Related Beal seeks to expand the Fenway’s lab space inventory with changes to its 300,000-square-foot redevelopment in Kenmore Square.

The developer says it’s reconfiguring designs of a new office building approved in 2018 to include lab and R&D uses, while reducing retail space. The modified program calls for 127,700 square-feet of lab space and 8,560 square feet of retail space, according to filing with the Boston Planning and Development Agency.

In 2018, the BPDA approved the project including an 8-story building with 119,000 square feet of office space at 533-541 Commonwealth Ave., and a 7-story building containing 125,000 square feet of office space at 650-660 Beacon St. Related Beal ground-leases the parcels from Boston University.

Conversions of office buildings to lab-ready space are sweeping through Greater Boston as developers reposition buildings amid uncertainty about companies’ return-to-office timelines in the pandemic.

The 1.8-million-square-foot Fenway/Longwood lab submarket currently has a 0-percent vacancy rate, according to research by Cushman & Wakefield.

Boston-based Samuels & Assoc. also is betting on the Fenway’s potential to attract more life science companies, breaking ground in February on a 500,000-square-foot office-lab tower at 201 Brookline Ave. That property already has attracted leases from Tango Therapeutics and venture capital firm Third Rock Ventures.