Risk-Adjusted Comparison of Survival in Chronic Myelomonocytic Leukemia With and Without Allogeneic Stem Cell Transplant: Mayo Clinic Experience in 775 Consecutive Patients.

The recently published BLAST clinical risk model for chronic myelomonocytic leukemia (CMML) and its molecular version (BLAST-Mol) differentiate low, intermediate, and high-risk groups. The objective of the current retrospective study was to examine the survival impact of allogeneic stem cell transplant (ASCT) in a consecutive series of Mayo Clinic patients (n = 775; 68% males, median age 71 years) with CMML, overall and adjusted for baseline BLAST/BLAST-Mol risk categories. At a median follow-up of 77 months, 151 (20%) patients underwent ASCT. Overall survival (OS) was longer in the ASCT compared to the non-ASCT cohorts (median 77 vs. 28 months; p < 0.01). The significant difference in OS between the ASCT and non-ASCT cohorts was retained after adjusting for BLAST clinical risk groups: high-risk (median 50 vs. 14 months; p < 0.01), intermediate-risk (81 vs. 28 months; p < 0.01), and low-risk (111 vs. 65 months; p = 0.04), respectively. The same was mostly the case when OS comparison was adjusted for BLAST-Mol with respective p values of < 0.01, < 0.01, and 0.08, respectively. Time-dependent cox models confirmed the favorable survival impact of ASCT in the BLAST/BLAST-Mol high- and intermediate-risk groups. The current study highlights the benefit of ASCT for BLAST/BLAST-Mol high- and intermediate-risk groups in CMML and its potential to overcome the adverse impact of some high risk cytogenetic or molecular abnormalities. These observations support the early use of ASCT in CMML, ideally before BT and regardless of genetic characteristics.