A team of researchers have engineered donor T-cells to treat childhood leukaemia that is resistant to other therapies.
The Phase I trial, conducted by University College London and Great Ormond Street Hospital for Children (GOSH) is the first to use “universal” CRISPR-edited cells in humans, which is a significant step towards employing gene editing technology for childhood leukaemia and other cancer treatment.
Childhood leukaemia is a type of blood cancer that affects children and young people. It targets the white blood cells in the blood and bone marrow. This cancer can either be acute or chronic, meaning it can either develop quickly or slowly over time. However, in most childhood leukaemia cases, the cancer is acute.
The findings are published in Science Translational Medicine.
Using gene editing technology in cancer care
The researchers, led by Professor Waseem Qasim (UCL Great Ormond Street Institute of Child Health & Consultant Immunologist at GOSH), used CRISPR/Cas9, which cuts into cells’ DNA and inserts a new genetic code. In the case of childhood leukaemia, the genetic code allows the T-cells to express a receptor – called a chimeric antigen reception (CAR) that can recognise a marker on the surface of cancerous B-cells and then destroy them.
The T-cells were gene-edited further so they could be used without any donor match needed.
Lead author, Professor Qasim, said: “This kind of unresponsive leukaemia is thankfully very rare, but we are pleased to be able to bring new therapies into play for some of the most difficult-to-treat childhood leukaemias, especially when all other options have been exhausted.
“Whilst there are challenges to overcome, this study is a promising demonstration of how emerging genome-editing technologies can be used to tackle unmet health needs in some of the sickest children we see.”
Trialling the new technology on childhood leukaemia patients
The clinical trial included six children aged 14 months to 11 years with relapsed and treatment-resistant B-Cell Acute Lymphoblastic Leukaemia (B-ALL). All participants were given the therapy up to February 2022.
The participants were given edited cells through intravenous infusion, and the treatment was expected to be active for around four weeks. The team hoped that this would be enough time to achieve deep remission, a state where their cancer is dramatically reduced or undetectable. If this treatment was successful, the patients could have a bone marrow stem cell transplant to help re-establish a healthy immune system.
Four out of the six children entered remission within 28 days, which allowed them to receive a stem cell transplant. Out of the four children, two remained in ongoing remission for nine and 18 months following treatment, whilst two relapsed following their stem cell transplant.
The overall side effects were as expected and manageable with hospital care, with one patient requiring a short period in intensive care.
Dr Kanchan Rao, Consultant in Bone Marrow Transplant at GOSH, said: “This study adds to the growing body of evidence that genome-edited T cells can be a viable alternative to currently available treatments. Whilst this hasn’t been successful in all cases, for some children in this study it has been life-saving.”
The trial showed that the edited T-cells could clear the otherwise-incurable leukaemia in some patients, but that side effects and challenges remained.
The next step is for researchers to offer the treatment to more children, earlier in their treatment pathways when their cancers have not progressed so far.