Cyteir Therapeutics is a leader in the discovery and development of next-generation synthetic lethal therapies for cancer.

Cyteir discovers, develops, and produces synthetic lethal therapies to treat cancer and autoimmune diseases.

Cyteir Therapeutics was founded in 2012 by Kevin Mills & Tim Romberger and is headquartered in Lexington, Massachusetts.

Cyteir exploits the synthetic lethality of gain-of-function DNA-damaging genes and DNA repair inhibition, resulting in selective death among cells with high levels of DNA damage.

Cyteir's platform is based on the discovery of a relationship between DNA-damaging enzymes known as cytidine deaminases, and RAD51, a protein that is essential for the repair of DNA breaks. These enzymes are non-damaging in healthy tissues, but gain hyperactive function in a wide range of cancers and cause elevated DNA damage.

Cyteir is developing selective small-molecule inhibitors of RAD51 to reduce the ability of cancer cells to self-repair through homologous recombination. This causes the cancer cells to become overwhelmed by accumulated DNA damage and undergo cell death – resulting in the therapeutic effect known as "synthetic lethality."

Cyteir is backed by RA Capital Management, Novo Holdings, Venrock, Janus Henderson Investors, DROIA, Osage University Partners, Lightstone, Celgene Corporation and others. The company raised $80M in Series C round on Feb 11, 2021. This brings Cyteir's total funding to $155.2M to date.