Treatment Efficacy for Pediatric Acute Myeloid Leukemias: Results of a Single-Center Trial

AIM. To assess the therapy outcomes in pediatric patients with acute myeloid leukemias (AMLs) as well as to identify the most important poor prognostic factors and predictors of treatment efficacy.

MATERIALS & METHODS. The retrospective analysis includes 35 newly diagnosed AML patients treated at the Moscow Regional Oncology Dispensary from 2018 to 2025. On diagnosis date, the age range was 0 to 17 years (median 7 years). Therapy (standardized induction and consolidation blocks, targeted drugs if needed, and allogeneic hematopoietic stem cell transplantation [allo-HSCT] in first remission) was administered in accordance with risk groups and obligatory monitoring of minimal residual disease (MRD). Clinical and laboratory features, cytogenetic and molecular markers (FLT3-ITD, NPM1, and CEBPA) as well as MRD were assessed after 1–2 courses of induction therapy. The distribution of FAB types was as follows: M7 in 6 (17.1 %), M1 in 5 (14.3 %), M4 in 5 (14.3 %), M5 in 4 (11.4 %), M5a in 4 (11.4 %), and M2 in 4 (11.4 %) cases; other types were detected in 7 (20 %) cases in total. Risk stratification identified 20 (57.1 %) high-, 12 (34.3 %) intermediate-, and 3 (8.6 %) standard-risk patients.

RESULTS. At the time of this publication, 21 (60 %) patients are alive, and 14 (40 %) patients have died. The 3-year overall survival was 60 %, and event-free survival (EFS) was 41 %. In the studied cohort of AML patients, early MRD-negative status appeared to be the main predictor of favorable outcome: with MRD ≥ 0.1 % as early as after the first control examination (25.7 % of patients), the number of events significantly increased and long-term rates decreased, whereas achieving MRD-negative status at the end points went hand in hand with the formation of a pronounced plateau on the EFS curve. Clinical and cytogenetic high-risk parameters (FLT3-ITD mutation, hyperleukocytosis at the start, and extramedullary lesions) were associated with earlier unfavorable outcomes and required treatment escalation. The strategy of incorporating allo-HSCT into first-line therapy proved to have outstanding clinical efficacy for high-risk patients and those with MRD persistence.

CONCLUSION. The results obtained are consistent with multi-center data on pediatric protocols of AML treatment. This study demonstrated that the risk-adapted therapy taking into account molecular genetic features of the tumor clone as well as MRD monitoring with the routing of patients to allo-HSCT if needed in first complete remission improve long-term survival rates in pediatric AML patients.

• E.V. Inyushkina Moscow Regional Oncology Dispensary, 6 Karbysheva ul., Balashikha, Russian Federation, 143900 ; AI Burnazyan Federal Medical Biophysical Center, 23 Marshala Novikova ul., Moscow, Russian Federation, 123098 https://orcid.org/0000-0002-3888-9656 (unauthenticated)
• Sergei Olegovich Gunyakov AI Burnazyan Federal Medical Biophysical Center, 23 Marshala Novikova ul., Moscow, Russian Federation, 123098 https://orcid.org/0009-0002-4796-8249 (unauthenticated)
• A.V. Bogucharskii Moscow Regional Oncology Dispensary, 6 Karbysheva ul., Balashikha, Russian Federation, 143900 https://orcid.org/0009-0006-0209-3249 (unauthenticated)
• V.O. Stepanova Moscow Regional Oncology Dispensary, 6 Karbysheva ul., Balashikha, Russian Federation, 143900 https://orcid.org/0009-0005-2500-5670 (unauthenticated)

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