Treatment of childhood acute myeloblastic leukemia: dose intensification improves outcome and maintenance therapy is of no benefit--multicenter studies of the French LAME (Leucémie Aiguë Myéloblastique Enfant) Cooperative Group

Intensive chemotherapy with dual induction and ALL-like consolidation for childhood acute myeloid leukemia: a respective report from multiple centers in China

Background

Pediatric acute myeloid leukemia (AML) has poor prognosis and high rate of relapse and mortality, and exploration of new treatment options is still critically needed.

Objectives

To summarize the outcome of our new treatment strategies for pediatric AML, which is characterized by dual induction and acute lymphoblastic leukemia (ALL) elements consolidation.

Design

Retrospective, single-arm study.

Methods

From July 2012 to December 2019, an intensive chemotherapy protocol was used for newly diagnosed children with AML, which contains dual induction, three courses of consolidations based on high-dose cytarabine, and two courses of consolidations composed of high-dose methotrexate, vincristine, asparaginase, and mercaptopurine (ALL-like elements). Blasts were monitored by bone marrow smears at intervals, and two lumbar punctures were performed during chemotherapy. We retrospectively analyzed the efficacy and safety of this study. The last follow-up was on 26 May 2023.

Results

A total of 70 pediatric AMLs were included. The median age at diagnosis was 6.7 (0.5-16.0) years. The median initial WBC count was 23.74 × 109/L, 11 of whom ⩾100 × 109/L. After dual induction, there were 62 cases of complete remission (CR), 5 cases of partial remission, and 3 cases of nonremission. The CR rate was 88.57%. The median follow-up time was 5.8 (0.2-9.4) years, the 5-year overall survival was 78.2% ± 5%, the event-free survival (EFS) was 71.2% ± 5.6%, and the cumulative recurrence rate was 27.75%. The 5-year EFS of patients with initial WBC < 100 × 109/L (n = 59) and ⩾100 × 109/L (n = 11) were 76.4% ± 5.7% and 45.5% ± 15% (p = 0.013), respectively. A total of 650 hospital infections occurred. The main causes of infection were respiratory tract infection (26.92%), septicemia (18.46%), stomatitis (11.85%), and skin and soft-tissue infection (10.46%).

Conclusion

This intensive treatment protocol with dual induction and ALL-like elements is effective and safe for childhood AML. Initial WBC ⩾ 100 × 109/L was the only independent risk factor in this cohort.

Trial registration

It is a retrospective study, and no registration on ClinicalTrials.gov.

Pediatric Acute Myeloid Leukemia—Past, Present, and Future

This review reports about the main steps of development in pediatric acute myeloid leukemia (AML) concerning diagnostics, treatment, risk groups, and outcomes. Finally, a short overview of present and future approaches is given.

[Management of pediatric leukemia]

Acute leukemias are the most common pediatric cancer. With a cure rate of about 80%, their treatment is based on a combination of cytotoxic chemotherapies whose intensity is adapted to prognostic factors. Sometimes, allogeneic hematopoietic stem cell transplantation is indicated. New therapeutic options are being developed, such as CAR T-cells.

Attempts to optimize postinduction treatment in childhood acute myeloid leukemia without core-binding factors: A report from the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG)

We previously reported that risk-stratified therapy and intensive postremission chemotherapy (PRC) contributed to the improved survival of childhood acute myeloid leukemia (AML) in the AML99 study, which led us to consider a reduction in the number of PRC courses with more restrictive indications for stem cell transplantation (SCT) in the successor AML-05 study. We here report the outcome of AML patients without core-binding factor mutation (non-CBF AML) in the AML-05 study. Two-hundred eighty-nine children (age < 18 years old) with non-CBF AML were eligible. Patients with unfavorable cytogenetics and/or poor bone marrow response to the first induction course were candidates for SCT in the AML-05 study. After two courses of induction, a further three courses of PRC were given in AML-05, while four courses were given in the AML99 study. The 3-year event-free survival (EFS) rate in the AML-05 study (46.7%, 95% CI: 40.6-52.6%) was comparable to that of non-CBF AML in the AML99 study (51.5%, 95% CI: 42.7-59.6%) (P = .16). However, the 3-year overall survival (OS) rate in the AML-05 study (62.9%, 95% CI: 56.3-68.8%) was slightly lower than that in the AML99 study (71.6%, 95% CI: 63.2-78.5%) (P = .060), mainly due to decreased remission induction rate and increased nonrelapsed mortality. In conclusion, reductions in the number of PRC courses from four to three, together with repetitive cycles of high-dose cytarabine, were acceptable for non-CBF childhood AML.

Metronomic Maintenance for High-Risk Pediatric Malignancies: One Size Will Not Fit All

Maintenance therapy sometimes relies on the use of metronomic chemotherapy (MC); that is, the continuous administration of low-dose chemotherapy. Maintenance therapy has been successfully used for decades in pediatric patients with acute lymphoblastic leukemia (ALL) and recent results have demonstrated improved outcomes in patients with pediatric high-risk rhabdomyosarcoma (RMS) on maintenance therapy. Here, we review the use of metronomic maintenance therapy in pediatric cancer and discuss its mechanisms of action on the tumor microenvironment and cancer cells. We also discuss its potential use as a chemotherapy alone or in combination with targeted therapies, immunotherapies, or agents for drug repurposing.

Pediatric acute myeloid leukemia: updates on biology, risk stratification, and therapy

PURPOSE OF REVIEW

Despite advances in therapy over the past decades, overall survival for children with acute myeloid leukemia (AML) has not exceeded 70%. In this review, we highlight recent insights into risk stratification for patients with pediatric AML and discuss data driving current and developing therapeutic approaches.

RECENT FINDINGS

Advances in cytogenetics and molecular profiling, as well as improvements in detection of minimal residual disease after induction therapy, have informed risk stratification, which now relies heavily on these elements. The treatment of childhood AML continues to be based primarily on intensive, conventional chemotherapy. However, recent trials focus on limiting treatment-related toxicity through the identification of low-risk subsets who can safely receive fewer cycles of chemotherapy, allocation of hematopoietic stem-cell transplant to only high-risk patients and optimization of infectious and cardioprotective supportive care.

SUMMARY

Further incorporation of genomic and molecular data in pediatric AML will allow for additional refinements in risk stratification to enable the tailoring of treatment intensity. These data will also dictate the incorporation of molecularly targeted therapeutics into frontline treatment in the hope of improving survival while decreasing treatment-related toxicity.

Response-guided chemotherapy for pediatric acute myeloid leukemia without hematopoietic stem cell transplantation in first complete remission: Results from protocol DB AML-01

BACKGROUND

Children with acute myeloid leukemia (AML) have a 70% survival rate with treatment regimens containing high doses of cytarabine and anthracyclines and, in some, hematopoietic stem cell transplantation (allo-HSCT).

PROCEDURE

In this multicenter Dutch-Belgian protocol (DB AML-01), 112 children with de novo AML were included. Treatment was stratified according to day 15 bone marrow response after the first induction course. Poor responders received a second course without delay while good responders awaited hematological recovery. Patients achieving CR after two induction courses continued with three consolidation courses without HSCT in CR1.

RESULTS

The overall remission rate was 93.5%. After a median follow-up of 4.1 years, three-year event-free survival (EFS) was 52.6% (95% CI, 42.9%-61.3%), three-year cumulative incidence of relapse 39.7% (95% CI, 30.1%-49.0%), and three-year overall survival (OS) 74.0% (95% CI, 64.8%-81.2%). Significantly more events occurred in patients with high WBC at diagnosis or FLT3-ITD/NPM1-WT, whereas core binding factor (CBF) leukemia had a significantly better EFS. KMT2A rearrangements and age > 10 years negatively impacted OS.

CONCLUSIONS

DB AML-01 response-guided therapy results in a favorable OS, particularly for children with CBF leukemia, children younger than 10 years or with initial WBC counts below 100 × 10⁹ /L. Outcome of patients with FLT3-ITD/NPM1-WT remains poor and warrants alternative treatment strategies.

Maintenance Therapy With Interleukin-2 for Childhood AML: Results of ELAM02 Phase III Randomized Trial

Despite significant progress in the treatment of pediatric acute myeloblastic leukemia (AML), relapse remains the commonest cause of death. Randomized ELAM02 trial questioned if maintenance therapy with interleukin-2 (IL2), for 1 year, improves disease-free survival (DFS). Patients aged 0 to 18 years, with newly diagnosed AML (excluding patients with acute promyelocytic leukemia or down syndrome AML) were enrolled. They received 1 course of induction treatment (cytarabine and mitoxantrone) and 3 courses of consolidation treatment (high-dose cytarabine in courses 1 and 3). According to the cytogenetics risk, patients not undergoing hematopoietic stem cell transplantation, still in complete remission (CR) after the third course of consolidation treatment, were eligible for randomization to 1 year of maintenance therapy with monthly courses of IL2 or no maintenance treatment. There were 438 evaluable patients, 154 of whom were randomized to the IL2/no maintenance groups. Relapse occurred in 28 patients from the IL2+ group and 29 patients in the IL2- group. Survival was similar in the 2 groups, with a 4-year DFS of 62% without IL2 and 66% with IL2 (P = 0.75). In the CBF population, 4-year DFS was 55% without IL2 and 78% with IL2 (P = 0.07). No deaths from toxicity or excess of serious adverse events related to IL2 treatment were recorded. Prolonged IL2 for maintenance therapy after intensive chemotherapy is feasible and safe in pediatric AML patients in their first CR. Such treatment did not improve DFS in this study, but a positive trend was observed in favor of IL2 maintenance therapy among core binding factor acute myeloblastic leukemia.

Harnessing the potential of epigenetic therapies for childhood acute myeloid leukemia

There is a desperate need for new and effective therapeutic approaches to acute myeloid leukemia (AML) in both children and adults. Epigenetic aberrations are common in adult AML, and many novel epigenetic compounds that may improve patient outcomes are in clinical development. Mutations in epigenetic regulators occur less frequently in AML in children than in adults. Investigating the potential benefits of epigenetic therapy in pediatric AML is an important issue and is discussed in this review.

Classification of pediatric acute myeloid leukemia based on miRNA expression profiles

Pediatric acute myeloid leukemia (AML) is a heterogeneous disease with respect to biology as well as outcome. In this study, we investigated whether known biological subgroups of pediatric AML are reflected by a common microRNA (miRNA) expression pattern. We assayed 665 miRNAs on 165 pediatric AML samples. First, unsupervised clustering was performed to identify patient clusters with common miRNA expression profiles. Our analysis unraveled 14 clusters, seven of which had a known (cyto-)genetic denominator. Finally, a robust classifier was constructed to discriminate six molecular aberration groups: 11q23-rearrangements, t(8;21)(q22;q22), inv(16)(p13q22), t(15;17) (q21;q22), NPM1 and CEBPA mutations. The classifier achieved accuracies of 89%, 95%, 95%, 98%, 91% and 96%, respectively. Although lower sensitivities were obtained for the NPM1 and CEBPA (32% and 66%), relatively high sensitivities (84%−94%) were attained for the rest. Specificity was high in all groups (87%−100%). Due to a robust double-loop cross validation procedure employed, the classifier only employed 47 miRNAs to achieve the aforementioned accuracies. To validate the 47 miRNA signatures, we applied them to a publicly available adult AML dataset. Albeit partial overlap of the array platforms and molecular differences between pediatric and adult AML, the signatures performed reasonably well. This corroborates our claim that the identified miRNA signatures are not dominated by sample size bias in the pediatric AML dataset. In conclusion, cytogenetic subtypes of pediatric AML have distinct miRNA expression patterns. Reproducibility of the miRNA signatures in adult dataset suggests that the respective aberrations have a similar biology both in pediatric and adult AML.

Impact of Conditioning Regimen on Outcomes for Children with Acute Myeloid Leukemia Undergoing Transplantation in First Complete Remission. An Analysis on Behalf of the Pediatric Disease Working Party of the European Group for Blood and Marrow Transplantation

Hematopoietic stem cell transplantation (HSCT) represents the cornerstone of treatment in pediatric high-risk and relapsed acute myeloid leukemia (AML). The aim of the present study was to compare outcomes of pediatric patients with AML undergoing HSCT using 3 different conditioning regimens: total body irradiation (TBI) and cyclophosphamide (Cy); busulfan (Bu) and Cy; or Bu, Cy, and melphalan (Mel). In this retrospective study, registry data for patients > 2 and <18 years age undergoing matched allogeneic HSCT for AML in first complete remission (CR1) in 204 European Group for Blood and Marrow Transplantation centers between 2000 and 2010 were analyzed. Data were available for 631 patients; 458 patients received stem cells from a matched sibling donor and 173 from a matched unrelated donor. For 440 patients, bone marrow was used as stem cell source, and 191 patients received peripheral blood stem cells. One hundred nine patients received TBICy, 389 received BuCy, and 133 received BuCyMel as their preparatory regimen. Median follow-up was 55 months. Patients receiving BuCyMel showed a lower incidence of relapse at 5 years (14.7% versus 31.5% in BuCy versus 30% in TBICy, P < .01) and higher overall survival (OS) (76.6% versus 64% versus 64.5%, P = .04) and leukemia-free survival (LFS) (74.5% versus 58% versus 61.9%, P < .01), with a comparable nonrelapse mortality (NRM) (10.8% versus 10.5% versus 8.1%, P = .79). Acute graft-versus-host disease (GVHD) grades III and IV but not chronic GVHD, was higher in patients receiving BuCyMel. Older age at HSCT had an adverse impact on NRM and the use of peripheral blood as stem cell source was associated with increased chronic GVHD and NRM as well as lower LFS and OS. Among pediatric patients receiving HSCT for AML in CR1, the use of BuCyMel conditioning proved superior to TBICy and BuCy in reducing relapse and improving LFS.

Residual disease detected by flow cytometry is an independent predictor of survival in childhood acute myeloid leukaemia; results of the NOPHO-AML 2004 study

Early response after induction is a prognostic factor for disease outcome in childhood acute myeloid leukaemia (AML). Residual disease (RD) detection by multiparameter flow cytometry (MFC) was performed at day 15 and before consolidation therapy in 101 patients enrolled in the Nordic Society of Paediatric Haemato-Oncology AML 2004 study. A multicentre laboratory approach to RD analysis was used. Event-free survival (EFS) and overall survival (OS) was significantly different in patients with and without RD at both time points, using a 0·1% RD cut-off level. RD-negative and -positive patients after first induction showed a 5-year EFS of 65 ± 7% and 22 ± 7%, respectively (P < 0·001) and an OS of 77 ± 6% (P = 0·025) and 51 ± 8%. RD-negative and -positive patients at start of consolidation therapy had a 5-year EFS of 57 ± 7% and 11 ± 7%, respectively (P < 0·001) and an OS of 78 ± 6% and 28 ± 11%) (P < 0·001). In multivariate analysis only RD was significantly correlated with survival. RD before consolidation therapy was the strongest independent prognostic factor for EFS [hazard ratio (HR):5·0; 95% confidence interval (CI):1·9-13·3] and OS (HR:7·0; 95%CI:2·0-24·5). In conclusion, RD before consolidation therapy identifies patients at high risk of relapse in need of intensified treatment. In addition, RD detection can be performed in a multicentre setting and can be implemented in future trials.

Collaborative Efforts Driving Progress in Pediatric Acute Myeloid Leukemia

Diagnosis, treatment, response monitoring, and outcome of pediatric acute myeloid leukemia (AML) have made enormous progress during the past decades. Because AML is a rare type of childhood cancer, with an incidence of approximately seven occurrences per 1 million children annually, national and international collaborative efforts have evolved. This overview describes these efforts and includes a summary of the history and contributions of each of the main collaborative pediatric AML groups worldwide. The focus is on translational and clinical research, which includes past, current, and future clinical trials. Separate sections concern acute promyelocytic leukemia, myeloid leukemia of Down syndrome, and relapsed AML. A plethora of novel antileukemic agents that have emerged, including new classes of drugs, are summarized as well. Finally, an important aspect of the treatment of pediatric AML--supportive care--and late effects are discussed. The future is bright, with a wide range of emerging innovative therapies and with more and more international collaboration that ultimately aim to cure all children with AML, with fewer adverse effects and without late effects.

Survival of Mexican children with acute myeloid leukaemia who received early intensification chemotherapy and an autologous transplant

Background. In Mexico and other developing countries, few reports of the survival of children with acute leukaemia exist. Objective. We aimed at comparing the disease-free survival of children with acute myeloid leukaemia who, in addition to being treated with the Latin American protocol of chemotherapy and an autologous transplant, either underwent early intensified chemotherapy or did not undergo such treatment. Procedure. This was a cohort study with a historical control group, forty patients, less than 16 years old. Group A (20 patients), diagnosed in the period 2005–2007, was treated with the Latin American protocol of chemotherapy with an autologous transplant plus early intensified chemotherapy: high doses of cytarabine and mitoxantrone. Group B (20 patients), diagnosed in the period 1999–2004, was treated as Group A, but without the early intensified chemotherapy. Results. Relapse-free survival for Group A was 90% whereas that for Group B it was 60% (P = 0.041). Overall survival for Group A (18, 90%) was higher than that for Group B (60%). Complete remission continued for two years of follow-up. Conclusions. Relapse-free survival for paediatric patients treated with the Latin American protocol of chemotherapy with an autologous transplant plus early intensified chemotherapy was higher than that for those who did not receive early intensified chemotherapy.

Pediatric AML: From Biology to Clinical Management

Pediatric acute myeloid leukemia (AML) represents 15%-20% of all pediatric acute leukemias. Survival rates have increased over the past few decades to ~70%, due to improved supportive care, optimized risk stratification and intensified chemotherapy. In most children, AML presents as a de novo entity, but in a minority, it is a secondary malignancy. The diagnostic classification of pediatric AML includes a combination of morphology, cytochemistry, immunophenotyping and molecular genetics. Outcome is mainly dependent on the initial response to treatment and molecular and cytogenetic aberrations. Treatment consists of a combination of intensive anthracycline- and cytarabine-containing chemotherapy and stem cell transplantation in selected genetic high-risk cases or slow responders. In general, ~30% of all pediatric AML patients will suffer from relapse, whereas 5%-10% of the patients will die due to disease complications or the side-effects of the treatment. Targeted therapy may enhance anti-leukemic efficacy and minimize treatment-related morbidity and mortality, but requires detailed knowledge of the genetic abnormalities and aberrant pathways involved in leukemogenesis. These efforts towards future personalized therapy in a rare disease, such as pediatric AML, require intensive international collaboration in order to enhance the survival rates of pediatric AML, while aiming to reduce long-term toxicity.

Pediatric AML: From Biology to Clinical Management

Pediatric acute myeloid leukemia (AML) represents 15%–20% of all pediatric acute leukemias. Survival rates have increased over the past few decades to ~70%, due to improved supportive care, optimized risk stratification and intensified chemotherapy. In most children, AML presents as a de novo entity, but in a minority, it is a secondary malignancy. The diagnostic classification of pediatric AML includes a combination of morphology, cytochemistry, immunophenotyping and molecular genetics. Outcome is mainly dependent on the initial response to treatment and molecular and cytogenetic aberrations. Treatment consists of a combination of intensive anthracycline- and cytarabine-containing chemotherapy and stem cell transplantation in selected genetic high-risk cases or slow responders. In general, ~30% of all pediatric AML patients will suffer from relapse, whereas 5%–10% of the patients will die due to disease complications or the side-effects of the treatment. Targeted therapy may enhance anti-leukemic efficacy and minimize treatment-related morbidity and mortality, but requires detailed knowledge of the genetic abnormalities and aberrant pathways involved in leukemogenesis. These efforts towards future personalized therapy in a rare disease, such as pediatric AML, require intensive international collaboration in order to enhance the survival rates of pediatric AML, while aiming to reduce long-term toxicity.

Acute myeloid leukemia in infants: biology and treatment

Children aged 0-2 years (i.e., infants) with acute myeloid leukemia (AML) are a peculiar subgroup of patients in the childhood AML scenario. They present with distinctive biological and clinical characteristics, including a high prevalence of prognostically unfavorable risk factors and an increased susceptibility to therapy-related toxicity. Remarkable improvements have been achieved over the last two decades in the treatment of these patients and their outcome is becoming superimposable to that of the older age groups. In this review, we will focus on peculiarities of this young subgroup of children with AML, describing their clinical presentation, the biology of disease, and factors influencing outcome. Treatment results and toxicity data reported by major collaborative groups are also summarized and compared.

How I treat paediatric relapsed acute myeloid leukaemia

The prognosis of paediatric acute myeloid leukaemia (AML) has improved significantly over the recent decades, but still about one-third of patients relapse. These patients have a relatively poor prognosis, with a probability of long-term survival from relapse of about 35%. This can only be achieved with very intensive chemotherapy and, usually, allogeneic stem cell transplantation, leading to very significant toxicity and even treatment-related mortality. Major improvements in the treatment of paediatric relapsed AML thus are required still, and several possibilities are discussed. In case of a suspected relapse, a comprehensive diagnostic work-up has to be undertaken, because significant changes in the biological features of the AML cells may have occurred between initial diagnosis and relapse. This review discusses many practical issues that one encounters in the treatment of children with relapsed AML. It will also be of interest for those involved in translational research in AML.

A critical review of which children with acute myeloid leukaemia need stem cell procedures

The last decades have seen parallel improvements in chemotherapy-based and haematopoietic stem cell transplantation (HSCT) regimens for acute myeloid leukaemia (AML) in children. There has been no consensus on indication for HSCT. Reserving HSCT for high-risk and relapsed patients spare many patients from the long-term toxicity of this treatment. The results of matched unrelated donor HSCT equal family donor transplantation and the presence of a matched sibling should no longer be a transplant indication. Minimal residual disease measured by flow cytometry may identify poor responders benefitting from HSCT in first complete remission (CR1) and those with a favourable response to induction therapy who do not need HSCT even with adverse cytogenetic aberrations. FLT3-internal tandem duplication without NPM1 mutation has a very high relapse rate despite favourable response and HSCT is indicated in CR1 in these cases. Finding the optimal indications for HSCT is a delicate balance between risk of relapse and late effects.

Pediatric relapsed or refractory leukemia: new pharmacotherapeutic developments and future directions

Over the past 50 years, numerous advances in treatment have produced dramatic increases in the cure rates of pediatric leukemias. Despite this progress, the majority of children with relapsed leukemia are not expected to survive. With current chemotherapy regimens, approximately 15 % of children with acute lymphoblastic leukemia and 45 % of children with acute myeloid leukemia will have refractory disease or experience a relapse. Advances in the treatment of pediatric relapsed leukemia have not mirrored the successes of upfront therapy, and newer treatments are desperately needed in order to improve survival in these challenging patients. Recent improvements in our knowledge of cancer biology have revealed an extensive number of targets that have the potential to be exploited for anticancer therapy. These advances have led to the development of a number of new treatments that are now being explored in children with relapsed or refractory leukemia. Novel agents seek to exploit the same molecular aberrations that contribute to leukemia development and resistance to therapy. Newer classes of drugs, including monoclonal antibodies, tyrosine kinase inhibitors and epigenetic modifiers are transforming the treatment of patients who are not cured with conventional therapies. As the side effects of many new agents are distinct from those seen with conventional chemotherapy, these treatments are often explored in combination with each other or combined with conventional treatment regimens. This review discusses the biological rationale for the most promising new agents and the results of recent studies conducted in pediatric patients with relapsed leukemia.

Outcome of pediatric acute myeloid leukemia patients receiving intensive care in the United States

OBJECTIVE

Children with acute myeloid leukemia are at risk for sepsis and organ failure. Outcomes associated with intensive care support have not been studied in a large pediatric acute myeloid leukemia population. Our objective was to determine hospital mortality of pediatric acute myeloid leukemia patients requiring intensive care.

DESIGN

Retrospective cohort study of children hospitalized between 1999 and 2010. Use of intensive care was defined by utilization of specific procedures and resources. The primary endpoint was hospital mortality.

SETTING

Forty-three children's hospitals contributing data to the Pediatric Health Information System database.

PATIENTS

Patients who are newly diagnosed with acute myeloid leukemia and who are 28 days through 18 years old (n = 1,673) hospitalized any time from initial diagnosis through 9 months following diagnosis or until stem cell transplant. A reference cohort of all nononcology pediatric admissions using the same intensive care resources in the same time period (n = 242,192 admissions) was also studied.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

One-third of pediatric patients with acute myeloid leukemia (553 of 1,673) required intensive care during a hospitalization within 9 months of diagnosis. Among intensive care admissions, mortality was higher in the acute myeloid leukemia cohort compared with the nononcology cohort (18.6% vs 6.5%; odds ratio, 3.23; 95% CI, 2.64-3.94). However, when sepsis was present, mortality was not significantly different between cohorts (21.9% vs 19.5%; odds ratio, 1.17; 95% CI, 0.89-1.53). Mortality was consistently higher for each type of organ failure in the acute myeloid leukemia cohort versus the nononcology cohort; however, mortality did not exceed 40% unless there were four or more organ failures in the admission. Mortality for admissions requiring intensive care decreased over time for both cohorts (23.7% in 1999-2003 vs 16.4% in 2004-2010 in the acute myeloid leukemia cohort, p = 0.0367; and 7.5% in 1999-2003 vs 6.5% in 2004-2010 in the nononcology cohort, p < 0.0001).

CONCLUSIONS

Pediatric patients with acute myeloid leukemia frequently required intensive care resources, with mortality rates substantially lower than previously reported. Mortality also decreased over the time studied. Pediatric acute myeloid leukemia patients with sepsis who required intensive care had a mortality comparable to children without oncologic diagnoses; however, overall mortality and mortality for each category of organ failure studied was higher for the acute myeloid leukemia cohort compared with the nononcology cohort.

Impact on long-term OS of conditioning regimen in allogeneic BMT for children with AML in first CR: TBI+CY versus BU+CY: a report from the Société Française de Greffe de Moelle et de Thérapie Cellulaire

Allogeneic hematopoietic SCT (HSCT) appears to be an efficient tool to cure high-risk AML in first CR but the choice between BU-based or TBI-based conditioning regimens still remains controversial. In order to analyze the impact of conditioning regimen on long-term survival, we conducted a retrospective analysis from French registry data including all consecutive patients under 18 years old (n=226) from 1980 to 2004 transplanted for AML in CR1 from sibling (n=142) or matched unrelated donors and given either TBI-1200 cGy and CY 120 mg/kg (TBI-Cy, n=84) or BU 16 mg/kg and CY 200 mg/kg (BuCy200, n=142). Patient subgroups were comparable for all criteria except for median age at diagnosis and HSCT and for donor type. Both 5-year OS and disease-free survival (DFS) were significantly better in BuCy200 group (P=0.02 and 0.005, respectively). In multivariate analysis, both HLA matching and BuCy200 appeared as good prognostic factors for treatment-related mortality and DFS. Grade 2-4 acute GvHD and chronic GvHD rates were statistically higher in TBI-Cy group than in Bu-Cy200 one with a RR at 2 (P=0.002). In total, Bu-Cy200 conditioning regimen gives better outcome compared with TBI-Cy irrespective of the stem cell source and the donor type.

Inhibiting glutamine uptake represents an attractive new strategy for treating acute myeloid leukemia

Cancer cells require nutrients and energy to adapt to increased biosynthetic activity, and protein synthesis inhibition downstream of mammalian target of rapamycin complex 1 (mTORC1) has shown promise as a possible therapy for acute myeloid leukemia (AML). Glutamine contributes to leucine import into cells, which controls the amino acid/Rag/mTORC1 signaling pathway. We show in our current study that glutamine removal inhibits mTORC1 and induces apoptosis in AML cells. The knockdown of the SLC1A5 high-affinity transporter for glutamine induces apoptosis and inhibits tumor formation in a mouse AML xenotransplantation model. l-asparaginase (l-ase) is an anticancer agent also harboring glutaminase activity. We show that l-ases from both Escherichia coli and Erwinia chrysanthemi profoundly inhibit mTORC1 and protein synthesis and that this inhibition correlates with their glutaminase activity levels and produces a strong apoptotic response in primary AML cells. We further show that l-ases upregulate glutamine synthase (GS) expression in leukemic cells and that a GS knockdown enhances l-ase-induced apoptosis in some AML cells. Finally, we observe a strong autophagic process upon l-ase treatment. These results suggest that l-ase anticancer activity and glutamine uptake inhibition are promising new therapeutic strategies for AML.

Results of the AIEOP AML 2002/01 multicenter prospective trial for the treatment of children with acute myeloid leukemia

Risk-adapted therapy and broad use of HSCT resulted in a significant improvement in outcome. AUTO- or ALLO-HSCT in high-risk patients resulted in a cumulative incidence of leukemia relapse superimposable to that of SR.

[Hematopoietic stem cell transplantation in 2012: who? Where? How?]

Allogeneic bone marrow transplantation has dramatically changed over the years since its beginnings. The diseases treated with transplantation (malignant hemopathies, severe benign hemopathies such as congenital or acquired congenital medullary aplasia, hemoglobinopathies, as well as severe immune system deficiencies and certain overload diseases), stem cell sources (bone marrow, peripheral stem cells, placental blood), donor types (intrafamilial, nonrelated, totally or partially compatible), conditioning regimen (immunosuppressors, graft manipulation), and supportive care increasingly vary. Allogeneic stem cell transplantation and more widely cellular therapies now need to be discussed. In this paper, we propose an overview of these therapies in 2012 for pediatric patients.

Very late isolated CNS relapse of acute myeloid leukemia

Isolated central nervous system (CNS) relapse in acute myeloid leukemia (AML) rarely occurs later than 2 years after remission. We present a child diagnosed with AML (FAB M5) without CNS involvement at diagnosis who was treated with chemotherapy and consolidated with autologous hematopoietic stem cell transplantation. He was in complete remission for >6 years until he had an isolated CNS relapse. He was treated with only intrathecal chemotherapy and achieved a second complete remission, but relapsed in the bone marrow 5 months after the CNS relapse. Treatment of late isolated CNS relapse of AML is discussed.

Chronic myeloid leukemia as a secondary malignancy after lymphoma in a child. A case report and review of the literature

BACKGROUND

Philadelphia chromosome-positive chronic myeloid leukemia (CML) in children is very rare. CML occurring as a secondary malignancy in individuals treated for diffuse large B-cell lymphoma (DLBCL) is also rare.

CASE REPORT

We present the case of a 5-year-old female patient who developed a right orbital mass that was diagnosed as DLBCL. 9 months after receiving treatment for DLBCL, she presented with a white cell count of 250,000/mm(3). Peripheral blood and bone marrow (BM) evaluation revealed a myeloproliferative disorder. Cytogenetic and molecular studies demonstrated the presence of t(9;22). CML following DLBCL has not been previously described in the younger population. To our knowledge, this is the first report of a child who developed a CML as a second malignancy after DLBCL. Therapy-related CML and non-therapy-related secondary CML are discussed as potential explanations of this highly unusual clinical presentation.

CONCLUSION

Hematological disorders such as CML may occur after lymphomas. With the increased use of BM cytogenetic studies during staging for lymphoid malignancies, future studies may be able to clarify the question of whether the CML clone in some of these patients existed before treatment for lymphoma.

Childhood acute myeloid leukaemia

Although acute myeloid leukaemia (AML) has long been recognized for its morphological and cytogenetic heterogeneity, recent high-resolution genomic profiling has demonstrated a complexity even greater than previously imagined. This complexity can be seen in the number and diversity of genetic alterations, epigenetic modifications, and characteristics of the leukaemic stem cells. The broad range of abnormalities across different AML subtypes suggests that improvements in clinical outcome will require the development of targeted therapies for each subtype of disease and the design of novel clinical trials to test these strategies. It is highly unlikely that further gains in long-term survival rates will be possible by mere intensification of conventional chemotherapy. In this review, we summarize recent studies that provide new insight into the genetics and biology of AML, discuss risk stratification and therapy for this disease, and profile some of the therapeutic agents currently under investigation.

Diagnosis and management of acute myeloid leukemia in children and adolescents: recommendations from an international expert panel

Despite major improvements in outcome over the past decades, acute myeloid leukemia (AML) remains a life-threatening malignancy in children, with current survival rates of ∼70%. State-of-the-art recommendations in adult AML have recently been published in this journal by Döhner et al. The primary goal of an international expert panel of the International BFM Study Group AML Committee was to set standards for the management, diagnosis, response assessment, and treatment in childhood AML. This paper aims to discuss differences between childhood and adult AML, and to highlight recommendations that are specific to children. The particular relevance of new diagnostic and prognostic molecular markers in pediatric AML is presented. The general management of pediatric AML, the management of specific pediatric AML cohorts (such as infants) or subtypes of the disease occurring in children (such as Down syndrome related AML), as well as new therapeutic approaches, and the role of supportive care are discussed.

Pediatric acute myeloid leukemia

Pediatric acute myeloid leukemia (AML) is currently associated with survival rates as high as 70%. However, many events still occur, side effects are significant, and late effects occur and can even be life-threatening. Thus, the treatment of pediatric AML still needs further improvement. While most study groups agree on several principles of AML treatment, many unanswered questions and even controversies remain, which will be the topic of this review. Relapsed AML, the most frequent event in children, will also be discussed. The controversies justify future clinical studies. Fortunately, biotechnical developments provide novel treatment targets and targeted drugs, and will enable minimal residual disease-driven tailored therapy. Moreover, a wide range of new drugs is being developed. International collaboration is required to perform randomized, or even single-arm clinical studies, in this setting of subgroup-directed therapy, and fortunately is being accomplished. Therefore, optimism is justified and the treatment of pediatric AML will continue to improve.

Gemtuzumab ozogamicin as postconsolidation therapy does not prevent relapse in children with AML: results from NOPHO-AML 2004

There are no data on the role of postconsolidation therapy with gemtuzumab ozogamicin (GO; Mylotarg) in children with acute myeloid leukemia (AML). The NOPHO-AML 2004 protocol studied postconsolidation randomization to GO or no further therapy. GO was administered at 5 mg/m(2) and repeated after 3 weeks. We randomized 120 patients; 59 to receive GO. Survival was analyzed on an intention-to-treat basis. The median follow-up for patients who were alive was 4.2 years. Children who received GO showed modest elevation of transaminase and bilirubin without signs of veno-occlusive disease. Severe neutropenia followed 95% and febrile neutropenia 40% of the GO courses. Only a moderate decline in platelet count and a minor decrease in hemoglobin occurred. Relapse occurred in 24 and 25 of those randomized to GO or no further therapy. The median time to relapse was 16 months versus 10 months (nonsignificant). The 5-year event-free survival and overall survival was 55% versus 51% and 74% versus 80% in those randomized to receive GO or no further therapy, respectively. Results were similar in all subgroups. In conclusion, GO therapy postconsolidation as given in this trial was well tolerated, showed a nonsignificant delay in time to relapse, but did not change the rate of relapse or survival (clinicaltrials.gov identifier NCT00476541).

RUNX1 mutations in clonal myeloid disorders: from conventional cytogenetics to next generation sequencing, a story 40 years in the making

Translocations and mutations in the core binding factor genes, RUNX1 or CBFB, are found in acute myeloid and lymphocytic leukemia, therapy-related myeloid leukemia, myelodysplastic syndrome, chronic myelomonocytic leukemia, and in familial platelet disorder with predisposition to acute myeloid leukemia. Here we review the biochemical and biological properties of the normal Runx1 protein, discuss the nature of RUNX1 mutations in myeloid leukemia, their prognostic significance, and the mutations that cooperate or co-exist with them in these various diseases.

A single-center cytogenetic study of 629 Chinese patients with de novo acute myeloid leukemia--evidence of major ethnic differences and a high prevalence of acute promyelocytic leukemia in Chinese patients

Cytogenetic information is important in the diagnosis, classification, and prognostication of acute myeloid leukemia (AML). Data obtained from multicenter treatment trials are well published. In this study, we contribute cytogenetic data from a large series of 629 Chinese patients with de novo AML that were karyotyped in a single laboratory. A higher prevalence of acute promyelocytic leukemia was observed when compared with non-Chinese series. The difference was most prominent in the younger age group. Abnormalities at chromosomal region 11q23 and inv(16) seemed uncommon. These ethnic differences may indicate underlying genetic susceptibility to AML development and/or environmental differences. More comprehensive data on AML in the elder population are needed to assess the role of cytogenetics in predicting prognosis and guiding treatment in this large subgroup of patients.

AAML03P1, a pilot study of the safety of gemtuzumab ozogamicin in combination with chemotherapy for newly diagnosed childhood acute myeloid leukemia: a report from the Children's Oncology Group

BACKGROUND

The development of antigen-targeted therapies may provide additional options to improve outcomes in children with acute myeloid leukemia (AML). The Children's Oncology Group AAML03P1 trial sought to determine the safety of adding 2 doses of gemtuzumab ozogamicin, a humanized anti-CD33 antibody-targeted agent, to intensive chemotherapy during remission induction and postremission intensification for children with de novo AML.

METHODS

AAML03P1 enrolled 350 children with previously untreated AML. Patients with a matched family donor received 3 courses of chemotherapy followed by hematopoietic stem cell transplantation; those without a matched family donor received 5 courses of chemotherapy. Gemtuzumab ozogamicin 3 mg/m(2)/dose was administered on Day 6 of Course 1 and Day 7 of Course 4.

RESULTS

Toxicities observed in all courses of therapy were typical of AML chemotherapy regimens, with infection being most common. Patients achieved a complete remission rate of 83% after 1 course and 87% after 2 courses. The mortality rate was 1.5% after the first gemtuzumab ozogamicin-containing induction course and 2.6% after 2 induction courses. The 3-year event-free survival and overall survival rates were 53 ± 6% and 66 ± 5%, respectively.

CONCLUSIONS

This trial determined that it is safe and feasible to include gemtuzumab ozogamicin in combination with intensive chemotherapy. The survival rates compare favorably with the recently published results of clinical trials worldwide.

Bone mineral density in adult survivors of childhood acute leukemia: impact of hematopoietic stem cell transplantation and other treatment modalities

Femoral and lumbar bone mineral densities (BMDs) were measured in 159 adults enrolled in the Leucémies de l'Enfant et de l'Adolescent program, a French prospective multicentric cohort of childhood leukemia survivors. BMDs were expressed as Z-scores, and multivariate linear regression analyses were used to construct association models with potential risk factors. Mean age at evaluation and follow-up was 23 and 14.7 years, respectively. In the whole cohort, mean femoral Z-score was -0.19 ± 0.08. Two factors were associated with lower femoral BMD transplantation (-0.49 ± 0.15 vs -0.04 ± 0.10 in the chemotherapy group; P = .006) and female sex (-0.34 ± 0.10 vs -0.03 ± 0.13; P = .03). Among patients who received a transplant, the only significant risk factor was hypogonadism (-0.88 ± 0.16 vs -0.10 ± 0.23; P = .04). A slight reduction in lumbar BMD (mean Z-score, -0.37 ± 0.08) was detected in the whole cohort without difference between the transplantation and chemotherapy groups. Among patients who received a transplant, younger age at transplantation was correlated with a low lumbar BMD (P = .03). We conclude that adults who had received only chemotherapy for childhood leukemia have a slight reduction in their lumbar BMD and a normal femoral BMD. Patients who received a transplant with gonadal deficiency have a reduced femoral BMD which might increase the fracture risk later in life.

Prognostic significance of additional cytogenetic aberrations in 733 de novo pediatric 11q23/MLL-rearranged AML patients: results of an international study

We previously demonstrated that outcome of pediatric 11q23/MLL-rearranged AML depends on the translocation partner (TP). In this multicenter international study on 733 children with 11q23/MLL-rearranged AML, we further analyzed which additional cytogenetic aberrations (ACA) had prognostic significance. ACAs occurred in 344 (47%) of 733 and were associated with unfavorable outcome (5-year overall survival [OS] 47% vs 62%, P < .001). Trisomy 8, the most frequent specific ACA (n = 130/344, 38%), independently predicted favorable outcome within the ACAs group (OS 61% vs 39%, P = .003; Cox model for OS hazard ratio (HR) 0.54, P = .03), on the basis of reduced relapse rate (26% vs 49%, P < .001). Trisomy 19 (n = 37/344, 11%) independently predicted poor prognosis in ACAs cases, which was partly caused by refractory disease (remission rate 74% vs 89%, P = .04; OS 24% vs 50%, P < .001; HR 1.77, P = .01). Structural ACAs had independent adverse prognostic value for event-free survival (HR 1.36, P = .01). Complex karyotype, defined as ≥ 3 abnormalities, was present in 26% (n = 192/733) and showed worse outcome than those without complex karyotype (OS 45% vs 59%, P = .003) in univariate analysis only. In conclusion, like TP, specific ACAs have independent prognostic significance in pediatric 11q23/MLL-rearranged AML, and the mechanism underlying these prognostic differences should be studied.

Acute myeloid leukemia with the t(8;21) translocation: clinical consequences and biological implications

The t(8;21) abnormality occurs in a minority of acute myeloid leukemia (AML) patients. The translocation results in an in-frame fusion of two genes, resulting in a fusion protein of one N-terminal domain from the AML1 gene and four C-terminal domains from the ETO gene. This protein has multiple effects on the regulation of the proliferation, the differentiation, and the viability of leukemic cells. The translocation can be detected as the only genetic abnormality or as part of more complex abnormalities. If t(8;21) is detected in a patient with bone marrow pathology, the diagnosis AML can be made based on this abnormality alone. t(8;21) is usually associated with a good prognosis. Whether the detection of the fusion gene can be used for evaluation of minimal residual disease and risk of leukemia relapse remains to be clarified. To conclude, detection of t(8;21) is essential for optimal handling of these patients as it has both diagnostic, prognostic, and therapeutic implications.

Prevalence and risk factors of the metabolic syndrome in adult survivors of childhood leukemia

We evaluate the prevalence and risk factors of the metabolic syndrome (MS) in young adults surviving childhood leukemia. During the years 2007 to 2008, assessment of MS was proposed to all adults included in the Leucémie de l'Enfant et de l'Adolescent program, a French prospective multicentric cohort of leukemia survivors. Among 220 eligible patients, 184 (83.6%) had complete evaluation. Median age at evaluation and follow-up duration were 21.2 and 15.4 years. Overall prevalence of MS was 9.2% (95% confidence interval, 5.5-14.4). There was no association of MS with sex, age at diagnosis, leukemia subtype, steroid therapy, and central nervous system irradiation. Patients were stratified according to 4 therapeutic modalities: chemotherapy alone (n = 97), chemotherapy and central nervous system irradiation (n = 27), hematopoietic stem cell transplantation (HSCT) without (n = 17) or with (n = 43) total body irradiation (TBI). MS occurred in 5.2%, 11.1%, 5.9%, and 18.6% of them, respectively. The higher risk observed in the HSCT-TBI group was significant in univariate and in multivariate analysis (odds ratio [OR] = 3.9, P = .03). HSCT with TBI was associated with a higher rate of hypertriglyceridemia (OR = 4.5, P = .004), low level of high-density lipoprotein cholesterol (OR = 2.5, P = .02), and elevated fasting glucose (OR = 6.1, P = .04) So, TBI is a major risk factor for MS. Further studies are warranted to explain this feature.

Biology, risk stratification, and therapy of pediatric acute leukemias: an update

PURPOSE

We review recent advances in the biologic understanding and treatment of childhood acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML), identify therapeutically challenging subgroups, and suggest future directions of research.

METHODS

A review of English literature on childhood acute leukemias from the past 5 years was performed.

RESULTS

Contemporary treatments have resulted in 5-year event-free survival rates of approximately 80% for childhood ALL and almost 60% for pediatric AML. The advent of high-resolution genome-wide analyses has provided new insights into leukemogenesis and identified many novel subtypes of leukemia. Virtually all ALL and the vast majority of AML cases can be classified according to specific genetic abnormalities. Cooperative mutations involved in cell differentiation, cell cycle regulation, tumor suppression, drug responsiveness, and apoptosis have also been identified in many cases. The development of new formulations of existing drugs, molecularly targeted therapy, and immunotherapies promises to further advance the cure rates and improve quality of life of patients.

CONCLUSION

The application of new high-throughput sequencing techniques to define the complete DNA sequence of leukemia and host normal cells and the development of new agents targeted to leukemogenic pathways promise to further improve outcome in the coming decade.

Response-guided induction therapy in pediatric acute myeloid leukemia with excellent remission rate

PURPOSE

To evaluate the early treatment response in children with acute myeloid leukemia (AML) using a response-guided induction strategy that includes idarubicin in the first course.

PATIENTS AND METHODS

All Nordic children with AML younger than 15 years (n = 151) were treated on the Nordic Society for Pediatric Hematology and Oncology (NOPHO) AML 2004 protocol. After the first course of idarubicin, cytarabine, etoposide, and 6-thioguanin, patients with good response were allowed hematologic recovery before the second course, whereas patients with a poor (≥ 15% blasts) or intermediate (5% to 14.9% blasts) were recommended to proceed immediately with therapy. Patients not in remission after the second course received fludarabine, cytarabine, and granulocyte colony-stimulating factor. Poor responders received allogeneic stem-cell transplantation (SCT) as consolidation.

RESULTS

Seventy-four percent of patients had good response, 17% had intermediate response, and 7% had poor response after the first course. The overall remission frequency was 97.4%, with 92% in remission after the second course. The rate of induction death was 1.3%. Patients with an intermediate response had a lower event-free survival of 35% compared with good (61%) and poor responders (82%).

CONCLUSION

The NOPHO-AML 2004 induction strategy gives an excellent remission rate with low toxic mortality in an unselected population. Outcome is worse in patients with intermediate response but may be improved by intensifying consolidation in this group using SCT.

Myeloid leukaemia in children with Down syndrome: report of the registry-based French experience between 1990 and 2003

AIM

To determine the epidemiology of myeloid leukaemia (ML) in children with Down syndrome (DS) and the efficacy of two approaches, low-dose cytarabine-based regimen (LDC) and standard-dose intensive chemotherapy (SD).

PROCEDURE

All children with Down syndrome aged from 2 months to 15 years with ML/myelodysplasia registered in the French registry between January 1990 and December 2003 were included.

RESULTS

Forty-four patients were included. The median age was 1.75 years. The French-America-British subtypes were as follows: M7: 24, M0: 6, M2: 5, M6: 2. Forty-three patients were treated with curative prospect, 20 patients with LDC regimen and 22 according to SD protocols, 1 was given the LDC regimen plus autologous stem-cell transplantation. The event-free survival (EFS) and overall survival (OS) at 5 years were 64.4% and 76.8%. At 5 years, OS in LDC and SD groups were 65% and 85.9% (P = 0.08). EFS were 45% and 80.3% respectively (P < 0.01).

CONCLUSION

Children with DS can adequately tolerate SD chemotherapy with a significant superiority of EFS relative to LDC. We suggest that higher levels of cure can be obtained in DS-ML with SD chemotherapy including cytarabine and anthracyclines.

A review on allogeneic stem cell transplantation for newly diagnosed pediatric acute myeloid leukemia

Survival of pediatric acute myeloid leukemia (AML) has improved considerably over the past decades. Since 1985, allogeneic stem cell transplantation (allo-SCT) is widely recommended for patients who have a matched sibling donor. However, it remains controversial whether allo-SCT is superior to chemotherapy for children with newly diagnosed AML. This review summarizes phase 3 clinical trials that compared allo-SCT with chemotherapy (including autologous SCT) in pediatric AML, excluding studies that did not use the intention-to-treat analysis or correct for time-to-transplantation. Although allo-SCT might prevent more relapses than chemotherapy, the number needed for transplantation (with allo-SCT) to prevent one relapse is in the order of 10 patients. Moreover, overall survival is similar with both methods in most recent studies, apparently because of increased salvagability of a relapse when initial therapy concerned chemotherapy only, and because of a higher treatment-related mortality with allo-SCT. Because allo-SCT also gives more severe side effects and results more often in secondary malignancies than chemotherapy, we do not recommend allo-SCT in first remission for pediatric AML in general. Further research should focus on the possibility that subgroups might benefit from allo-SCT, aiming at further improvements in the prognosis of pediatric AML.

Acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogeneous group of leukemias that result from clonal transformation of hematopoietic precursors through the acquisition of chromosomal rearrangements and multiple gene mutations. As a result of highly collaborative clinical research by pediatric cooperative cancer groups worldwide, disease-free survival has improved significantly during the past 3 decades. Further improvements in outcomes of children who have AML probably will reflect continued progress in understanding the biology of AML and the concomitant development of new molecularly targeted agents for use in combination with conventional chemotherapy drugs.