Image courtesy Breakthrough Properties

A Swiss biopharma company that’s working on treatments for type 1 diabetes and cancer will occupy a speculative new life science development in South Boston.

CRISPR Therapeutics signed a 12-year lease for all 263,500 square feet at “The 105,” being developed by a partnership of Tishman Speyer and Bellco Capital at 105 West First St.

The lease commences with annual payment of $21 million, or $80 per square foot, and increases at 4 percent per year to nearly $28 million in the final year, according to an SEC filing.

Headquartered in Zug, Switzgerland, CRISPR has had research operations at 610 Main St. in Cambridge.

The developers’ partnership, Breakthrough Properties, was formed last year to pursue life science development opportunities in markets including Greater Boston. The owners acquired the property for $80 million in July 2019 and broke ground in November.

Architects Payette designed the building which will include two floors with outdoor terraces and a fitness facility.

While some life science companies have put their real estate space searches on hold during the COVID-19 pandemic, the lab market remained resilient in the second quarter. In Downtown Boston, lab users accounted for 78,000 square feet of positive absorption and asking rents rose 8 percent to $82.36 per square foot on a triple-net basis, according to a research report this month by CBRE.