Two infants with leukemia are now in remission, thanks to a world-first treatment that uses genetically engineered T-cells from healthy donors.

The UK patients were first given the treatment back in 2015, after chemotherapy failed to show results. Now, after two years, both remain cancer-free.

If similar success is seen in future trials, the treatment could offer a cheap and universal way to fight cancers, without needing to tailor T-cells specifically for different patients.

“This application of an emerging technology has provided a demonstration of the potential of gene-editing strategies for engineered cell therapies, albeit with a clinical experience limited to two infants,” the team from London’s Great Ormond Street Hospital writes.

The infants, who were 11 months and 16 months when they started the new treatment, had previously undergone chemotherapy to treat leukemia. Both treatments failed to show any results, and their parents were told they should prepare for the worst.

With no other options, doctors at London’s Great Ormond Street Hospital tried a new procedure: injecting the infants with genetically engineered T-cells – known as chimeric antigen receptor, or CAR-T cells – taken from healthy donors.

T-cells are a type of white blood cell that can attack and destroy infected cells within the body, including cancer cells.

Unfortunately, the body’s T-cells aren’t always up to the task of finding and destroying all cancerous cells, especially if they’re growing particularly fast.

There have been attempts in the past to improve T-cells’ ability specifically seek and destroy cancer cells.

This new treatment, on the other hand, doesn’t require a patient’s own T-cells, meaning doctors could soon have genetically engineered treatments ready to be implemented as soon as cancer is diagnosed, instead of having to wait for the patient’s own T-cells to be engineered.

“We’re in a wonderful place compared to where we were five months ago, but that doesn’t mean cure,” team member Paul Veys from University College London told the BBC back in 2015.

“The only way we will find out if this is a cure is by waiting that one or two years, but even having got this far from where we were is a major, major step.”

It has now been one to two years, and both children are still in remission, suggesting that the treatment has worked so far.

Journal article: