Juno says two patients die in leukemia drug trial

(Reuters) - Juno Therapeutics Inc said two more patients had died after suffering cerebral edema during a trial of its experimental leukemia drug, bringing the total to five. The company's shares tumbled nearly 45 percent to $15.90 in premarket trading on Wednesday. Juno said in July that three leukemia patients had died from similar side effects during the trial of its genetically engineered cancer therapy, known as JCAR015. The company said on Wednesday it had voluntarily put the mid-stage study on hold and informed the U.S. Food and Drug Administration earlier this week. JCAR015 is an experimental therapy requiring a complicated process of extracting immune system T-cells from a patient, altering their DNA to sharpen their ability to spot and kill cancer cells and infusing them back into the same patient. The drug is being evaluated in adult patients with relapsed or refractory B-cell acute lymphoblastic leukemia, a type of blood cancer. Seattle-based Juno had said the three patient deaths in July occurred after the chemotherapy agent fludarabine was added to the trial program. The FDA, which had imposed a hold on the trial after the deaths, lifted it after Juno reverted to its original drug regimen, excluding fludarabine. (Reporting by Natalie Grover in Bengaluru; Editing by Savio D'Souza and Saumyadeb Chakrabarty)