive T cells might reduce the number of these autoreactive cells in MS patients.

FDA Trials

The vaccine has been granted Fast Track status by the U.S. Food and Drug Administration in Secondary-Progressive MS based on the unmet need of treatments for the progressive disease and the potential of the vaccine to benefit this patient population.

In October 2005, the company presented positive interim research findings of its Phase I/II trials of Tcelna at a congress held in Thessaloniki, Greece. The trial results indicated that the treatment appeared safe and well tolerated with no dose-limiting toxicities, and that it depleted the myelin-peptide reactive T cells thought to contribute to multiple sclerosis disease processes.

Phase IIb study

The company announced in late 2005 that the U.S. Food and Drug Administration had approved the protocol for the Phase IIb clinical trial of Tcelna.

The multicenter, randomized, double blind, placebo-controlled Phase IIb clinical study on 150 patients was designed to evaluate the efficacy, safety and tolerability of the therapy with clinically isolated syndrome (CIS) and early relapsing-remitting MS (RR-MS) patients.

The first phase of the trial finished in March 2008.[2] All patients who completed the trial were to be eligible for an optional one-year extension study, OLTERMS, to receive Tcelna open-label without a placebo group; however, that program was terminated suddenly for lack of funding.

After several financial troubles, the trials have been restarted in 2011[3] and Opexa rebranded the therapy, previous called Tovaxin, with the new name Tcelna.

References

  1. ↑ Loftus B, Newsom B, Montgomery M, Von Gynz-Rekowski K, Riser M, Inman S, Garces P, Rill D, Zhang J, Williams JC (2009). "Autologous attenuated T cell vaccine (Tcelna) dose escalation in multiple sclerosis relapsing-remitting and secondary progressive patients nonresponsive to approved immunomodulatory therapies". Clinical Immunology. 131 (2): 202–15. doi:10.1016/j.clim.2009.01.005. PMID 19230777.
  2. ↑ "Opexa Therapeutics Announces Completion Of Mid Study Descriptive Analysis On Phase IIb Trial Of Tcelna"
  3. ↑ "Tcelna phase III announced" Opexatherapeutics
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