Blinatumomab in de novo AYA ALL-Results of the Australasian Leukaemia and Lymphoma Group ALL09 "SUBLIME" study

Abstract

Pediatric regimens improve outcomes in adolescent and young adult (AYA) acute lymphoblastic leukemia (ALL) patients. End-consolidation (time point 2 [TP2]) minimal residual disease negativity (MRDneg) is associated with improved survival. In this study, standard consolidation chemotherapy was replaced with blinatumomab to improve TP2 MRDneg-a key survival surrogate in B-lineage ALL. From 2019 to 2022, 55 patients constituted the intention-to-treat (ITT) cohort, median age 25 (range, 16-39) years. Using a Simon's 2-stage design, blinatumomab replaced standard consolidation chemotherapy cycles with TP2 MRDneg as the primary endpoint. Blinatumomab was associated with an improved TP2 MRDneg rate of 70.8% (95% CI, 55.9%-83.0%) versus the null hypothesis of 60% (P = 0.037). When compared to our previous ALL06 study, median time from protocol I commencement to next treatment phase was 84 versus 97 days (P = 0.0001), with 82.7% versus 45.1% (P < 0.0001), commencing protocol M or high-risk block therapy by day 94. Induction mortality was 1.8%. Blinatumomab was well tolerated. Median follow-up was 42.9 (range, 1.9-54.7) months, with 3-year disease-free survival (DFS) 88.6% (95% CI, 76.3%-94.7%) and 3-year overall survival (OS) 90.5% (95% CI, 78.6%-95.9%) in the ITT cohort. Higher than medium-risk patients had poorer DFS but not OS. Standard genomic risk patients had 100% 3-year DFS and OS. Adverse genomic risk stratified by TP2 MRDpos predicted poorer DFS but not OS. Blinatumomab consolidation for de novo B-lineage AYA ALL was associated with high MRDneg rates and excellent survival, particularly in standard-risk disease. Genomics may assist in predicting response to blinatumomab in de novo ALL (ACTRN12618001734257).