Tango, Third Rock sign on to space in new Fenway lab building

It’s the latest example of the area becoming a magnet for life science businesses.

A rendering of 201 Brookline Ave. in The Fenway, which is starting construction.Elkus Manfredi Architects

In the latest sign of the Fenway neighborhood emerging as a life science hub, two big names in biotech are moving to a building under construction on Brookline Avenue.

Cancer drug maker Tango Therapeutics and investment firm Third Rock Ventures will lease space in 201 Brookline Ave., the building’s developer, Samuels & Associates, said Monday. They’re the first two tenants in what will be a roughly 500,000-square-foot office and lab building under construction alongside Landmark Center — the massive former Sears complex that Samuels has remade in recent years.

The deal comes amid a wave of life science investment in the Fenway. Samuels has lured several other biotech tenants to its office buildings along Boylston Street, while newly formed health care real estate firm IQHQ just bought 109 Brookline Ave. earlier this month, and is partnering with developer John Rosenthal to turn his long-planned Fenway Center tower atop the Massachusetts Turnpike into a life science complex. They hope to start construction later this year.

With its proximity to both booming Longwood Medical Area and to the Back Bay, Fenway is emerging as a popular alternative to crowded Cambridge’s Kendall Square. Tango, which is currently based in Kendall, will take 65,000 square feet at 201 Brookline Ave., while Third Rock — whose portfolio includes fast-growing Boston-area life science companies, including Tango — will move its office from Newbury Street into 25,000 square feet.

“Our portfolio companies are launched from bold ideas at the intersection of science, business, medicine and strategy,” said Kevin Gillis, partner and COO at Third Rock. “We’re thrilled to be anchored within The Fenway’s budding innovation scene.”

It’s a shot of confidence for Samuels, which along with the real estate arm of J.P. Morgan launched construction on the project without tenants, or “on spec.” The 14-story office and lab building still has about 400,000 square feet of space to lease, and is on track to open in 2022.