On May 22, 2023, Amgen announced it was relocating its cancer research division to Seattle following its acquisition of Immunex prompting a 100,000-square-foot increase in its plans for the Helix corporate campus.

Amgen owns ten buildings and lease space in nine buildings in the Seattle, Washington area, which house research, manufacturing, and administrative facilities. In connection with the Immunex acquisition in 2002, they initiated an integration plan to consolidate certain Immunex leased facilities, and occupy three of the nine leased buildings.