Amgen's headquarters in Thousand Oaks puts it squarely in Ventura County — not the obvious place for one of the world's pharmaceutical giants. The Conejo Valley location was chosen in part for its proximity to the research universities of Los Angeles while remaining outside the dense urban core. The campus grew considerably over the decades, becoming one of the largest employers in Ventura County. What began as a small group of scientists working in recombinant DNA technology became a significant economic anchor for the region. The company's decision to remain headquartered here, rather than moving closer to Wall Street or to larger biotech hubs in San Francisco, shaped Thousand Oaks's identity as a suburban research corridor.

Amgen's early breakthroughs came in erythropoietin — EPO, a protein that stimulates red blood cell production. The company developed Epogen, a synthetic version approved by the FDA in 1989, which became one of the most commercially successful biotechnology drugs in history. It allowed people with kidney disease and cancer patients undergoing chemotherapy to manage severe anemia without repeated blood transfusions. That single product demonstrated that biotechnology could move from university labs to mass production to the pharmacy counter — a proof of concept that launched an industry. Subsequent drugs including Neupogen and Enbrel extended the company's reach into oncology and rheumatology.

What Amgen represented, at its founding, was a wager: that the new tools of molecular biology could be industrialized. The founders — which included venture capital firm Kleiner Perkins — bet that proteins could be manufactured at scale if you could clone the genes that encoded them and express them in bacteria or mammalian cells. The bet paid off enormously. Amgen's success helped establish the Biotechnology Industry Organization and made Ventura County an unlikely node in the global biotech network. The company has won numerous awards for its manufacturing quality and safety record, and its campus includes research, manufacturing, and clinical operations.

The Amgen campus in Thousand Oaks is large enough to be visible from the air, a cluster of modern low-rise buildings set against the Conejo Valley's characteristic oak-covered hills. The campus is a short drive from the Stagecoach Inn Museum and the Santa Monica Mountains. The company employs tens of thousands worldwide, with its largest concentration in Ventura County. Like many biotech companies, it has faced controversies over drug pricing alongside recognition for its scientific contributions. The duality — remarkable medicines at enormous cost — defines the modern pharmaceutical landscape that Amgen helped create.