Life-sciences developer lands a big site near Assembly Row

BioMed Realty plans to build 1.3 million square feet of labs and offices

An artist's rendering of the life-sciences campus planned in Somerville.

Developers with a focus on building lab space keep scooping up sites all over Greater Boston, with the latest deal being for nine acres near Assembly Row.

BioMed Realty says it plans to build a 1.3 million-square-foot lab-and-office campus where a mid-size office building and parking lots now stand. Deeds filed in Middlesex County indicate the real estate firm paid $163 million for the site.

The deal, announced Tuesday, was first disclosed last summer, when BioMed sought approvals from Somerville to change plans for the site — then known as XMBLY — from a mixed-use project that included apartments into something suited for life-sciences companies. It closed on the property just before Christmas, and BioMed is now preparing a proposal for the first phase of the project. The company aims to start construction later this year.

“Our vision for the Assembly Square location is to create a premier innovation campus where science and technology intersect,” said BioMed vice president Sal Zinno. “It’s an ideal location and size for a large life-science company to establish a prominent headquarters.”

BioMed, a veteran Kendall Square developer that’s owned by the private equity giant Blackstone, is one of several life-sciences real estate heavyweights that lately have been on buying sprees in and around Boston.

Last month, the group bought 601 Congress St. in the Seaport District — an empty office building that once housed John Hancock’s corporate headquarters — and plans to convert it into life-sciences space. Real estate industry sources say BioMed also has an agreement to purchase 321 Harrison Ave., an office building under construction in the South End, likely for conversion to lab space. And the company recently won approvals in Cambridge for a new tower on Third Street in Kendall Square.

The deals are driven by the booming growth of drug development in Greater Boston, and by life-sciences firms looking for alternatives to crowded and costly Kendall Square. Several pockets of eastern Somerville, including Union Square, nearby Boynton Yards, and Assembly Row are emerging as popular sites. Somerville Mayor Joe Curtatone said he welcomes the investment and job growth.

“Having a world-leading life science developer launch this new major life science cluster in Somerville will open up the growth, jobs and new opportunities our community seeks,” Curtatone said in a statement. “Simply put, it opens the door for our city to become a pioneer in the biotechnology space.”