A century-old building that once served as Moderna's Cambridge headquarters could be reborn as affordable housing, under a proposal from Alexandria Real Estate Equities that would trade the residential conversion for more commercial square footage nearby at Technology Square. The building at 161 First St. has cycled through several biotech tenants over the years before landing at the center of this new housing push.
According to NBC Boston, Alexandria Real Estate Equities is looking to unlock an additional 250,000 square feet of commercial development at Technology Square in exchange for converting the existing building at 161 First St. into affordable housing. The 1907 building has housed Moderna, Sigilon Therapeutics and Solid Biosciences over the years, according to the Boston Business Journal. That outlet also reports that Alexandria is partnering with Beacon Communities on the residential conversion.
A Trade of Housing for More Office Space
The proposal hinges on a straightforward exchange: give up lab and office space at 161 First St. for a shot at building out more commercial square footage elsewhere on the Technology Square campus. The Boston Business Journal's reporting does not detail the precise terms of that exchange, and it remains unclear how many affordable units the project would ultimately create, how the building would be financed, or what timeline Alexandria and Beacon Communities are working toward.
Cambridge has been a hub for biotech tenants for years, and 161 First St.'s history reflects that churn — the building has passed from Moderna to Sigilon Therapeutics and then to Solid Biosciences before this latest chapter. Whether Cambridge officials have weighed in on or approved the conversion has not been established.
Part of a Broader Push to Convert Office Space Statewide
The Alexandria proposal arrives as Massachusetts pursues a broader strategy of identifying underused commercial buildings that could be converted into housing. MassHousing's Commercial Conversion Initiative, for example, provides municipalities with planning services intended to speed up the reuse of underutilized commercial buildings across the state, according to MassHousing. The agency has completed one phase of that initiative across 11 participating municipalities, identifying roughly 190 “physically viable” commercial buildings across those communities' main streets and downtowns.
In Pittsfield alone, MassHousing's analysis found 23 conversion-viable buildings among about 62 buildings with commercial office uses, per the same source. It is not established whether 161 First St. was part of that MassHousing analysis. Boston has pursued a parallel effort through its own Office to Residential Conversion Program, which the Boston Planning Department says is designed to support owners and developers of older commercial office buildings looking to convert that space into residential units.
Other Conversions Underway Around the State
Similar office-to-housing conversions have already moved forward elsewhere in Massachusetts. A former Fallon headquarters building in Worcester received a $3.6 million tax credit tied to its conversion, part of what Governor Maura Healey has described as a statewide push to boost office-to-housing efforts, according to the Worcester Business Journal. That project has been described as generating roughly 340 new housing units spread across Boston, Fitchburg, New Bedford and Worcester.
For now, the fate of 161 First St. remains a proposal rather than a done deal. Key details — including how many affordable units the Cambridge project would produce, its construction timeline, affordability levels and financing structure — have not been disclosed.
