Risk-adapted treatment of acute promyelocytic leukemia based on all-trans retinoic acid and anthracycline with addition of cytarabine in consolidation therapy for high-risk patients: further improvements in treatment outcome

Chemotherapy-free approaches to newly-diagnosed acute promyelocytic leukaemia: is oral-arsenic trioxide/all-trans retinoic acid/ascorbic acid the answer?

INTRODUCTION

Acute promyelocytic leukemia (APL) is a distinct form of acute myeloid leukemia characterized by the presence of t(15;17)(q24;21) and the PML:RARA gene fusion. Frontline use of intravenous arsenic trioxide (i.v.-ATO) and all-trans retinoic acid (ATRA) has vastly improved cure rates in APL. Researchers in Hong Kong invented the oral formulation of ATO (oral-ATO) and have confirmed a bioavailability comparable to i.v.-ATO. A plethora of studies have confirmed the safety and efficacy of oral-ATO-based regimens in the frontline and relapsed setting.

AREAS COVERED

Aspects on the development of oral-ATO-based regimens for APL in the frontline and relapsed setting are discussed. The short-term and long-term safety and efficacy of oral-ATO-based regimens are discussed. The frontline use of oral-ATO in combination with ATRA and ascorbic acid (AAA) induction in a 'chemotherapy-free' is highlighted.

EXPERT OPINION

Current and ongoing data on the use of oral-ATO-based regimens in APL support the use of oral-ATO as an alternative to i.v.-ATO allowing a more convenient and economical approach to the management of APL.

Diagnosis and management of acute promyelocytic leukemia: Brazilian consensus guidelines 2024 on behalf of the Brazilian Association of Hematology, Hemotherapy and Cellular Therapy

Improvements in clinical assessment have occurred since the last published recommendations on the diagnosis and treatment of acute promyelocytic leukemia in 2013. Here, a committee of specialists of the Brazilian Association of Hematology, Hemotherapy and Cellular Therapy presents a comprehensive review on the current knowledge, focusing on the advances in diagnosis, risk assessment, and frontline and salvage therapy. The concept of urgent diagnosis is explored as well as the management of critical situations such as coagulopathy and differentiation syndrome. Recent adjustments in risk stratification based on white blood cell counts only are presented together with the incorporation of chemo-free regimens for non-high-risk patients. Special conditions such as acute promyelocytic leukemia in children, the elderly and pregnant women are discussed. Finally, acute promyelocytic leukemia is presented as a highly curable disease because of the real possibility of targeted therapy towards differentiation, and, paradoxically, as a serious and urgent condition that deserves prompt recognition and management to avoid early mortality.

Response Rates and Transplantation Impact in Patients with Relapsed Acute Promyelocytic Leukemia

BACKGROUND

The introduction of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) has radically improved the prognosis of acute promyelocytic leukemia (APL), with cure rates above 80%. While relapse occurs in less than 20% of cases, addressing this issue remains challenging. Identifying effective salvage therapies for relapsed APL is crucial to improve patient outcomes.

METHODS

A retrospective analysis was performed on a multicentric cohort of 67 APL patients in first relapse, treated in three Italian hematology centers from June 1981 to November 2021. The overall survival (OS) and cumulative incidence of relapse (CIR) were calculated, and predictive factors were assessed using Cox regression models.

RESULTS

Overall, 61 patients (91%) received ATO ± ATRA (40.3%), chemo-based regimens (40.3%), or ATRA ± Gemtuzumab ozogamicin (GO) (10.4%). Complete remission (CR) was achieved in 98.2% of patients (molecular CR, n = 71.4%). With a median follow-up time of 54.5 months, the 5-year OS was 73% in the ATO ± ATRA group, 44% in the chemo-based group, and 29% in the ATRA ± GO group (p = 0.035). The 5-year OS rate was also higher for transplant recipients vs. non-recipients within the chemo-based cohort (50% vs. 33%, p = 0.017), but not in the ATO-based cohort (p = 0.12). ATO-based salvage therapy resulted in better OS in both univariate (p = 0.025) and multivariate analyses (p = 0.026). The 2-year CIR was higher in patients without molecular CR vs. patients in molecular CR (66% vs. 24%, p = 0.034). Molecular CR was a significant predictor of second relapse in both univariate (p = 0.035) and multivariate analyses (p = 0.036).

CONCLUSIONS

Our findings support the efficacy of ATO-based therapies in first relapse of APL and confirm the achievement of molecular remission as an independent outcome predictor in both first and second APL relapse.

Clinical networking results in continuous improvement of the outcome of patients with acute promyelocytic leukemia

ABSTRACT

The introduction of all-trans retinoic acid combined with anthracyclines has significantly improved the outcomes for patients diagnosed with acute promyelocytic leukemia (APL), and this strategy remains the standard of care in countries in which arsenic trioxide is not affordable. However, data from national registries and real-world databases indicate that low- and middle-income countries (LMIC) still face disappointing results, mainly because of high induction mortality and suboptimal management of complications. The American Society of Hematology established the International Consortium on Acute Leukemias (ICAL) to address this challenge through international clinical networking. Here, we present the findings from the International Consortium on Acute Promyelocytic Leukemia study involving 806 patients with APL recruited from 2005 to 2020 in Brazil, Chile, Paraguay, Peru, and Uruguay. The induction mortality rate has notably decreased to 14.6% compared with the pre-ICAL rate of 32%. Multivariable logistic regression analysis revealed as factors associated with induction death: age of ≥40 years, Eastern Cooperative Oncology Group performance status score of 3, high-risk status based on the Programa Español de Tratamiento en Hematologia/Gruppo Italiano Malattie EMatologiche dell'Adulto classification, albumin level of ≤3.5 g/dL, bcr3 PML/RARA isoform, the interval between presenting symptoms to diagnosis exceeding 48 hours, and the occurrence of central nervous system and pulmonary bleeding. With a median follow-up of 53 months, the estimated 4-year overall survival rate is 81%, the 4-year disease-free survival rate is 80%, and the 4-year cumulative incidence of relapse rate is 15%. These results parallel those observed in studies conducted in high-income countries, highlighting the long-term effectiveness of developing clinical networks to improve clinical care and infrastructure in LMIC.

Cytoreductive chemotherapy in induction therapy plays a key role in the prognosis of patients with low-risk acute promyelocytic leukaemia

In order to explore the risk factors of relapse and potential optimized therapeutic regimen of low-risk acute promyelocytic leukaemia (APL), here we retrospectively analysed 282 patients who were diagnosed between February 2014 and September 2021. The median follow-up was 59 (9-102) months. The 5-year overall survival and cumulative relapse incidence were 97.9% and 5.9%, respectively. In terms of different cytoreductive therapies, 86 patients were administered with hydroxycarbamide (30.5%), 113 with anthracyclines or cytarabine (40.1%), 31 with etoposide (11.0%) and 52 with no cytoreductive therapy (18.4%) during the induction therapy. The hydroxycarbamide treatment group did not decrease the relapse rate compared to the no cytoreduction group (11.4% vs. 5.9%, p = 0.289). Compared with the hydroxycarbamide group, the anthracyclines/cytarabine treatment group showed improved 5-year RFS (88.145% vs. 98.113%, p = 0.008). Multivariate Cox regression analysis revealed that myeloblasts in bone marrow at diagnosis, and PML-RARA transcript level of 6.5% or more after induction therapy were associated with a subsequent risk of relapse. The only factor positively reducing the relapse rate was anthracyclines/cytarabine cytoreductive treatment. In conclusion, cytoreductive chemotherapy in induction therapy plays a potential key role in the prognosis of low-risk APL.

Evaluation of a machine-learning model based on laboratory parameters for the prediction of acute leukaemia subtypes: a multicentre model development and validation study in France

BACKGROUND

Acute leukaemias are life-threatening haematological cancers characterised by the infiltration of transformed immature haematopoietic cells in the blood and bone marrow. Prompt and accurate diagnosis of the three main acute leukaemia subtypes (ie acute lymphocytic leukaemia [ALL], acute myeloid leukaemia [AML], and acute promyelocytic leukaemia [APL]) is of utmost importance to guide initial treatment and prevent early mortality but requires cytological expertise that is not always available. We aimed to benchmark different machine-learning strategies using a custom variable selection algorithm to propose an extreme gradient boosting model to predict leukaemia subtypes on the basis of routine laboratory parameters.

METHODS

This multicentre model development and validation study was conducted with data from six independent French university hospital databases. Patients aged 18 years or older diagnosed with AML, APL, or ALL in any one of these six hospital databases between March 1, 2012, and Dec 31, 2021, were recruited. 22 routine parameters were collected at the time of initial disease evaluation; variables with more than 25% of missing values in two datasets were not used for model training, leading to the final inclusion of 19 parameters. The performances of the final model were evaluated on internal testing and external validation sets with area under the receiver operating characteristic curves (AUCs), and clinically relevant cutoffs were chosen to guide clinical decision making. The final tool, Artificial Intelligence Prediction of Acute Leukemia (AI-PAL), was developed from this model.

FINDINGS

1410 patients diagnosed with AML, APL, or ALL were included. Data quality control showed few missing values for each cohort, with the exception of uric acid and lactate dehydrogenase for the cohort from Hôpital Cochin. 679 patients from Hôpital Lyon Sud and Centre Hospitalier Universitaire de Clermont-Ferrand were split into the training (n=477) and internal testing (n=202) sets. 731 patients from the four other cohorts were used for external validation. Overall AUCs across all validation cohorts were 0·97 (95% CI 0·95-0·99) for APL, 0·90 (0·83-0·97) for ALL, and 0·89 (0·82-0·95) for AML. Cutoffs were then established on the overall cohort of 1410 patients to guide clinical decisions. Confident cutoffs showed two (0·14%) wrong predictions for ALL, four (0·28%) wrong predictions for APL, and three (0·21%) wrong predictions for AML. Use of the overall cutoff greatly reduced the number of missing predictions; diagnosis was proposed for 1375 (97·5%) of 1410 patients for each category, with only a slight increase in wrong predictions. The final model evaluation across both the internal testing and external validation sets showed accuracy of 99·5% for ALL diagnosis, 98·8% for AML diagnosis, and 99·7% for APL diagnosis in the confident model and accuracy of 87·9% for ALL diagnosis, 86·3% for AML diagnosis, and 96·1% for APL diagnosis in the overall model.

INTERPRETATION

AI-PAL allowed for accurate diagnosis of the three main acute leukaemia subtypes. Based on ten simple laboratory parameters, its broad availability could help guide initial therapies in a context where cytological expertise is lacking, such as in low-income countries.

FUNDING

None.

Risk factors and remaining challenges in the treatment of acute promyelocytic leukemia

The treatment of acute promyelocytic leukemia (APL) has evolved with the introduction of all-trans retinoic acid (ATRA) and subsequent arsenic trioxide (ATO), particularly in standard-risk APL with an initial white blood cell count (WBC) < 10,000/μL, where a high cure rate can now be achieved. However, for some patients with risk factors, early death or relapse remains a concern. Insights from the analysis of patients treated with ATRA and chemotherapy have identified risk factors such as WBC, surface antigens, complex karyotypes, FLT3 and other genetic mutations, p73 isoforms, variant rearrangements, and drug resistance mutations. However, in the ATRA + ATO era, the significance of these risk factors is changing. This article provides a comprehensive review of APL risk factors, taking into account the treatment approach, and explores the challenges associated with APL treatments.

Incidence, risk factors, and outcomes of second neoplasms in patients with acute promyelocytic leukemia: the PETHEMA-PALG experience

The most important challenges in acute promyelocytic leukemia (APL) is preventing early death and reducing long-term events, such as second neoplasms (s-NPLs). We performed a retrospective analysis of 2670 unselected APL patients, treated with PETHEMA "chemotherapy based" and "chemotherapy free" protocols. Only de novo APL patients who achieved complete remission (CR) and completed the three consolidation cycles were enrolled into the analysis. Out of 2670 APL patients, there were 118 (4.4%) who developed s-NPLs with the median latency period (between first CR and diagnosis of s-NPL) of 48.0 months (range 2.8-231.1): 43.3 (range: 2.8-113.9) for s-MDS/AML and 61.7 (range: 7.1-231.1) for solid tumour. The 5-year CI of all s-NPLs was of 4.43% and 10 years of 7.92%. Among s-NPLs, there were 58 cases of s-MDS/AML, 3 cases of other hematological neoplasms, 57 solid tumours and 1 non-identified neoplasm. The most frequent solid tumour was colorectal, lung and breast cancer. Overall, the 2-year OS from diagnosis of s-NPLs was 40.6%, with a median OS of 11.1 months. Multivariate analysis identified age of 35 years (hazard ratio = 0.2584; p < 0.0001) as an independent prognostic factor for s-NPLs. There were no significant differences in CI of s-NPLs at 5 years between chemotherapy-based vs chemotherapy-free regimens (hazard ratio = 1.09; p = 0.932). Larger series with longer follow-up are required to confirm the potential impact of ATO+ATRA regimens to reduce the incidence of s-NPLs after front-line therapy for APL.

Risk stratification for early mortality in newly diagnosed acute promyelocytic leukemia: a multicenter, non-selected, retrospective cohort study

Introduction

Despite the current effective treatments for acute promyelocytic leukemia (APL), early mortality (EM), defined as death within 30 days of presentation, is a major hurdle to long-term survival.

Methods

We performed a multicenter retrospective study to evaluate the incidence and clinical characteristics of EM in patients with newly diagnosed APL and to develop a risk stratification model to predict EM.

Results

We identified 313 eligible patients diagnosed between 2000 and 2021 from five academic hospitals. The median age was 50 years (range 19-94), and 250 (79.9%) patients were <65 years. Most patients (n=274, 87.5%) received their first dose of all-trans retinoic acid (ATRA) within 24 hours of presentation. EM occurred in 41 patients, with a cumulative incidence of 13.1%. The most common cause of EM was intracranial hemorrhage (n=22, 53.6%), and most EMs (31/41, 75.6%) occurred within the first seven days of APL presentation. In a multivariable analysis, we identified three independent factors predicting EM: age ≥65 years (HR, 2.56), white blood cell count ≥8.0 x 109/L (HR, 3.30), and ATRA administration >24 hours of presentation (HR, 2.95). Based on these factors, patients were stratified into three categories with a significantly increasing risk of EM: 4.1% for low risk (54.3%; no risk factors; HR 1), 18.5% for intermediate risk (34.5%; 1 factor; HR 4.81), and 40.5% for high risk (11.2%; 2-3 factors; HR 13.16).

Discussion

The risk of EM is still not negligible in this era of ATRA-based therapies. Our risk model serves as a clinically useful tool to identify high-risk patients for EM who may be candidates for novel treatments and aggressive supportive strategies.

Acute myeloid leukemia: challenges for diagnosis and treatment in Latin America

OBJECTIVE

to review the current diagnostic and therapeutic landscape of AML in Latin America as a reflection of other low- and middle-income countries and regions of the world. Encompassing both acute promyelocytic and non-promyelocytic disease types.

METHODS

We reviewed the literature and study registries concerning epidemiological features of patients with AML/APL treated in Latin America, as well as evaluated diagnostic and genetic stratification and patient fitness assessment challenges, the importance of early mortality and supportive care capacity, intensive and non-intensive chemotherapy alternatives, consolidation, and maintenance strategies including novel agents and hematopoietic stem cell transplantation.

RESULTS

Although most of the current technologies and treatment options are available in the region, a significant fraction of patients have only limited access to them. In addition, mortality in the first weeks from diagnosis is higher in the region compared to developed countries.

CONCLUSIONS

Disparities in access to technologies, supportive care capacity, and availability of novel agents and HSCT hinder results in our region, reflecting barriers common to other LMICs. Recent developments in the diagnosis and treatment of this disease must be implemented through education, collaborative clinical research, and advocacy to improve outcomes.

Differentiation Syndrome in Acute Leukemia: APL and Beyond

Differentiation syndrome (DS) is a frequent and potentially life-threatening clinical syndrome first recognized with the advent of targeted therapeutics for acute promyelocytic leukemia (APL). DS was subsequently observed more broadly with targeted therapeutics for acute myeloid leukemia (AML). DS is typically characterized by fever, dyspnea, hypotension, weight gain, pleural or pericardial effusions, and acute renal failure. The incidence in patients with APL ranges from 2 to 37%, with the wide variation likely attributed to different diagnostic criteria, use of prophylactic treatment, and different treatment regimens. Treatment with corticosteroids +/- cytoreductive therapy should commence as soon as DS is suspected to reduce DS-related morbidity and mortality. The targeted anti-leukemic therapy should be discontinued in patients with severe DS. Here, we discuss the pathogenesis of DS, clinical presentations, diagnostic criteria, management strategies, and implementation of prospective tracking on clinical trials.

Prompt Initiation of Conventional Chemotherapy to Avoid Early Death in Patients with Newly Diagnosed Acute Promyelocytic Leukemia

Objective Compared to prospective trials, the early death rate of newly diagnosed acute promyelocytic leukemia (APL) in the real-world clinical setting is higher. However, the early death rate was heterogeneous according to the reported institutes. Thus, the therapeutic approach at each institute may be important for preventing early death. This study evaluated the management strategy for untreated APL in our institute to avoid early death. Methods We identified consecutive 21 patients with untreated APL who received induction therapy including all-trans retinoic acid (ATRA) between July 2007 and December 2021 at the University of Tokyo Hospital. Results As therapeutic approaches, 16 patients (76%) received ATRA administration on the day of admission, and the remaining 5 received ATRA within 4 days from admission. Notably, all patients received conventional chemotherapy added to ATRA at a median of 1 day from admission (range: 0-9 days). As clinical outcomes, no patient died during induction therapy for untreated APL, and all achieved complete molecular remission. Conclusion Compared to the previous nationwide survey, a higher proportion of patients at our institute received conventional chemotherapy in addition to ATRA, and it was initiated more promptly, which may have helped prevent early death.

Treating low- and intermediate-risk acute promyelocytic leukemia with and without chemotherapy: A comparison in a tertiary care center

Background

Acute promyelocytic leukemia (APL) comprises approximately 10% of acute myeloid leukemia (AML) cases.

Material and Methods

Both options of treatment (ATRA-ATO and ATRA-chemotherapy) were discussed with patients with low- and intermediate-risk APL, pros and cons explained in details, and treatment regimen selected after getting informed written consent.

Results

Total 71 patients were included in the study; among these patients, 3 were negative for both FISH for t (15,17) and RT-PCR for promyelocytic leukemia retinoic acid receptor alpha, and 36 patients with APL had white blood cell count at diagnosis >10 × 109/l. Total 30 patients with newly diagnosed as low- and intermediate-risk-APL fulfilled all inclusion criteria, treated and followed for a minimum period of 2 years up to June, 2016. Fifteen patients liked to be treated with all-trans retinoic acid (ATRA) and arsenic trioxide (ATO), while rest of the 15 patients preferred treatment with ATRA and chemotherapy.

Conclusion

Combination of ATRA and ATO is equally effective, less toxic, and more feasible in comparison to ATRA and chemotherapy for patients with low- and intermediate-risk APL and is a viable option for this subset of patients, especially in countries with limited resources.

Real-life comparison of posaconazole versus fluconazole for primary antifungal prophylaxis during remission-induction chemotherapy for acute leukemia

BACKGROUND

Patients undergoing remission-induction intensive chemotherapy for acute leukemia are at high risk for life-threatening invasive fungal infections (IFIs). Primary antifungal prophylaxis with posaconazole has been shown to reduce the incidence of IFI compared to fluconazole, but real-life data are limited and the effect on mortality remains unclear.

METHODS

This retrospective cohort study compared fluconazole and posaconazole as primary prophylaxis in real-life practice over a 10-year period, in a Canadian hospital.

RESULTS

A total of 299 episodes were included (fluconazole, n = 98; posaconazole, n = 201), of which 68% were first inductions. The underlying hematologic malignancy was acute myeloid leukemia or myelodysplastic syndrome in 88% of episodes and acute lymphoblastic leukemia in 9%. Overall, 20 cases of IFI occurred (aspergillosis, n = 17; candidiasis, n = 3) and 14 were considered as breakthrough IFI. IFI incidence was significantly lower in the posaconazole group (3.5% versus 13.2%; p = 0.001). Empirical or targeted antifungal therapy was also reduced in the posaconazole cohort. Mortality was similar in both groups.

CONCLUSIONS

In a real-life setting in Canada, primary posaconazole prophylaxis reduces the incidence of IFI during remission-induction chemotherapy, compared to fluconazole.

Early mortality continues to be a barrier to excellent survival in childhood acute promyelocytic leukemia: a retrospective study of 62 patients spanning 17 years

Data on childhood acute promyelocytic leukemia (APL) from low-and middle-income countries is limited. Early mortality is a concern and often not highlighted in clinical trials. The retrospective study was conducted on patients (≤12 years) with APL from 2003 to 2021 at a single center in India. Patients were treated with all-trans-retinoic acid (ATRA) and chemotherapy. Induction and three courses of consolidation were followed by maintenance for 2 years. In 2015, the protocol was updated with following modifications: (a) obtaining diagnostic cerebrospinal fluid at end-of-induction rather than at diagnosis, (b) administering intrathecal cytarabine regardless of risk-category, (c) risk-stratified administration of chemotherapy, and (d) inclusion of ATRA in all the cycles of consolidation. Sixty-two patients were diagnosed over the 17 years. The median age was 8 years (range: 0.9-12). Half had high-risk disease. Differentiation syndrome was observed in 32%, none being fatal. Eighteen (29%) patients died due to hemorrhage (83%) or septicemia (17%). Thirteen (21%) had early mortality (≤15 days), all due to hemorrhage. A platelet count <20 × 10⁹/L predicted early mortality (odds ratio: 4.5; 95% CI: 0.9-22, p = 0.06). Treatment abandonment reduced from 23.5% during 2003-2015 to nil during 2015-2021 (p = 0.006). Three (8%) patients relapsed. The 4-year OS of all patients and the patients who survived >15 days was 70.1% and 89.6%, respectively. The 4-year EFS, including abandonment and early mortality, before and following updated protocol, was 61.4% and 65.5%, respectively (p = 0.77). Early mortality continues to be a barrier to an otherwise excellent survival in childhood APL. A significant reduction in treatment abandonment in recent years is gratifying.

Acute myeloid leukemia: 2023 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Acute myeloid leukemia (AML) is a frequently fatal bone marrow stem cell cancer characterized by unbridled proliferation of malignant marrow stem cells with associated infection, anemia, and bleeding. An improved understanding of pathophysiology, improvements in measurement technology and at least 10 recently approved therapies have led to revamping the diagnostic, prognostic, and therapeutic landscape of AML.

DIAGNOSIS

One updated and one new classification system were published in 2022, both emphasizing the integration of molecular analysis into daily practice. Differences between the International Consensus Classification and major revisions from the previous 2016 WHO system provide both challenges and opportunities for care and clinical research.

RISK ASSESSMENT AND MONITORING

The European Leukemia Net 2022 risk classification integrates knowledge from novel molecular findings and recent trial results, as well as emphasizing dynamic risk based on serial measurable residual disease assessment. However, how to leverage our burgeoning ability to measure a small number of potentially malignant myeloid cells into therapeutic decision making is controversial.

RISK ADAPTED THERAPY

The diagnostic and therapeutic complexity plus the availability of newly approved agents requires a nuanced therapeutic algorithm which should integrate patient goals of care, comorbidities, and disease characteristics including the specific mutational profile of the patient's AML. The framework we suggest only represents the beginning of the discussion.

Acute promyelocytic leukaemia: population-based study of epidemiology and outcome with ATRA and oral-ATO from 1991 to 2021

BACKGROUND

The epidemiology and treatment of acute promyelocytic leukaemia (APL) are changing. We have incorporated oral arsenic trioxide (oral-ATO) into induction/maintenance.

METHODS

Newly-diagnosed APL from 1991 to 2021 divided into three 10-year periods were studied to define its epidemiology and how oral-ATO impacted on its outcome. Primary endpoints included APL incidence, early deaths (ED, first 30 days), and overall survival (OS). Secondary endpoints included post-30-day OS, relapse-free survival (RFS), and incidence of second cancers.

RESULTS

APL occurred in 374 males and 387 females at a median age of 44 (1-97) years. Annual incidences increased progressively, averaging 0.32 per 100,000 people. All-trans retinoic acid (ATRA)-based and oral-ATO-based regimens were used in 469 and 282 patients. There were 144 EDs, occurring almost exclusively in ATRA-based inductions (N = 139), being more with males, age > 50 years, leucocyte > 10 × 10⁹/L, diagnosis during 1991-2009 and fewer with oral-ATO-based regimens. After a median of 75 (interquartile range: 14-161) months, 5-year and 10-year OS were 68.1% and 63.3%, inferior with males, age > 50 years, leucocyte > 10 × 10⁹/L, high-risk Sanz score and superior with oral-ATO-based regimens. Factoring out EDs, 5-year and 10-year post-30-day OS were 84.0% and 78.1%, inferior with males and superior with oral-ATO-based regimens. In 607 CR1 patients, the 5-year RFS was 83.8%, superior with diagnosis in 2010-2021 and oral-ATO-based regimens. Second cancers developed in 21 patients, unrelated to oral-ATO-based regimens.

CONCLUSIONS

There was an increasing incidence of APL, and all survivals were superior with the use of oral-ATO-based regimens. This study formed part of the Acute Promyelocytic Leukaemia Asian Consortium Project (ClinicalTrials.gov identifier: NCT04251754).

Case report: High-risk acute promyelocytic leukemia and COVID-19-related myocarditis one patient, two cytokine storms

Acute promyelocytic leukemia (APL) is a unique, highly curable subtype of acute myeloid leukemia, owing to the therapeutic advances of the last decades which led to high complete remission rates and excellent long-term survival. Nevertheless, it remains associated with high early mortality rates. Early death is the major cause of treatment failure in APL and is mainly attributed to coagulopathy, differentiation syndrome, and less commonly, infectious events. Timely recognition of each complication plays a crucial role in the management of patients diagnosed with APL. Coronavirus Infectious Disease 2019 (COVID-19) has shown great heterogeneity in patient presentation. Clinical manifestations range from asymptomatic disease to severe forms, mainly characterized by a hyperinflammatory syndrome leading to acute respiratory distress and multiorgan failure. Patients with acute leukemia and concomitant COVID-19-related hyperinflammatory syndrome have particularly poor outcomes. We hereby report the case of a 28-year-old male patient who was diagnosed with high-risk APL, with severe associated coagulopathy at presentation. He was treated with chemotherapy according to the AIDA regimen. The first week of induction therapy was complicated by a differentiation syndrome manifesting as fever not attributable to infection and respiratory distress with pulmonary infiltrates, resolved after ATRA discontinuation and corticotherapy. On the fourth week of treatment, he tested positive for acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with minor pulmonary involvement. Clinical manifestations over the following days included tachycardia and hypotension, associated with elevated inflammatory markers and cardiac biomarkers (troponin I x58 upper NV). Cardiovascular magnetic resonance imaging was consistent with myocarditis. COVID-19-associated myocarditis was successfully treated with methylprednisolone, intravenous immunoglobulins and Anakinra. Differentiation syndrome and COVID-19-associated myocarditis are two life-threatening complications that adversely impact survival. However, early recognition and prompt treatment initiation can improve clinical outcomes, as was the case of our patient.

Long-term retrospective study of retinoic acid combined with arsenic and chemotherapy for acute promyelocytic leukemia

Chemotherapy, all-trans retinoic acid (ATRA), and arsenic are effective options for acute promyelocytic leukemia (APL). We conducted a 20-year retrospective analysis of newly diagnosed (ND) APL patients treated with arsenic, ATRA and mitoxantrone. After achieving complete remission (CR), patients received 3-5 cycles of chemotherapy followed by AS4S4 maintenance for 3 years. Eighty-eight ND APL patients were treated with either oral AS4S4 (n = 42) or arsenic trioxide (ATO) (n = 46). The 8-year overall survival (OS) rate was 100% in the AS4S4 group and 90% in the ATO group. The disease-free survival (DFS) rates were 100% and 87.1% (p = 0.027), respectively. Patients in the ATO group had more side effects. A subsequent cohort of 33 ND APL patients received triple therapy with oral AS4S4, ATRA, and chemotherapy. The 13-year OS and DFS rates were 100% and 90.9%. Our long-term analyses show that APL patients with oral AS4S4 had better outcomes compared to ATO, with no need for hospitalization.

Role of Prophylactic Steroids in Differentiation Syndrome

Acute promyelocytic leukemia (APML) is defined as a balanced chromosomal translocation between chromosomes 15 and 17 t(15;17)(q24;q21), which results in the formation of promyelocytic leukemia-retinoic acid receptor-alpha (PML-RARA) fusion protein. A widespread recommendation for APML treatment is combined all-trans retinoic acid (ATRA)/arsenic trioxide (ATO) therapy. Differentiation syndrome (DS), or retinoic acid syndrome, is one of the well-known complications of APML treated with ATRA or ATO. The presenting symptoms of APML-induced DS are diverse, and rare symptoms are easily misdiagnosed. However, unexplained fever, dyspnea, weight gain > 5 kg, leukocytosis, acute renal failure, and a chest radiograph demonstrating pleural or pericardial effusion are the most common manifestations of DS. Early recognition and prompt initiation of corticosteroids are key factors in the management of DS. As soon as ATRA/ATO therapy is started, prophylactic treatment with steroids has been recommended to minimize the severity of DS. It is proposed that ATRA/ATO should be stopped or held once the signs and symptoms of DS develop. This case report describes a 45-year-old male who was diagnosed with APML after he developed episodes of hematuria and nose bleeding at home. The patient was also given an empiric steroid along with ATRA/ATO to lessen the intensity of DS. Our study suggests that early initiation of prophylactic steroid treatment can improve the prognosis and mortality of patients with APML-induced DS.

The recognition of oral manifestations of haematological disease saves lives: a case report

BACKGROUND

Acute Leukaemias are haematological disorders characterised by the proliferation of immature white blood cells in the bone marrow and/or peripheral blood. Oral manifestations of leukaemia are common and may be the first sign of the disease. The clinical presentation of these Acute Leukaemias may include neutropenic sepsis, hyperviscocity and coagulopathy which confer a potential morbidity and mortality. Clinicians must be able to recognise this pattern of presentation.

CASE REPORT

We report a 34-year-old female who was referred to the Oral and Maxillofacial Surgery department with acute dental pain and pericoronitis. She subsequently had a simple dental extraction but re-presented with a bleeding socket that did not respond to local treatment. Investigation of this led to a diagnosis of Acute Promyelocytic Leukemia (APL). She was admitted under the care of the haematology team for urgent, life-saving, treatment.

CONCLUSIONS

Early diagnosis and treatment of the Acute Leukaemias can be life saving. The oral manifestations of disease are common and may be the first sign. Clinicians must be able to recognise this pattern of presentation and arrange urgent investigation and specialist management.

CLINICAL/CPD RELEVANCE

This case report discusses leukaemia and highlights the important role General Dental Practitioners can play in early diagnosis. We frame a safe approach to managing these patients in a typical case. Whilst this disease subtype is rare, the learning points can be universally applied.

Treatment for relapsed acute promyelocytic leukemia

The advent of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) has significantly improved the outcomes of acute promyelocytic leukemia (APL); nevertheless, a small fraction of patients still experience relapse. Due to the infrequency of APL relapse coupled with the rapid change in the therapeutic landscape, there are limited available data regarding the treatment of relapsed APL. In this situation, however, ATO-based therapy has been shown to result in high rates of hematological and molecular complete remission (CR). Autologous hematopoietic cell transplantation (HCT) is considered the postremission therapy of choice when patients achieve molecular CR, whereas recent studies have suggested that molecular CR is not prerequisite for the success of autologous HCT. Allogeneic HCT can be reserved for selected patients, i.e., those who cannot achieve CR and those who relapse after autologous HCT, because of high toxicities and the expectation of highly favorable outcomes with autologous HCT during CR. For patients who are ineligible for HCT, prolonged administration of ATRA + ATO would be a viable option. To further refine the therapy for patients with relapsed APL, it is imperative to aggregate clinical data of patients who relapse after the ATRA + ATO frontline therapy within the framework of national and international collaboration.

Oral Realgar-Indigo Naturalis Formula Treatment for Acute Promyelocytic Leukemia in Children: A Randomized, Control Clinical Trial

Objective

To analyze the efficacy, safety, and economy of RIF compared with intravenous arsenic trioxide (ATO) for the induction and consolidation therapy of pediatric APL.

Materials and Methods

In this randomized control clinical trial (NCT02200978), children with newly diagnosed APL from June 2013 to December 2017 were randomly divided into RIF and ATO groups. The groups were treated with RIF or ATO in combination with all-trans retinoic acid (ARTA) and conventional chemotherapeutic drugs during induction and consolidation therapy.

Results

Ninteen patients were enrolled, including eight in the RIF group and 11 in the ATO group. After induction therapy, the bone marrow morphologic complete remission (CR) rate, the median time to CR, and molecular remission (promyelocytic leukemia protein (PML)/retinoic acid receptor α (RARα) conversion) rates showed no significant differences between patients in the RIF versus ATO groups (100% vs. 100%, p=1.000; 22 vs. 24 days, p=0.395; 28.5% vs. 54.5%, p=0.367, resp.). After consolidation therapy, the molecular remission rate was 100% in both groups. At the end of more than two years of follow-up, the disease-free survival (DFS) rate was 100% in both groups.

Conclusion

Oral RIF can achieve similar efficacy to intravenous ATO for APL in children with good safety, less toxicity, fewer side effects, and fewer inpatient days. Therefore, oral RIF can be used as an alternative to intravenous ATO for the treatment of APL in children.

Interleukin-4 gene intron 3 VNTR polymorphism in adult acute myeloid leukemia

Background

The proliferation of acute myeloid leukemia (AML) blast into the bone marrow microenvironment is controlled by cytokines. Interleukin-4 (IL-4) has recently been discovered to suppress the development and persistence of AML cells selectively. Intron three of the Interleukin-4 (IL-4) gene contains a 70-bp minisatellite region polymorphism that may influence gene transcriptional activity and subsequently affect the production level of IL4. We investigated the IL-4 gene intron three variable number tandem repeat (VNTR) polymorphism as a molecular marker in AML associated with clinical and laboratory variables and a prognostic factor for therapeutic response and disease outcome.

Results

IL-4 gene intron three minisatellite regions polymorphism was assessed in 60 adult AML patients and 60 healthy controls, comparable concerning age and gender, using polymerase chain reaction. Three study marker genotypes were detected in AML patients; P1/P1 (3%), P1/P2 (40%), and P2/P2 (56.7%). The frequency of P2 alleles was significantly more in AML patients than in healthy controls (76.7% versus 25%; P < 0.001). Compared to the heterozygous group and P1/P1 carriers, AML patients with the homozygous P2/P2 genotype had a higher total leucocytic count and increased blast percentages in bone marrow or peripheral blood, besides a lower platelet count. P2P2 genotype was also significantly associated with poor therapeutic response, higher susceptibility to disease recurrence and shorter overall survival and disease-free survival.

Conclusion

The IL-4 intron 3 VNTR polymorphism could be included in the molecular risk stratification of AML to predict poor disease. This information can be utilized in incorporating biological therapy into the present therapeutic protocols to enhance chemotherapy regimens’ current low response rates.

History of Acute Promyelocytic Leukemia

In this article, we discuss the history of acute promyelocytic leukemia (APL) from the pre-therapeutic era, which began after its recognition by Hillestad in 1947 as a nosological entity, to the present day. It is a paradigmatic history that has transformed the “most malignant leukemia form” into the most curable one. The identification of a balanced reciprocal translocation between chromosomes 15 and 17, resulting in fusion between the promyelocytic leukemia gene and the retinoic acid receptor alpha, has been crucial in understanding the mechanisms of leukemogenesis, and responsible for the peculiar response to targeted therapy with all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). We review the milestones that marked successive therapeutic advances, beginning with the introduction of the first successful chemotherapy in the early 1970s, followed by a subsequent incorporation of ATRA and ATO in the late 1980s and early 1990s which have revolutionized the treatment of this disease. Over the past two decades, treatment optimization has relied on the combination of ATRA, ATO, and chemotherapy according to risk-adapted approaches, which together with improvements in supportive therapy have paved the way for cure for most patients with APL.

Assessment of Arsenic Trioxide and All-trans Retinoic Acid for the Treatment of Pediatric Acute Promyelocytic Leukemia: A Report From the Children's Oncology Group AAML1331 Trial

Importance

All-trans retinoic acid (ATRA) and arsenic trioxide therapy without the use of maintenance therapy has been found to be beneficial for the treatment of adults with standard-risk acute promyelocytic leukemia (APL). However, it is unclear whether similar regimens are safe and beneficial for the treatment of high-risk APL or pediatric patients with standard-risk APL.

Objective

To assess whether treatment with an ATRA and arsenic trioxide-based regimen is safe and allows for the elimination or substantial reduction of chemotherapy use among pediatric patients with standard-risk or high-risk APL, respectively.

Design, Setting, and Participants

The Children's Oncology Group AAML1331 study is a nonrandomized, noninferiority trial that examined survival outcomes among 154 pediatric patients with APL compared with a historical control group of patients with APL from the AAML0631 study. Patients aged 1 to 21 years were enrolled at 85 pediatric oncology centers (members of the Children's Oncology Group) in Australia, Canada, and the US from June 29, 2015, to May 7, 2019, with follow-up until October 31, 2020. All patients had newly diagnosed APL and were stratified into standard-risk APL (white blood cell count <10 000/μL) and high-risk APL (white blood cell count ≥10 000/μL) cohorts.

Interventions

All patients received ATRA and arsenic trioxide continuously during induction therapy and intermittently during 4 consolidation cycles. Patients with high-risk APL received 4 doses of idarubicin during induction therapy only. The duration of therapy was approximately 9 months, and no maintenance therapy was administered.

Main Outcomes and Measures

Event-free survival (EFS) at 2 years after diagnosis.

Results

Among 154 patients (median age, 14.4 years [range, 1.1-21.7 years]; 81 male participants [52.6%]) included in the analysis, 98 patients (63.6%) had standard-risk APL, and 56 patients (36.4%) had high-risk APL. The median follow-up duration was 24.7 months (range, 0-49.5 months) for patients with standard-risk APL and 22.8 months (range, 0-47.7 months) for patients with high-risk APL. Patients with standard-risk APL had a 2-year EFS rate of 98.0% and an overall survival rate of 99.0%; adverse events included 1 early death during induction therapy and 1 relapse. Patients with high-risk APL had a 2-year EFS rate of 96.4% and an overall survival rate of 100%; adverse events included 2 relapses and 0 deaths. These outcomes met predefined noninferiority criteria (noninferiority margin of 10% among those with standard-risk APL and 14.5% among those with high-risk APL).

Conclusions and Relevance

In this nonrandomized, noninferiority trial, pediatric patients with standard-risk APL who received treatment with a chemotherapy-free ATRA and arsenic trioxide regimen experienced positive outcomes. Patients with high-risk APL also had positive outcomes when treated with a novel ATRA and arsenic trioxide-based regimen that included 4 doses of idarubicin during induction therapy only and no maintenance therapy. The 2-year EFS estimates were noninferior to the historical comparator group, and advantages of the regimen included shorter treatment duration, lower exposure to anthracycline and intrathecal chemotherapy, and fewer days hospitalized.

Trial Registration

ClinicalTrials.gov Identifier: NCT02339740.

High Risk Acute Promyelocytic Leukemia - An Enigma for Hematologists: Optimizing Treatment with APML-4 Protocol

Management of Acute Promyelocytic Leukemia (APML) has improved drastically after the introduction of ATRA (All-trans-retinoic acid) and Arsenic trioxide (ATO). The use of APML-4 protocol has shown its effectiveness in Australian population. We know that high-risk APML represents a subset with poor outcomes. There is scarcity of literature reporting outcomes of high-risk APML from India. We present a 5-year retrospective analysis of the safety and efficacy of APML-4 protocol in our 28 high-risk patients. Of 28 patients, there were 8(28.5%) early deaths; all 20 patients (100%) who were alive achieved hematologic complete remission post-induction and molecular complete remission post-consolidation. The 5-year disease free survival, failure free survival (FFS) and overall survival were 100%, 69% and 69% respectively. Factors affecting FFS were age > 45 years (p = 0.008), baseline ECOG-PS > 1 (p < 0.0001), and grade 3-4 differentiation syndrome (p = 0.008). APML-4 protocol in high-risk patients is capable of achieving excellent disease control with less toxicities. While early induction deaths in high-risk APML still remain an issue, protocol modifications (for steroid and anthracyclines) are important considering high frequency of infections at baseline and during induction therapy in our population.

Walking a Tightrope: Dosage Modifications and Treatment Outcomes of All-Trans-Retinoic Acid, Arsenic Trioxide, and Daunorubicin for High-Risk Acute Promyelocytic Leukemia

PURPOSE

The use of all-trans-retinoic acid (ATRA) and arsenic trioxide (ATO) in the treatment of low- and intermediate-risk acute promyelocytic leukemia (APL) is the standard of care. We report the combined use of ATRA, ATO, and daunorubicin (DNR) in patients newly diagnosed with high-risk APL. The primary focus was to describe the drug dosage modifications made in the real-world scenario.

METHODS

In this descriptive study, we included 16 out of 28 patients with high-risk APL from two tertiary care centers in South India (Vijayawada and Trichy) between January 2015 and December 2018. A unique approach of initiating ATRA at a dose of 25 mg/m² on day 1 and escalation to 45 mg/m² after cytoreduction with DNR and hydroxyurea was followed in all patients to avert differentiation syndrome, in the setting of hyperleukocytosis at presentation.

RESULTS

All patients who survived the first 3 days of admission achieved complete remission after a median duration of 29 days. There were no deaths during induction or consolidation, and the regimen was well tolerated; two patients developed grade 3/4 peripheral neuropathy requiring treatment modification. After a median follow-up duration of 1.9 years, there were no hematologic or molecular relapses.

CONCLUSION

The study sheds light on the modifications made to recommended dosages of ATRA, ATO, and DNR to optimize outcomes in high-risk APL and reaffirms the importance of ATO use in the front-line setting to achieve durable responses with minimal toxicity.

Characteristics and predictors of early hospital deaths in newly diagnosed APL: a 13-year population-wide study

Despite therapeutic advances, early death (ED) remains a major factor curtailing survival of acute promyelocytic leukemia (APL). Studies examining factors that cause early death (ED; within 30 days of admission) and the correlation of survival with the timing of administration of all-trans retinoic acid (ATRA) and hemostatic parameters are scarce. We performed a cohort analysis of nonselect patients with newly diagnosed APL who presented to the health care system in Hong Kong, where oral arsenic trioxide was used. From 1 January 2007 to 30 April 2020, 358 patients (median age, 47 [1-97] years) with newly diagnosed APL were identified. ED occurred in 56 patients (16%): 11 (3%) died in the first 2 days after admission (intracranial hemorrhage [ICH], n = 6; APL-differentiation syndrome [APL-DS], n = 4; infection, n = 1); 22 (6%) died within 3 to 7 days (ICH, n = 12; APL-DS, n = 8; infections, n = 2), and 23 (6%) died within 8 to 30 days (ICH, n = 7; APL-DS, n = 11; infection, n = 5). Factors significantly associated with ED by multivariate analysis included male sex (P = .01); presenting leukocyte count ≥10 × 109/L (P = .03); fibrinogen <1.5 g/L (P = .02); and ATRA administration >24 hours after hospital admission (P < .001). After a median follow-up of 47 (0-166) months, the 5- and 10-year overall survival (OS) was 68.6% and 61.2%, respectively. Excluding EDs, the 5- and 10-year post-30-day OS improved to 81.3% and 72.5%. Early administration of ATRA (<24 hours) and vigorous correction of hemostatic abnormalities, including hypofibrinogenemia, are key to reducing ED.

Efficacy and Tolerability of First Line Arsenic Trioxide in Combination With All-Trans Retinoic Acid in Patients With Acute Promyelocytic Leukemia: Real Life Experience

Acute promyelocytic leukemia is a variant of acute myeloid leukemia characterized by t(15;17) and PML/RAR alfa fusion gene. The discovery of the molecular pathogenesis has led to entitle all-trans retinoic acid (ATRA) as the first targeted therapy for acute leukemia. It is usually associated to anthracycline-based chemotherapy with high response rates, but potential long-term sequelae including therapy-related malignancies have been observed. Arsenic trioxide (ATO) was added to obviate these complications and investigational trials aimed to a new strategy with the incorporation of arsenic trioxide (ATO) into initial therapy instead of chemotherapy in selected patients. ATRA plus ATO without chemotherapy was the first attempt to treat low and intermediate-risk patients with APL. Our study aims to describe a monocentric cohort of patients with newly diagnosed APL effectively treated with ATO plus ATRA underlying its efficacy together with the high grade of tolerability of this association. From January 2009 to December 2019 23 APL patients were diagnosed and treated with ATO plus ATRA regimen: 14 males and 9 females patients with a median age of 45 years (range 18-72), for the majority intermediate risk (15 patients, 65%). The treatment was well tolerated and all patients achieved molecular remission after a median time of 3 months (range 1-6 months). All patients proceeded to consolidation phase as outpatients, they maintained complete molecular response at a median time of 44 months (range 15-127) except for 1 patient. All but one patient are alive and in response at a median follow-up of 48 months (range 9-141) without late effects. ATO plus ATRA regimen shows advantages in comparison to chemotherapy; in fact it allowed to treat patients in which chemotherapy could even not be applicable and it did not show secondary hematological diseases. The association of ATO to ATRA as chemo-free regimen enabled to treat APL even without chemotherapy.

Oral etoposide combined with oral arsenic plus retinoic acid for two cases with newly diagnosed high-risk acute promyelocytic leukemia during COVID19 pandemic

•

Cytotoxic drug oral Vp-16 replace anthracyclines as cytoreductive agent at the initial stage of induction therapy for high-risk APL;.

•

Oral Vp-16 is convenient and it overcomes the limitation of intravenous chemotherapy drugs in some special circumstances;.

•

High-risk APL patients should receive oral Vp-16 as early as possible to reduce tumor load in order to secure safety of induction therapy.

•

It is indicated that pure oral induction regimen: oral etoposide, ATRA and RIF provides a novel effective therapy in outpatient clinics.

Acute promyelocytic leukemia (APL) is a highly curable hematology malignancy. The major factor influence prognosis of APL is early deaths (ED) during the course of induction therapy, especially in high-risk APL. Therefore, effective reduction of white blood cells and correction of coagulation abnormalities are the key points of treatment for high-risk APL. Due to COVID19 pandemic in China since Jan 2020, some patients with hematologic malignancies suspected of COVID-19 infection had been isolated and traditional intravenous chemotherapy drugs is not available in isolated wards. We had explored a regimen of an oral etoposide to reduce the tumor burden for high-risk APL and dual induction with retinoic acid (ATRA) and oral arsenic realgar-Indigo nautralis formula (RIF), and finally two cases of high-risk APL patients received complete remission in one month. It is indicated that pure oral induction regimen: oral etoposide, ATRA and RIF provides a novel therapy in outpatient clinics.

Arsenic trioxide replacing or reducing chemotherapy in consolidation therapy for acute promyelocytic leukemia (APL2012 trial)

As all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) are widely accepted in treating acute promyelocytic leukemia (APL), deescalating toxicity becomes a research hotspot. Here, we evaluated whether chemotherapy could be replaced or reduced by ATO in APL patients at different risks. After achieving complete remission with ATRA-ATO-based induction therapy, patients were randomized (1:1) into ATO and non-ATO groups for consolidation: ATRA-ATO versus ATRA-anthracycline for low-/intermediate-risk patients, or ATRA-ATO-anthracycline versus ATRA-anthracycline-cytarabine for high-risk patients. The primary end point was to assess disease-free survival (DFS) at 3 y by a noninferiority margin of -5%; 855 patients were enrolled with a median follow-up of 54.9 mo, and 658 of 755 patients could be evaluated at 3 y. In the ATO group, 96.1% (319/332) achieved 3-y DFS, compared to 92.6% (302/326) in the non-ATO group. The difference was 3.45% (95% CI -0.07 to 6.97), confirming noninferiority (P < 0.001). Using the Kaplan-Meier method, the estimated 7-y DFS was 95.7% (95% CI 93.6 to 97.9) in ATO and 92.6% (95% CI 89.8 to 95.4) in non-ATO groups (P = 0.066). Concerning secondary end points, the 7-y cumulative incidence of relapse (CIR) was significantly lower in ATO (2.2% [95% CI 1.1 to 4.2]) than in non-ATO group (6.1% [95% CI 3.9 to 9.5], P = 0.011). In addition, grade 3 to 4 hematological toxicities were significantly reduced in the ATO group during consolidation. Hence, ATRA-ATO in both chemotherapy-replacing and -reducing settings in consolidation is not inferior to ATRA-chemotherapy (https://www.clinicaltrials.gov/, NCT01987297).

Real-life outcomes of unselected acute promyelocytic leukemia patients: a single-center 14-year experience

BACKGROUND

After the inclusion of all-trans retinoic acid (ATRA) into the treatment of Acute Promyelocytic leukemia (APL), a notable improvement concerning the survival rates of patients with APL has been observed. However, the population-based studies demonstrated that there was no marked improvement in the survival of patients after the 2000s. We aim to describe the clinical response and prognosis of adult patients diagnosed with APL and examine the change in these outcomes by the time period of diagnosis.

METHODS

We retrospectively reviewed thirty-six unselected APL patients who were diagnosed between September 2003 and February 2016.

RESULTS

The probability of survival at two years was 58%, while disease-free survival (DFS) was 87%. The overall early death (ED) rate was 33% and remain stable over time [42% in 2003-2009 vs. 24% in 2010-2016 (p=.20)]. In addition, the 2-year overall survival (OS) rates were 47% in 2003-2009 and 70% in 2010-2016 (p=.29), and no differences were noted. Univariate analyses showed possible predictors of poor OS were defined as leukocytosis (≥10x109/L), high Sanz score, hemorrhage, infection, disseminated intravascular coagulopathy (DIC) at presentation and microgranular morphologic subtype.

CONCLUSIONS

This study shows that long-term survival remains low in APL patients, particularly related to a high ED rate. Initiatives to reduce ED are exceedingly substantial for improving the survival in APL.

Crosstalk between hnRNP K and SET in ATRA-induced differentiation in acute promyelocytic leukemia

HnRNP K protein is a heterogeneous nuclear ribonucleoprotein which has been proposed to be involved in the leukemogenesis of acute promyelocytic leukemia (APL), as well as in differentiation induced by all‐trans retinoic acid (ATRA). We previously demonstrated a connection between SET and hnRNP K function in head and neck squamous cell carcinoma (HNSCC) cells related to splicing processing. The objective of this study was to characterize the participation of hnRNP K and SET proteins in ATRA‐induced differentiation in APL. We observed higher (5‐ to 40‐fold) levels of hnRNP K and SET mRNA in APL patients at the diagnosis phase compared with induction and maintenance phases. hnRNP K knockdown using short‐hairpin RNA led to cell death in ATRA‐sensitive NB4 and resistant NB4‐R2 cells by apoptosis with SET cleavage. In addition, hnRNP K knockdown increased granulocytic differentiation in APL cells, mainly in NB4‐R2 with ATRA. hnRNP K knockdown had an effect similar to that of treatment with U0126 (an meiosis‐specific serine/threonine protein kinase/ERK inhibitor), mainly in NB4‐R2 cells. SET knockdown in APL cells revealed that apoptosis induction in cells with hnRNP K knockdown occurred by SET cleavage rather than by reduction in SET protein. Transplantation of NB4‐R2 cells into nude mice confirmed that arsenic trioxide (ATO) combined with U0126 has higher potential against tumor progression when compared to ATO. Therefore, hnRNP K/SET and ERK are potential therapeutic targets for both antineoplastic leukemia therapy and relapsed APL patients with ATRA resistance.

Dynamic changes and multiplication rate of white blood cell count may direct the timing of cytoreduction chemotherapy during induction treatment in newly diagnosed acute promyelocytic leukemia with low-intermediate risk

In order to explore the optimal timing for initiating cytoreduction chemotherapy following all-trans retinoic acid plus arsenic trioxide administration, 58 newly diagnosed patients with acute promyelocytic leukemia (APL) with low-intermediate mortality risk were retrospectively analyzed. During induction treatment, white blood cell (WBC) count >4x109/l and multiplication rate of WBC <3 days were defined as rapid WBC multiplication. Patients were divided into two groups: With or without rapid WBC multiplication. Comparison between the two groups revealed that the incidence of differentiation syndrome (DS) (48.1% vs. 6.5%; P<0.001), grade 3-4 bleeding (34.8% vs. 6.5%; P=0.022) and peak WBC count (30.4±20.0x109/l vs. 8.67±5.4x109/l; P<0.001) were significantly higher in the group with rapid WBC multiplication compared with in the group without rapid WBC multiplication. No significant differences were observed in bone marrow depression, infection, complete remission (CR) rate, time to achieve CR and early mortality rate between the two groups. Multivariate analysis revealed that WBC count at chemotherapy initiation was an independent risk factor for the occurrence of DS (P=0.040). Peak WBC count and rapid WBC multiplication were significantly associated with grade 3-4 bleeding (P=0.019 and P=0.002, respectively). Hence, WBC count at chemotherapy initiation along with its multiplication rate may direct the timing of cytoreduction chemotherapy during induction treatment in newly diagnosed APL with low-intermediate risk.

All-trans Retinoic Acid, Arsenic Trioxide, and Anthracycline-based Chemotherapy Improves Outcome in Newly Diagnosed Acute Promyelocytic Leukemia Regardless of FLT3-ITD Mutation Status

All-trans retinoic acid (ATRA) and pre-upfront arsenic trioxide (ATO) have revolutionized the therapy of acute promyelocytic leukemia (APL). However, internal tandem duplication of FMS-like tyrosine kinase 3 (FLT3-ITD) mutations is associated with increased risk of relapse. The aim of this study was to analyze the prognostic impact of FLT3-ITD on APL patients who received remission induction with ATRA, idarubicin (IDA) and/or ATO, followed by ATRA plus ATO along with anthracycline, as consolidation therapy. A total of 72 patients newly diagnosed with APL were included in this study. 83.3% of the patients achieved complete remission (CR) after induction therapy. FLT3-ITD mutations were detected in 16 (22.2%) patients and closely related to bcr-3 PML-RARa transcript (P<0.001). The 5-year overall survival (OS) rate was 100% in both FLT3-ITD^positive and FLT3-ITD^negative groups, and there was no significant difference in 5-year event-free survival (EFS) between the two groups (78.3% vs. 83.3%, P=0.85). ATRA plus ATO and anthracycline-based chemotherapy achieved great outcome in newly diagnosed APL regardless of the FLT3-ITD mutation status.

Safety and efficacy of different doses of anthracyclines combined with arsenic trioxide and all-trans retinoic acid in the treatment of de novo acute promyelocytic leukemia

OBJECTIVES

The purpose of this study was to evaluate the efficacy and safety of different doses of anthracyclines combined with arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) for induction in newly diagnosed acute promyelocytic leukemia (APL).

METHODS

One hundred and forty patients were included between January 2011 and December 2017. Seventy patients received low dose anthracycline, ATO and ATRA for induction chemotherapy; and other seventy patients received standard dose anthracycline, ATO and ATRA for induction chemotherapy.

RESULTS

The outcomes of both groups were similar: low dose group versus standard dose group: early mortality 5.7% vs. 10.0% (P = 0.532), disease-free survival (DFS), probabilities of overall-survival (OS) at 2 years 94.6% vs. 95.1% (P = 0.657), 92.8% vs. 88.2% (P = 0.951), respectively. However, the standard-dose group was associated with a longer duration of neutropenia (p < 0.001) and thrombocytopenia (p < 0.001), more volumes of platelets (p = 0.037) and red blood cell transfusions (p < 0.001), and a higher rate of infections (p = 0.042).

CONCLUSION

Low-dose group achieves outcomes similar to those of standard dose group for APL patients, but the low-dose group may be even safer than standard-dose group. So the low-dose anthracycline may be a better choice for newly diagnosed APL patients.

Absolute Circulating Leukemic Cells as a Risk Factor for Early Bleeding Events in Patients with Non-High-Risk Acute Promyelocytic Leukemia

Background

Hemorrhagic complications are the most common cause of early death in patients with APL and remain a major challenge in the management of APL. Early fatal bleeding events occur not only in high-risk but also in non-high-risk acute promyelocytic leukemia (APL) patients with normal or low WBC counts.

Objectives and Methods

To demonstrate the role of the absolute number of circulating leukemic cells in early bleeding events in APL patients. Clinical and laboratory characteristics of 149 patients newly diagnosed with APL were obtained from medical records and retrospectively investigated.

Results

In this study, circulating absolute leukemic cells were positively correlated with the WBC count (r=0.9813, p<0.001) in all patients with APL, and importantly, they were strongly associated with significant bleeding events in non-high-risk patients. Multivariate logistic regression analysis showed that the absolute number of leukemia cells was an independent risk factor for significant bleeding events in APL patients. A cut-off value of 2.59×10⁹/L for circulating leukemic cells to predict significant bleeding events in APL patients was obtained by ROC curve analysis. We further confirmed that the significant bleeding rate of patients with non-high-risk APL was statistically increased when the absolute number of circulating leukemic cells was ≥2.59×10⁹/L.

Conclusion

Circulating leukemic cell content has great clinical value for predicting early bleeding events in APL patients, especially in non-high-risk APL.

Acute Promyelocytic Leukemia: A Long-Term Retrospective Study in Mexico

Background

The present retrospective study reviewed acute promyelocytic leukemia (APL) cases recorded in Mexico between January 2007 and January 2017. The primary objective of the study was to evaluate overall survival (OS) in Mexican patients with APL. Secondary objective was to evaluate the impact of induction treatment with different anthracyclines on OS, event-free survival (EFS) and complications in this patient population.

Methods

The medical charts of patients referred to medical institutions in Mexico from January 2007 through January 2017 for the treatment of suspected APL were reviewed retrospectively. Patients aged 15 - 75 years, in whom the diagnosis of APL was confirmed, who had an Eastern Cooperative Group performance status of 0 - 2, and who were eligible for combined treatment with intensive chemotherapy and all-trans retinoic acid (ATRA), were included in the study. Study participants received induction and consolidation treatment with ATRA plus either daunorubicin or idarubicin, followed by 2 years of single-agent ATRA as maintenance therapy. Patients who were unable to pay for ATRA treatment received anthracycline-based induction and consolidation, with methotrexate plus mercaptopurine as maintenance therapy.

Results

A total of 360 patients from 21 public and private hospitals were included in the study. The median age of the population was 37 years, and 51% were male. Of the 360 patients, 205 (57%) vs. 155 (43%) received daunorubicin vs. idarubicin as induction treatment for APL. ATRA was administered to 201 (98%) patients in the daunorubicin group vs. 138 (89%) in the idarubicin group (P = 0.001), and was initiated at diagnosis in 92% vs. 73% of recipients, respectively (P = 0.0001). At 150 months, OS and EFS for the entire population were 84% and 79%, respectively. Both OS (90% vs. 76%, P = 0.003) and EFS (85% vs. 72%, P = 0.001) were significantly prolonged in daunorubicin vs. idarubicin recipients. Rates of complications were similar in the two groups.

Conclusions

As arsenic trioxide (ATO) is not currently available in Mexico, anthracycline plus ATRA is the mainstay of treatment for APL here. Our results confirm the efficacy of this strategy, with high OS and EFS rates being observed 12.5 years after diagnosis.

A phase 2 study of ATRA, arsenic trioxide, and gemtuzumab ozogamicin in patients with high-risk APL (SWOG 0535)

High-risk acute promyelocytic leukemia (APL) remains a therapeutic challenge, with higher associated rates of early mortality and relapse than standard-risk APL. All-trans retinoic acid (ATRA) plus arsenic trioxide (ATO) is a well-established treatment for patients with standard-risk APL, but it is not well defined for those with high-risk APL. In a prior study of patients with high-risk APL, the addition of gemtuzumab ozogamicin (GO) to ATO plus ATRA suggested benefit. The SWOG Cancer Research Network conducted a phase 2 study to confirm the efficacy and safety of the combination of ATRA plus ATO plus GO in treating high-risk APL patients. The primary end points were 3-year event-free survival (EFS) and early (6-week) death rates associated with this combination. Seventy patients were treated. With a median follow-up of 3.4 years, the 3-year EFS and overall survival estimates were 78% (95% confidence interval [CI], 67%-86%) and 86% (95% CI, 75%-92%), respectively. Overall, 86% of patients achieved complete response. The 6-week mortality rate was 11%. The most common treatment-emergent toxicities during the induction phase included febrile neutropenia, aspartate aminotransferase/alanine aminotransferase elevation, hyperglycemia, hypoxia, headache, and prolonged QT interval corrected for heart rate. Retinoic acid syndrome occurred in 9% of patients. Approximately 37% of patients did not complete all planned courses of postremission therapy. The combination of ATRA plus ATO plus GO in high-risk APL patients was effective and generally well tolerated, suggesting an opportunity to offer a chemotherapy-free induction platform for patients with this disease. This trial was registered at www.clinicaltrials.gov as #NCT00551460.

Role of Hematopoietic Stem Cell Transplantation in Acute Promyelocytic Leukemia

The indication of hematopoietic stem cell transplantation (HSCT) in acute promyelocytic leukemia (APL) has evolved historically from a widespread use in front-line therapy during the pre-ATRA era to a virtual rejection of this indication for patients treated with modern treatments. HSCT in first complete remission could only be considered for an extremely small fraction of patients with persistent MRD at the end of consolidation or for those who relapse. In the pre-ATO era, relapsed patients were usually treated with readministration of ATRA and chemotherapy as salvage therapy, generally containing high-dose cytarabine and an anthracycline, followed by further post-remission chemotherapy and/or HSCT. ATO-based regimens are presently regarded as the first option for relapsed APL. The selection of the most appropriate post-remission treatment option for patients in second CR (CR2), as well as the modality of HSCT when indicated, depends on several variables, such as pre-transplant molecular status, duration of first remission, age, and donor availability. Although with a moderate level of evidence, based on recent retrospective studies, autologous HSCT would be at present the preferred option for consolidation for patients in molecular CR2. Allogeneic HSCT could be considered in patients with a very early relapse or those beyond CR2. Nevertheless, the superiority of HSCT as consolidation over other alternatives without transplantation has recently been questioned in some studies, which justify a prospective controlled study to resolve this still controversial issue.

Early mortality and overall survival in acute promyelocytic leukemia – a single-center experience

Acute promyelocytic leukemia (APL) is a subtype of acute leukemia (AL) with distinct cytogenetics, clinical and biological characteristics. APL was considered as one of the most rapidly lethal forms of acute myeloblastic leukemia (AML), but recently, with the introduction of all-trans retinoic acid (ATRA) it has become the most curable subtype of AL. The main difficulty with APL is early death (ED), defined as death because of any cause within 30 days after diagnosis, and it has emerged as the most important cause of treatment failure. Our retrospective-prospective study was realized at the University Clinic for Hematology from January 2004 until December 2020. It included 46 patients with APL, according to FAB and WHO classification with confirmed molecular diagnosis. The following patients’ risk stratification factors were analyzed: age, Sanz risk score, WBC, PL, clinical presentation of the disease, levels of fibrinogen and D-dimers. During the study period, APL was diagnosed in 46 patients, 24 females (52.2%) and 22 males (47.8%), with mean age of 45 years. The overall survival showed that 24 patients (52.1%) were alive and 22 (47.8%) had lethal outcome. Regarding treatment, five patients (10.9%) died before starting the chemo-treatment. But, still, ED was observed in 13 patients (59%), and in 9 patients (40.9%) death occurred 30 days after establishing the diagnosis. The main reasons of mortality were also analyzed. To prevent ED prior to treatment, suspected APL patients should be immediately hospitalized and treated as medical emergency. Keywords: acute promyelocytic leukemia, early death, all-trans retinoic acid

Outcomes for Patients With Acute Promyelocytic Leukemia in South Africa

BACKGROUND

The characteristics and outcomes of patients with acute promyelocytic leukemia (APL) from sub-Saharan Africa have not been published.

PATIENTS AND METHODS

We report retrospectively on consecutively diagnosed APL patients treated in Cape Town, South Africa, during 1998-2019. A total of 69 patients were treated, of whom 27 (39%) were classified as having high risk APL.

RESULTS

Early death rates at 7 and 30 days were 7% and 13%, respectively, including 4 patients who died before any treatment could be administered. Overall survival at 3 years was 76.5% (95% confidence interval, 63.9-85.2) for the entire cohort, and 82.5% (95% confidence interval, 69.7-90.2) if patients who died within 7 days of diagnosis were excluded. For 13 patients (18.8%), there was a delay of 5 or more days from time of initial presentation at a peripheral hospital until arrival at the leukemia center and administration of all-trans retinoic acid; only 1 of these patients died within 30 days.

CONCLUSION

Despite the challenges faced in the public healthcare system of a developing country, outcomes of APL patients treated at our center are similar to outcomes from developed countries.

Prognostic significance of DNMT3a gene expression and reactive nitrogen species in newly diagnosed Egyptian de novo adult acute myeloid leukemia patients

Background

DNA methyltransferase 3a (DNMT3a) gene is a frequently dysregulated epigenetic modifier gene involved in the process of carcinogenesis. Also, there is a dichotomous nature of nitric oxide action with the ability to both promote and repress cancers. There is a host of research work delineating the frequency of DNMT3a mutation in acute myeloid leukemia (AML), but little is known about its level of expression in AML patients or its probable relationship to nitrosative stress. This study aims at the assessment DNMT3a gene expression as well as nitric oxide levels in newly diagnosed adult patients with de novo AML. Moreover, it aims at relating these two variables to other disease features and prognostic indicators as well as treatment outcomes. The study included 45 adult de novo AML patients and 10 healthy control subjects. Measurement of DNMT3a messenger ribonucleic acid (mRNA) transcripts was done by real-time quantitative polymerase chain reaction (RQ-PCR) followed by Sanger sequencing to identify the presence or absence of DNMT3a arginine 882 (R882) mutation. This was followed by the assessment of serum nitrite level as a surrogate marker for nitric oxide radical (NO) using colorimetric methods.

Results

DNMT3a gene expression, as well as serum nitrite levels, were significantly higher among AML cases in relation to controls before chemotherapy with P values of < 0.001 and 0.035, respectively. Dividing patients into low and high expressors in relation to the hotspot mutation demonstrated no difference between the two groups in terms of demographic, clinical, and laboratory characteristics or treatment outcomes.

Conclusion

DNMT3a gene expression is increased among the AML population in relation to normal healthy controls. This may point out the need for the assessment of the influence of this gene expression on methylcytosine content of tumor samples with the subsequent implementation of hypomethylating agents as a line of therapy in cases exhibiting excessive hypermethylation.

Incidence of Differentiation Syndrome Associated with Treatment Regimens in Acute Myeloid Leukemia: A Systematic Review of the Literature

Differentiation syndrome (DS) is a potentially fatal adverse drug reaction caused by the so-called differentiating agents such as all-trans retinoic acid (ATRA) and arsenic trioxide (ATO), used for remission induction in the treatment of the M3 subtype of acute myeloid leukemia (AML), acute promyelocytic leukemia (APL). However, recent DS reports in trials of isocitrate dehydrogenase (IDH)-inhibitor drugs in patients with IDH-mutated AML have raised concerns. Given the limited knowledge of the incidence of DS with differentiating agents, we conducted a systematic literature review of clinical trials with reports of DS to provide a comprehensive overview of the medications associated with DS. In particular, we focused on the incidence of DS reported among the IDH-inhibitors, compared to existing ATRA and ATO therapies. We identified 44 published articles, encompassing 39 clinical trials, including 6949 patients. Overall, the cumulative incidence of DS across all treatment regimens was 17.7%. Incidence of DS was notably lower in trials with IDH-inhibitors (10.4%) compared to other regimens, including ATRA and/or ATO (15.4-20.6%). Compared to other therapies, the median time to onset was four times longer with IDH-inhibitors (48 vs. 11 days). Treating oncologists should be mindful of this potentially fatal adverse drug reaction, as we expect the current trials represent an underestimation of the actual incidence.

Gemtuzumab ozogamicin in acute myeloid leukemia: past, present and future

After being in the therapeutic wilderness for several decades, acute myeloid leukemia has been recently thrust into the limelight with a series of drug approvals. Technical refinements in production, genetic manipulation and chemical modification of monoclonal antibodies led to growing interest in antibodies-based treatment strategies. Much of the focus of these efforts in acute myeloid leukemia has been on CD33 as a target. On September 2, 2017, the U.S. Food and Drug Administration approved gemtuzumab ozogamicin for treatment of relapsed or refractory CD33⁺ acute myeloid leukemia. This signals a new chapter in the long and unusual story of gemtuzumab ozogamicin, which was the first antibody-drug conjugate approved for human use by the Food and Drug Administration. In this review we have analyzed the history of this drug which, among several mishaps, is experiencing a second youth and still represents a field to be further explored.

Predictors of early death, serious hemorrhage, and differentiation syndrome in Japanese patients with acute promyelocytic leukemia

Significant advancements have been achieved with regard to the outcomes of acute promyelocytic leukemia (APL) patients through the introduction of all-trans retinoic acid; however, early hemorrhagic death and differentiation syndrome remain the major causes of remission induction failure in patients with APL. To investigate early death, serious hemorrhage, and differentiation syndrome during remission induction therapy in terms of incidence, risk factors, influence on outcomes, and prophylactic effects of several new anticoagulants, the results of 344 patients enrolled in the Acute Promyelocytic Leukemia 204 study conducted by the Japan Adult Leukemia Study Group were analyzed. Early death was observed in 16 patients (4.7%), of whom 14 had serious hemorrhage and 2 had differentiation syndrome. Serious hemorrhage and differentiation syndrome of grade 2 or higher were observed in 21 and 54 patients, respectively. Patients who achieved complete remission had a 7-year disease-free survival of 84.8% if they did not experience serious hemorrhage and 40.0% if they experienced serious hemorrhage during remission induction therapy (P = 0.001). Risk factor analyses showed that higher white blood cell count was associated with early death, higher white blood cell count and lower platelet count with serious hemorrhage, and leukocytosis during induction therapy and higher body surface area with differentiation syndrome. In conclusion, these results indicate that patients with such high-risk features may benefit from more intensive supportive care. The hemorrhagic risk was not relieved by the introduction of new anticoagulants. Further studies are required to establish the predictive impact of body surface area on differentiation syndrome. This trial is registered with UMIN-CTR as C000000154 on September 13, 2005.

Biotransformation of arsenic trioxide by AS3MT favors eradication of acute promyelocytic leukemia: revealing the hidden facts

Arsenic trioxide (ATO) is one of the most effective drugs for treatment of acute promyelocytic leukemia (APL). It could specifically target the PML/RARα fusion oncoprotein stability and induces APL cell differentiation as well as apoptosis. Although many studies have been conducted to document the anticancer effects and mechanism of ATO, there is little information about the association between biotransformation of ATO to active arsenic metabolites and APL therapy. Generally, ATO can be rapidly converted into trivalent methylated metabolites by arsenic (+3 oxidation state) methyltransferase (AS3MT) mostly in liver and redistributed to bloodstream of APL patients who receiving ATO treatment, thereby leading to a balance between cytotoxicity and differentiation, which is proposed to be the key event in successful treatment of APL. In this review, we comprehensively discussed possible roles of AS3MT and methylated arsenic metabolites in APL therapy, so as to reveal the association between individual differences of AS3MT expression and activity with the therapeutic efficacy of ATO in APL patients.