Single Institution Observational Study of Risk-Adapted Therapy for Children with Newly Diagnosed Core-Binding Factor Acute Myeloid Leukemia

Background: Pediatric acute myeloid leukemia (AML) with core-binding factor (CBF) rearrangements (RUNX1-RUNX1T1/CBFβ-MYH11) have favorable outcomes. Therefore, hematopoietic stem cell transplantation (HSCT) is usually not offered to these patients during their first remission (CR1). However, more than one third of patients experienced relapse.

Objective: To explore whether HSCT in CR1 for pediatric CBF-AML would benefit this subgroup.

Design and Methods: We describe the outcomes of 68 cases with RUNX1-RUNX1T1 and 21 with the CBFβ-MYH11 consecutively treated in a single institution between 2012 and 2018. Practice patterns in pediatric CBF-AML treatment varied according to the presumed risk of relapse or treatment abandonment. Remission induction consisted of two courses of a low-intensity or standard-intensity regimen. Post-remission treatment consisted of two or three courses of standard AML therapy. Hematopoietic stem cell transplantation (HSCT) was offered in first complete remission (CR1) for selected patients.

Results: Eighty-nine patients received two courses of a low-intensity or standard-intensity regimen for remission induction and two or three courses of standard AML therapy for post-remission. C-KIT mutations were present in 49.4% of the cases. Eight-three of 87 (95.4%) children attained CR, and two patients were not evaluable. Twenty-nine patients at high risk of relapse underwent HSCT in CR1. The 5-year event-free survival (EFS), overall survival (OS), and relapse rates were 74.8%, 85.0%, and 13.9%, respectively. There was a significant difference in 5-year OS (100% vs. 81.5%, P = 0.016), EFS (96.4% vs. 67.1%, P = 0.003), and relapse-free survival (RFS) (96.4% vs. 68.8%, P = 0.005) between patients who underwent HSCT in CR1 and those treated with chemotherapy alone.

Conclusion: Our data suggest a potential benefit of HSCT for selected patients with CBF-AML and reveal a need to improve risk stratification for pediatric CBF-AML.

No relevant conflicts of interest to declare.