Image courtesy of HFF/JLL

Life science space is the preferred future for a 10-story Downtown Crossing office building acquired in 2022 for $107 million.

Phase 3 Partners of San Diego proposes converting the upper floors of the 115,000-square-foot building at 55 Summer St. into research laboratory space.

Phase 3 bought the property, which includes a CVS Pharmacy, in March 2022.

The half-acre property has frontage on Summer, Chauncy and Kingston streets, and the 115,000-square-foot office building was developed in the mid-1970s.

The project will comply with the Boston Planning & Development Agency’s recently-launched life sciences action agenda, which will include new definitions of research uses and design guidelines for lab and research buildings.

Although the current zoning allows research laboratory use by right, developers are seeking a BPDA large project review because the lab conversion would cost more than 50 percent of the assessed value of the building, according to a Jan. 20 notification letter from attorney Jared Eigerman of Reuben, Junius & Rose LLP in Boston.

No changes are proposed to the ground-floor retail use.