Superior Survival with Allogeneic Hematopoietic Stem Cell Transplantation versus Chemotherapy for High-Risk Adult Acute Lymphoblastic Leukemia in PDT-ALL-2016 Pediatric-Inspired Cohort

Abstract

The role of allogeneic hematopoietic stem cell transplantation (allo-HSCT) for adult high-risk acute lymphoblastic leukemia (HR-ALL) remained elusive in the pediatric-inspired regimen era. We conducted a cohort study on the outcome of allo-HSCT post-consolidation versus chemotherapy for HR-ALL in the first complete remission in PDT-ALL-2016 pediatric-inspired cohort. A total of 245 patients with HR-ALL were enrolled, according to donor availability and patients’ preferences, among which 159 received allo-HSCT after consolidation therapy, and 86 received post-remission chemotherapy. With a median follow-up of 43.6 months, the 3-year overall survival (OS) in allo-HSCT cohort was 77.1% (70.6–84.2%), and 51.7% (41.7–64.1%) in chemotherapy cohort, respectively (p < .001). In multivariate analysis, allo-HSCT cohort showed superior OS (HR = 0.33, 0.21–0.54, p < .001), event-free-survival (EFS, HR = 0.36, 0.23–0.56, p < .001), cumulative incidence of relapse (CIR, HR = 0.13, 0.07–0.22, p < .001), and increased non-relapse mortality (NRM, HR = 4.06, 1.23–13.4, p = .021), compared to chemotherapy cohort. Notably, allo-HSCT improved the outcome of minimal residue disease (MRD)-positive subset (OS, HR = 0.42,0.20–0.90, p = .025), as well as MRD-negative subset (OS, HR = 0.21, 0.10–0.43, p < .001). Our study demonstrates that allo-HSCT post-consolidation, compared to chemotherapy, could further improve survival of HR-ALL in pediatric-inspired cohort, regardless of MRD status.