Context Pediatric patients with solid tumors can have a significant symptom burden that impacts quality of life and end-of-life care needs. Objectives We evaluated outcomes and symptoms in children with solid tumors, and compared patterns of end-of-life care after implementation of a dedicated institutional pediatric palliative care service. Methods We performed a retrospective cohort study of children with solid tumors treated at St. Jude Children’s Research Hospital, before and after implementation of the institutional Quality of Life/Palliative Care (QoL/PC) Service in January 2007. Patients who died between July 2001- February 2005 (historical cohort; n=134) were compared to those who died between January 2007- January 2012 (QoL/PC cohort; n=57). Results Median time to first QoL/PC consultation was 17.2 months (range, 9–33 months). At consultation, 60% of children were not receiving or discontinued cancer-directed therapy. Within the QoL/PC cohort, 54 patients had documented symptoms; 94% required intervention for ≥ 3 symptoms; 76% received intervention for ≥ 5 symptoms. Eighty-three percent achieved their preferred place of death. Compared to the historical cohort, the QoL/PC cohort had more end-of-life discussions per patient (median, 12 vs. 3; P<0.001), earlier end-of-life discussions, with longer times before do-not-resuscitate orders (median, 195 vs. 2 days; P<0.001), and greater hospice enrollment (71% vs. 46%, P=0.002). Conclusion Although children with solid tumor malignancies may have significant symptom burden towards end of life, positive changes were documented in communication and in places of care and death following implementation of a pediatric palliative care service.

Chimeric antigen receptor (CAR) T cell immunotherapies targeting CD19 or CD22 induce remissions in the majority of patients with relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL), although relapse due to target antigen loss or downregulation has emerged as a major clinical dilemma. Accordingly, great interest exists in developing CAR T cells directed against alternative leukemia cell surface antigens that may help to overcome immunotherapeutic resistance. The fms-like tyrosine kinase 3 receptor (FLT3) is constitutively activated via FLT3 mutation in acute myeloid leukemia (AML) or wild-type FLT3 overexpression in KMT2A (lysine-specific methyltransferase 2A)-rearranged B-acute lymphoblastic leukemia (ALL), which are associated with poor clinical outcomes in children and adults. We developed monovalent FLT3-targeted CAR T cells (FLT3CART) and bispecific CD19xFLT3CART and assessed their anti-leukemia activity in preclinical models of FLT3-mutant AML and KMT2Arearranged infant ALL. We report robust in vitro FLT3CART-induced cytokine production and cytotoxicity against AML and ALL cell lines with minimal cross-reactivity against normal hematopoietic and non-hematopoietic tissues. We also observed potent in vivo inhibition of leukemia proliferation in xenograft models of both FLT3-mutant AML and KMT2A-rearranged ALL, including a post-tisagenlecleucel ALL-to-AML lineage switch patient-derived xenograft model pairing. We further demonstrate significant in vitro and in vivo activity of bispecific CD19xFLT3CART against KMT2A-rearranged ALL and posit that this additional approach might also diminish potential antigen escape in these high-risk leukemias. Our preclinical data credential FLT3CART as a highly effective immunotherapeutic strategy for both FLT3-mutant AML and KMT2A-R ALL that is poised for further investigation and clinical translation.