Seattle Children's Pediatric Leukemia Adoptive Therapy (PLAT-02) Clinical Trial Boasts 91% Complete Remission Rate in Children with Relapsed Leukemia

SEATTLE, April 21, 2015 /PRNewswire/ -- Seattle Children's announced today that 20 of 22 patients treated thus far in a clinical trial using genetically reprogrammed T cells to treat relapsed acute lymphoblastic leukemia (ALL) have achieved complete remission, confirmed by highly sensitive tests designed to detect minute amounts of cancer cells. The 20 patients who have achieved complete remission included children with very high tumor burdens as well as children who were diagnosed with ALL as infants.

"These results are extremely encouraging," said Dr. Mike Jensen, director of Ben Towne Center for Childhood Cancer Research at Seattle Children's Research Institute, who presented the results this morning at the American Association for Cancer Research (AACR) Annual Meeting 2015 in Philadelphia. "This trial is helping us understand how the therapy works, which will hopefully lead to it working for all forms of pediatric cancer."

The trial, known as Pediatric Leukemia Adoptive Therapy-02 (PLAT-02), includes patients with acute lymphoblastic leukemia who have relapsed after a bone marrow transplant, or who are unable to get into remission to proceed with a bone marrow transplant, and typically have only a 10% to 20% chance of survival with standard treatment. Using immunotherapy, which reprograms the body's T cells to hunt down and destroy cancer cells, researchers have seen a 91% complete remission rate.

"Some of our earliest treated patients are now a year post-therapy and are still in remission," said Seattle Children's oncologist, Dr. Rebecca Gardner, who is the lead investigator for the trial. "They've remained in remission without further chemotherapy or other treatments. This gives us hope that, eventually, we'll be able to use this therapy in patients who are newly diagnosed, reducing the need for toxic therapies and bone marrow transplants."

In the first phase of the trial, Gardner treated 22 patients with relapsed acute lymphoblastic leukemia using cancer immunotherapy. This phase was designed to demonstrate the safety of cancer immunotherapy as a treatment for leukemia and to determine the optimal dose of engineered T cells to administer to patients. Of the 22 patients treated, 20 responded to the treatment and achieved complete remission. Gardner expects to treat another 8-10 patients before completing the first phase of the trial in about 12 weeks.

The second phase of the trial, which is expected to begin later this year, will allow even more patients to be treated with what researchers determine is the optimal dose of reengineered T cells.

Juno Therapeutics, Inc. (Nasdaq: JUNO) has entered into a licensing arrangement with respect to Seattle Children's Research Institute's PLAT-02 trial, which is designated as JCAR017 by Juno.

For more information on immunotherapy research trials at Seattle Children's, please call (206) 987-2106 or email immunotherapy@seattlechildrens.org.  

About Seattle Children's

Three simple words define Seattle Children's Hospital, Foundation and Research Institute – Hope. Care. Cure. Together, the three deliver superior patient care, advance new discoveries and treatments through pediatric research, and serve as the pediatric and adolescent academic medical referral center for Washington, Alaska, Montana and Idaho – the largest region of any children's hospital in the country.

Consistently ranked as one of the best children's hospitals in the country by U.S. News & World Report, Seattle Children's Hospital specializes in meeting the unique physical, emotional and developmental needs of children from infancy through young adulthood. For more than 100 years, the hospital has been dedicated to providing top-quality care to every child in who needs it, regardless of the family's ability to pay.

Seattle Children's Hospital and Research Foundation gathers community support and raises funds for Seattle Children's Hospital and Seattle Children's Research Institute.

Located in downtown Seattle's biotech corridor, Seattle Children's Research Institute is pushing the boundaries of medical research to find cures for pediatric diseases and improve outcomes for children all over the world. Internationally recognized investigators and staff at the research institute are advancing new discoveries in cancer, genetics, immunology, pathology, infectious disease, injury prevention and bioethics, among others.

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SOURCE Seattle Children’s