Strain engineered without the lethal toxin gene and used in cancer therapy. Clostridium novyi NT strain:NT

Clostridium novyi strain NT. This strain (NT) was created so that it lacks the lethal toxin. Injection of spores of this organism into mice harboring tumors resulted in an increased immune response and destruction of the tumor tissue in a method known as COBALT (combination bacteriolytic therapy) when the spores along with chemotherapeutic agents or radiation are co-administered. The anaerobic bacteria preferentially target hypoxic cancer tissue and stimulate immune responses to that tissue.