A leading life science developer is taking over redevelopment of an Assembly Square site with plans for a larger office-lab project than was originally approved by Somerville officials in 2018.

BioMed Realty is seeking to increase the total square-footage for the master-planned development by 100,000 square feet to 1.6 million square feet. 

The Boston Business Journal reported that the firm has agreed to acquire the site from the previous development team, Cresset Group and Novaya Real Estate Partners. The master plan previously included approvals for 167 apartments, which would be eliminated.

The proposed amendment calls for 1.2 million square feet of office-lab space in three buildings, an increase of 58,000 square feet of public open space and 24,500 square feet of ground-floor retail.

A 329-unit residential complex is under construction by Wood Partners on the southeastern corner of the property.

The 9-acre site is located on Middlesex Avenue next to Federal Realty’s Assembly Marketplace and contains surface parking and an office building. BioMed, which is owned by Blackstone Real Estate, owns over 11 million square feet of commercial real estate in the U.S. and United Kingdom.

The Somerville planning board will begin its review of the amendments at a virtual meeting at 6 p.m. The board also will review plans for a 525,000-square-foot commercial building at 74 Middlesex Ave., which is proposed by Boston Global Investors and Amsterdam-based EDGE.

Boston-based Leggat McCall Properties broke ground last fall on Somerville’s first major life science development at 101 South St., a 289,000-square-foot speculative office-lab building in the transforming Boynton Yards neighborhood.