Thousand Oaks-based Amgen plans to lay off 70 people, primarily in its information systems department at its headquarters.

The affected employees were told this week, spokeswoman Kristen Davis said in an email.

“The majority of the positions were eliminated due to recently outsourced work,” Davis said. “Each of the individuals notified was offered comprehensive severance benefits that provide cash, health insurance and career transition services.”

The cuts at the biotech giant bring the total number of jobs eliminated since 2007 to 1,223, according to Business Times records and research.

Amgen has about 20,000 employees around the world and 6,000 in Thousand Oaks. In late 2006, the company told the Business Times it had about 7,500 employees in Ventura County.

Amgen has been steadily reducing its workforce in Thousand Oaks even as its global headcount has grown through acquisitions. In 2007, the company cut 675 jobs in Ventura County in the first major layoff in its history. In 2011, it eliminated 226 positions in Thousand Oaks as part of sweeping changes to its research and development operations. Earlier this year, Amgen eliminated 252 jobs in Thousand Oaks.

“Like all companies, Amgen adjusts staffing levels to meet the needs of the business,” Davis said in an email.