Despite having its own internal program and a collaboration with Merck & Co. Inc. to develop antagonists of the VLA-4 receptor, Biogen Inc. has decided to cut ahead in line by partnering with Elan Corp. plc to develop ELN's Antegren natalizumab humanized monoclonal antibody against integrin alpha(4). Although the deal consolidates some of the action in the VLA-4 arena, ELN and BGEN said that potential conflict over VLA-4 intellectual property was not a motivating factor in their collaboration.

Integrin alpha(4) is part of both the integrin alpha(4)beta(1) (VLA-4) and integrin alpha(4)beta(7) receptors on white blood cells, which mediate binding to vascular cell adhesion molecule-1 (VCAM-1) on endothelial cells to