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Rebecca Olin, MD, MS


Reduced-Intensity Conditioning Regimen: Effect on Outcomes After Transplantation in AML

By: Celeste L. Dixon
Posted: Tuesday, April 6, 2021

Preliminary results are in for the first randomized trial to test an augmented reduced-intensity conditioning regimen in older patients with high-risk acute myeloid leukemia (AML) and myelodysplasia undergoing allogeneic stem cell transplantation. However, outcomes did not improve with the regimen. Additionally, no evidence of interaction was seen between measurable residual disease status and conditioning regimen intensity for relapse or survival, the authors described in the Journal of Clinical Oncology. What the results did indicate, though, is that the development of full-donor T-cell chimerism by 3 months after transplantation seemed to help counter the adverse impact of pretransplant measurable residual disease on relapse and overall survival.

Previously, registry data and data from unrandomized phase II trials had indicated the intensified conditioning regimen of fludarabine/amsacrine/cytarabine-busulphan (FLAMSA-Bu) might be associated with improved outcomes, noted Sylvie D. Freeman, MD, of the Institute of Immunology and Immunotherapy, University of Birmingham, United Kingdom, and colleagues. Their phase III FIGARO results point, instead, to the continued importance of measurable residual disease as a pretransplant risk factor and the exploration of ways to accelerate full-donor T-cell chimerism.

With a median age of 59 years, patients with high-risk AML (n = 164) or myelodysplasia (n = 80) were randomly assigned 1:1 to a fludarabine-based reduced-intensity conditioning regimen or FLAMSA-Bu. The arms saw no statistical difference in 2-year overall survival or cumulative incidence of relapse (P = .81 for both). However, detectable pretransplant measurable residual disease (monitored by flow cytometry) was associated with an increased 2-year cumulative incidence of relapse (41.0% vs. 20.0%; P = .01) in the overall trial cohort.

Disclosure: The study authors’ disclosure information can be found at

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