Medical oncologist Guenther Koehne, the Medical Director of Memorial Sloan Kettering’s Cytotherapy Lab, explains how a patient with refractory multiple myeloma and plasma cell leukemia achieved remission with WT1-specific T-cell therapy. Patient Ruth Lacey describes developing plasma cell leukemia after treatment for multiple myeloma that included intensive chemotherapy. She then received a stem cell transplant from a donor, followed by infusions of Wilms tumor antigen 1 (WT1)–specific T cells as part of a clinical trial. The modified T cells were generated from the T lymphocytes of the original stem cell donor and were grown in a lab and immunized against the WT1 protein, which is overproduced and expressed by multiple myeloma cells. The WT1-sensitized T cells are designed to attach to the WT1 protein and kill the myeloma cells. Lacey has been in remission for two years.