Thousand Oaks-based Amgen plans to lay off 252 employees in Thousand Oaks by the end of April, bringing the total jobs cut since 2007 from Ventura County’s largest private-sector employer to about 1,150.

Amgen spokeswoman Kristen Davis said the affected jobs are in “field sales, operations and corporate functions.”

Amgen has about 20,000 employees around the world and 6,000 in Thousand Oaks. As recently as 2007 the company had 7,500 employees in Ventura County, according to Business Times records.

“Like all companies, Amgen adjusts staffing levels to meet the needs of the business,” the company said in a statement. “In January, we informed a number of staff members that their positions are impacted. Each of the individuals notified was offered comprehensive severance benefits that provide cash, health insurance and career transition services.”

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.