Differentiation syndrome in patients with acute promyelocytic leukemia treated with all-trans retinoic acid and anthracycline chemotherapy: characteristics, outcome, and prognostic factors. Blood. 2009;113:775-783. [PMID: 18945964 DOI: 10.1182/blood-2008-07-168617]

Current management of newly diagnosed acute promyelocytic leukemia

The management of acute promyelocytic leukemia (APL) has considerably evolved during the past two decades. The advent of all-trans retinoic acid (ATRA) and its inclusion in combinatorial regimens with anthracycline chemotherapy has provided cure rates exceeding 80%; however, this widely adopted approach also conveys significant toxicity including severe myelosuppression and rare occurrence of secondary leukemias. More recently, the advent of arsenic trioxide (ATO) and its use in association with ATRA with or without chemotherapy has further improved patient outcome by allowing to minimize the intensity of chemotherapy, thus reducing serious toxicity while maintaining high anti-leukemic efficacy. The advantage of ATRA-ATO over ATRA chemotherapy has been recently demonstrated in two large randomized trials and this option has now become the new standard of care in low-risk (i.e. non-hyperleukocytic) patients. In light of its rarity, abrupt onset and high risk of early death and due to specific treatment requirements, APL remains a challenging condition that needs to be managed in highly experienced centers. We review here the results of large clinical studies conducted in newly diagnosed APL as well as the recommendations for appropriate diagnosis, prevention and management of the main complications associated with modern treatment of the disease.

Acute Coronary Syndrome Manifesting as an Adverse Effect of All-trans-Retinoic Acid in Acute Promyelocytic Leukemia: A Case Report with Review of the Literature and a Spotlight on Management

Background. Acute promyelocytic leukemia is characterized by t(15;17). This leads to the formation of PML/RARα which blocks the differentiation of blasts at the stage of promyelocytes. This is reversed by all-trans-retinoic acid (ATRA), a vitamin A derivative. Acute myocardial ischemia is a rare side effect of ATRA. Case Report. We report a case of acute coronary syndrome manifesting as an adverse effect of ATRA in a lady with APL who had no other risk factors for cardiovascular disease. Conclusions. We emphasize the need for high index of suspicion for the diagnosis of this entity. In the light of this case, the rare instances of ATRA associated acute myocardial ischemia recorded in the literature and the options available for treatment of acute promyelocytic leukemia sans ATRA have been reviewed.

Relationship between obesity and clinical outcome in adults with acute myeloid leukemia: A pooled analysis from four CALGB (alliance) clinical trials

Obesity has been previously suggested as an adverse prognostic marker in patients with acute leukemia. To evaluate the relationship between obesity and clinical outcome, disease-free survival (DFS) and overall survival (OS), in patients with acute myelogenous leukemia (AML), including acute promyelocytic leukemia (APL), we performed a pooled analysis of four CALGB (Alliance) clinical trials. Our study included 446 patients with APL from CALGB 9710, and 1,648 patients between 18 and 60 years of age with non-APL AML from CALGB 9621, 10503, and 19808. Obesity was defined as BMI ≥30 kg/m(2). Multivariate Cox proportional-hazard regression models were fitted for DFS and OS. Obesity was seen in 50% and 38% of APL and non-APL AML patients, respectively. In APL patients, obesity was associated with worse DFS (HR 1.53, 95% CI 1.03-2.27; P = 0.04) and OS (HR 1.72, 95% CI 1.15-2.58; P = 0.01) after adjusting for age, sex, performance status, race, ethnicity, treatment arm and baseline white blood cell count. Obesity was not significantly associated with DFS or OS in the non-APL AML patients. In conclusion, our study indicates that obesity has significant prognostic value for DFS and OS in APL patients, but not for non-APL AML patients.

Long-term outcome of 31 cases of refractory acute promyelocytic leukemia treated with compound realgar natural indigo tablets administered alternately with chemotherapy

The aim of the present study was to investigate the long-term survival of patients with refractory acute promyelocytic leukemia (APL) that were administered alternately with compound realgar natural indigo tablet (CRNIT) treatment and chemotherapy. In total, 31 patients with refractory APL were administered with CRNIT treatment alternately with chemotherapy. The complete remission (CR) and relapse rates were estimated by bone marrow (BM) examination. The expression of the promyelocytic leukemia-retinoic acid receptor α (PML-RARα) fusion protein and the apoptosis rate in the retinoic acid (RA)-resistant NB4-R1 cell line administered with CRNIT treatment in vitro were measured by western blot analysis and flow cytometry, respectively. The patients were followed up for 12-60 months, with a median follow-up time of 43 months. The total continuous CR rate was 90.32% (28/31), and the duration of response was between 10.3 and 60 months (median, 42.4 months). The total relapse rate was 9.68% (3/31), and the median time of relapse was 13 months (range, 8-27 months). During the treatment with CRNITs, there was no evident BM depression and only limited side-effects were experienced. Additionally, in vitro cell molecular biology results revealed that CRNIT treatment resulted in a marked induction of apoptosis and degradation of the PML-RARα fusion protein. The present results revealed that CRNIT treatment in combination with chemotherapy is an effective and feasible therapy for the treatment of patients with refractory APL.

Synergistic targeted therapy for acute promyelocytic leukaemia: a model of translational research in human cancer

Acute promyelocytic leukaemia (APL), the M3 subtype of acute myeloid leukaemia, was once a lethal disease, yet nowadays the majority of patients with APL can be successfully cured by molecularly targeted therapy. This dramatic improvement in the survival rate is an example of the advantage of modern medicine. APL is characterized by a balanced reciprocal chromosomal translocation fusing the promyelocytic leukaemia (PML) gene on chromosome 15 with the retinoic acid receptor α (RARα) gene on chromosome 17. It has been found that all-trans-retinoic acid (ATRA) or arsenic trioxide (ATO) alone exerts therapeutic effect on APL patients with the PML-RARα fusion gene, and the combination of both drugs can act synergistically to further enhance the cure rate of the patients. Here, we provide an insight into the pathogenesis of APL and the mechanisms underlying the respective roles of ATRA and ATO. In addition, treatments that lead to more effective differentiation and apoptosis of APL cells, including leukaemia-initiating cells, and more thorough eradication of the disease will be discussed. Moreover, as a model of translational research, the development of a cure for APL has followed a bidirectional approach of 'bench to bedside' and 'bedside to bench', which can serve as a valuable example for the diagnosis and treatment of other malignancies.

Is There Still a Role for Low-Dose All-Transretinoic Acid in the Treatment of Acute Promyelocytic Leukemia in the Arsenic Trioxide Era?

BACKGROUND

Low-dose all-transretinoic acid (LD-ATRA) has shown similar peak plasma concentrations and a mean area under the concentration time curve in comparison with standard doses of ATRA. We evaluated the efficacy of LD-ATRA plus anthracycline-based chemotherapy in patients with newly diagnosed acute promyelocytic leukemia (APL).

PATIENTS AND METHODS

Patients diagnosed with APL during the period of 2002 to 2014 were included. They received ATRA 25 mg/m(2) plus anthracycline (doxorubicin or mitoxantrone) as induction chemotherapy, followed by 3 consolidations with LD-ATRA and anthracycline and maintenance therapy with intermittent LD-ATRA and oral chemotherapy for 2 years.

RESULTS

Twenty-two patients with a median age of 28 years (range, 18-55 years) were included; 17 (77%) were in the low-risk group. Complete remission occurred in 86%, and the early death rate was 9%. At a median follow-up of 32 months (range, 4-126 months) disease-free survival (DFS) was 75% and overall survival (OS) was 86%, with a relapse rate of 27% for the entire follow-up period.

CONCLUSION

LD-ATRA plus anthracycline is safe and effective in achieving CR of APL. The early death rate is similar to that of treatment with standard doses, but it appears to be inferior in preventing relapses.

Successful management of pulmonary hemorrhage and aspergillosis in a patient with acute myeloid leukemia (AML-M3)

A 35-year-old man presented with a one month history of gingival bleeding. He was diagnosed with Acute Myeloid Leukemia (AML-M3). During treatment he developed alveolar hemorrhage for which he was treated with a steroid. After the steroid treatment he developed a nodule, a cavitary lesion and atelectasia in the left lung. He was treated with voriconazole. After therapy with voriconazole his lesion significantly decreased. This case illustrates the efficacy and safety of antifungal therapy with voriconazole for aspergillosis complicated by AML.

All-trans retinoic acid with daunorubicin or idarubicin for risk-adapted treatment of acute promyelocytic leukaemia: a matched-pair analysis of the PETHEMA LPA-2005 and IC-APL studies

Front-line treatment of acute promyelocytic leukaemia (APL) consists of all-trans retinoic acid (ATRA) and anthracycline-based chemotherapy. In this setting, a comparison of idarubicin and daunorubicin has never been carried out. Two similar clinical trials using ATRA and chemotherapy for newly diagnosed APL were compared using matched-pair analysis. One was conducted by the PETHEMA/HOVON group with idarubicin and the other by the International Consortium on APL (IC-APL) using daunorubicin. Three hundred and fifty patients from the PETHEMA/HOVON cohort were matched with 175 patients in the IC-APL cohort, adjusting for the significantly unbalanced presenting features of the two entire cohorts. Complete remission (CR) rate was significantly higher in the PETHEMA/HOVON (94 %) than in the IC-APL cohort (85 %) (P = 0.002). The distribution of causes of induction failure and the time to achieve CR were similar in both cohorts. Patients who achieved CR had comparable cumulative incidence of relapse and disease-free survival rates, but lower overall and event-free survivals were observed in the IC-APL cohort, which was mainly due to a higher death rate during induction therapy. A higher death rate during consolidation therapy was also observed in the IC-APL. These results show that daunorubicin and idarubicin have similar antileukaemic efficacy in terms of primary resistance, molecular persistence, as well as molecular and haematological relapse rates when combined with ATRA in treatment of APL. However, a higher toxic death rate during induction and consolidation therapy was observed in the IC-APL cohort. This trial was registered at www.clinicaltrials.gov as #NCT00408278 [ClinicalTrials.gov].

A Complicated Case of Acute Promyelocytic Leukemia in the Second Trimester of Pregnancy Successfully Treated with All-trans-Retinoic Acid

A 40-year-old female at 26-week gestation was diagnosed with acute promyelocytic leukemia (APL) after an abnormal prenatal lab workup showed pancytopenia. She was treated with all-trans-retinoic acid (ATRA), idarubicin, and dexamethasone. After day one of treatment, she developed differentiation syndrome, which was treated with dexamethasone. At 30-week gestation, she had preterm premature rupture of membranes and delivered by cesarean section because of the fetus' breech presentation. Despite ATRA's potential for teratogenicity, a viable infant was born without apparent anomalies. Postpartum, she underwent consolidation treatment with ATRA and arsenic trioxide (ATO). The patient continued ATRA therapy after delivery and is currently in remission.

A 56-year-old man with acute promyelocytic leukemia and pulmonary infiltrates

A 56-year-old man presented to the ED of an outside hospital with 2 days of bleeding gums and easy bruising. He denied episodes of melena, hematemesis, or hematuria and had no epistaxis. Routine blood work showed pancytopenia and evidence of diffuse intravascular coagulation. A bone marrow biopsy confirmed the diagnosis of acute promyelocytic leukemia. He was transferred to our hospital for treatment.

All-trans retinoic Acid differentiation syndrome chorioretinopathy: a case of multifocal serous neurosensory detachments in a patient with acute promyelocytic leukemia treated with all-trans retinoic Acid

PURPOSE

The purpose of this study was to report a case of multifocal serous neurosensory retinal detachments associated with systemic differentiation syndrome (DS) (formerly known as all-trans retinoic acid [ATRA] syndrome) in a patient with acute promyelocytic leukemia.

METHODS

In this observational case report, we identify a case of DS because of ATRA induction therapy with associated multiple focal serous neurosensory retinal detachments in a 39-year-old man with acute promyelocytic leukemia.

RESULTS

While suffering from a rebound episode of DS secondary to ATRA therapy, the patient experienced deterioration of his vision bilaterally. Within 8 days of discontinuing ATRA and the initiation of dexamethasone, the patient's systemic status and ocular findings resolved completely. Optical coherence tomography and fluorescein angiography confirmed the resolution of the subretinal fluid.

CONCLUSION

Given the time of onset of the patient's visual symptoms with associated chorioretinopathy, his concurrent systemic manifestations of DS, along with his concurrent systemic, and ocular response to treatment, we speculate that this is the first reported occurrence of ATRA-associated chorioretinopathy in a patient with ATRA DS.

Late differentiation syndrome in acute promyelocytic leukemia: a challenging diagnosis

Detailed knowledge about differentiation syndrome (DS) has remained limited. There are 2 large studies conducted by the Spanish workgroup PETHEMA (Programa Español de Tratamientos en Hematología; Spanish Program on Hematology Treatments) and the European group trial (LPA 96-99 and APL 93) in which the incidence, characteristics, prognostic factors and outcome of patients developing DS are evaluated. Both have described the median time of DS development between 10 and 12 days. The severity of the DS has been evaluated in the study conducted by PETHEMA, and severe DS usually occurs at the beginning of the treatment (median of 6 days), as compared with moderate DS (median of 15 days). We report here in two cases of late severe DS, with late diagnosis due to both time and form of presentation. We discuss the physiopathology, clinical presentation, prophylaxis and treatment of DS.

Myopericarditis in a pregnant woman with acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is a form of acute leukemia with a characteristic translocation, t(15;17), and is considered a hematologic emergency, typically treated with all-trans retinoic acid and an anthracycline. We present the case of a young, gravid woman who was diagnosed with APL in the third trimester, initiated typical treatment, and suffered uncommon cardiac complications. .

Pathophysiology, clinical features and radiological findings of differentiation syndrome/all-trans-retinoic acid syndrome

In acute promyelocytic leukemia, differentiation therapy based on all-trans-retinoic acid can be complicated by the development of a differentiation syndrome (DS). DS is a life-threatening complication, characterized by respiratory distress, unexplained fever, weight gain, interstitial lung infiltrates, pleural or pericardial effusions, hypotension and acute renal failure. The diagnosis of DS is made on clinical grounds and has proven to be difficult, because none of the symptoms is pathognomonic for the syndrome without any definitive diagnostic criteria. As DS can have subtle signs and symptoms at presentation but progress rapidly, end-stage DS clinical picture resembles the acute respiratory distress syndrome with extremely poor prognosis; so it is of absolute importance to be conscious of these complications and initiate therapy as soon as it was suspected. The radiologic appearance resembles the typical features of cardiogenic pulmonary edema. Diagnosis of DS remains a great skill for radiologists and haematologist but it is of an utmost importance the cooperation in suspect DS, detect the early signs of DS, examine the patients’ behaviour and rapidly detect the complications.

All-trans retinoic acid-induced inflammatory myositis in a patient with acute promyelocytic leukemia

All-trans retinoic acid (ATRA), a component of standard therapy for acute promyelocytic leukemia (APL), is associated with potentially serious but treatable adverse effects involving numerous organ systems, including rare skeletal muscle involvement. Only a handful of cases of ATRA-induced myositis in children have been reported, and none in the radiology literature. We present such a case in a 15-year-old boy with APL, where recognition of imaging findings played a crucial role in making the diagnosis and facilitated prompt, effective treatment.

Clinical characteristics, outcome and early induction deaths in patients with acute promyelocytic leukaemia: a five-year experience at a tertiary care centre

INTRODUCTION

Acute promyelocytic leukaemia (APL) is a distinct clinical and biological subtype of acute myeloid leukaemia. APL is notorious for causing early death during induction therapy, resulting in induction failure. The aim of our study was to report the clinical characteristics, outcome and early induction deaths with regard to patients with APL seen at our hospital.

METHODS

This was a retrospective study carried out at Aga Khan University Hospital, Karachi, Pakistan. Patients aged > 15 years diagnosed with APL within the period September 2007-September 2012 were included in the study.

RESULTS

Within the study period, 26 patients were diagnosed with APL based on morphology and the detection of t(15;17)(q24.1;q21.1) and promyelocytic leukaemia-retinoic acid receptor alpha (PML-RARA). The male to female ratio was 1:1. The median age of the patients was 41 (range 16-72) years. In all, there were 13 (50.0%) high-risk patients, and early induction death rate was 61.5%. Causes of early induction deaths (n = 16) included haemorrhage in 7 (43.8%) patients, differentiation (ATRA) syndrome in 7 (43.8%) and infection in 2 (12.5%). The survival rate among patients who survived the early period was 70% at 42 months. The relapse rate was 30%.

CONCLUSION

Early induction death rate was very high in patients with APL. The most common cause of early induction death in our study was haemorrhage. Outcome among patients with APL was found to be better among those who survived the initial period.

Management of Acute Myeloid Leukemia in the Intensive Care Setting

Patients with acute myeloid leukemia (AML) who are newly diagnosed or relapsed and those who are receiving cytotoxic chemotherapy are predisposed to conditions such as sepsis due to bacterial and fungal infections, coagulopathies, hemorrhage, metabolic abnormalities, and respiratory and renal failure. These conditions are common reasons for patients with AML to be managed in the intensive care unit (ICU). For patients with AML in the ICU, providers need to be aware of common problems and how to manage them. Understanding the pathophysiology of complications and the recent advances in risk stratification as well as newer therapy for AML are relevant to the critical care provider.

Induction of retinol dehydrogenase 9 expression in podocytes attenuates kidney injury

The intracellular concentration of retinoic acid is determined by two sequential oxidation reactions that convert retinol to retinoic acid. We recently demonstrated that retinoic acid synthesis is significantly impaired in glomeruli of HIV-1 transgenic mice (Tg26), a murine model of HIV-associated nephropathy. This impaired retinoic acid synthesis correlates with reduced renal expression of retinol dehydrogenase 9, which catalyzes the rate-limiting step of retinoic acid synthesis by converting retinol to retinal. Because retinoic acid has renal protective effects and can induce podocyte differentiation, we hypothesized that restoration of retinoic acid synthesis could slow the progression of renal disease. Herein, we demonstrate that overexpression of retinol dehydrogenase 9 in cultured podocytes induces the expression of podocyte differentiation markers. Furthermore, we confirm that podocyte-specific overexpression of retinol dehydrogenase 9 in mice with established kidney disease due to either HIV-associated nephropathy or adriamycin-induced nephropathy decreases proteinuria, attenuates kidney injury, and restores podocyte differentiation markers. Our data suggest that restoration of retinoic acid synthesis could be a new approach to treat kidney disease.

How we prevent and treat differentiation syndrome in patients with acute promyelocytic leukemia

Differentiation syndrome (DS), formerly known as retinoic acid syndrome, is a relatively common and potentially severe complication seen in patients with acute promyelocytic leukemia treated with all-trans retinoic acid and/or arsenic trioxide. The full-blown syndrome consists of unexplained fever, weight gain, dyspnea with pulmonary infiltrates, pleuropericardial effusion, hypotension, and renal failure. Most measures currently used for management of DS have very little evidence-based support, and therefore, many remain controversial. Despite the lack of evidence supporting DS prophylaxis, several groups have adopted a preventive strategy with corticosteroids, especially for patients with leukocyte levels higher than from 5 to 10 × 10(9)/L. DS diagnosis should be suspected in the presence of any of the above-mentioned signs and symptoms, and preemptive treatment with dexamethasone should be started immediately. Other supportive measures can also be crucial for the correct management of DS, especially in those patients with life-threatening complications. Temporary discontinuation of all-trans retinoic acid or arsenic trioxide is indicated only for patients in very poor clinical condition or with severe renal or pulmonary dysfunction, sometimes requiring admission to the intensive care unit. Recognition of specific biomarkers and a better understanding of DS pathogenesis can be helpful for the development of specific therapies to counteract DS in a timely manner.

Haematological Emergencies

In a hospital setting, it is common to encounter certain haematological emergencies irrespective of whether or not the patient has an underlying haematological condition or if the hospital has a well-established haematology service. This article aims to define and illustrate common and less common haematological emergencies that a physician may encounter on the wards and the appropriate initial management for the patient prior to a formal hematological consult.

Induction mortality, ATRA administration, and resource utilization in a nationally representative cohort of children with acute promyelocytic leukemia in the United States from 1999 to 2009

BACKGROUND

Limited data exist on induction mortality of pediatric patients with acute promyelocytic leukemia in the United States, usage of all-trans retinoic acid (ATRA) during acute promyelocytic leukemia induction, and the resources needed to deliver induction therapy.

PROCEDURE

Using the Pediatric Health Information System database we established a retrospective cohort of patients treated for newly diagnosed acute promyelocytic leukemia with ATRA between January 1999 and September 2009 in 32 of 43 PHIS contributing free-standing pediatric hospitals in the United States. Standard statistical methods were used to determine in-hospital induction mortality, ATRA administration, and resource utilization during a 60-day observation period.

RESULTS

A total of 163 children were identified who met eligibility criteria for cohort inclusion; 52% were female and 76% were white with an average age of 12.7 years. A total of 12 patients (7.4%) died, with 7 (58.3%) dying within the first 7 days of first admission. The mean time to first ATRA exposure increased with decreasing age (P = 0.0016). Resource utilization for management of retinoic acid syndrome was higher than anticipated based on prior studies and differed significantly from patients with non-M3 acute myeloid leukemia.

CONCLUSIONS

The induction mortality for pediatric acute promyelocytic leukemia remains substantial with wide variation in ATRA administration and high rates of resource utilization.

Retinoic acid and arsenic trioxide for acute promyelocytic leukemia

BACKGROUND

All-trans retinoic acid (ATRA) with chemotherapy is the standard of care for acute promyelocytic leukemia (APL), resulting in cure rates exceeding 80%. Pilot studies of treatment with arsenic trioxide with or without ATRA have shown high efficacy and reduced hematologic toxicity.

METHODS

We conducted a phase 3, multicenter trial comparing ATRA plus chemotherapy with ATRA plus arsenic trioxide in patients with APL classified as low-to-intermediate risk (white-cell count, ≤10×10(9) per liter). Patients were randomly assigned to receive either ATRA plus arsenic trioxide for induction and consolidation therapy or standard ATRA-idarubicin induction therapy followed by three cycles of consolidation therapy with ATRA plus chemotherapy and maintenance therapy with low-dose chemotherapy and ATRA. The study was designed as a noninferiority trial to show that the difference between the rates of event-free survival at 2 years in the two groups was not greater than 5%.

RESULTS

Complete remission was achieved in all 77 patients in the ATRA-arsenic trioxide group who could be evaluated (100%) and in 75 of 79 patients in the ATRA-chemotherapy group (95%) (P=0.12). The median follow-up was 34.4 months. Two-year event-free survival rates were 97% in the ATRA-arsenic trioxide group and 86% in the ATRA-chemotherapy group (95% confidence interval for the difference, 2 to 22 percentage points; P<0.001 for noninferiority and P=0.02 for superiority of ATRA-arsenic trioxide). Overall survival was also better with ATRA-arsenic trioxide (P=0.02). As compared with ATRA-chemotherapy, ATRA-arsenic trioxide was associated with less hematologic toxicity and fewer infections but with more hepatic toxicity.

CONCLUSIONS

ATRA plus arsenic trioxide is at least not inferior and may be superior to ATRA plus chemotherapy in the treatment of patients with low-to-intermediate-risk APL. (Funded by Associazione Italiana contro le Leucemie and others; ClinicalTrials.gov number, NCT00482833.).

Thrombosis in acute promyelocytic leukemia

INTRODUCTION

Compared to bleeding, major thromboses are a less commonly encountered problem in acute promyelocytic leukemia (APL), and our knowledge about the epidemiology of major thromboses in APL stems mainly from individual case reports. The purpose of this study was to provide a better understanding of the epidemiology of APL-related thrombosis as a first step towards developing preventive strategies.

MATERIALS AND METHODS

We report a rare case of catastrophic acute myocardial infarction in a patient with APL while she developed the all-trans retinoic acid (ATRA) syndrome. We describe the pathogenesis of APL-related thrombosis and review all previously reported cases of major thromboses in APL.

RESULTS

We found 94 cases of major thromboses in patients with APL. Both genders were almost equally affected. More than 80% of events occurred before or during induction therapy with deep vein thrombosis/pulmonary embolism (DVT/PE), cardiac events, and cerebrovascular accidents (CVA) constituting more than 75% of all cases. Arterial events were slightly more common than venous events. Only 2 arterial events occurred after completion of induction therapy. Thrombosis was associated with life-threatening hemorrhage in about 15%, significant coagulative defects in about 50%, and ATRA syndrome in about 13% of cases. Cardiac thrombotic events, DVT/PE, and CVA were associated with ATRA syndrome in 24%, 4.5%, and 5% of cases, respectively (p=0.09). None of the observed trends and associations reached statistical significance.

CONCLUSIONS

This review advances our understanding of the epidemiology of major thromboses in APL. With accumulation of more cases in the literature, some of our results may become statistically significant.

Acute promyelocytic leukemia, study of predictive factors for Differentiation Syndrome, single center experience

Reports about patients with acute promyelocytic leukemia from the Middle East are few; in this study we are reporting our single center experience of treating 29 patients over 6years. Acute promyelocytic leukemia treatment response is markedly improved after the introduction of ATRA. Treatment related complication is still an important issue particularly Differentiation Syndrome. Prediction to its occurrence has been tried by other groups. We aimed to study all the possible predictive factors of acute promyelocytic leukemia. Our chemotherapy induction protocol is AIDA protocol which includes ATRA 45mg/m(2)/d in divided doses every12h, and Idarubicin 12mg/m(2)/d IV on days 3, 5, 7, and 9. Differentiation Syndrome occurred in 48.3% of patients and was mainly presented by pulmonary symptoms in 55.2%, 6 cases died during induction. None of the predictive factors studied showed a statistically significant difference between patients who developed Differentiation Syndrome and those who did not. Differentiation Syndrome did not affect overall survival. Cox regression showed an inverse yet a non significant association between PETHEMA and overall survival probability (P=0.168). In conclusion, Differentiation Syndrome has no clear predictive factor to date. The best approach is to hold ATRA and give dexamethasone which is quite effective as reported in the literature. PETHEMA risk model has a moderately significant prognostic value.

Case of pediatric acute promyelocytic leukemia presenting as extramedullary tumor of the mandible

BACKGROUND

Acute promyelocytic leukemia (APL) is a malignant subtype of acute myeloid leukemia caused by the PML-retinoic acid receptor (RAR)α fusion gene. APL may be discovered in adulthood and diagnosed after spontaneous gingival bleeding or difficulty in hemostasis after oral surgery such as tooth extraction. However, APL is extremely rare in children.

METHODS AND RESULTS

A 1-year-old boy presented with a mass on the mentum of the mandible. The marked periosteal reaction was seen on CT and MRI, leading to strong suspicion of a malignant bone-derived tumor such as a sarcoma. Chromosome banding by fluorescence in situ hybridization (FISH) showed PML-RARα, confirming the diagnosis of APL. Treatment with tretinoin was immediately initiated. No signs of recurrence have been noted 1 year after treatment.

CONCLUSIONS

We report herein a rare case involving an infant with APL who presented with an extramedullary tumor of the mandible, whom we treated with good results.

How I treat hematologic emergencies in adults with acute leukemia

Acute myeloid leukemia and acute lymphoblastic leukemia remain devastating diseases. Only approximately 40% of younger and 10% of older adults are long-term survivors. Although curing the leukemia is always the most formidable challenge, complications from the disease itself and its treatment are associated with significant morbidity and mortality. Such complications, discussed herein, include tumor lysis, hyperleukocytosis, cytarabine-induced cellebellar toxicity, acute promyelocytic leukemia differentiation syndrome, thrombohemorrhagic syndrome in acute promyelocytic leukemia, L-asparaginase-associated thrombosis, leukemic meningitis, neutropenic fever, neutropenic enterocolitis, and transfussion-associated GVHD. Whereas clinical trials form the backbone for the management of acute leukemia, emergent clinical situations, predictable or not, are common and do not readily lend themselves to clinical trial evaluation. Furthermore, practice guidelines are often lacking. Not only are prospective trials impractical because of the emergent nature of the issue at hand, but clinicians are often reluctant to randomize such patients. Extensive practical experience is crucial and, even if there is no consensus, management of such emergencies should be guided by an understanding of the underlying pathophysiologic mechanisms.

Bleeding and thrombosis in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) has evolved from being a deadly to a highly curable disease, due to targeted molecular therapy with all-trans retinoic acid (ATRA). As a result, the incidence of early hemorrhagic deaths for which APL is notorious has reduced to 5-10% as reported in clinical trials. These results are not replicated outside of clinical trials as is evident from recent population-based registries. High incidence of early hemorrhagic deaths remains the greatest contributor to treatment failure in this otherwise curable leukemia. Additionally, thrombosis is now being increasingly recognized in APL patients and may be associated with ATRA usage.

CS055 (Chidamide/HBI-8000), a novel histone deacetylase inhibitor, induces G1 arrest, ROS-dependent apoptosis and differentiation in human leukaemia cells

CS055 (Chidamide/HBI-8000) is a novel benzamide-type HDACi (histone deacetylase inhibitor), which has entered Phase I clinical trials in the U.S. and Phase II/III in China. In the present study, we investigated the effects of CS055 on proliferation, differentiation and apoptosis in human leukaemia cell lines and primary myeloid leukaemia cells. The results showed that at low concentrations (<1 μM), CS055 induced G1 arrest. At moderate concentrations (0.5 μM–2 μM), CS055 induced differentiation, as determined by the increased expression of the myeloid differentiation marker CD11b. At relatively high concentrations (2 μM–4 μM), CS055 potently induced caspase-dependent apoptosis. Co-treatment with the ROS (reactive oxygen species) scavengers N-acetyl-L-cysteine or Tiron blocked CS055-induced cell differentiation and apoptosis, suggesting an essential role for ROS in these effects. Cytochrome c release and ROS-mediated mitochondrial dysfunction are involved in CS055-induced apoptosis of leukaemia. In addition to cell lines, CS055 also exhibits therapeutic effects in human primary leukaemia cells. Moreover, daily oral CS055 treatment of nude mice bearing HL60 cell xenografts suppressed tumour growth, induced tumour cell apoptosis and prolonged the survival of tumour-bearing mice. In conclusion, our findings demonstrate that CS055 is a novel HDACi with potential chemotherapeutic value in several haematological malignancies, especially leukaemia.

How to manage acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is a unique subtype of acute myeloid leukemia (AML). The prognosis of APL is changing, from the worst among AML as it used to be, to currently the best. The application of all-trans-retinoic acid (ATRA) to the induction therapy of APL decreases the mortality of newly diagnosed patients, thereby significantly improving the response rate. Therefore, ATRA combined with anthracycline-based chemotherapy has been widely accepted and used as a classic treatment. It has been demonstrated that high doses of cytarabine have a good effect on the prevention of relapse for high-risk patients. However, as the indications of arsenic trioxide (ATO) for APL are being extended from the original relapse treatment to the first-line treatment of de novo APL, we find that the regimen of ATRA, combined with ATO, seems to be a new treatment option because of their targeting mechanisms, milder toxicities and improvements of long-term outcomes; this combination may become a potentially curable treatment modality for APL. We discuss the therapeutic strategies for APL, particularly the novel approaches to newly diagnosed patients and the handling of side effects of treatment and relapse treatment, so as to ensure each newly diagnosed patient of APL the most timely and best treatment.

Newly diagnosed acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) represents a medical emergency with a high rate of early mortality. As a consequence, as soon as the diagnosis is suspected based upon cytologic criteria, it is necessary to start all- trans retinoic acid (ATRA) treatment without delay. For patients with newly diagnosed APL, induction therapy with ATRA plus anthracycline based chemotherapy is recommended. At present the combination of arsenic trioxide plus ATRA should be considered for patients who are not candidates for anthracycline-based therapy. For pediatric and adult patients with APL aged < 60 years who achieve a CR with induction, I recommend 3 intensive courses of consolidation chemotherapy associated to ATRA, targeted on the basis of the risk group at diagnosis. In patients treated with a very intensive consolidation chemotherapy maintenance treatment can be omitted. However If a maintenance treatment has to be adopted I suggest the use of intermittent ATRA for 15 days every 3 months for a period of 2 years, rather than ATRA associated to chemotherapy. Moreover, taking into account the medical literature, a reduced dosage of ATRA ( 25 mg/m(2)) in pediatric patients and a consolidation chemotherapy of reduced intensity in elderly patients is recommended. Furthermore, in order to maximize survival, careful attention should be reserved to the coagulopathy and to the appearance of the differentiation syndrome. Finally, PCR for the PML/RARA fusion gene on a bone marrow specimen every three months for two years, and then every six months for additional three years are needed during the follow-up.

The differentiation syndrome in patients with acute promyelocytic leukemia: experience of the pethema group and review of the literature

Differentiation syndrome (DS), formerly known as retinoic acid syndrome, is the main life-threatening complication of therapy with differentiating agents (all-trans retinoic acid [ATRA] or arsenic trioxide [ATO]) in patients with acute promyelocytic leukemia (APL). The differentiation of leukemic blasts and promyelocytes induced by ATRA and/or ATO may lead to cellular migration, endothelial activation, and release of interleukins and vascular factors responsible of tissue damage. Roughly one quarter of patients with APL undergoing induction therapy will develop the DS, characterized by unexplained fever, acute respiratory distress with interstitial pulmonary infiltrates, and/or a vascular capillary leak syndrome leading to acute renal failure. Although the development of the DS, particularly of the severe form, is still associated with a significant increase in morbidity and mortality during induction, the early administration of high-dose dexamethasone at the onset of the first symptoms seems likely to have dramatically reduced the mortality rate of this complication. In this article, we will review the clinical features, incidence, prognostic factors, management, and outcome of the DS reported in the scientific literature. We will make focus in the experience of the three consecutive Programa Español de Tratamientos en Hematología trials (PETHEMA LPA96, LPA99, and LPA2005), in which more than one thousand patients were treated with ATRA plus idarubicin for induction.