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

<b>Background</b>: 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. <b>Methods</b>: 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. <b>Results</b>: For the consolidation (<i>n</i> = 72) and no consolidation groups (<i>n</i> = 63), the 5-year cumulative incidence of relapse (CIR) was (17.6% vs. 19.9%; <i>p</i> = 0.54), the 5-year non-relapse mortality rate (NRM) was (9.7% vs. 17.5%; <i>p</i> = 0.20), the 5-year leukemia-free survival (LFS) was (72.7% vs. 62.7%; <i>p</i> = 0.15), and the 5-year overall survival (OS) was (81.9% vs. 68.3%; <i>p</i> = 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%, <i>p</i> = 0.2) and OS (88.3% vs. 75.0%, <i>p</i> = 0.14). Multivariable analysis indicated that consolidation chemotherapy did not significantly affect CIR, NRM, LFS, or OS. <b>Conclusions</b>: Our findings suggest no significant differences in clinical outcomes between the groups, indicating that AML patients in CR2 might proceed to HSCT without delay.