S112: TISAGENLECLEUCEL IN PEDIATRIC AND YOUNG ADULT PATIENTS (PTS) WITH RELAPSED/REFRACTORY (R/R) B-CELL ACUTE LYMPHOBLASTIC LEUKEMIA (B-ALL): FINAL ANALYSES FROM THE ELIANA STUDY
Susana Rives, Shannon L. Maude, H. Hiramatsu, André Baruchel, Peter Bader, Henrique Bittencourt, Jochen Buechner, Ted Laetsch, Barbara De Moerloose, Muna Qayed, Heather E. Stefanski, Kara L. Davis, Paul Martin, Eneida R. Nemecek, Christina Peters, Greg Yanik, Adriana Balduzzi, Nicolas Boissel, Seong Lin Khaw, Joerg Krueger, Jun Levine, Sandra Davies, Gary D. Myers, Astrid Yeo, Darragh O’Donovan, Roberto Ramos, M. Pulsipher, S. Grupp
Abstract
Background: Pediatric and young adult pts with R/R B-ALL experience a treatment journey characterized by diminishing likelihood of cure and increasing morbidity. Tisagenlecleucel is an autologous CD19-directed chimeric antigen receptor (CAR) T-cell therapy approved for use in pediatric and young adults with B-ALL and adults with B-cell lymphomas. Tisagenlecleucel provided high rates of remission (>80%) in children and young adults with R/R B-ALL in ELIANA, with 62% of responders remaining relapse-free at 24 mo (Grupp et al, Blood, 2018). Aims: Here, we report the final efficacy and safety analyses in pts followed up to 5.9 years post-tisagenlecleucel infusion. Methods: ELIANA (NCT02435849) was a pivotal, Phase II, open-label, multicenter, global study of tisagenlecleucel in pediatric and young adult pts with R/R B-ALL. Pts received a single infusion of tisagenlecleucel at 0.2-5.0×106 CAR+ viable T cells/kg body weight for pts ≤50 kg and 0.1-2.5×108 CAR+ viable T cells for pts >50 kg. Endpoints included overall remission rate (ORR) within 3 mo, relapse-free survival (RFS), duration of remission (DOR), overall survival (OS), persistence of B-cell aplasia, and short- and long-term safety events. Results:Results: As of September 24, 2021, 97 pts were enrolled and 79 pts (81%) received tisagenlecleucel. Median time from infusion to data cutoff was 5.5 y; 64 pts had ≥5 y of follow-up. At study entry, the median age was 11 y (range, 3-24). Pts were heavily pretreated with a median of 3 prior lines of therapy (range, 1-8) and 61% had a history of prior stem cell transplant (SCT). ORR (complete remission [CR] or CR with incomplete hematologic recovery within 3 mo after infusion) was 82% (95% CI, 72-90). Among pts in remission (CR/CRi), the 5y RFS rate was 49% (95% CI, 34-62), and the median RFS was not reached (Figure, 46.8 mo when censoring for SCT; n=15). The median time to B-cell recovery was 38.6 mo (95% CI, 23-not reached) and the probability of B-cell aplasia at 6 mo and 12 mo was 83% (95% CI, 71-91) and 71% (95% CI, 57-82), respectively. Pts with B-cell recovery (<6 mo, n=10; 6-12 mo, n=4; >12 mo, n=7) experienced a 2y cumulative incidence of relapse of 25.2% (with SCT treated as a competing risk). Among all pts, the 5y EFS and OS rates were 42% (95%CI, 29-54) and 55% (95% CI, 43-66), respectively. There were no significant differences in any efficacy endpoint between pediatric (<18 y; n=65) and young adult (≥18 y; n=14) pts. No new or unexpected AEs were reported during long-term follow-up. Among pts in remission, the most commonly reported grade ≥3 AEs occurring >1 y post-infusion were infection (20%) and cytopenias (6%). Ten (14%) pts in remission experienced long-term cytopenias persisting for >1 y; however, none of these pts experienced cytopenias persisting for >5 y (median 2 y; range, 1.1-5y). Eighty-two percent of pts received IVIG any time post-infusion. Image:Summary/Conclusion: This >5 y follow-up study demonstrates continued durable efficacy of tisagenlecleucel without late adverse effects in heavily pretreated pediatric and young adult pts with R/R B-ALL. Tisagenlecleucel continues to be a potentially curative treatment option for pediatric and young adult patients with R/R B-ALL.