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Leukemia T-Cell Trial Stopped After Patients’ Deaths

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(dimitrisvetsikas1969, Pixabay)

Update, 13 July 2016. Juno Therapeutics said late yesterday, the Food and Drug Administration lifted its clinical hold on its intermediate-stage clinical trial testing engineered T-cells as a treatment for B-cell acute lymphoblastic leukemia. The company says under the revised plan for the trial, patients will first receive chemotherapy with the drug cyclophosphamide, not fludarabine, which was implicated in the deaths of 3 patients, leading to stoppage of the study.

8 July 2016. The U.S. Food and Drug Administration halted a clinical trial testing engineered T-cells as a treatment for leukemia, after 3 participants died. The treatments for adult B-cell acute lymphoblastic leukemia were developed by Juno Therapeutics, a biotechnology company in Seattle.

B cell acute lymphoblastic leukemia is a cancer of blood and bone marrow that progresses quickly, making an overabundance of immature lymphocytes, a type of white blood cell. It is the most common type of cancer among children, although it can also affect adults.

The treatments, code-named JCAR015 by Juno, harness the cancer-fighting ability of a patient’s own T-cells, white blood cells in the immune system, engineered with a gene adding molecules known as chimeric antigen receptors to their DNA. Without these added weapons, cancerous cells evade the immune system, allowing tumors to grow unchecked.

The chimeric antigen receptors added to T-cells, called CAR-Ts, are designed in this case to attack cancer cells identified with specific CD19 proteins. These CD19 molecules act as indicators of weakened B-cells in the immune system found with blood-related cancers. The modified T-cells are then infused back into the patient.

In the clinical trial, an intermediate-stage study testing JCAR015, patients with B-cell acute lymphoblastic leukemia are pre-treated with chemotherapy, then given 2 infusions of CAR-T cells that replace original T-cells depleted by chemotherapy. As reported by Matthew Herper in Forbes, one of the chemotherapy drugs given to participants was fludarabine, marketed as Fludara by the Genzyme division of Sanofi. Three patients out of 20 recruited so far for the trial developed inflammation in the brain and died after receiving fludarabine and the CAR-T treatments.

FDA put a clinical hold on the trial after the first two deaths were reported. The agency is asking Juno for documents showing changes in its clinical trial protocol — the overall plan for the study — and instructions for investigators, a new patient consent form, and the presentation given to FDA on Wednesday.

Up to now, Juno reported a string of favorable results from its CAR-T therapies for blood-related cancers. As described in Science & Enterprise last month, an early-stage trial of JCAR015 with B-cell acute lymphoblastic leukemia patients showed high rates of response and remission, where all signs of leukemia disappear. However, the trial also showed high rates of adverse effects, including severe cytokine release syndrome that occurs when enzymes are emitted from cells targeted by treatments, which can cause flu-like symptoms such as fevers, nausea, and muscle pain, as well as neurological symptoms including hallucinations and delirium.

Juno Therapeutics is a spin-off company from from Fred Hutchinson Cancer Research Center in Seattle, Memorial Sloan-Kettering Cancer Center in New York, and Seattle Children’s Research Institute.

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