Opexa Therapeutics Reports Positive Top-line Data in Phase I/II Extension Trial with Tovaxin™ for Multiple Sclerosis
June 21, 2007 09:19 AM Eastern Daylight Time
Effectiveness Shown in Relapsing Remitting Subjects Across Both Phase I/II Dose Escalation and Extension Trials
THE WOODLANDS, Texas--(BUSINESS WIRE)--Opexa Therapeutics, Inc. (NASDAQ:OPXA), a company involved in the development and commercialization of cell therapies, today announced positive top-line data in an open-label Phase I/II extension clinical trial of the investigational T-cell vaccine, Tovaxin™, for multiple sclerosis (MS). In this one-year, 8-subject extension clinical trial of relapsing remitting (RRMS) and secondary progressive (SPMS) subjects, Tovaxin therapy was shown to be safe and effective. The "per-protocol" analysis of Tovaxin therapy achieved a 92% reduction in annualized relapse rate (ARR) in subjects who received two treatment doses of 30 – 45 x 106 attenuated T-cells eight weeks apart and were monitored for an additional 44 weeks. Subjects in the extension study had previously been treated an average of 5.2±1.8 (1, 8; median 5.4) years earlier at Baylor College of Medicine under the direction of Jingwu Zhang, M.D., Ph.D with a T-cell vaccine developed from myelin basic protein (MBP) reactive T-cells. The safety profile revealed only injection site mild reactions and no severe adverse reactions related to T-cell vaccination.
Both Phase I/II clinical studies have demonstrated that T-cell vaccination depletes myelin reactive T-cells in peripheral blood. In the extension study patient population, the myelin reactive T-cell frequencies were reduced by 84% and 72% at 6 and 12 months on study, respectively. Reductions in myelin reactive T-cell frequencies in the dose escalation study were 76.7% and 64.8% at 6 and 12 months on study, respectively.
All subjects currently are enrolled in a retreatment extension study to collect longitudinal safety and effectiveness data.
Effectiveness data for the 13 RRMS subjects across the two Phase I/II trials showed an 80% reduction in ARR. The Expanded Disability Scoring Scale (EDSS) for the RRMS subjects for a 0.5 point effect was improved, unchanged and worsened by 64.3%, 21.4% and 14.3%, respectively. The EDSS for a 0.5 point sustained (no change over 3 months) effect was improved, unchanged and worsened by 42.9%, 42.9% and 14.2%, respectively. The EDSS for a 1.0 sustained effect was improved, unchanged and worsened by 28.6%, 57.1% and 14.3%, respectively.
Brian Loftus, M.D. of Bellaire Neurology, the Principal Investigator of these Tovaxin studies, commented, “This data, combined with prior data presented on myelin reactive T-cell frequencies and ARR reductions, laid the ground work for the placebo-controlled Tovaxin IIb clinical trial (TERMS). We have shown that myelin reactive T-cells can be identified and used to produce T-cell vaccine which effectively induces the depletion of an individual’s autoreactive T-cells and results in positive clinical outcomes. I anticipate Tovaxin will usher in the age of personalized therapy for MS.”
David McWilliams, president and chief executive officer of Opexa, said, "We are particularly encouraged by the data from this extension trial which indicates that subjects previously treated with T-cell vaccine can be safely and effectively retreated with Tovaxin. This outcome is important to our planned extension trial for subjects currently enrolled in our TERMS trial following the one year core study time period.” In addition, the effectiveness data in RRMS subjects across the two Phase I/II trials indicate strongly positive outcomes in both ARR and EDSS improvements following Tovaxin therapy.”