Background: In MS, immune cells called T cells attack and destroy myelin, the substance that protects nerve fibers, and cause other damage in the brain and spinal cord. These attacks lead to clinical symptoms. In people who don’t have MS, these T cells do not attack myelin because it is recognized as part of their own body, and their immune systems are trained to be “tolerant” to myelin and so do not attack it. One goal in MS therapy is to selectively restore normal tolerance to one’s own myelin, leaving the rest of the immune system intact. In previous studies, researchers have administered a myelin protein (myelin basic protein) orally to mice with EAE, an MS-like disease, and succeeded in suppressing disease, but a clinical trial of this approach involving people with MS was not successful.
The skin is the first line of immune defense, and contains large numbers of immune cells. Applying myelin peptides to the skin of mice with an MS-like disease resulted in suppression of disease (Journal of Autoimmunity, 2007;28:208). The current study tested this approach in a small study in people with relapsing-remitting MS.
The study: Investigators enrolled thirty participants with relapsing-remitting MS, and randomly assigned 16 to receive a 1-mg patch containing a mixture of three myelin peptides (myelin basic protein, proteolipid protein, and myelin oligodendrocyte protein), four to receive a 10-mg myelin peptide patch, and 10 to receive an inactive placebo patch. The adhesive skin patch was placed on the right upper arm and was changed once a week for 4 weeks and then once a month for 11 months. MRI scans were performed at the start of the study and every three months until the end of the study.
The primary outcome measured was whether treatment reduced new disease activity seen on MRI scans significantly more than placebo, and secondary outcomes measured included other MRI findings, annual relapse rate, the proportion of relapse-free patients, and the proportion of patients who experienced 3 months of confirmed disability worsening, as measured by the EDSS disability scale.
The investigators reported that for those on the 1-mg patch, disease activity on MRI scans was reduced significantly, a reduction that was detected at three months of treatment. The annual relapse rate was reduced by 69.3% versus placebo. The proportion of relapse-free patients was 63% of the 1-mg group, versus 10% of those on placebo. The proportion of those with worsening disability decreased by 51%. The 10-mg dose was less effective. No serious adverse events occurred. A mild local skin reaction was observed in some people receiving the myelin peptide patch but resolved without treatment. Laboratory test results also did not show any blood, liver or kidney abnormalities.
Comments: This study used a novel and intriguing attempt to induce the immune system to stop attacking the nervous system in people with relapsing MS. Further studies in larger numbers of people are necessary to determine whether this method has potential as a safe and effective treatment approach for people with MS.