Evolution of tisagenlecleucel use for the treatment of pediatric and young adult relapsed/refractory (r/r) B-cell acute lymphoblastic leukemia (B-ALL): Center for International Blood &amp; Marrow Transplant Research (CIBMTR) registry results.
Authors: Rayne H. Rouce, Susanne H.C. Baumeister, Kevin J. Curran, Vanessa A. Fabrizio, Erin M. Hall, Emily M. Hsieh, Nicole A. Karras, Amy K. Keating, Amy Moskop, Marcelo C. Pasquini, Christine L. Phillips, Michael A. Pulsipher, Marja Nuortti, Jennifer Willert, Roberto Ramos, Samuel John, Stephan A. Grupp
Journal: Journal of Clinical Oncology (2024)

10016 Background: Tisagenlecleucel is an autologous CD19-directed chimeric antigen receptor (CAR) T-cell immunotherapy indicated for patients (pts) up to 25 y of age with B-ALL that is refractory or in second or later relapse. Since the pivotal ELIANA trial, pt characteristics now include pts &lt; 3 y, pts with isolated central nervous system relapse, and pts with leukemia burden &lt; 5%. Here we examine the impact of tisagenlecleucel on the pt treatment journey since FDA approval in 2017. Methods: Data were collected as a part of a noninterventional, prospective, longitudinal study using the CIBMTR registry. Pts were treated in the United States, Canada, Korea, or Taiwan. Results: As of May 4, 2023, 974 pts received tisagenlecleucel. Primary disease history has evolved since 2017. Notably, disease burden prior to infusion has decreased (≥50% blasts: 18% in 2018, 4% in 2022) and a higher proportion of pts received tisagenlecleucel while in morphological complete remission (34% in 2018, 51% in 2022). Between 2018 and 2022, the proportion of pts who were in third or greater relapse decreased (14% vs 2%, respectively). Pts ≥18 y had more prior exposure to blinatumomab and inotuzumab compared with pts &lt; 18 y: 27% vs 16% and 17% vs 7%, respectively. The proportion of pts undergoing ≥1 hematopoietic stem cell transplantation (HSCT) before tisagenlecleucel infusion decreased (37% in 2018, 15% in 2022), coinciding with the use of tisagenlecleucel in earlier lines of therapy. Reporting of B-cell recovery was suboptimal. In total, 34.5% (314/911) of pts received postinfusion HSCT (reasons for HSCT were not captured for most pts); 8.5% (77/911) of pts received postinfusion HSCT to treat relapse, persistent/progressive disease, or positive minimal residual disease. Although the overall rate of postinfusion HSCT did not change, pts with high-risk cytogenetics showed a decrease in HSCT frequency. Previously, most pts &lt; 3 y with KMT2A rearrangement received a HSCT. Since 2017, only 16% (12/75) of pts &lt; 3 y received a prior HSCT despite 72% (54/75) having a KMT2A rearrangement. Furthermore, of the pts with rearrangement, only 43% (23/53) received a HSCT postinfusion. With censoring for HSCT, median RFS improved: 18 mo in 2018, 27 mo in 2020, and not estimable in 2021. OS was not substantially affected by HSCT censoring; 36-mo probabilities (95% CI) with and without censoring were 66 (61-71) and 62 (57-66), respectively. Conclusions: Pediatric and young adult pts with r/r B-ALL are receiving tisagenlecleucel earlier in the course of their disease treatment, reducing the use of HSCT for r/r disease, and prolonging RFS. As both real-world and clinical trial data supporting the curative potential of tisagenlecleucel grow, the use of HSCT in pts with remission after CAR-T should be carefully evaluated.