Out of all the drugs is Merck's massive chemical library, they found only one that would block a protein they believe is a key player in multiple sclerosis.
The protein is a chemokine -- a small protein that carries messages across the body. Chemokines dock with receptor proteins that sit on the surfaces of cells. This particular chemokine, called CCR2, activates the immune system. Scientists at Merck rationalized that if they could find a chemical that blocks the CCR2 receptor, it would be capable of reducing inflammation and some autoimmune diseases by calming the immune system down.
When companies first start looking for a chemical that can be used to treat a disease, they develop a test called an assay and then screen tens to hundreds of thousands of compounds.
Merck tested every single chemical in their library and found only a single molecule that blocks the CCR2 receptor. At the American Chemical Society meeting last Sunday, Christopher Moyes described how their team sought the perfect drug by making small incremental changes to the one molecule that was found by their massive drug dragnet.
The drug is in phase II clinical trails for the treatment of multiple sclerosis. It may also become a major alternative to methotrexate for the treatment of rheumatoid arthritis.
