Sesen Bio, Inc., a late-stage clinical company, focuses on designing, engineering, developing, and commercializing targeted fusion protein therapeutics (TFPTs) for the treatment patients with cancer.

Its lead product candidates include Vicineum, a locally-administered targeted fusion protein that is in Phase III clinical trials for the treatment of bacillus Calmette-Guérin (BCG)-unresponsive non-muscle invasive bladder cancer; to treat non-muscle invasive carcinoma in situ of the bladder in patients previously treated with BCG; and for the treatment of squamous cell carcinoma of the head and neck, as well as VB6-845d, a product candidate for use in the treatment of various types of an anti-epithelial cell adhesion molecule-positive solid tumors.

Sesen Bio, Inc. has an agreement with Leiden University Medical Center to co-develop an imaging agent.

The company was formerly known as Eleven Biotherapeutics, Inc. and changed its name to Sesen Bio, Inc. in May 2018.

Sesen Bio, Inc. was incorporated in 2008 and is headquartered in Cambridge, Massachusetts.