421 Park Drive, left, is at the Alexandria Center for Life Science in Boston's Fenway neighborhood. Photo courtesy of Alexandria Real Estate Equities

Boston Children’s Hospital will acquire nearly half of a new Fenway life science complex being developed by Alexandria Real Estate Equities.

The 660,000-square-foot development is scheduled to break ground this year at 421 Park Drive. Children’s Hospital will pay $155 million for a 268,000-square-foot section of the new building’s 550,000-square-foot office-lab space, which will include a 50,000-square-foot Star Market as its retail tenant.

Completion of the 421 Park Drive building is scheduled for 2026, Alexandria announced.

The development is the third phase of a 2 million-square-foot redevelopment of the former Landmark Center property. In April 2022, Children’s Hospital leased 42,000 square feet at 201 Brookline Ave., a new 480,251-square-foot life science tower developed on a section of the nearly 9-acre property.

Alexandria paid $1.5 billion in 2021 for an ownership share of the property with Samuels & Assoc., including the Art Deco-style building that functioned as a Sears catalog warehouse from 1928 to 1988 before being converted into office and retail space.

The Star Market will relocate from 1400 Boylston St., where Samuels is seeking approval for a 553,000-square-foot life science building.