The team behind a $4.5B development in Cambridge's Alewife Quadrangle that could take up to three decades to build has gotten the green light to begin.

Healthpeak Properties received Cambridge Planning Board approval for the special permits needed to begin its roughly 5M SF development. The project would transform an underutilized strip of industrial property that has been highly sought after. 

The Cambridge Planning Board at a Tuesday night meeting unanimously approved the special permit for the project, which received support from residents and local officials.

"This final development plan is going to fulfill the city’s longstanding vision to transform the Quadrangle into a fully functional neighborhood with residential and commercial density, connectivity, new streets and parks, first-floor active uses, a bicycle-pedestrian bridge and the DPW site," Cambridge Director of Community Planning and Design Daniel Messplay said.

In July 2025, Healthpeak filed plans for the project with the Massachusetts Environmental Policy Act Office.

The updated project consists of 24 buildings, including more than 2,300 housing units, 2.6M SF of office and lab space, and 75K SF of retail. The project also includes 12 acres of open space and $300M in infrastructure investment.

The development has been in the works since the fall of 2021.

"If someone told us the journey we were going on with that first acquisition, we probably wouldn't have believed you," Healthpeak Director of Investments Rylan Squirrell said at the meeting. "But throughout that journey, it's been extremely rewarding, and we have met many amazing people."

The project is expected to be broken into two large phases over 20 to 30 years. The second phase will be triggered by the development of a highly anticipated pedestrian bridge on the site. 

While starting new development has been challenging in today's economic climate, Squirrell said the residential component is likely to work first "based on some of the value engineering that we've been working on in conversations that we've been having with the city."

"We're eager to move forward with that," he said.

Tuesday's meeting featured several big changes and updates to the final plan, including a letter from the MBTA signaling interest in developing a new commuter rail line or urban line in addition to the existing Alewife stop on the Red Line.

"A high-quality connection from the Alewife Quadrangle over the Fitchburg line will happen, and we look forward to structuring agreements, advancing MBTA infrastructure studies, and reporting back to the Cambridge Planning Board no later than three years from the date of final PUD master plan approval," MBTA General Manager Phillip Eng said in the letter.

Healthpeak plans to develop a pedestrian and bicycle bridge and bike path with the new MBTA stop in mind. Additional studies will be conducted for the bridge and the MBTA stop.

Other changes include a reduction in parking from the planned maximum of 4,482 parking spaces to 3,900. Squirrell said he anticipates the contraction because office tenants, residents and guests can share spaces.

The development team plans to monitor the parking usage and might contract the number further to 3,648 spaces, depending on usage.

"Part of the reason why we built mechanisms into the zoning to reduce parking if utilization is shown to be lower than what has been built — in that case, where a rail stop is built or the bridge is built, future parking will be actively reduced in order to meet that adjusted demand," Squirrell said.

Another change saved a 1.75-acre parcel for a Department of Public Works facility to be moved onto the site within one of the residential portions of the development.

Healthpeak began acquiring properties just before the pandemic, collecting 46 acres that consist primarily of industrial and Class-B and C office buildings. The shopping spree prompted city council members to place a temporary moratorium on development in the neighborhood.

In 2023, the ban was lifted, and the city council approved a rezoning of the neighborhood that would allow for taller buildings. In April, Houston-based Hines joined the development team, focusing on the housing part of the project. 

"The secret is residences," Squirrell said. "Residents unlock the neighborhood uses, the art installations, the open space, the connective tissue that is so desperately missing from the Quad that will allow us to connect and build and generate commercial activity."