Engineering certain immune cells to kill cancerous cells in leukaemia has driven the disease into remission for up to two years in more than half of participants in an early-stage clinical trial.

Stephan Grupp at the Children's Hospital of Philadelphia, Pennsylvania, and his co-workers tested their approach on 30 people with acute lymphoblastic leukaemia, including 25 children, who had failed to respond to conventional treatment or relapsed.

The team engineered a patient's T cells to express a receptor that targets the cancerous B cell, and infused the T cells back into the person. After one month, 27 people were in remission, and after up to 2 years, 78% survived — a much higher rate than with chemotherapy. Those in remission had high blood levels of the engineered T cells.

However, all of the participants had inflammatory side effects that required hospitalization.

N. Engl. J. Med. 371, 1507–1517 (2014)