However, if you are like me, putting in the effort to understand some of these approaches to treating MS will pay off greatly in terms of excitement…and hope. My current favorite is Tovaxin. I’ve put together some articles to introduce you to Tovaxin, explain what it is, what it is designed to do, how it is made and where it is in the research process.
First of All, Who is Making Tovaxin?Tovaxin is being manufactured and tested by a company called Opexa Therapeutics, which used to be called PharmaFrontiers. Opexa is a publicly-traded company, located in the Woodlands, TX (near Houston). Right now, Opexa’s two main products are Tovaxin and a stem-cell program for diabetes, which is in preclinical development.
Tovaxin in a Nutshell
This is the way that I have explained Tovaxin to some relatives or friends who do not have a medical background:
MS is caused when certain immune cells attack the myelin in the central nervous system. These immune cells are called myelin-reactive T-cells (MRTCs). Everyone has them, but in people with MS, they become “active” and “pathogenic” (which simply means they are causing disease). No one knows why they “turn on” in this way in certain people – it is probably a combination of factors, including genetics, infections, vitamin D exposure and metabolism, etc. (See What Causes MS?) The fact remains that when these MRTCs get going, they cause MS. That means that the ideal way to treat MS would be to stop these MRTCs from doing their bad work.
Tovaxin is an attempt to do more than stop these MRTCs – it actually is designed to eliminate the exact T-cells that are doing the damage from our bodies, without affecting the rest of the immune system. How does it do this?
1) First, the Vaccine is ManufacturedThe vaccine is made from each person’s MRTCs. That’s right – blood is taken from each person with MS, the MRTCs are isolated, multiplied to large quantities and attenuated (which means they are weakened so as not to pose a threat). (See How is Tovaxin Made? for details.)
2) Next, It is Injected Into the PatientThe vaccine, containing 30 to 45 million of these attenuated MRTCs is put back into the patient, using a simple subcutaneous injection.
3) The Body RespondsThe body recognizes these MRTCs as invaders, both because they are damaged and because there are so many of them. The immune system attacks these MRTCs, but more importantly, it attacks all of the circulating MRTCs (the ones that are still alive doing damage). Ultimately the MRTCs are eliminated by other T-cells. These T-cells are produced by memory white blood cells (memory WBCs), which will keep producing them as long as any MRTCs are detected.
This has two effects: 1) Controls and gets rid of MRTCs, and 2) Rebalances the whole immune system so that it is no longer in “inflammation” mode. The second point is important, because in a person with relapsing forms of MS, it is not just MRTCs that cause damage – an army of other immune cells that are signaled by the activity of the MRTCs also contribute to the creation of lesions, which in turn cause the symptoms of MS.
4) The Patient is MonitoredThe patient is monitored with blood tests, MRIs and neurological exams, and given additional doses of their unique Tovaxin as needed. Right now patients in clinical studies of Tovaxin are receiving 5 doses per year. Monitoring of patients’ disease is particularly important since MS is a disease that evolves over time. As a result, many patients’ MS will change over time to be caused by different MRTCs that are not targeted with the initial Tovaxin vaccine. This leads to the need for a new individual Tovaxin vaccine to be manufactured. Opexa has a proprietary screening test that is able to detect shifts in a patient’s disease and signal to the company that a new Tovaxin vaccine is needed. The result is a personalized vaccine for each patient at each point in the progression of their MS.
What Have the Results Been So Far?The results are exciting. The most first Phase I/II Tovaxin studies showed the following results at two years:
- Reduction in relapses – 73% remained relapse-free after 2 years (however, since 9/22 participants had SPMS, relapses would not be expected in these people); there was also an 82% decrease in annualized relapse rate, from an average of 1.38 to 0.21 relapses per patient per year
- No worsening of disease in 86% of participants
- 27% showing “sustained improvement” – meaning at least 1 point change on the EDSS
- No side effects have been experienced, except a little bit of irritation at the injection site