Cell-editing trial sees 93pc of participants with leukaemia go into remission

29 Apr 2016

An early-stage and very small trial of sufferers of an acute form of leukaemia has provided “exciting” results, with 93pc entering into remission.

Acute lymphocytic leukaemia (ALL) is a nasty thing to suffer from, however, a trial of a new treatment in the US has provided some remarkable results that point to a potentially rosier future.

Despite it being incredibly early stage, and a small test pool, 27 of 29 participants in the study – each suffering from ALL – went into complete remission after their T-cells were ‘re-engineered’ to fight the cancer.

“In early-phase trials, you’re continually learning. You don’t expect results like these from early-phase trials. That’s why these response rates are so extraordinary,” said senior author Dr David Maloney.

Cut, multiply and reintroduce

Taking place at the Fred Hutchinson Cancer Research Centre in the US, patients had T-cells extracted, tweaked and multiplied into the billions before being reintroduced after their chemotherapy treatment.

The genetic modification added an element that helps the T-cells to recognise, as well as kill, particular cancer cells.

A few weeks after the process was completed, 27 of the 29 patients had no trace of cancer left in their bone marrow – the doctored T-cells killed off cancer in whatever part of the body they were introduced.

It wasn’t all plain sailing, though. Two didn’t respond well enough, with one of those only going into remission after a higher dose of doctored cells was administered. Also, of those who successfully went into remission, some relapsed with leukaemias that were immune to the treated T-cells.

The dramatic initial success, though, is impressive. “This is just the beginning,” said study leader Dr Cameron Turtle.

“It sounds fantastic to say that we get over 90pc remissions, but there’s so much more work to do make sure they’re durable remissions, to work out who’s going to benefit the most, and extend this work to other diseases.”

Doors are opening

Genetic scientists have been making remarkable discoveries in the past three or four years. Last July, researchers at UC San Francisco successfully worked out a way to modify human T-cells – which play a key role in diseases like diabetes, AIDS and cancer – using CRISPR-Cas9.

“Genome editing in human T-cells has been a notable challenge for the field,” said Alexander Marson, PhD, a UCSF Sandler Fellow, and senior and co-corresponding author of the study.

“We wanted not only to cut the genome, but to paste in sequences of DNA into the genome of T-cells. We have now been able to cut as well as paste pieces of the genome into human T-cells,” he said.

Human cells illustration via Shutterstock

Gordon Hunt was a journalist with Silicon Republic