Annual treatments with patient specific vaccine appear beneficial
Opexa Therapeutics, Inc. (NASDAQ:OPXA), a company leading in the
development of cell therapies for multiple sclerosis (MS) and diabetes,
has completed an internal assessment of data from its Phase I/II two
year extension study with Tovaxin in patients with MS. While confirming
the favorable safety and efficacy profile of Tovaxin, further analysis
also confirms both the benefit of consecutive annual treatments with
Tovaxin and the advantage of tailoring each vaccination to the patient's
changing disease profile.
The extension study evaluated 22 intent-to-treat patients that had
enrolled in two Phase I/II open-label clinical studies with Tovaxin. 13
patients were enrolled with Relapse Remitting Multiple Sclerosis (RRMS)
and 9 with Secondary Progressive Multiple Sclerosis (SPMS). After the
first annual course of treatment the company conducted an analysis of
each patient's specific disease profile and
myelin peptide epitope profile using Opexa's
proprietary Epitope Analysis Assay (EAA). The analysis showed that 19 of
the 22 patients (86%) had undergone an epitope shift, or change in
disease pattern since the original course of treatment. Based on the
epitope analysis, Opexa manufactured a new and specific vaccine for each
of these patients for their second course of treatment. This enabled
Opexa to tailor each vaccine to the individual's
current disease profile, thereby maximizing the effect.
The treatment regimen of five subcutaneous injections per year for each
of the two years with two different vaccines tailored to each patient's
disease profile produced promising results. Pooled data from the RRMS
and SPMS patients showed that, as a group, 73% remained relapse free
after two years and 86% demonstrated no worsening of disease (27% of
these showed sustained improvement). Additionally, there was an overall
decrease in the Annualized Relapse Rate (ARR) of 82% (from 1.38 to 0.21
relapses/patient/year). Each of these endpoints was compared to the
patient's own baseline reading, taken prior to
enrollment in the trials.
A further analysis of several effectiveness parameters showed that
Tovaxin effectively decreased the number of circulating Myelin Reactive
T-Cells (MRTCs) but did not cause any detectable reduction in the
general lymphocyte populations. The lack of generalized immune
suppression observed at this stage of development is one important
aspect that distinguishes the safety of Tovaxin from certain marketed
drugs.