Amgen Inc. on Wednesday told 380 research and development employees, including 226 in Thousand Oaks, that their jobs are being eliminated.

The Thousand Oaks biotech, which employs 17,600 people worldwide and 6,200 in the Los Angeles area, said the decision was part of a plan to shift resources toward more expensive later stage research.

“Staff reductions are never easy and the company only considers them when they are necessary based on business conditions,” spokeswoman Mary Klem said, “After careful consideration, Amgen believes this restructuring effort is the appropriate response to the changes in our business environment.”

The company, which makes drugs treating anemia, rheumatoid arthritis and many other conditions, last year spent $2.9 billion on research and development. That figure is about 19 percent of last year’s $15.1 billion in revenue. Some analysts and investors have said that the level was too high. The company’s share price is about a third lower than in early 2006, before sales of its flagship anemia drugs Aranesp and Epogen were significantly hurt by safety concerns.

Affected employees are eligible for comprehensive severance benefits of cash, health insurance and career transition services, Klem said. In addition to Thousand Oaks, the company has R&D facilities in the San Francisco Bay Area, Washington state, Massachusetts and the United Kingdom

Amgen is scheduled to announce its third quarter earnings on Monday.

Shares in Wednesday midday trading were up 41 cents, or less than 1 percent, to $57.69 on the Nasdaq.