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.