How I treat children and adolescents with acute promyelocytic leukaemia

Treatment of Pediatric Acute Promyelocytic Leukemia with Retinoic Acid and Arsenic Trioxide along with Chemotherapy

OBJECTIVES

Outcomes of childhood acute promyelocytic leukemia (APL) have exceeded 90% in the era of differentiating agents. In resource-limited settings, early mortality secondary to coagulopathy remains a significant challenge. Differentiation syndrome is a unique complication of APL therapy that requires a high degree of suspicion for timely initiation of therapy.

METHODS

A retrospective study of children ≤15 y of age with APL diagnosed between January-2013 and June-2019 treated at a tertiary cancer centre was conducted. Patients with a total leukocyte count ≥10,000/µL were risk stratified as high-risk. Treatment included differentiating agents, all-trans retinoic acid and arsenic trioxide along with chemotherapy. Baseline demographics, clinical complications and outcomes were analysed.

RESULTS

Out of 90 patients treated, 48 (53%) had high-risk APL and 25 (28%) presented with significant bleeding manifestations. Response to therapy was excellent with 96% of evaluable patients achieving molecular remission by the end of consolidation phase. Differentiation syndrome occurred in 23 (25%) patients of which two expired. Early mortality rate was 5.5% and was due to severe hemorrhage most often at the time of presentation. The 3-y overall survival of the entire cohort was 91% (95% CI: 85-97%). Two of 4 patients with relapse of disease could be salvaged with only differentiating agents followed by autologous transplantation.

CONCLUSIONS

Long-term outcomes of Indian children with APL are excellent. Timely management of coagulopathy and prompt initiation of differentiating agents along with appropriate cytoreductive measures is critical. Efforts to build academic-community partnerships to ensure timely diagnosis and emergency care in order to reduce early mortality are needed.

Torque teno mini virus as a cause of childhood acute promyelocytic leukemia lacking PML/RARA fusion

Astolf et al provide the first report of acute promyelocytic leukemia driven by viral insertion into the RARA locus. This represents a clear demonstration of a pathology driven by the member of the anelloviruses, a group of viruses otherwise thought to have minimal or no pathogenic potential.

Therapeutic interventions for childhood cancer: An umbrella review of randomized evidence

Treatment advancements in pediatric cancer have improved prognosis, but the strength of supporting evidence has not been thoroughly evaluated. To critically appraise it, we performed an umbrella review of meta-analyses of randomized controlled trials examining the efficacy and safety of therapeutic interventions for pediatric malignancies. Fourteen publications (68 meta-analyses, 31,496 participants) were eligible. Acute lymphoblastic leukemia (ALL) was investigated at most. Substantial heterogeneity was detected in 10 associations, with limited indications for small-study effects and excess-significance bias. The most concrete evidence pertained to the use of methotrexate and vincristine-prednisone pulses for ALL, improving event-free survival. Evidence regarding other cancers was relatively weak. Conclusively, we found few small meta-analyses focusing mainly on ALL. Randomized evidence stemming from adult populations still seems to serve as valuable indirect evidence backup. More randomized evidence and individual patient data meta-analyses are needed to increase certainty and precision in the care of pediatric cancer patients.

Pediatric Fibrinogen PART II-Overview of Indications for Fibrinogen Use in Critically Ill Children

Bleeding is frequently seen in critically ill children and is associated with increased morbidity and mortality. Fibrinogen is an essential coagulation factor for hemostasis and hypofibrinogenemia is an important risk factor for bleeding in pediatric and adult settings. Cryoprecipitate and fibrinogen concentrate are often given to critically ill children to prevent bleeding and improve fibrinogen levels, especially in the setting of surgery, trauma, leukemia, disseminated intravascular coagulopathy, and liver failure. The theoretical benefit of fibrinogen supplementation to treat hypofibrinogenemia appears obvious, yet the evidence to support fibrinogen supplementation in children is sparce and clinical indications are poorly defined. In addition, it is unknown what the optimal fibrinogen replacement product is in children and neonates or what the targets of treatment should be. As a result, there is considerable variability in practice. In this article we will review the current pediatric and applicable adult literature with regard to the use of fibrinogen replacement in different pediatric critical care contexts. We will discuss the clinical indications for fibrinogen supplementation in critically ill children and the evidence to support their use. We summarize by highlighting current knowledge gaps and areas for future research.

Clinical Characteristics and Treatment Outcomes of Childhood Acute Promyelocytic Leukemia in Korea: a Nationwide Multicenter Retrospective Study by Korean Pediatric Oncology Study Group

Purpose

Acute promyelocytic leukemia (APL) is a rare disease in children and there are some different characteristics between children and adult. We aimed to evaluate incidence, clinical characteristics and treatment outcomes of pediatric APL in Korea.

Materials and Methods

Seventy-nine pediatric APL patients diagnosed from January 2009 to December 2016 in 16 tertiary medical centers in Korea were reviewed retrospectively.

Results

Of 801 acute myeloid leukemia children, 79 (9.9%) were diagnosed with APL. The median age at diagnosis was 10.6 years (range, 1.3 to 18.0). Male and female ratio was 1:0.93. Thirty patients (38.0%) had white blood cell (WBC) count greater than 10×10⁹/L at diagnosis. All patients received induction therapy consisting of all-trans retinoic acid and chemotherapy. Five patients (6.6%) died during induction chemotherapy and 66 patients (86.8%) achieved complete remission (CR) after induction chemotherapy. The causes of death were three intracranial hemorrhage, one cerebral infarction, and one sepsis. Five patients (7.1%) suffered a relapse during or after maintenance chemotherapy. The estimated 4-year event-free survival and overall survival (OS) rates were 82.1%±4.4%, 89.7%±5.1%, respectively. The 4-year OS was significantly higher in patients with initial WBC < 10×10⁹/L than in those with initial WBC ≥ 10×10⁹/L (p=0.020).

Conclusion

This study showed that the CR rates and survival outcomes in Korean pediatric APL patients were relatively good. The initial WBC count was the most important prognostic factor and most causes of death were related to serious bleeding in the early stage of treatment.

Opportunities and Challenges in Drug Development for Pediatric Cancers

The use of targeted small-molecule therapeutics and immunotherapeutics has been limited to date in pediatric oncology. Recently, the number of pediatric approvals has risen, and regulatory initiatives in the United States and Europe have aimed to increase the study of novel anticancer therapies in children. Challenges of drug development in children include the rarity of individual cancer diagnoses and the high prevalence of difficult-to-drug targets, including transcription factors and epigenetic regulators. Ongoing pediatric adaptation of biomarker-driven trial designs and further exploration of agents targeting non-kinase drivers constitute high-priority objectives for future pediatric oncology drug development. SIGNIFICANCE: Increasing attention to drug development for children with cancer by regulators and pharmaceutical companies holds the promise of accelerating the availability of new therapies for children with cancer, potentially improving survival and decreasing the acute and chronic toxicities of therapy. However, unique approaches are necessary to study novel therapies in children that take into account low patient numbers, the pediatric cancer genomic landscape and tumor microenvironment, and the need for pediatric formulations. It is also critical to evaluate the potential for unique toxicities in growing hosts without affecting the pace of discovery for children with these life-threatening diseases.

Population-Level Outcomes of Pediatric Acute Promyelocytic Leukemia in the United States

OBJECTIVE

To determine whether the population level outcomes of pediatric acute promyelocytic leukemia have improved over time.

STUDY DESIGN

We conducted a retrospective analysis of the Surveillance Epidemiology and End Results database for patients with acute promyelocytic leukemia, up to 20 years of age, diagnosed between 1976 and 2016 and actively followed. Patients were stratified based on their period of diagnosis (1976-1989, 1990-1999, 2000-2009, 2010-2016) to assess the temporal trends in overall survival and early mortality.

RESULTS

A total of 553 patients with a median age of 15 years (range, 0-20 years) were included. The 5-year overall survival increased significantly over time (by 22.6% from 1976 to 1989; by 59.2% from 1990 to 1999; by 77.7% from 2000 to 2009; and by 88.9% from 2010 to 2016; P < .001). Early mortality showed an improvement over time in the most recent cohort (by 14% from 1976 to 1989; by 13.5% from1990 to 1999; by 13.3% 2000 to 2009; and by 7.2% from 2010 to 2016) after adjusting for other demographic characteristics in a logistic regression model. On multivariate analysis of overall survival, diagnosis in the earlier time periods was associated with higher mortality as compared with the 2010-2016 period. Age, sex, and race/ethnicity were not significant predictors of overall survival.

CONCLUSIONS

Outcomes of pediatric acute promyelocytic leukemia have continued to improve over time at the population level.

Enteral tube administration of oral chemotherapy drugs

Objective

Patients receiving oral chemotherapies face treatment interruptions if they require placement of an enteral tube for nutrition, potentially leading to adverse outcomes in cancer treatment. Enteral tube medication administration can provide a suitable alternative. The purpose of this review is to compile available data that describe enteral tube administration of oral chemotherapy agents. Data sources: A systematic evaluation of all Food and Drug Administration-approved oral chemotherapy agents through 31 July 2019 was conducted. Information on crushing or opening of the tablet or capsule, enteral tube administration, and extemporaneous formulations was compiled from the prescribing information, tertiary resources, and primary literature. Drug manufacturers were contacted for additional information. Data summary: A total of 87 oral chemotherapy agents were evaluated. Of the 87 drugs, 33 agents (37.9%) had information regarding enteral tube administration with only four drugs with nasogastric or gastric tube administration instructions in their prescribing information. The strength of evidence varied from non-peer reviewed data to complete evaluations of efficacy and safety. The majority of chemotherapies (62%) had no available data on enteral tube administration.

Conclusions

The results of this review suggest that there is limited data surrounding enteral tube administration of most oral chemotherapies, demonstrating the need for more studies to be conducted to provide more guidance to healthcare providers when administration via an enteral tube is needed in their patients.

Long-term follow-up of children with acute promyelocytic leukemia treated with Beijing Children's Hospital APL 2005 protocol (BCH-APL 2005)

We studied the outcomes of children with APL treated by the Beijing Children's Hospital's (BCH) acute promyelocytic leukemia (APL) 2005 protocol (BCH-APL2005). The clinical data of 77 patients enrolled from January 2005 to June 2015 were analyzed retrospectively. The hematologic complete remission (CR) rate and overall survival (OS) rate were evaluated between standard-risk (SR) and high-risk (HR) groups. Prognostic factors and complications were investigated in these two groups. CR in the SR and HR groups was 96.4% (54/56) and 85.7% (18/21), respectively, while the 10-year OS was 94.6% (53/56) and 76.2% (16/21), respectively. The cumulative incidence of early death was 6.5% (5/77), and the SR and HR groups were 1.8% (1/56) and 19.0% (4/21), respectively. Only two patients relapsed, and the relapse rate was 2.6% (2/77). According to Kaplan-Meier analysis, the SR group had a significantly better long-term survival than HR counterparts (p= .016). Initial leukocyte count was the only prognostic factor (p= .016) by univariate analysis, while other factors, such as FLT3-ITD and platelet count, had no correlation with prognosis. In addition, early deaths were mainly due to intracranial hemorrhage. Although the combination of all-trans retinoic acid (ATRA) and chemotherapy can improve the outcome of APL patients, the early deaths and anthracycline-related cardiac toxicity were relatively higher in our study. Current efforts focus on reducing or even avoiding chemotherapy in APL children and rest on the frontline regimen of intravenous arsenic trioxide or oral realgar-indigo naturalis formula plus ATRA, which is the direction for APL treatment.

Cytogenetic abnormalities, WHO classification, and evolution of children and adolescents with acute myeloid leukemia

OBJECTIVES

To describe cytogenetic and molecular abnormalities observed in children and adolescents with acute myeloid leukemia (AML), classify AML according to the World Health Organization (WHO) classifications from 2008 and 2016, and evaluate the prognosis according to clinical characteristics and cytogenetic abnormalities.

METHODS

A retrospective longitudinal study was performed on a population of 98 patients with AML, aged up to 16 years, seen in a single hospital from 2004 to 2015.

RESULTS

Among the 80 patients for whom it was possible to analyze the karyotype, 78.7% had chromosomal changes, the most frequent being t(15;17)(q22;q21). Of the 86 patients for whom we had cytogenetic or molecular data, making it possible to classify their AML according to the WHO classification, 52.3% belonged to the group with recurrent genetic abnormalities, 22% to the "AML not otherwise specified" group, 18.6% to the group with myelodysplasia-related cytogenetic changes, and 7% to the group with Down syndrome-related leukemia. Five-year overall survival (OS) for the whole group was 49.7%±5.2%. In the univariate and multivariate analyses, patients with myelodysplasia-related cytogenetic changes (OS 28.1%±12.2%) and those with "AML not otherwise specified" (OS 36.1%±11.2%) had an unfavorable prognosis when compared to patients with AML with recurrent genetic abnormalities (OS 71%±5.8%) and patients with Down syndrome-related AML (OS 83%±15.2%, p=0.011).

CONCLUSIONS

The results corroborate the importance of cytogenetic abnormalities as a prognostic factor and indicate the need for cooperative and prospective studies to evaluate the applicability of the WHO classification in the pediatric population.

Pediatric Acute Promyelocytic Leukemia Presenting to the Emergency Department as Refusal to Ambulate

A previously healthy 10-year-old girl presented to the emergency department (ED) with a headache and vomiting which resolved with oral NSAIDs. The patient returned two days later unable to ambulate with mental slowing and lower extremity bruising. Labs demonstrated marked leukocytosis, severe anemia and thrombocytopenia, and disseminated intravascular coagulation (DIC). Brain MRI showed multiple intracranial hemorrhages. A peripheral blood smear demonstrated blasts with many Auer rods. A diagnosis of acute promyelocytic leukemia (APL) was made and therapy including all-transretinoic acid (ATRA) was initiated. Neurologic status returned to baseline within 1 week in the pediatric intensive care unit.

Acute Promyelocytic Leukemia in Children: A Single Centre Experience from Turkey

Background and objectives

Acute promyelocytic leukemia (APL), is a distinct subtype of acute myeloid leukemia (AML) characterized by a tendency to hemorrhage and excellent response to all-trans retinoic acid (ATRA). In this retrospective study, we aimed to determine the incidence, clinical symptoms, toxicities, and outcome of children with APL in our center.

Methods

We retrospectively reviewed the medical records of children (age < 18 years) diagnosed with APL in our pediatric hematology department between January 2006-December 2016.

Results

Pediatric APL represents 20.5% of AML cases in this cohort. Most of the cases presented as classical M3, albeit hypogranular variant was described in 12% of the cohort. Patients with hypogranular variant APL were differed from classical APL by co-expression of CD2 and CD34. About ¾ of APL patients had hemorrhagic findings at admission or the induction treatment. Severe bleeding manifested as intracranial hemorrhage was present in three patients and intracranial arterial thrombosis was present in one. Six patients showed side effects of ATRA such as pseudotumor cerebri, differentiation syndrome resulting in dilated cardiomyopathy, and pulmonary infiltrates. Five-year overall survival (OS) and early death rate were found to be 82.5% and 12% respectively.

Conclusions

A high frequency (20.5%) of APL was noted among children with AML in this single-center study. The overall mortality rate was 17.5%. Since the induction death rate was 12% and life-threatening bleeding was the primary problem, awareness and urgent treatment are critical factors to reduce early losses.

Molecular Malfeasance Mediating Myeloid Malignancies: The Genetics of Acute Myeloid Leukemia

A remarkable number of different, but recurrent, structural cytogenetic abnormalities have been observed in AML, and the 2016 WHO AML classification system incorporates numerous distinct entities associated with translocations or inversions, as well as others associated with single gene mutations into a category entitled "AML with recurrent genetic abnormalities." The AML classification is heavily reliant on cytogenetic and molecular information based on conventional genetic techniques (including karyotype, fluorescence in situ hybridization, reverse transcriptase polymerase chain reaction, single gene sequencing), but large-scale next generation sequencing is now identifying novel mutations. With targeted next generation sequencing panels now clinically available at many centers, detection of mutations, as well as alterations in epigenetic modifiers, is becoming part of the routine diagnostic evaluation of AML and will likely impact future classification schemes.

Application of GATA-3 gene marker in the detection of hematologic disorders in children

The aim of the present study was to investigate the use of GATA-3 markers in the detection of hematologic disorders in children. In total, 35 pediatric patients diagnosed with blood disease and treated in Henan Red Cross Blood Center from January 2014 to June 2015 were selected for the observation group. Another 32 healthy children were selected for the control group. The differences in the GATA-3 mRNA expression levels between the control and observation groups were detected via reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The differences in the GATA-3 protein expression levels were detected via enzyme-linked immunosorbent assay (ELISA) and western blot analysis. Compared with those in the healthy children, the mRNA expression levels of GATA-3 in patients with hematologic malignancies, acute lymphoblastic leukemia, myeloproliferative disorder, acute non-lymphocytic leukemia or thrombocytopenic purpura were significantly higher, and there were statistically significant differences between the groups (P<0.05). The results of ELISA showed that the GATA-3 protein expression levels in patients with hematologic malignancies (241.3±42.6 µg/l), acute lymphoblastic leukemia (196.3±21.6 µg/l), myeloproliferative disorder (284.2±45.1 µg/l), acute non-lymphocytic leukemia (269.3±31.4 µg/l) or thrombocytopenic purpura (272.1±39.1 µg/l) were significantly higher than those in healthy subjects (69.3±15.2 µg/l). The results of western blot analysis were consistent with those of ELISA. Based on our results, the expression levels of GATA-3 in healthy children and pediatric patients with blood diseases exhibit significant differences, and can be used as important markers for the clinical diagnosis of blood diseases in children.

Outcome of Adolescents and Young Adults Compared With Pediatric Patients With Acute Myeloid and Promyelocytic Leukemia

BACKGROUND

Studies on the outcome of adolescents and young adults (AYAs) with acute myeloid leukemia (AML) and acute promyelocytic leukemia (APL) are limited.

METHODS

We compared the outcome of AYA (19-30 years) patients with AML and PML and pediatric (0-18 years) patients with AML (pAMLs) and APL (pAPLs) utilizing the Surveillance Epidemiology and End Results-18 registry. Early mortality rate (EMR), defined as mortality within 1 month of diagnosis, was used as a surrogate for treatment-related mortality. Survival statistics were computed using the Kaplan-Meier method. Multivariate analysis was done using logistic regression and the Cox proportional hazard regression model.

RESULTS

A total of 6343 patients with AML were identified; 44.7% were AYAs. pAMLs had lower EMR (6.2% vs. 9.2%; P < .01) and higher overall survival (OS) (1-year, 70.3% vs. 62.1%; 5-year, 48.2% vs. 36.4%; P < .01). Nine hundred twenty patients with APL were also identified; 59.5% were AYAs. No statistically significant difference was found between AYAs with APL and pAPLs in EMR (11.4% vs. 14.1%; P = .23) and OS (1-year, 83.8% vs. 81.2%; P = .31 and 5-year, 68.2% vs. 73.1%; P = .11]. Comparing all patients with AML and APL, AYAs with APL and pAPLs had higher EMR (11.4% and 14.1% vs. 6.2% and 9.2%; P ≤ .01) but better OS than AYAs with AML and pAMLs (5-year OS, 68.2% and 73.1% vs. 48.2% and 36.4%; P ≤ .01).

CONCLUSION

Our analysis shows AYAs with AML have worse EMR and OS compared with pAMLs. AYAs with APL and pAPLs have similar outcomes. To our knowledge, this is the first study reporting outcomes of AYAs with APL and pAPLs using a large population-based registry and their comparison with same age patients with AML.

Arsenic Trioxide as a Radiation Sensitizer for 131I-Metaiodobenzylguanidine Therapy: Results of a Phase II Study

Arsenic trioxide has in vitro and in vivo radiosensitizing properties. We hypothesized that arsenic trioxide would enhance the efficacy of the targeted radiotherapeutic agent (131)I-metaiodobenzylguanidine ((131)I-MIBG) and tested the combination in a phase II clinical trial.

METHODS

Patients with recurrent or refractory stage 4 neuroblastoma or metastatic paraganglioma/pheochromocytoma (MP) were treated using an institutional review board-approved protocol (Clinicaltrials.gov identifier NCT00107289). The planned treatment was (131)I-MIBG (444 or 666 MBq/kg) intravenously on day 1 plus arsenic trioxide (0.15 or 0.25 mg/m(2)) intravenously on days 6-10 and 13-17. Toxicity was evaluated using National Cancer Institute Common Toxicity Criteria, version 3.0. Response was assessed by International Neuroblastoma Response Criteria or (for MP) by changes in (123)I-MIBG or PET scans.

RESULTS

Twenty-one patients were treated: 19 with neuroblastoma and 2 with MP. Fourteen patients received (131)I-MIBG and arsenic trioxide, both at maximal dosages; 2 patients received a 444 MBq/kg dose of (131)I-MIBG plus a 0.15 mg/kg dose of arsenic trioxide; and 3 patients received a 666 MBq/kg dose of (131)I-MIBG plus a 0.15 mg/kg dose of arsenic trioxide. One did not receive arsenic trioxide because of transient central line-induced cardiac arrhythmia, and another received only 6 of 10 planned doses of arsenic trioxide because of grade 3 diarrhea and vomiting with concurrent grade 3 hypokalemia and hyponatremia. Nineteen patients experienced myelosuppression higher than grade 2, most frequently thrombocytopenia (n = 18), though none required autologous stem cell rescue. Twelve of 13 evaluable patients experienced hyperamylasemia higher than grade 2 from transient sialoadenitis. By International Neuroblastoma Response Criteria, 12 neuroblastoma patients had no response and 7 had progressive disease, including 6 of 8 entering the study with progressive disease. Objective improvements in semiquantitative (131)I-MIBG scores were observed in 6 patients. No response was seen in MP. Seventeen of 19 neuroblastoma patients continued on further chemotherapy or immunotherapy. Mean 5-year overall survival (±SD) for neuroblastoma was 37% ± 11%. Mean absorbed dose of (131)I-MIBG to blood was 0.134 cGy/MBq, well below myeloablative levels in all patients.

CONCLUSION

(131)I-MIBG plus arsenic trioxide was well tolerated, with an adverse event profile similar to that of (131)I-MIBG therapy alone. The addition of arsenic trioxide to (131)I-MIBG did not significantly improve response rates when compared with historical data with (131)I-MIBG alone.

A Multicenter Experience from Lebanon in Childhood and Adolescent Acute Myeloid Leukemia: High rate of Early Death in Childhood Acute Promyelocytic Leukemia

Background

Acute myeloid leukemia (AML) is a disease with marked heterogeneity. Despite major improvement in outcome, it remains a life-threatening malignancy. Demographic and clinical data on pediatric AML is lacking among the Lebanese population.

Purpose

We aimed to identify clinical, molecular and outcome data in children with AML in Lebanon.

Methods

A retrospective chart review of children with AML diagnosed in three Lebanese hospitals during the past 8 years was conducted.

Results

From May 2002 through March 2010, we identified 24 children with AML in Saint George Hospital University Medical Center, University Medical Center Rizk Hospital, and Abou-Jaoude Hospital. Males and females were equally represented; median age at diagnosis was 9 years (range 1–24) and median WBC at diagnosis was 31 × 10⁹/L (range: 2.1–376 × 10⁹/L). Twenty five percent of patients (6 out of 24) had acute promyelocytic leukemia (APL). Karyotype was normal in 33% of patients; t(8;21), inv (16), t(8;9), t(7;11), t(9;11), complex chromosomal abnormality, monosomy 7 and trisomy 8 were the most common cytogenetic abnormalities encountered. Patients were treated on different European and North American protocols. Twelve patients (50%) achieved morphologic CR after cycle 1, 6 of them (50%) had bone marrow relapse within 11 months from diagnosis. Nine patients underwent allogeneic stem cell transplant, and 3 of them are alive at 5 years post-transplant. Early death rate was 16.6% of patients, mainly those with APL and a presenting WBC > 10 × 10⁹/L. Fifty per cent of APL patients had an early death due to DIC despite starting ATRA therapy. Overall, median survival for AML patients who died from disease progression was 25.8 months (range: 1–60 months). Overall disease-free survival was 30.4%. Patients < 10 years of age had a 50% survival rate compared to 0% in patients > 10 years.

Conclusions

Our report highlights the needs in Lebanon for better supportive care of children with APL, including faster ATRA administration and, aggressive transfusions, easy access to stem cell transplant for high-risk AML patients and the need for a national homogenous treatment strategy for children with AML.

Acute Promyelocytic Leukemia (APL): Comparison Between Children and Adults

The outcome of adults and children with Acute Promyelocytic Leukemia (APL) has dramatically changed since the introduction of all trans retinoic acid (ATRA) therapy. Based on the results of several multicenter trials, the current recommendations for the treatment of patients with APL include ATRA and anthracycline-based chemotherapy for the remission induction and consolidation, and ATRA combined with low-dose chemotherapy for maintenance. This has improved the prognosis of APL by increasing the complete remission (CR) rate, actually > 90%, decreasing the induction deaths and by reducing the relapse rate, leading to cure rates nowadays exceeding 80% considering both adults and children.1-9 More recently the combination of ATRA and arsenic trioxide (ATO) as induction and consolidation therapy has been shown to be at least not inferior and possibly superior to ATRA plus chemotherapy in adult patients with APL conventionally defined as non-high risk (Sanz score).10 Childhood APL has customarily been treated on adult protocols. Data from several trials have shown that the overall outcome in pediatric APL appears similar to that reported for the adult population; however, some clinical and therapeutic aspects differ in the two cohorts which require some important considerations and treatment adjustments.