Prime Therapeutics, the fast-growing $2 billion pharmacy benefit management firm, has extended its lease at Normandale Lake Office Park. It remains the largest tenant in the Bloomington complex.

The company moved into the Twin Cities' largest Class A office complex, at Interstate 494 and Hwy. 100, in 2008 with 200 employees. Now the firm has 700 employees who occupy 180,000 square feet on seven floors of the 8400 Tower.

Terms of the lease, including its length, were not disclosed.

"The Normandale location is very proximate to our employee base," said Michael Showalter, Prime Therapeutic's chief marketing officer.

Privately held Prime Therapeutics is actually based in Eagan, where it has two locations, one of which is the old headquarters for Buffets Inc. Last year, Prime Therapeutics received a forgivable $500,000 loan from the state Department of Employment and Economic Development to remodel the building.

About 575 people work at the Eagan sites, making the firm the largest employer in Dakota County. All told, Prime Therapeutics employs 1,275 people in Minnesota.

With annual revenue of about $2 billion, Prime Therapeutics handles claims processing, formulary management, mail service and pharmacy network management for 20 million people. It is collectively owned by 13 Blue Cross and Blue Shield plans, or subsidiaries or affiliates of those plans. Last year, it started handling pharmacy benefits for the University of Minnesota and has broadened into specialty pharmaceuticals.

Normandale Lake Office Park has been in the news because it was recently sold for $265 million to Equity Group Investments, which is linked to Chicago-based investor Sam Zell. Encompassing some 1.7 million square feet, the five-building complex is leased and managed by Cushman & Wakefield/NorthMarq.

Normandale is 86 percent leased.