Blocking the melanoma cell adhesion molecule (MCAM) may delay the onset of multiple sclerosis (MS) and significantly slow the disease’s progression, according to a study published in the Annals of Neurology.
The discovery, made by a team of researchers at the University of Montreal, may make the possibility of an MS-halting drug a reality in the near future.
“We believe we have identified the first therapy that will impact the quality of life of people with multiple sclerosis by significantly reducing the disability and the disease’s progression,” said researcher Alexandre Prat, MD, PhD.
Currently, there are no treatments that can slow the progression of MS, which affects up to 2.3 million people across the world.
In healthy people, the blood-brain barrier prevents lymphocytes from entering the central nervous system. However, in MS patients, the lymphocytes CD4 and CD8 cross this barrier and destroy the myelin sheaths of neurons. The destruction of these protective sheaths causes plaque formation and a decrease in transmission of nerve impulses.
In 2008, the researchers discovered that MCAM is necessary for CD4 and CD8 to cross the blood-brain barrier. Thus, blocking MCAM’s activity can stop lymphocytes from crossing the barrier and reduce MS disease activity.
They tested this theory in mice models. “We observed a decrease of approximately 50% of the disease in mice with experimental autoimmune encephalomyelitis (EAE), the most widely used animal model of MS,” said Prat. “What is especially significant is that we can stop the disease from the first symptoms in addition to having an impact on its progression, which is a first.”
The researchers have worked with Prothena Corporation, a biotechnology company who had discovered complementary data on MCAM. Prothena has developed an antibody called PRX003 that inhibits MCAM function, preventing lymphocyte migration. The company hopes to begin clinical trials of the antibody in healthy participants beginning in June 2015. Next year, they hope to test PRX003 in patients with psoriasis.
The researchers believe that their discovery represents a new treatment avenue for various neuroinflammatory conditions, including MS.