Background: The global ELIANA trial (NCT02435849) evaluates the efficacy and safety of CTL019, a single infusion of genetically modified autologous chimeric antigen receptor–expressing T cells targeting CD19+ cells in pediatric and young adult r/r B-ALL pts. Analyses show a complete response rate of 82% with or without complete blood count recovery ≤ 3 months. A serious adverse event rate of 71% was observed in ≤ 8 weeks of infusion, decreasing to 17% at > 8 weeks (Grupp S, et al. Blood. 2016;128(22) [abstract 221].). This analysis further evaluates the clinical benefit of CTL019. QOL was assessed before and after CTL019 infusion. Methods: Infused pts were 3-23 y/o with CD19+ B-ALL who were chemo refractory, relapsed after allogeneic stem cell transplant (SCT), or otherwise ineligible for SCT. Pts ≥ 8 y completed the Pediatric Quality of Life Inventory (PedsQL) and EuroQol EQ-5D at baseline and following CTL019 infusion. Minimal clinically important differences are estimated to be 4.4 and 7 to 10 for PedsQL and EQ-5D, respectively. Results: 62 of 81 enrolled pts were infused; 56% had relapsed after SCT with median of 3 prior therapies. At interim analysis, 50 pts were treated ≥ 3 months prior to data cutoff and eligible for primary efficacy analysis. A total of 39 pts were ≥ 8 y. Mean PedsQL total and EQ-5D VAS scores, respectively, were 58.4 and 69.4 at baseline. Mean changes from baseline for the PedsQL total and EQ VAS scores, respectively, were 13.9 and 13.7 at month 3 and 12.8 and 10.9 at month 6, supporting clinically meaningful improvements in QOL. Similar trends were observed with each PedsQL subscale. With EQ-5D, the proportions of pts reporting problems with mobility, self-care, usual activities, anxiety/depression, or pain/discomfort were notably decreased at months 3 and 6 compared with baseline. Conclusions: Clinically meaningful improvements in QOL were observed at 3 and 6 months after CTL019 therapy in pediatric and young adult r/r B-ALL pts, including fewer problems in each EQ-5D domain. These results suggest improved QOL after this one-time immunocellular therapy beyond the period of acute toxicities. Clinical trial information: NCT02435849