A research on the treatment of leukemia using genetically re-engineered cells stopped unexpectedly this week as a result of the deaths of two patients on the new therapy. Juno Therapeutic, a biotechnology company, was conducting a trial test on the use of genetically engineered immune cells called CAR-T to treat acute lymphoblastic leukemia. This new therapy has reached an advanced developmental stage and seems to be a potential drug in the treatment of cancer, a sign for indicators to come in.


The Food and Drug Administration, FDA, stopped the trial test for this new therapy on Wednesday. This development followed a report by Juno that two of the patients on the trial treatment died from swollen brain. The company’s executives on Thursday disclosed in a conference call that a similar cause of death was reported in May. However, FDA and the biotechnology company concluded that the death may be from other causes.


The Seattle based Biotechnology company has blamed the recent deaths on the administration of a chemotherapeutic drug which was not part of the company’s new therapy. However, it is expected that FDA will allow the trial test to continue without the added drug. Hans Bishop, the CEO of Juno revealed that the company used only one drug in its initial experiments to increase the patients’ immune system. However, the addition of Fludarabine led to an increased “severe neurotoxicity”.


Though, the use re-engineered cells to enhance patients’ immune system is promising, it has not been certified. The therapy involves isolation of white blood cells’ T-cells through filtration and modification of these cells genetically to fight cancer. The modified cells are then re-introduced into the patients’ blood. However, one of the researchers revealed that brain swelling has not been reported in over 300 cases treated with this new therapy.