‘This is unprecedented in medicine, to be honest, to get response rates in this range in these very advanced patients,’ says lead scientist Stanley Riddell.

In one study, 94 per cent of participants suffering from acute lymphoblastic leukaemia (ALL) said their symptoms vanished completely after they were treated with the modified blood cells, known as T-cells.

In another study, 80 per cent of patients with non-Hodgkin’s lymphoma responded positively to the treatment, while more than half ended up symptom-free.“This is extraordinary,” said lead researcher Professor Stanley Riddell from the Fred Hutchinson Cancer Research Center in Seattle. “This is unprecedented in medicine, to be honest, to get response rates in this range in these very advanced patients.”

Cancer cells under a microscope.Source:News Limited

The treatment involves removing the T-cells from patients, tagging them with “receptor” molecules that target cancer, and putting them back into the body in an infusion. The targeting molecules, known as chimeric antigen receptors or Cars, came from specially bred genetically engineered mice.

Once attached to the T-cells, they reduce the ability of the cancer to shield itself from the body’s immune system.

Such reprogramming of the immune system is often considered a last-ditch option due to its dangerous side effects. The researchers noted that seven of the ALL patients required intensive care after suffering an immune reaction called cytokine release syndrome (sCRS). Two of those patients died.

Prof Riddell said much more work was still required, and it was not clear how long the symptom-free patients would remain in remission.

“Much like chemotherapy and radiotherapy, it’s not going to be a save-all,” Prof Riddell said, adding, “I think immunotherapy has finally made it to a pillar of cancer therapy.”

Prof Riddell also said he hoped to try the therapy on patients suffering from cancers with solid tumours, but said that would present challenges.