On Jul. 16, 2002, Amgen completed it’s acquisition of Immunex Corporation for $16 billion in stock and net cash. Immunex, the largest biotechnology company in the Pacific Northwest at the time, was founded in 1981 by Steven Gillis and Christopher Henney from the Fred Hutchinson Cancer Research Center, and Stephen Duzan, the founding CEO of the company.

Immunex became publicly traded in 1983, and in 1991, with U.S. Food and Drug Administration (FDA) approval of the drug Leukine, it became only the third fully integrated pharmaceutical company to be created in the United States since 1945.