A quality improvement initiative standardizing premedication for blood product transfusions.

For children with cancer, blood product transfusions are crucial, but can be complicated by transfusion reactions. To prevent these complications, premedication is often given, although not always evidence-based. Herein, we describe a significant decrease in the use of premedication (72%-28%) at our institution after the implementation of standardized guidelines, without an increase in transfusion reactions (3.2% prior vs. 1.5% after standardization). Importantly, there were no severe transfusion reactions leading to hospitalization or death. Our results provide evidence in favor of more judicious use of premedication prior to transfusions in patients 21 years and younger being treated for cancer.

Developing a membrane-proximal CD33-targeting CAR T cell.

BACKGROUND: CD33 is a tractable target in acute myeloid leukemia (AML) for chimeric antigen receptor (CAR) T cell therapy, but clinical success is lacking. METHODS: We developed 3P14HLh28Z, a novel CD33-directed CD28/CD3Z-based CAR T cell derived from a high-affinity binder obtained through membrane-proximal fragment immunization in humanized mice. RESULTS: We found that immunization exclusively with the membrane-proximal domain of CD33 is necessary for identification of membrane-proximal binders in humanized mice. Compared with clinically validated lintuzumab-based CAR T cells targeting distal CD33 epitopes, 3P14HLh28Z showed enhanced in vitro functionality as well as superior tumor control and increased overall survival in both low antigen density and clinically relevant patient-derived xenograft models. Increased activation and enhanced polyfunctionality led to enhanced efficacy. CONCLUSIONS: Showing for the first time that a membrane-proximal CAR is superior to a membrane-distal one in the setting of CD33 targeting, our results demonstrate the rationale for targeting membrane-proximal epitopes with high-affinity binders. We also demonstrate the importance of optimizing CAR T cells for functionality in settings of both low antigen density and clinically relevant patient-derived models.