Juno Therapeutics, Inc. (Nasdaq: JUNO), a biopharmaceutical company focused on re-engaging the body's immune system to revolutionize the treatment of cancer, today announced that it has voluntarily placed on hold the Phase II clinical trial of JCAR015 in adult patients with relapsed or refractory B cell acute lymphoblastic leukemia, known as the "ROCKET" trial. The clinical hold was initiated after two patients suffered cerebral edema earlier this week. One patient died and as of last night the other is not expected to recover. Juno has notified the Food & Drug Administration of the voluntary hold and is working with the agency and the Data and Safety Monitoring Board to determine next steps. The company is assessing data from the cases and the trial and is evaluating its options regarding the JCAR015 program. Juno's trials and plans for its other CD19-directed CAR T cell product candidates, including JCAR017, are not affected. Conference Call Information Juno will host a conference call today to discuss today's announcement beginning at 5:30 a.m. Pacific Time (PT) / 8:30 a.m. Eastern Time (ET). Analysts and investors can participate in the conference call by dialing (855) 780-7198 for callers in the United States and Canada and +1 (631) 485-4870 for international callers, using the conference ID# 26549311. The webcast can be accessed live on the Investor Relations page of Juno's website, www.JunoTherapeutics.com, and will be available for replay for 30 days following the call. About Juno Juno Therapeutics is building a fully integrated biopharmaceutical company focused on re-engaging the body's immune system to revolutionize the treatment of cancer. Founded on the vision that the use of human cells as therapeutic entities will drive one of the next important phases in medicine, Juno is developing cell-based cancer immunotherapies based on chimeric antigen receptor and high-affinity T cell receptor technologies to genetically engineer T cells to recognize and kill cancer. Juno is developing multiple cell-based product candidates to treat a variety of B-cell malignancies as well as solid tumors. Several product candidates have shown compelling clinical responses in clinical trials in refractory leukemia and lymphoma conducted to date. Juno's long-term aim is to leverage its cell-based platform to develop new product candidates that address a broader range of cancers and human diseases. Juno brings together innovative technologies from some of the world's leading research institutions, including the Fred Hutchinson Cancer Research Center, Memorial Sloan Kettering Cancer Center, Seattle Children's Research Institute, and The National Cancer Institute. Juno Therapeutics has an exclusive license to the St. Jude Children's Research Hospital patented technology for CD19 directed product candidates that use 4-1BB, which was developed by Dario Campana, Chihaya Imai, and St. Jude Children's Research Hospital.