A novel CAR-T cell therapy, developed by researchers at UCL and designed to target cancerous tumours, has shown early promising results in children with neuroblastoma – a rare form of childhood cancer.
Neuroblastoma is the most common extracranial solid tumour in children. It accounts for about 6% of all cancers in children. However, treatment of high-risk neuroblastoma remains challenging. Current treatment regimens achieve long-term survival in only 50-60% of patients. They are also associated with considerable morbidity.
This tumour typically has high expression of the ganglioside GD2. Previous attempts at targeting these tumours via GD2 have not been entirely successful. This is partly due to the fact that GD2 is also present on non-malignant nervous tissue. Consequently, treatment with therapeutic antibodies targeting GD2 is frequently associated with an acute neuropathic infusional pain syndrome and some reports of infrequent central neurotoxicity.
Chimeric antigen receptor (CAR)-T cells are a relatively new class of immunotherapy. Specifically, they are genetically engineered T cells with an artificial T-cell receptor. Previous studies have shown that CAR-T cells can induce lasting responses in relapsed B cell malignancies.
In a study, published in Science Translational Medicine, researchers investigated treatment of relapsed neuroblastoma using second-generation modified CAR-T cells directed against GD2. They developed a second-generation GD2-CAR with CD28/CD3ζ signalling domains incorporating a humanised anti-GD2 scFv based on the K666 antibody. Twelve children with relapsed/refractory neuroblastoma were treated as part of the Cancer Research UK-funded Phase I clinical trial.
Researchers found that receiving ≥108/meter2 of the CAR-T cells induced rapid reduction in tumour size in some patients. Importantly, in all patients who received the therapy, there were no harmful side effects within healthy tissue.
Dr Martin Pule, UCL Cancer Institute and senior author, stated:
“The rapid regression in neuroblastoma cells is promising, particularly as this activity was observed in the absence of neurotoxicity which occurs with antibody-based approaches that target GD2.”
This is one of the first studies to demonstrate CAR-T cells achieving rapid regression against a solid cancer. Nonetheless, the authors noted that this strategy requires further modification to promote CAR-T cell longevity.
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