This excerpt taken from the ELN 20-F filed Feb 28, 2008.
Alpha 4 Integrin and Tysabri
Our therapeutic strategy for treating autoimmune diseases is to identify mechanisms common to autoimmune diseases and develop novel therapeutics that stop the underlying causes of disease. Alpha 4 integrin is a protein expressed by immune cells that allows those cells to leave the bloodstream and invade target tissues. Blocking alpha 4 integrin stops immune cells from entering tissues.
Tysabri is an alpha 4 integrin antagonist. Tysabri is designed to inhibit immune cells from leaving the bloodstream and to prevent these immune cells from migrating into chronically inflamed tissue where they may cause or maintain inflammation. Tysabri was developed and is now being commercialized by Elan in collaboration with Biogen Idec.