Utility of allogeneic stem cell transplantation for adult Ph+ALL with complete molecular remission

Abstract This study aimed to investigate the usefulness of allogeneic stem cell transplantation (allo‐SCT) for Philadelphia chromosome‐positive acute lymphoblastic leukemia (Ph+ALL) in the first complete remission (CR1) with complete molecular remission (CMR). We compared the outcomes between Ph+ALL patients who did or did not undergo allo‐SCT in CR1. We included patients enrolled in the prospective clinical studies in the tyrosine kinase inhibitor era conducted by the Japan Adult Leukemia Study Group, who achieved CMR within 3 months. A total of 147 patients (allo‐SCT: 101; non‐SCT: 46) were eligible for this analysis. In the multivariate analyses, allo‐SCT was significantly associated with both superior overall survival (OS) (adjusted hazard ratio (aHR): 0.54; 95% CI: 0.30–0.97; p = .04) and relapse‐free survival (RFS) (aHR: 0.21; 95% CI: 0.12–0.38; p < .001). The 5‐year adjusted OS and RFS were 73% and 70% in the allo‐SCT cohort, whereas they were 50% and 20% in the non‐SCT cohort. Despite the higher non‐relapse mortality (aHR: 3.49; 95% CI: 1.17–10.4; p = .03), allo‐SCT was significantly associated with a lower relapse rate (aHR: 0.10; 95% CI: 0.05–0.20; p < .001). In addition, allo‐SCT was also associated with superior graft‐versus‐host disease‐free, relapse‐free survival (aHR: 0.43; 95% CI: 0.25–0.74; p = .002). Propensity score‐matched analyses confirmed the results of the multivariate analyses. In patients who achieved CMR within 3 months, allo‐SCT in CR1 had superior survival and lower relapse compared with the non‐SCT cohort.