A revolutionary T-cell therapy could offer young leukemia patients new hope in treating the disease. The personalized cellular potentially revolutionary therapy, CTL019, showed positive effects on subjects taking part in a recent study.

Ninety percent of patients diagnosed with advanced acute lymphoblastic leukemia (ALL), who had previously experienced relapses of the disease, went into full remission after being treated with the drug. However, the sample size was small, studying the results of the treatment on just 30 patients.

Researchers from the Perelman School of Medicine at the University of Pennsylvania developed the treatment.

Seven of the patients with advanced acute lymphoblastic leukemia (ALL) in the study relapsed after taking the drug, presenting one piece of bad news to researchers who developed the treatment.

Previous research on effects of the treatment on patients suffering from ALL mostly focused on adults. This was the first major study of the effectiveness of the drug in children.

"The patients who participated in these trials had relapsed as many as four times, including 60 percent whose cancers came back even after stem cell transplants. Their cancers were so aggressive they had no treatment options left. The durable responses we have observed with CTL019 therapy are unprecedented," Stephan Grupp, MD, professor of Pediatrics in Penn's Perelman School of Medicine and the Children's Hospital of Philadelphia, said.

Treatment with CTL019 begins by collecting T-cells, a type of white blood cell essential to the immune system, through a process called apheresis. In this process, blood taken from a patient is separated into components, and T-cells extracted. Then, the remainder of the fluid is pumped back into the person receiving treatment. The T-cells are "trained" using genetic therapy to fight cancer, using a protein known as a chimeric antigen receptor (CAR), before being placed back into the sick individual. This protein binds onto another protein called CD19 found on B cells, including cancerous versions. Once inside the body, these "hunter cells" multiply and attack the cancer. Each engineered cell placed into a patient can create up to 10,000 hunter cells to destroy cancerous cells.

A nine-year-old in the study was the youngest patient ever to receive the therapy, over two years ago. Three of the patients who experienced relapses of cancer suffered from CD19-negative forms of cancer that would not have been affected by CTL019.

Treatment with the therapy killed healthy B-cells, along with cancerous forms. These normally play a role in healthy immune systems, so immunoglobulin replacement is prescribed to take on that function.

Development and testing of CTL019 was detailed in The New England Journal of Medicine.