Mutational Dynamics in AML Relapse Post-Allogeneic Hematopoietic Cell Transplantation

Overview

This retrospective multicenter study analyzed mutational changes in 57 AML patients relapsing after allo-HCT. Genetic instability was observed in 68% of patients, with frequent alterations in FLT3-ITD, NRAS, and KRAS, while founding mutations like DNMT3A were generally retained. Relapse timing, rather than clonal evolution pattern, was the strongest predictor of survival.

Background

Acute myeloid leukemia (AML) is a genetically heterogeneous malignancy with diverse mutations influencing prognosis and treatment response. Allogeneic hematopoietic cell transplantation (allo-HCT) remains a key curative approach for intermediate and adverse-risk AML, leveraging graft-versus-leukemia effects. However, relapse post-allo-HCT is common and associated with complex clonal evolution and immune escape mechanisms. Understanding mutational dynamics at relapse may guide targeted therapies and improve patient outcomes.

Data Highlights

Key Findings

• 68% of AML patients relapsing post-allo-HCT exhibited genetic instability with acquisition or loss of mutations.
• FLT3-ITD, NRAS, and KRAS mutations were the most frequently altered at relapse, whereas founding mutations such as DNMT3A were usually retained.
• Four distinct clonal evolution patterns were identified: constant (35%), linear (30%), branching (23%), and parallel (12%).
• Clonal evolution pattern did not significantly impact progression-free or overall survival.
• Early relapse (≤6 months post-transplant) was associated with significantly higher mortality risk compared to late relapse, independent of mutation evolution pattern.
• Longitudinal molecular monitoring post-allo-HCT is important, especially during the early post-transplant period, to detect actionable genetic changes.

Clinical Implications

The timing of AML relapse after allo-HCT is a critical prognostic indicator, with early relapse portending worse outcomes regardless of clonal evolution. Genetic instability at relapse suggests the need for repeated molecular profiling to identify emerging mutations that may be targetable. These findings support integrating longitudinal mutation monitoring into post-transplant surveillance to guide personalized therapeutic strategies.

Conclusion

Relapse of AML following allo-HCT is characterized by diverse mutational changes and clonal evolution patterns, but relapse timing remains the most important determinant of patient survival. Molecular monitoring during the early post-transplant period is essential to inform treatment decisions.

Related Resources & Content

1. Study Authors/Multicenter Retrospective Analysis/2024 -- Alterations in the Mutational Profile of AML in Patients Experiencing Relapse Post-Allo-HCT