The difficulties of clinical trials and treatment of primary progressive multiple sclerosis

Primary Progressive MS (PP-MS) is a less common form of MS, while Relapsing-Remitting MS(RR-MS) is the more common form. PP-MS and RR-MS have distinct features.RR-MS is caused by immune cells attacking the brain and spinal cord.

This leads to contrast enhancing lesion by MRI. All the drugs available for system. Therefore, this reduces the frequency of relapses and the number of contrast enhancing lesions by MRI. In PP-MS, the brain cells die independently of an attack by the immune system. This loss of brain cells is slow and progression of symptoms. Unlike patients with RR-Ms, patients with PP-MS do no have relapses- and they do not have contrast enhancing lesions by MRI. As could be expected, none of the drugs that are effective for RR-MS have worked in PP-MS.

There have not been many clinical trials for PP-MS. In Clinical trials, it is essential or not.

At present, there is no reliable way to measure disease worsening or improvement in PP-MS over short periods of time.

In relapsing-remitting MS, having a good marker of disease activity (contrast enhancing lesion) has led to the rapid increase of treatment options. PP-MS does not have contrast enhancing lesion, therefore other markers must be found. Since the changes in PP-MS occur very slowly, it could take years to know if a drug actually works. More sensitive markers are needed � and once these are found, clinical trials for PP-Ms will increase. This may lead to an increase in treatment options in the future.