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New Gene-Editing Technique Treats Baby's Leukemia

British researchers say they’re excited about an experiment in which they used a new technique called gene-editing to treat a baby girl who was dying of leukemia.
Image: Layla, 1, was treated with gene-edited immune cells for her ‘incurable’ leukemia.
Layla, 1, was treated with gene-edited immune cells for her ‘incurable’ leukemia.NBC News

It’s got all the elements of a movie script — a dying baby, desperate parents, and a team of doctors with a completely untried and highly experimental treatment.

With nothing to lose, they try it on the baby. And…it works. Maybe. Maybe not. But one-year-old Layla Richards is better, and everyone involved is elated.

The researchers admit it is far too soon to say whether the treatment actually helped Layla, and they are far from certain that her remission will last. But at the very least, the experiment did not make her any worse, they reported late Thursday.

The approach is called gene editing. It’s a way to modify the body’s cells in a very precise way — much more precise than old-fashioned gene therapy, in which new genes are inserted somewhat haphazardly into a cell’s nucleus.

In this case, the team at Great Ormond Street Hospital in London had developed a batch of immune system cells called T-cells that are precisely snipped in just the right way to prevent them from attacking the patient’s own cells. They’re also modified to resist chemotherapy drugs. And they’re boosted to attack leukemia cells.

"We asked the doctors to try anything for our daughter, even if it hadn’t been tried before."

Unlike approaches being used by other teams, which modify a patient’s own T-cells, this allows for a donor’s cells to be used in a patient. It worked, the team is preparing to tell a meeting of the American Society of Hematology next month.

"The treatment was highly experimental and we had to get special permissions, but she appeared ideally suited for this type of approach,” said Waseem Qasim, the researcher at Great Ormond Street Hospital who led the experiment.

It’s unusual for researchers to publicize this type of research in this way. Usually, several patients are treated and the work is submitted to panels of experts for review. But the abstracts — brief summaries of all the research to be presented at the meeting —were published late Thursday and the hospital put out a news release.

So there are few details available. Layla did get another round of chemotherapy right before the treatment, and that could have made her better, too, outside experts say.

It’s an advance on a technique researchers have been doing it for years. It’s been very successful, says Dr. Renier Brentjens of the Memorial Sloan Kettering Cancer Center in New York.

What Brentjens and teams at other cancer centers have been doing is taking out a patient’s own T-cells and fixing them.

“Your own T-cells won’t recognize your tumor cells. They think the tumor cell is, in fact, a normal cell,” he told NBC News. “You need to re-educate these T-cells.”

They’ve been using less-precise techniques to genetically modify a patient’s T-cells, and spend about a week or two growing them in a lab before re-infusing them back into the patient. Around 90 percent of patients go into remission, Brentjens said.

But because they are the patient’s own T-cells, they don’t have to be additionally modified to prevent graft-versus-host disease, a potentially fatal side-effect that happens when the transfused t-cells start attacking the patient.

The idea behind the Great Ormond Street team’s approach is to have off-the-shelf T-cells prepared and waiting for use in patients. It’s not yet clear if this approach is superior to the older approaches.

“Previously, the engineered T-cell treatments that have shown very significant efficacy in clinical trials have been obtained from patients themselves, and so you have to make a T-cell product for every single patient,” said Dr. Stephan Grupp of the University of Pennsylvania Perelman School of Medicine, who’s also treating leukemia patients with genetically modified T-cells.

“The potential of this new approach is that you might not have to make the T-cell product from every patient, but instead have a single donor from whom you could treat many patients. The innovation here is gene-editing T-cells so that one person’s T-cells could be given to another even if they are not a donor match.”

“Your own T-cells won’t recognize your tumor cells. They think the tumor cell is, in fact, a normal cell."

What’s clear is that Layla was very ill and her parents, Ashleigh and Lisa Richards, were ready to try anything.

"We didn’t want to accept palliative care and so we asked the doctors to try anything for our daughter, even if it hadn’t been tried before,” Lisa Richards said.

Layla had been diagnosed with acute lymphoblastic leukemia at the age of 14 months and nothing had cured it.

That the researchers think their approach worked would be an understatement.

"As this was the first time that the treatment had been used, we didn’t know if or when it would work and so we were over the moon when it did. Her leukemia was so aggressive that such a response is almost a miracle,” said Paul Veys, director of bone marrow transplant at the hospital, who treated Layla.

Outside experts are a bit more cautious.

"This is a very exciting first effort and the authors imply that they are taking this to wider trial. More patients treated will give us a better idea of what the true impact these genetically engineered T cells will have on leukemia,” Grupp said.

Grupp and Brentjens agree that it is not at all clear whether Layla was in fact helped by the T-cell treatment. Chemotherapy had driven her leukemia to very low levels already, they said, and it takes more than a few months to see if the leukemia will come back.

"This is an incremental advance on very exciting technology," Brentjens said.