The Clinical Influence of Complete Remission With Incomplete Count Recovery (CRi) on Single-Unit Unrelated Cord Blood Transplantation in Patients With Acute Leukemia

Recent evidence has indicated that measurable residual disease (MRD) markedly affects the prognosis of patients with acute leukemia post-transplantation. However, the prognostic relevance of complete remission with incomplete count recovery (CRi) before transplantation has not been extensively explored. In this single-center, longitudinal study, we assessed the outcomes of 466 MRD-negative acute leukemia patients who underwent single-unit unrelated cord blood transplantation (sUCBT), including 117 patients with CRi. We observed that acute myeloid leukemia (AML) patients with CRi had a significantly lower cumulative incidence of both neutrophil (90.8% versus 96.5%) and platelet engraftment (67.2% versus 85.3%) and experienced increased transplant-related mortality (TRM) (100-day TRM: 14.2% versus 5.3%; 1-year TRM: 20.6% versus 11.3%; P = .024 and .063, respectively), mainly due to infection-related deaths, compared to those in complete remission (CR). Multivariate analysis revealed that CRi was an independent adverse predictor of both neutrophil and platelet engraftment and increased 100-day TRM in AML patients. However, CRi status did not affect relapse or reduce 5-year overall survival (OS), leukemia-free survival (LFS), or GVHD-free relapse-free survival (GRFS) in the AML cohort. Conversely, for patients with acute lymphoblastic leukemia (ALL), CRi did not impact engraftment, TRM, relapse or survival after sUCBT. Our findings underscore that CRi status before sUCBT portends poorer engraftment outcomes and a greater TRM in AML patients, although it does not significantly affect the prognosis of ALL patients.