This prospective observational study aims to evaluate the clinical significance of measurable residual disease (MRD) monitoring using digital PCR (dPCR) in patients with acute myeloid leukemia (AML) following allogeneic hematopoietic stem cell transplantation (allo-HSCT). The study will specifically enroll patients harboring clonal hematopoiesis (CH) and/or myelodysplasia-related (MR) gene mutations.

Patient-specific dPCR assays will be established to enable highly sensitive, longitudinal quantification of mutation burden. Serial assessments will be performed at predefined time points within the first 12 months after transplantation. The study will investigate the prognostic value of dPCR-based MRD dynamics for predicting relapse, relapse-free survival, and overall survival, and will further explore its potential to enable earlier detection of molecular relapse compared with conventional methods.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains a potentially curative treatment for patients with intermediate- and high-risk acute myeloid leukemia (AML). Post-transplant monitoring of measurable residual disease (MRD) is critical for early detection of relapse and timely clinical intervention.

This study focuses on AML patients harboring clonal hematopoiesis (CH) and/or myelodysplasia-related (MR) gene mutations (e.g., DNMT3A, TET2, ASXL1, SRSF2), who lack recurrent fusion genes and NPM1 mutations, representing a population with an unmet need for sensitive molecular MRD monitoring strategies.

For each enrolled patient, an individualized digital PCR (dPCR) assay will be developed to detect patient-specific mutations with high sensitivity. Bone marrow samples will be collected longitudinally at predefined time points (baseline [month 0], and months 1, 2, 3, 4.5, 6, 9, and 12 post-allo-HSCT).

Longitudinal dynamics of mutation burden will be analyzed to evaluate their association with clinical outcomes, including cumulative incidence of relapse (CIR) and overall survival (OS). This study aims to establish dPCR-based MRD monitoring as a precise and clinically actionable tool to guide early intervention and ultimately improve post-transplant outcomes in AML.

Inclusion Criteria:

1. Diagnosis of acute myeloid leukemia (AML).
2. Undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) at the investigating center.
3. Negative for recurrent fusion genes routinely monitored in the clinical laboratory, including but not limited to AML1::ETO, CBFB::MYH11, KMT2A (MLL) rearrangements, NUP98::NSD1, NUP98::HOXA9, FUS::ERG, DEK::NUP214, SET::NUP214, PICALM::AF10, and BCR::ABL1.
4. Availability of next-generation sequencing (NGS) results at initial diagnosis with accessible original reports.
5. Negative for NPM1 mutations at initial diagnosis.
6. Presence of clonal hematopoiesis (CH) and/or myelodysplasia-related (MR) gene mutations at initial diagnosis, including but not limited to DNMT3A, TET2, ASXL1, SRSF2, SF3B1, U2AF1, JAK2, IDH2, BCOR, EZH2, RUNX1, STAG2, and ZRSR2.

Exclusion Criteria:

1. Patients with mutation profiles unsuitable for the design of patient-specific digital PCR (dPCR) assays achieving a sensitivity of ≤0.1%.
2. Absence of evaluable molecular targets for longitudinal MRD monitoring.

AML patients who underwent allo-HSCT, specifically those lacking common fusion genes and NPM1 mutations but carrying CH and/or MR gene mutations.