Lack of Evidence Supporting a Significant Benefit of Pre-Transplant Consolidation Therapy in AML CR2 Patients Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is a well-established curative treatment option for acute myeloid leukemia (AML) in second complete remission (CR2). However, whether the addition of consolidation chemotherapy after achieving CR2 can improve transplant outcomes remains controversial. Methods: In this single-center retrospective study, we analyzed consecutive AML patients who underwent their first HSCT in CR2 at our institution between January 2015 and December 2019. Results: For the consolidation (n = 72) and no consolidation groups (n = 63), the 5-year cumulative incidence of relapse (CIR) was (17.6% vs. 19.9%; p = 0.54), the 5-year non-relapse mortality rate (NRM) was (9.7% vs. 17.5%; p = 0.20), the 5-year leukemia-free survival (LFS) was (72.7% vs. 62.7%; p = 0.15), and the 5-year overall survival (OS) was (81.9% vs. 68.3%; p = 0.08). Additional consolidation therapy to achieve negative measurable residual disease (MRD) did not result in significantly improved outcomes compared to immediate HSCT in MRD positive status, with similar LFS (76.9% vs. 67.0%, p = 0.2) and OS (88.3% vs. 75.0%, p = 0.14). Multivariable analysis indicated that consolidation chemotherapy did not significantly affect CIR, NRM, LFS, or OS. Conclusions: Our findings suggest no significant differences in clinical outcomes between the groups, indicating that AML patients in CR2 might proceed to HSCT without delay.