University of Louisville School of Medicine and Norton Children’s mourn the loss of world-renowned researcher Dr. William Tse

A trailblazer in life saving treatments for childhood leukemia, immune deficiencies and solid tumors, Dr. William Tse, unexpectedly passed away on March 12, 2025.

March 27, 2025 (Louisville, KY) – Since 2018, Dr. Tse served as the director of the Pediatric Bone Marrow Transplant Program for University of Louisville School of Medicine and Norton Children’s Hospital since 2018Dr. Tse was best known for his groundbreaking CAR T-cell research program that continues to revolutionize how we fight childhood cancers, particularly hard-to-treat brain tumors.

Dr. Tse began his career as a stem cell transplant physician and researcher at Lurie Children’s Hospital, where his innovative work transformed the treatment of severe combined immune deficiency (SCID). His development of a reduced-intensity transplant approach turned SCID from a fatal diagnosis into a curable condition, vastly improving survival rates and quality of life for affected children.

Dr. Tse once said “We do this because it is a rewarding experience. We can make a difference.” His legacy is reflected not only in the countless lives he saved but also in the groundbreaking research he set into motion. His ongoing studies, a multi-center Phase 3 trial in acute leukemias and a chemotherapy-free bone marrow transplant approach for sickle cell disease, are testaments to his unwavering commitment to advancing pediatric medicine

Dr. Tse’s impact extended far beyond the walls of our department. He was a mentor, a leader, and an inspiration to all who had the privilege of working alongside him. His passion for innovation and patient care will continue to shape the future of pediatric hematology and oncology, ensuring that children battling life-threatening illnesses receive the best possible treatments. While his loss is deeply felt, his work and dedication will live on in the lives he touched, the breakthroughs he championed, and the future discoveries his vision has made possible.