A one-year-old girl diagnosed with incurable aggressive leukemia is now in remission after receiving “designer cells” from a donor. The therapy made use of a powerful new gene-editing technique that could eventually be used to treat an array of hereditary diseases.
Layla Richards from London, England, is the first patient in the world to receive the pioneering therapy, which was performed by Great Ormond Street hospital doctors. They’re not calling it a cure, but her condition has improved vastly from just a few months ago, when her prognosis looked grim. The therapy appears to be holding the leukemia at bay.
Her situation had been dire, prompting the medical staff, along with biotech firm Cellectis, to seek permission to use the untested technology. The only prior application of the technique, known as site-specific genome editing, was performed on mice. Layla, who was diagnosed with leukemia when she was three months old, started to take a turn for the worse, compelling her doctors — and her parents — to take the desperate measure, one that now appears to be paying off.
“I didn’t want to go down that road [and admit her to palliative care], I’d rather that she tried something new and I took the gamble,” noted Layla’s father, Ashleigh, in a BBC article. “And this is her today standing laughing and giggling, she was so weak before this treatment, it was horrible and I’m just thankful for this opportunity.”
For the therapy, the doctors made use of a biotechnology known as transcription activator-like effector nuclease, or TALENs for short. It’s an enzyme that allows scientists to cut DNA strands at specific sequences, which is why it’s often referred to as a molecular scissor. In this case, immunologist Wasseem Qasim and his team at GOSH used the TALENS scissor to deactivate the genes in healthy, donated immune T-cells that would normally cause the foreign cells to be rejected when transplanted into a leukemia patient. The cells were also modified to protect them from anti-cancer drugs.
The details of the procedure, which will be presented at the 54th American Society of Hematology, now appear at the science journal, Blood.
To make room for the new “designer cells,” Layla’s existing immune system had to be destroyed. After the procedure, Layla’s health improved almost instantly. Team member Paul Veys was quoted in the BBC as saying the transformation was one of the most remarkable things he’d seen in 20 years, describing the turn of events as “almost like a miracle.”
However, while Layla’s leukemia is currently in remission, it’s still early, and it represents a single case. The technique has not yet been tested in formal, long-term clinical trials. What’s more, the therapy is not meant to be permanent; as noted by Qasim in Nature News, it’s meant to serve as a “bridge” to keep Layla and future patients alive until a matched T-cell donor can be found.
Looking to the future, and assuming this technique can work in the ways intended, it could be used to treat an assortment of ailments, including hemophilia, beta thalassemia, and hemoglobinopathy (a hereditary condition involving an abnormality in the structure of hemoglobin).