Image courtesy of Gensler

The speculative redevelopment of Weston’s former Liberty Mutual office park into life science space received its first tenant commitment from a Natick biotech that was acquired last year for $300 million.

ModeX leased 33,056 square feet at the Riverside Road development near the junction of Route 128 and the Massachusetts Turnpike.

Boston developer Greatland Realty Partners and Rockwood Capital received $150 million in financing from Royal Bank of Canada last year for the speculative redevelopment of the two-building campus into 340,000 square feet of office-lab space. Greatland acquired the vacant property from Liberty Mutual in 2020 for $26 million.

A clinical-stage biotech specializing in cancer and infectious disease treatments, ModeX was acquired by Miami-based OPKO Health Inc. in May 2022 for $300 million.

The firm plans to double its workforce to more than 60 employees with the expansion in Weston. It will occupy the first 90,000-square-foot building, which is scheduled for completion this fall.

CBRE’s John Lashar, Ron Friedman, Alex Plaisted, Don Domoretsky and Elena Ochsenreither represented Greatland Realty Partners in the lease negotiations. Newmark’s Mark Winters and Juliette Reiter represented ModeX.