Allogeneic hematopoietic stem cell transplantation using reduced intensity conditioning regimen for patients with acute myeloid leukemia not in complete remission.

Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is the only potentially curative treatment option for patients with refractory and relapsed acute myeloid leukemia (R/R AML) not in complete remission. Many studies investigating the prognosis of patients with R/R AML not in remission focused on patients who received myeloablative conditioning regimen (MAC). Conversely, reduced intensity conditioning regimen (RIC) could be a considerable conditioning regimen for some patients because of the high frequency of R/R AML in older patients who are not candidates for MAC.

Objective: This study aimed to evaluate the prognosis and identify factors associated with outcomes in patients with R/R AML who underwent allogeneic HSCT with RIC.

Study Design: This study included 707 adult patients with AML not in complete remission who had received RIC. The primary endpoint was progression-free survival (PFS), which was estimated using the Kaplan-Meier method. Prognostic factors were identified using a Cox proportional hazards model with multiple imputations using a chained equation approach.

Results: The 5-year PFS, overall survival, relapse, and nonrelapse mortality were 18.8% (95% confidence interval [CI]: 15.6-22.2), 22.0% (95% CI: 8.5-25.7), 53.6% (95% CI 49.7-57.4%) and 27.5% (95% CI: 24.0-31.2), respectively. Multivariable analysis revealed that male sex, poor performance status, karyotype risk, and blasts in the peripheral blood were significantly associated with PFS.

Conclusions: This study identified prognostic factors in patients with R/R AML not in complete remission. These results can help to develop a transplant strategy for the treatment of R/R AML.