Blocking the action of alpha4 integrin would be expected to be of therapeutic benefit in the management of
autoimmune diseases. Although this has been successfully demonstrated in the clinic with a monoclonal antibody for the
treatment of multiple sclerosis, there are no small molecule alpha4 integrin antagonists on the market despite significant
endeavour over the last 15-20 years. We review our efforts in this area, starting from a cyclic peptide based on an integrin
recognition sequence and culminating in the low molecular weight clinical candidate, CDP323. We include a discussion
on pre-clinical pharmacological data for CDP323.