Teenager Becomes World’s First to Beat “Incurable” Leukaemia with Revolutionary Gene-Edited Cell Therapy

Alyssa Tapley was just 13 when doctors told her family that palliative care might be the only path left. Diagnosed with aggressive T-cell acute lymphoblastic leukaemia (T-ALL) in 2021 after months of unexplained fatigue, infections and weight loss, the Leicester teenager had already failed both chemotherapy and a bone marrow transplant. Her cancer appeared unstoppable.

Then, in May 2022, she became the first person on Earth to receive an experimental treatment called BE-CAR7 at Great Ormond Street Hospital (GOSH) in London.

Three and a half years later, at age 16, Alyssa is cancer-free, back at school, sailing, completing her Duke of Edinburgh Award, and dreaming of learning to drive. She has been officially discharged from active treatment and moved to long-term follow-up.

“I wanted to try it because even if it didn’t work for me, it might help someone else,” Alyssa says. “Now I know it worked — I’m living the teenage life I thought I’d lost. My next big goal is to become a research scientist and help discover the next treatment that saves people like me.”

How the breakthrough therapy works

Traditional CAR-T cell therapy — already a game-changer for some blood cancers — harvests a patient’s own T cells, engineers them in a laboratory to attack cancer, and infuses them back. But in T-ALL, the cancer itself arises from faulty T cells, making the standard approach impossible.

BE-CAR7 solves this by starting with healthy donor T cells and using an ultra-precise gene-editing tool called base editing to make seven critical changes in a single step:

• Adding a chimeric antigen receptor (CAR) that targets CD7, a protein found on virtually all T-ALL cells (and normal T cells).
• Knocking out the donor cells’ own CD7 so they don’t destroy each other.
• Disabling other safety switches to prevent the engineered cells from attacking the patient or being rejected.

The result: an “off-the-shelf” army of killer T cells that wipes out every CD7-positive cell in the body — including the leukaemia — within weeks.

Once the cancer is cleared, patients receive a bone marrow transplant to rebuild a healthy immune system.

Latest clinical trial results

The findings, published today in the New England Journal of Medicine and presented at the American Society of Hematology annual meeting, cover 13 high-risk T-ALL patients (nine children and four adults) treated at GOSH and King’s College Hospital:

• 82% achieved deep remission in time to proceed to stem-cell transplant
• 64% (almost two-thirds) remain leukaemia-free long-term

Side effects were significant but manageable — mainly low blood counts and skin rashes — and no unexpected severe toxicities occurred.

Professor Waseem Qasim, the UCL and GOSH scientist who pioneered the approach, said: “These results confirm that precision base-edited, universal CAR-T cells can tackle even the most resistant CD7-positive leukaemias. It’s a major step toward making advanced cell therapies faster and more widely available.”

Dr Robert Chiesa, consultant in bone marrow transplantation at GOSH and co-investigator, added: “About one in five children with T-ALL still relapse or fail standard treatment. For them, options have been extremely limited. This therapy is bringing real hope.”

Since Alyssa, eight more children and two adults have received BE-CAR7. Researchers are now planning larger trials and exploring the same base-editing platform for other hard-to-treat cancers.

For the Leicester schoolgirl who once thought she would never see 14, the future has never looked brighter.