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10th November 2015

How gene editing saved a little girl’s life

Layla’s parents never expected their baby girl to become the poster child for a life-saving new blood cancer treatment. They just wanted her to get better.

Having exhausted all treatment options including chemotherapy and a bone marrow transplant, doctors had told Layla’s parents that there was nothing else they could do other than minimise her suffering until her inevitable death from Acute Lymphoblastic Leukaemia (ALL), a form of blood cancer that Layla was diagnosed with when she was just 14 weeks old.

“We didn’t want to accept palliative care and give up on our daughter though so we asked the doctors to try anything,” says her mum, Lisa. There was one other possible treatment, but it was so new that it had only ever been tested in mice and it required her doctors at Great Ormond Street Hospital (GOSH) to get special emergency permission to use it.

Lisa and Layla’s dad, Ashleigh, decided to take the gamble. Ashleigh said it was scary to think that it had never been used in a human before “but even with the risks, there was no doubt that we wanted to try the treatment. She was sick and in lots of pain so we had to do something.”

The treatment involved gene editing, a procedure that’s been described as the scientific equivalent of film splicing done by movie editors. In this case, the “film” is a person’s DNA and the “scissors” are genetically modified or “engineered” cells that can find the place in the DNA where there’s a disease-causing gene mutation, cut the DNA there, and then fix the mutation by letting the body’s natural cellular repair process take over.

The life-saving donor cells were given as a 1ml infusion into Layla’s Hickman line, a tube that’s used to administer medicine into a patient’s veins or to draw blood. The whole procedure took about 10 minutes. Her mum said that she didn’t even notice anything was happening “and was bouncing around her cot all the way through.”

Within a few weeks, Layla developed a rash, which was a good sign ‒ it was the immune response that doctors had been waiting for, and it meant the treatment was working. Two months later, she was cancer free.

Layla’s parents weren’t the only ones holding their breaths. Her lead doctor, Professor Paul Veys, admits that the medical team “didn’t know if or when it would work and so we were over the moon when it did. Her leukaemia was so aggressive that such a response is almost a miracle.”

Once doctors were confident that the leukaemia was gone, Layla had another bone marrow transplant to replace her entire blood and immune system, which had been wiped out by the treatment. She’s now recovering well at home, although she goes back to GOSH regularly to get her bone marrow cells and blood counts monitored.

Lisa and Ashleigh feel extremely lucky, but still worry about the future. “It’s always at the back of your mind. It’s not like chickenpox that clears away, this is constant. You always have doubts. She’ll still have monthly bone marrow checks for now and might be on some medicines for the rest of her life. Hopefully Layla will stay well and lots more children can be helped with this new treatment,’ says Lisa.

With around 400 new diagnoses of childhood ALL every year in UK alone, gene editing has the potential to revolutionise the treatment of this as well as other cancers and diseases. Though it’s still early days and doctors are cautious about claiming that this will be a suitable treatment option for all children, Layla’s case was a major medical breakthrough.

Photo credit goes to: Sharon Leese, GOSH.