Azacitidine Maintenance Therapy Post-Allogeneic Stem Cell Transplantation in Poor-Risk Acute Myeloid Leukemia

Allogeneic hematopoietic stem cell transplant (HSCT) is the potential curative modality for poor-risk acute myeloid leukemia (AML), relapse remains the main reason for transplant failure. Early-phase studies showed azacitidine is safe for post-transplant maintenance therapy in AML.

We performed a single institutional prospective cohort study to evaluate the benefit of azacitidine maintenance therapy following allogeneic HSCT in poor-risk AML. The main objective of this study is to generate a hypothesis aiming to optimize post-transplantation outcomes in poor-risk AML. Forty-nine adults with poor-risk AML who underwent allogeneic HSCT were evaluated in a nonrandomized prospective cohort fashion. Thirty-one participants received post-transplant azacitidine (32 mg/m²) on Days 1-5 for a 28-day treatment cycle beginning approximately 40 days after transplantation. The study was controlled using 18 matched individuals who were on a noninterventional surveillance protocol.

The relapse rate was significantly higher in the control cohort (66.67%) versus (25.81%) in the azacitidine maintenance cohort ( p < .005). Time to relapse was significantly prolonged by azacitidine maintenance, not reached versus 4.1 months in the control arm ( p < .0001). In addition, median overall survival was lower in the control cohort at 7.6 versus 27.4 months in the interventional cohort ( p < .0001). At a median follow-up of 24 months, incidence of graft-versus-host disease (GVHD) did not differ between study groups ( p = .325). In both cohorts, minimal residual disease was correlated with higher hazard of relapse (95% confidence interval, 2.31-13.74; p < .001).

We conclude that low dose azacitidine maintenance following allogeneic HSCT in poor-risk AML, decreased relapse rate, and increased both the time to relapse and overall survival without increased risk of GVHD.