Acute promyelocytic leukemia (APL) is a rare disease accounting for only 5%–10% of pediatric acute myeloid leukemia (AML) and fewer than 1000 cases occur annually in the United States across all age groups. Characterized by t (15; 17), with a resultant PML-RARA gene fusion driving leukemia development, advances in therapy have improved outcomes for APL significantly in the past several decades, now making APL the most curable form of AML in both children and adults. Cure rates in APL are now comparable to pediatric B-lymphoid leukemias. The success of APL treatment is due, in part, to the breadth of understanding of the driver PML-RARA mutation as well as collaborative efforts to quickly introduce and maximize the benefit of new therapies. Here, we review the presentation, clinical features, pathogenesis, and treatment advances in pediatric APL.

The BCL-2 inhibitor venetoclax improves survival for adult patients with acute myeloid leukemia (AML) in combination with lower-intensity therapies, but its benefit in pediatric patients with AML remains unclear. We retrospectively reviewed two Texas Medical Center institutions’ experience with venetoclax in 43 pediatric patients with AML; median age 17 years (range, 0.6–21). This population was highly refractory; 44% of patients (n = 19) had ≥3 prior lines of therapy, 37% (n = 16) had received a prior bone marrow transplant, and 81% (n = 35) had unfavorable genetics KMT2A (n = 17), WT1 (n = 13), FLT3-ITD (n = 10), monosomy 7 (n = 5), TP53 (n = 3), Inv(3) (n = 3), IDH1/2 (n = 2), monosomy 5 (n = 1), NUP98 (n = 1) and ASXL1 (n = 1). The majority (86%) received venetoclax with a hypomethylating agent. Grade 3 or 4 adverse events included febrile neutropenia in 37% (n = 16), non-febrile neutropenia in 12% (n = 5), anemia in 14% (n = 6), and thrombocytopenia in 14% (n = 6). Of 40 patients evaluable for response, 10 patients (25%) achieved complete response (CR), 6 patients (15%) achieved CR with incomplete blood count recovery (CRi), and 2 patients (5%) had a partial response, (CR/CRi composite = 40%; ORR = 45%). Eleven (25%) patients received a hematopoietic stem cell transplant following venetoclax combination therapy, and six remain alive (median follow-up time 33.6 months). Median event-free survival and overall survival duration was 3.7 months and 8.7 months, respectively. Our findings suggest that in pediatric patients with AML, venetoclax is well-tolerated, with a safety profile similar to that in adults. More studies are needed to establish an optimal venetoclax-based regimen for the pediatric population.

Acute Myeloid Leukemia (AML) is characterized by aggressive proliferation and metabolic reprogramming that support its survival and resistance to therapy. This review explores the metabolic distinctions between AML cells and normal hematopoietic stem cells (HSCs), emphasizing the role of altered mitochondrial function, oxidative phosphorylation (OXPHOS), and biosynthetic pathways in leukemic progression. AML cells exhibit distinct metabolic vulnerabilities, including increased mitochondrial biogenesis, reliance on glycolysis and amino acid metabolism, and unique signaling interactions that sustain leukemic stem cells (LSCs). These dependencies provide potential therapeutic targets, as metabolic inhibitors have demonstrated efficacy in disrupting AML cell survival while sparing normal hematopoietic cells. We examine current and emerging metabolic therapies, such as inhibitors targeting glycolysis, amino acid metabolism, and lipid biosynthesis, highlighting their potential in overcoming drug resistance. However, challenges remain in translating these strategies into clinical practice due to AML’s heterogeneity and adaptability. Further research into AML’s metabolic plasticity and precision medicine approaches is crucial for improving treatment outcomes. Understanding and exploiting AML’s metabolic vulnerabilities could pave the way for novel, more effective therapeutic strategies.

Transient abnormal myelopoiesis (TAM) is a common and potentially fatal neonatal complication of newborn babies with Down syndrome (DS). Children born with mosaic DS are also at risk of developing TAM. However, due to their variable phenotypes, early identification of patients with mosaic DS may be difficult; thus, early diagnosis of TAM is just as challenging. In this report, we describe a case of a phenotypically normal newborn who presented with concerns for neonatal leukemia. The diagnosis of mosaic DS and TAM was confirmed with abnormal GATA1 mutation testing, highlighting the importance of early GATA1 mutation testing in newborn leukemia with high suspicion for TAM.

Background: Pediatric non-Down Syndrome Acute Megakaryoblastic Leukemia (non-DS-AMKL) is a rare subtype of Acute Myeloid Leukemia (AML) arising from primitive megakaryocytes and is associated with poor outcomes. Given its high incidence of relapse, this subpopulation of children is frequently referred for allogeneic hematopoietic stem cell transplant (allo-HSCT) in first complete remission (CR1). Objectives: The objective of this study was to describe the clinical outcomes of non-DS-AMKL pediatric patients in a large, single-institution cohort. Methods: A retrospective review of the medical records of thirty-six patients diagnosed with non-DS-AMKL treated at Texas Children’s Hospital from 2000 to 2022 was conducted. Results: Twenty-nine patients were included in the analysis, with cohorts defined by intention to treat. Twelve patients received chemotherapy only during upfront therapy, and seventeen received upfront HSCT. The 5-year overall survival (OS) and disease-free survival (DFS) for the entire cohort were 19.1% and 24.1%, respectively, with a median survival of 17.4 months. A higher percentage of patients in the chemotherapy-only group had relapsed/refractory disease at death (chemotherapy only, n = 9; HSCT, n = 8). However, 5-year OS and DFS were similar for both groups (OS = 18.8% vs. 31.3%, p = 0.58; DFS = 37.6% vs. 22.2%, p = 0.51). Relapse was the leading cause of death (5-year cumulative incidence of relapse (CIR) 0.78). Treatment with allo-HSCT did not improve outcomes due to the high CIR, even after HSCT in CR1. Conclusions: These dismal outcomes highlight the need for development and incorporation of novel targeted agents into upfront therapy or in the post-HSCT setting for patients with this challenging disease.

This Special Issue brings together an original research report, a fascinating case report, and three timely reviews on a variety of topics related to pediatric leukemia