Amgen’s corporate headquarters in Thousand Oaks (Amgen courtesy photo)

Thousand Oaks-based Amgen will cut staff at its Conejo Valley headquarters and consolidate into fewer buildings as part of a company-wide restructuring plan that will eliminate between 2,400 and 2,900 jobs and shutter facilities in Colorado and Washington.

Amgen said the moves are designed to reduce operating expenses by $700 million by 2016, money that it plans to reinvest to support new drug launches. The company said the layoffs will constitute between 12 and 15 percent of its 20,000-member workforce but did not immediately respond to questions about how many jobs would be cut in Thousand Oaks specifically.

“We will retain our headquarters in Thousand Oaks, with a reduced number of staff consolidated into fewer buildings,” Amgen said in a news release. “The talented staff members in Thousand Oaks have made enormous contributions to advancing biotechnology over the years and the surrounding community has been very supportive.”

The firm said July 29 that it will close sites in Seattle and Bothell, Washington, and Boulder and Longmont, Colorado, in 2015.

“We’ll retain our headquarters in Thousand Oaks, albeit with a reduced staff,” CEO Robert Bradway said in an earnings call with investors.

The company occupies about 3.7 million square feet of building space on 120 acres in Thousand Oaks. It plans to reduce that footprint, said Amgen spokeswoman Kristen Davis.

“As a result, we expect to close several buildings and sell some of the buildings on the outlying areas of our central campus. We are actively engaging in discussions with third-parties about potential future use of the facilities,” Davis told the Business Times in an email.

The restructuring at Amgen comes after several years of job cuts at Ventura County’s largest private-sector employer.

In June, Amgen confirmed plans to lay off 70 people, primarily in its information systems department at its headquarters. Those cuts brought the total number of jobs eliminated since 2007 to 1,223, according to Business Times records and research.

Davis said the Amgen will offer a “voluntary transition program” to qualifying employees to help mitigate the impact of the restructuring.

“The voluntary transition program provides an enhanced benefits package to those staff members who may be ready to move on to another career or to pursue other interests,” Davis said in a email.

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. Before the layoffs announced July 29, Amgen had about 6,000 workers in Thousand Oaks. In late 2006, the company told the Business Times it had about 7,500 employees in Ventura County.

Amgen said that the moves were geared towards cutting costs so that it could “invest in continuing innovation and the launch of its new pipeline molecules, while improving its cost structure. Initial efforts include streamlining the organization, reducing layers of management, increasing managerial spans of responsibility and beginning implementation of a revised geographic site plan,” the company said in a news release.

Overall, its global facilities footprint will be reduced 23 percent, the firm said. It will begin exiting its Washington and Colorado facilities, which are largely research and development sites, in the fourth quarter, it said. Going forward, its R&D operations will be concentrated in South San Francisco and Cambridge, Massachusetts.

Amgen also disclosed its third-quarter earnings. Revenues rose 11 percent to $5.2 billion and profits increased 25 percent to $2.37 per share, beating analyst expectations of $4.9 billion and $2.07 per share, respectively. Shares were up 4.2 percent to $128.60 in after-hours trading after the news was released.