Image courtesy of SGA and DREAM Collaborative

A development group led by Related Beal completed its financing for development of a Vertex Pharmaceutical-leased research center that’s ramping up construction in South Boston’s Raymond L. Flynn Marine Park.

Known as Innovation Square Phase III, the 345,000-square-foot complex is located at the corner of Drydock Avenue and Northern Avenue next to Vertex’s Jeffrey Leiden Center for Cell and Genetic Therapies I at 316-318 Northern Ave.

The financing includes a $280 million loan from Santander Bank, according to a Suffolk County mortgage filed Wednesday.

Related Beal is partnering with an ownership group that includes Mitsui Fudosan America, Vertex, Kavanagh Advisory Group and the Boston Real Estate Inclusion Fund (BREIF).

The developers are leasing the property from the Economic Development and Industrial Corp. of Boston. The Boston Planning & Development Agency awarded the development rights to Related Beal, Kavanagh and BREIF in 2022.

Santander Bank, Ullico, LBBW and Washington Capital provided construction financing, according to an statement from the development team.

The project breaks ground as Vertex reportedly weighs a potential relocation of its headquarters of the past decade, located a mile away at the Fan Pier in the Seaport District.

Two developers have lab projects planned near the ISQ campus, including Beacon Capital Partners’ South Boston Innovation Campus at 2 and 4 Harbor St. and Marcus Partners’ approved development at 310 Northern Ave.

Designed by SGA and DREAM Collaborative, ISQ3 will be Boston’s first LEED Platinum and zero-net carbon life science building, incorporating electric heat pumps and a rooftop solar array, developers said. Completion is scheduled for 2026.