Irish pharmaceutical giant Shire has leased an additional 200,000 square feet in Lexington where it’s expanding its office and lab operations on Hayden Avenue.

The rare disease specialist signed a 10-year, 200,000-square-foot lease at Waltham-based Hobbs Brook Management’s 95 Hayden Ave., four months after expanding into 177,000 square feet previously occupied by Cubist Pharmaceuticals. Hobbs Brook recently renovated the building in conjunction with Jacobs Global Building Design. Shire will move 850 employees into the 4-story building from locations in Waltham and Lexington, spokeswoman Katie Joyce said.

The lease gives Shire a footprint of 1.92 million square feet in Massachusetts, with a headcount of more than 3,000 employees.

Shire has office and labs at former Baxalta sites in Cambridge and Milford along with its own facilities in Cambridge, Lexington, Waltham, Belmont, North Reading and Burlington.

Hobbs Brook Management’s principal architect, Brad Cardoso, AIA, was responsible for base building renovations; Jacobs Global Building Design provided the interior fit-out design; and Columbia Construction was the construction manager.

Chip Batchelder from Wyman Street Advisors represented Hobbs Brook Management in the lease transaction. Robert Richards and Brian Cohen of Transwestern | RBJ represented Shire in lease negotiations and secured interim office space at Hobbs Brook’s 235 Wyman St.

Shire earlier this year leased 177,000 square feet at 45-55 Hayden Ave. in Lexington in an expansion of what is already the Boston suburbs’ largest life science campus. That gave Shire control of two of three former Cubist Pharmaceuticals office and lab buildings next door to its Lexington campus.

Shire added 700 employees to its Massachusetts workforce last year in a corporate restructuring at the expense of 600 jobs in Chesterbrook, Pennsylvania.