Epigenetic Therapy in a Patient With Down Syndrome and Refractory Acute Myeloid Leukemia

Azacitidine treatment for myeloid leukemia associated with Down syndrome: A nationwide retrospective study in Japan

Hypomethylating agent treatment for myeloid leukemia associated with Down syndrome (ML-DS) has been scarcely reported. Herein, we collected information on azacitidine treatment for ML-DS in Japan. Forty-eight cycles of azacitidine treatment were performed for 12 patients, including 11 relapsed or refractory (R/R) patients. In 40 cycles, azacitidine was used as monotherapy. No azacitidine-related death was observed. One cycle concurrently administered with methotrexate-based intrathecal therapy was discontinued due to toxicities. Only 4 of the 19 cycles given in non-remission achieved complete or partial remission. In conclusion, although most toxicities were acceptable, azacitidine monotherapy might be insufficient for R/R ML-DS cases.

Guideline for treating relapsed or refractory myeloid leukemia in children with Down syndrome

Treatment of relapsed and refractory myeloid leukemia in Down syndrome (r/r ML-DS) poses significant challenges, as prognosis is dire and there is no established standard treatment. This guideline provides treatment recommendations based on a literature review and collection of expert opinions, aiming to improve overall and event-free survival of patients. Treatment options include fludarabine and cytarabine (FLA) ± gemtuzumab ozogamicin (GO), azacytidine (AZA) ± panobinostat, and hematopoietic stem cell transplantation (HSCT). Preferred approaches are AZA ± panobinostat for cases with low blast count or FLA ± GO for cases with high blast count, followed by HSCT after remission. Further research is crucial for the investigation of targeted therapies (e.g., BH3 mimetics, LSD1, JAK inhibitors).

Down syndrome and leukemia: An insight into the disease biology and current treatment options

Children with Down syndrome (DS) have a 10- to 20-fold greater predisposition to develop acute leukemia compared to the general population, with a skew towards myeloid leukemia (ML-DS). While ML-DS is known to be a subtype with good outcome, patients who relapse face a dismal prognosis. Acute lymphocytic leukemia in DS (DS-ALL) is considered to have poor prognosis. The relapse rate is high in DS-ALL compared to their non-DS counterparts. We have a better understanding about the mutational spectrum of DS leukemia. Studies using animal, embryonic stem cell- and induced pluripotent stem cell-based models have shed light on the mechanism by which these mutations contribute to disease initiation and progression. In this review, we list the currently available treatment strategies for DS-leukemias along with their outcome with emphasis on challenges with chemotherapy-related toxicities in children with DS. We focus on the mechanisms of initiation and progression of leukemia in children with DS and highlight the novel molecular targets with greater success in preclinical trials that have the potential to progress to the clinic.

Down syndrome and leukemia: from basic mechanisms to clinical advances

Children with Down syndrome (DS, trisomy 21) are at a significantly higher risk of developing acute leukemia compared to the overall population. Many studies investigating the link between trisomy 21 and leukemia initiation and progression have been conducted over the last two decades. Despite improved treatment regimens and significant progress in iden - tifying genes on chromosome 21 and the mechanisms by which they drive leukemogenesis, there is still much that is unknown. A focused group of scientists and clinicians with expertise in leukemia and DS met in October 2022 at the Jérôme Lejeune Foundation in Paris, France for the 1st International Symposium on Down Syndrome and Leukemia. This meeting was held to discuss the most recent advances in treatment regimens and the biology underlying the initiation, progression, and relapse of acute lymphoblastic leukemia and acute myeloid leukemia in children with DS. This review provides a summary of what is known in the field, challenges in the management of DS patients with leukemia, and key questions in the field.

Management of Down Syndrome-Associated Leukemias: A Review

Importance

Down syndrome (DS), caused by an extra copy of material from chromosome 21, is one of the most common genetic conditions. The increased risk of acute leukemia in DS (DS-AL) has been recognized for decades, consisting of an approximately 150-fold higher risk of acute myeloid leukemia (AML) before age 4 years, and a 10- to 20-fold higher risk of acute lymphoblastic leukemia (ALL), compared with children without DS.

Observations

A recent National Institutes of Health-sponsored conference, ImpacT21, reviewed research and clinical trials in children, adolescents, and young adults (AYAs) with DS-AL and are presented herein, including presentation and treatment, clinical trial design, and ethical considerations for this unique population. Between 10% to 30% of infants with DS are diagnosed with transient abnormal myelopoiesis (TAM), which spontaneously regresses. After a latency period of up to 4 years, 20% to 30% develop myeloid leukemia associated with DS (ML-DS). Recent studies have characterized somatic mutations associated with progression from TAM to ML-DS, but predicting which patients will progress to ML-DS remains elusive. Clinical trials for DS-AL have aimed to reduce treatment-related mortality (TRM) and improve survival. Children with ML-DS have better outcomes compared with non-DS AML, but outcomes remain dismal in relapse. In contrast, patients with DS-ALL have inferior outcomes compared with those without DS, due to both higher TRM and relapse. Management of relapsed leukemia poses unique challenges owing to disease biology and increased vulnerability to toxic effects. Late effects in survivors of DS-AL are an important area in need of further study because they may demonstrate unique patterns in the setting of chronic medical conditions associated with DS.

Conclusions and Relevance

Optimal management of DS-AL requires specific molecular testing, meticulous supportive care, and tailored therapy to reduce TRM while optimizing survival. There is no standard approach to treatment of relapsed disease. Future work should include identification of biomarkers predictive of toxic effects; enhanced clinical and scientific collaborations; promotion of access to novel agents through innovative clinical trial design; and dedicated studies of late effects of treatment.

The Paradox of Myeloid Leukemia Associated with Down Syndrome

Children with Down syndrome constitute a distinct genetic population who has a greater risk of developing acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) compared to their non-Down syndrome counterparts. The risk for developing solid tumors is also distinct from the non-Down syndrome population. In the case of myeloid leukemias, the process of leukemogenesis in Trisomy 21 begins in early fetal life where genetic drivers including GATA1 mutations lead to the development of the preleukemic condition, transient abnormal myelopoiesis (TAM). Various other mutations in genes encoding cohesin, epigenetic regulators and RAS pathway can result in subsequent progression to Myeloid Leukemia associated with Down Syndrome (ML-DS). The striking paradoxical feature in the Down syndrome population is that even though there is a higher predisposition to developing AML, they are also very sensitive to chemotherapy agents, particularly cytarabine, thus accounting for the very high cure rates for ML-DS compared to AML in children without Down syndrome. Current clinical trials for ML-DS attempt to balance effective curative therapies while trying to reduce treatment-associated toxicities including infections by de-intensifying chemotherapy doses, if possible. The small proportion of patients with relapsed ML-DS have an extremely poor prognosis and require the development of new therapies.

Outcomes of patients with Down syndrome and acute leukemia: A retrospective observational study

ABSTRACT

Children with Down syndrome (DS) have a higher risk of developing acute leukemia than do those without DS. There are few studies in the literature about outcome, survival, and difficulties of treating patients with DS and acute leukemia in a developing country. This study aimed to analyze the outcome, response to treatment, survival, treatment complications, and causes of death in patients with DS and acute leukemia compared with those in patients with acute leukemia without DS diagnosed in the same period of time.We conducted a retrospective observational analysis including a cohort of 21 patients with DS and acute leukemia diagnosed between 2009 and 2018 in 3 hemato-oncology centers (2 pediatric centers and 1 adult hematology center). A group of patients with DS-acute lymphoblastic leukemia (DS-ALL) was analyzed and compared with a group of 165 patients with acute lymphoblastic leukemia without DS, and a group of patients with DS-acute myeloid leukemia (DS-AML) was analyzed and compared with a group of 50 patients with acute myeloid leukemia without DS, which was diagnosed during the same period of time (2009-2018) and treated under similar conditions in terms of both treatment protocols and economic resources.The overall survival rates in children with DS-ALL and DS-AML were 35.7% and 57.1%, respectively (P = .438). The overall survival rate was significantly worse in children with DS-ALL than in those with acute lymphoblastic leukemia without DS (35.71% vs 75.80%, P = .001). We noted that treatment-related mortality in the patients with DS-ALL was high (50%) (infections and toxicities related to chemotherapy); this result was significantly different from that for patients with leukemia without DS (P < .0001). The relapse rate was higher in patients with DS-ALL but not significantly higher than that in patients without DS (P = .13).In contrast, the overall survival rate was better for patients with DS-AML than for those with acute myeloid leukemia without DS (57.1% vs 45.1%, P = .47).Because of the particularities of the host, we suggest that DS-ALL and DS-AML should be considered as independent diseases and treated according to specific protocols with therapy optimization per the minimal residual disease.

Alterations of epigenetic landscape in Down syndrome carrying pregnancies: A systematic review of case-control studies

OBJECTIVE

Great attention is currently paid to both the pathogenetic mechanisms and non-invasive prenatal diagnosis (NIPD) of Down syndrome (DS). It has been posited that dysregulation of epigenetic signatures including DNA methylation and microRNAs (miRNAs) crucially contribute to the pathomechanism of DS. Therefore, we aimed to perform a systematic review of case-control publications that have examined the differences in epigenetic landscape between pregnancies bearing euploid fetuses and those affected with DS to provide a focused insight into the pathophysiology of DS and also novel biomarkers for NIPD of DS.

STUDY DESIGN

Pertinent keywords were utilized to search into PubMed, Scopus, and Google Scholar. We enrolled studies that have compared the pattern of miRNAs expression profile or DNA methylation between pregnant women who carries DS fetuses and those with euploid fetuses.

RESULTS

An assessment of 599 articles resulted in, finally, 18 eligible studies (12 miRNAs and 6 DNA methylation). The most investigated miRNAs were those that are encoded by genes on chromosome 21 and more hypermethylation regions in DS fetuses than euploids with nearly evenly distribution on all chromosomes were found. Distinct mechanisms with potential therapeutic purposes have been put forward for the involvement of epigenetic perturbations in the etiopathogenesis of DS.

CONCLUSION

There is a disagreement in the recruiting of epigenetic biomarkers for NIPD of DS. This heterogeneity in results of the qualified publications emanates from confounding factors such as differences in demographic data of participants, analytical platforms, and study design. Hence, before harnessing epigenetic signatures for NIPD of DS, more experiments are required.

Epigenetic drug screen identifies the histone deacetylase inhibitor NSC3852 as a potential novel drug for the treatment of pediatric acute myeloid leukemia

BACKGROUND

Acute myeloid leukemia (AML) is a heterogeneous disease regarding morphology, immunophenotyping, genetic abnormalities, and clinical behavior. The overall survival rate of pediatric AML is 60% to 70%, and has not significantly improved over the past two decades. Children with Down syndrome (DS) are at risk of developing acute megakaryoblastic leukemia (AMKL), which can be preceded by a transient myeloproliferative disorder during the neonatal period. Intensification of current treatment protocols is not feasible due to already high treatment-related morbidity and mortality. Instead, more targeted therapies with less severe side effects are highly needed.

PROCEDURE

To identify potential novel therapeutic targets for myeloid disorders in children, including DS-AMKL and non-DS-AML, we performed an unbiased compound screen of 80 small molecules targeting epigenetic regulators in three pediatric AML cell lines that are representative for different subtypes of pediatric AML. Three candidate compounds were validated and further evaluated in normal myeloid precursor cells during neutrophil differentiation and in (pre-)leukemic pediatric patient cells.

RESULTS

Candidate drugs LMK235, NSC3852, and bromosporine were effective in all tested pediatric AML cell lines with antiproliferative, proapoptotic, and differentiation effects. Out of these three compounds, the pan-histone deacetylase inhibitor NSC3852 specifically induced growth arrest and apoptosis in pediatric AML cells, without disrupting normal neutrophil differentiation.

CONCLUSION

NSC3852 is a potential candidate drug for further preclinical testing in pediatric AML and DS-AMKL.

Transient leukemia of Down syndrome

Childhood leukemia is mostly a "developmental accident" during fetal hematopoiesis and may require multiple prenatal and postnatal "hits". The World Health Organization defines transient leukemia of Down syndrome (DS) as increased peripheral blood blasts in neonates with DS and classifies this type of leukemia as a separate entity. Although it was shown that DS predisposes children to myeloid leukemia, neither the nature of the predisposition nor the associated genetic lesions have been defined. Acute myeloid leukemia of DS is a unique disease characterized by a long pre-leukemic, myelodysplastic phase, unusual chromosomal findings and a high cure rate. In the present manuscript, we present a comprehensive review of the literature about clinical and biological findings of transient leukemia of DS (TL-DS) and link them with the genetic discoveries in the field. We address the manuscript to the pediatric generalist and especially to the next generation of pediatric hematologists.