US scientists claim to have successfully wiped out an aggressive form of childhood leukaemia in a young girl using her own modified T cells to fight the cancer.
The treatment reprogrammed her immune cells to rapidly multiply and destroy leukaemia cells, researchers from the Children's Hospital of Philadelphia and the University of Pennsylvania reported in The New England Journal of Medicine.
The 7-year-old Emily Whitehead, is reported to be healthy and cancer-free, 11 months after receiving bio-engineered T cells.
The other patient, a 10-year-old girl, who also had a complete response to the same treatment, however, suffered a relapse two months later when other leukaemia cells appeared that did not harbour the specific cell receptor targeted by the therapy.
"This study describes how these cells have a potent anticancer effect in children," said co-first author Stephan A Grupp.
"However, we also learned that in some patients with acute lymphoblastic leukaemia (ALL), we will need to further modify the treatment to target other molecules on the surface of leukaemia cells," Grupp said in a statement.
Two of those patients remain in remission more than 2 and a half years following their treatment, and seven out of ten adult patients treated at that point responded to the therapy.
"In the long run, if the treatment is effective in these late-stage patients, we would like to explore using it up front, and perhaps arrive at a point where leukaemia can be treated without chemotherapy," Carl H June, current study's senior author, said.
The new study used a relatively new approach in cancer treatment: immunotherapy, which manipulates the immune system to increase its cancer-fighting capabilities. The researchers engineered T cells to selectively kill another type of immune cell called B cells, which had become cancerous.
They removed some of each patient's own T cells and modified them in the laboratory to create a type of CAR (chimeric antigen receptor) cell called a CTL019 cell - designed to attack a protein called CD19 that occurs only on the surface of certain B cells.
By creating an antibody that recognises CD19 and then connecting that antibody to T cells, the researchers created in CTL019 cells a sort of guided missile that locks in on and kills B cells, thereby attacking B-cell leukaemia.
After being returned to the patient's body, the CTL019 cells multiply a thousand times over and circulate throughout the body.
Importantly, they persist for months afterwards, guarding against a recurrence of this specific type of leukaemia.
