Acute Promyelocytic Leukemia Differentiation Syndrome Research Articles

All-Trans-Retinoic Acid Induction Overcomes Immune Evasion through Downregulating Immune Checkpoint Molecules and Inducing a Cytokine Storm Triggered By Overexpression of S100A8/A9 Signaling

Background: More than 95% of acute promyelocytic leukemia (APL) patients can achieve complete remission by dual induction of all-trans-retinoic acid (ATRA) and arsenic trioxide (ATO). However, early death is a treatment obstacle of APL. The main causes of early death in APL include hemorrhage, differentiation syndrome (DS) related to induction therapy, and infection. Currently, the mechanism of DS in APL largely remains unclear. This study aims to investigate the pathogenetic mechanism and treatment pattern for APL DS and find a suitable biomarker for DS using multiomics approaches. Methods: Eighty newly diagnosed APL patients were recruited through Jan 2019 to Jan 2021 from a clinical trial (NCT04446806). Matched RNA and plasma samples of APL at presentation and DS were studied by RNA-seq and Human Cytokine Array. Two matched peripheral blood samples at presentation and DS from 2 severe DS patients were selected for 10×scRNA-seq analysis, compared with 3 peripheral blood and 2 bone marrow controls. Results: The incidence of DS was 35.3% (29/80), including 21.3% (17/80) moderate DS and 15% (12/80) severe DS. Bulk RNA-seq suggested immune response and cytokines interaction might play important roles in the development of DS ( Figure 1A and B). Significant downregulation of immune checkpoint molecules was shown in the DS period, such as GAL-9, which plays a crucial role in regulating the immune response ( Figure 1C). The activated CD4 +T and CD8 +T cells were amplification at diagnosis period compared with the corresponding CR/CRi period, then declined dramatically at DS period ( Figure 1 D). 10×scRNA-seq analysis revealed the activation of neutrophils and monocytes through innate immune response and inflammatory response ( Figure 1 E). Consistent with bulk RNA-seq results, apparent elevated expression of multiple inflammatory storm-related cytokines/receptors are shown in the DS period in monocytes and neutrophils, which indicates they contribute to the inflammatory cytokine storm ( Figure 1 F). These results indicated that ATRA induction overcomes immune evasion and induces highly activated immune response through downregulating immune checkpoint molecules. Based on 10×scRNA-seq data, differentiated promyelocytic leukemic cell, neutrophils and monocytes are major cell populations and expressed significantly higher cytokine and chemokine in DS stage, indicating that these cells might be major sources of the cytokine storm ( data not shown). We found S100A8 and S100A9, which function as danger-associated molecular pattern (DAMP) molecules and activate innate immune responses via binding to PRRs, significantly upregulated among all known alarmins ( Figure 1G). S100A8/A9 can be induced by ATRA induction, and also activate ERK, JAK-STAT and NF-κB signaling pathways ( Figure 1H). S100A8/A9 expression can be repressed by ERK inhibitor ( Figure 1I). Knockdown of S100A9 induced lower phosphorylation level of STAT1 and P65 ( Figure 1J). These results indicated S100A8/A9 were regulated by the ERK signaling and controlled the JAK-STAT and NF-κB signaling pathway. As a result, JAK-STAT related cytokines could be regulated by S100A8/A9 signaling. Importantly, ROC analysis showed that S100A8/A9 displayed both high sensitivity and specificity as a biomarker for predicting APL DS ( Figure 1K). According to clinical and cytokine storm characteristics of APL DS patients, Dexamethasone (DEX) and Ruxolitinib (RUX) were applied in the treatment of APL DS patients. The percentage of severe DS reduced remarkably after DEX prevention ( Figure 1L, P<0.05). The early death rate of APL declined under the DEX prevention and RUX treatment, and no patient died due to DS ( Figure 1M). The expression of a series of inflammatory cytokines dramatically decreased, indicating that the cytokine storm was effectively suppressed by the treatment of DEX and/or RUX ( Figure 1N). Conclusion s : Our data indicate that ATRA induction could overcome immune evasion through downregulating immune checkpoint molecules. ATRA-induced upregulation of S100A8/A9 may contribute to the cytokine storm observed in the DS stage of APL patients by activating the JAK-STAT and NF-κB signaling pathway. S100A8/A9 is recommended as a biomarker for predicting APL DS. Dexamethasone and Ruxolitinib are appropriate prevention and treatment pattern for APL DS patients.

ATRA treatment slowed P-selectin-mediated rolling of flowing HL60 cells in a mechano-chemical-dependent manner.

All-trans retinoic acid (ATRA)-induced differentiation of acute promyelocytic leukemia (APL) toward granulocytes may trigger APL differentiation syndrome (DS), but there is less knowledge about the mechano-chemical regulation mechanism of APL DS under the mechano-microenvironment. We found that ATRA-induced changes in proliferation, morphology, and adhesive molecule expression levels were either dose or stimulus time dependent. An optimal ATRA stimulus condition for differentiating HL60 cells toward neutrophils consisted of 1 × 10-6 M dose and 120h of stimulus time. Under wall shear stresses, catch-slip bond transition governs P-selectin-mediated rolling for neutrophils and untreated or ATRA-treated (1 × 10-6 M, 120h) HL60 cells. The ATRA stimuli slowed down the rolling of HL60 cells on immobilized P-selectin no matter whether ICAM-1 was engaged. The β2 integrin near the PSGL-1/P-selectin axis would be activated within sub-seconds for each cell group mentioned above, thus contributing to slow rolling. A faster β2 integrin activation rate and the higher expression levels of PSGL-1 and LFA-1 were assigned to induce the over-enhancement of ATRA-treated HL60 adhesion in flow, causing APL DS development. These findings provided an insight into the mechanical-chemical regulation for APL DS development via ATRA treatment of leukemia and a novel therapeutic strategy for APL DS through targeting the relevant adhesion molecules.

Roles of PADI4 in the expression of cytokines involved in inflammation and adhesion in differentiated NB4 cells treated with ATRA.

Differentiation syndrome (DS) is a common complication in patients with acute promyelocytic leukemia (APL) treated with all-trans-retinoic acid (ATRA). However, the target of ATRA during DS in patients with APL remains to be elucidated. Therefore, the current study aimed to investigate the role of peptidylarginine deiminase 4 (PADI4) in the differentiation of ATRA-induced NB4 APL cells. The results showed that PADI4 was significantly upregulated in peripheral blood samples derived from patients with APL DS compared with patients with APL only. In addition, whether ATRA could enhance the expression levels of PADI4 in NB4 cells in vitro was subsequently investigated. The results also showed that PADI4 overexpression promoted the differentiation of NB4 cells treated with ATRA, which was reversed after PADI4 silencing. To uncover the potential mechanisms underlying the above process, PADI4 overexpression induced the secretion of inflammation-related cytokines, such as TNF-α, IL-1β, IL-8, C-C motif chemokine (CCL)2, CCL4, CCR1 and intercellular adhesion molecule-1 in ATRA-treated NB4 cells. However, PADI4 knockdown in the same cells had the opposite effect. The above findings indicated that PADI4 could be involved in the differentiation of ATRA-induced NB4 cells and upregulation of cytokines.

Safety and Efficacy of Arsenic Trioxide in the Treatment of Newly Diagnosed Pediatric Acute Promyelocytic Leukemia: Results from the JPLSG AML-P13 Study

Aims: Arsenic trioxide (ATO) has shown to be effective in patients with acute promyelocytic leukemia (APL), which has led to a dose reduction of cytotoxic agents in the treatment of APL. To investigate safety and efficacy of ATO in Japanese children with APL, we conducted a nationwide prospective study, JPLSG AML-P13 (jRCTs051180191). Patients & Methods: Between December 2014 and November 2018, children (0-18 years old) with newly diagnosed APL were enrolled in the AML-P13 study. All patients received two courses of induction therapy consisting of ATRA, cytarabine, and daunorubicin. Patients who achieved hematological complete remission (HCR) were allocated to the standard risk (SR) group and received three intensification cycles consisting of ATRA and ATO, followed by intermittent ATRA maintenance therapy. Patients who did not obtain HCR after induction courses were allocated to the high risk (HR) group and received intensified schedule of ATO, followed by gemtuzumab ozogamicin monotherapy and maintenance therapy consisting of 6-mercaptopurine and methotrexate. Results & Discussions: Among the 32 patients registered, 5 patients were excluded due to a lack of PML::RARA fusion or other reasons, and the remaining 27 patients received the protocol therapy (full analysis set). During induction courses, grade 3 disseminated intravascular coagulation was observed in 9 patients (33.3%). APL differentiation syndrome and induction death were not reported. Two patients were taken off protocol therapy due to a progressive disease (regarded as an event) and a safety issue, respectively. Among the 25 patients who completed induction therapy, 23 patients obtained HCR. During intensification cycles of ATO, grade 3 or higher non-hematological adverse events (AEs) were observed in 3 patients: prolonged QTc interval in 2 and dysesthesia in one. Regarding hematological AEs, 10 to 30% patients exhibited grade 4 neutropenia during each intensification cycles, but no patients experienced severe infectious complications. Two patients who did not obtain HCR received HR regimen without any apparent AEs. All 25 patients including 2 HR patients achieved molecular remission at the end of intensification and molecular remission rate was 100.0% [95% C.I. 86.3-100.0%]. No patients suffered from relapse, and 3-year EFS rate and 3-year OS rate in full analysis set were 96.3% [76.5-99.5%] (Figure) and 100.0% [87.2-100.0%], respectively. We previously reported an inferior outcome of younger children (less than 5 years old) treated with conventional ATRA and chemotherapy in the JPLSG AML-P05 study (Takahashi H. Br J Haematol 2016). However, 4 children under 5 years of age at diagnosis in the AML-P13 study remains in molecular remission, indicating efficacy of ATO in this age group of children. Interpretations: The AML-P13 study demonstrated an excellent outcome in children with APL and showed that ATO could be administered safely in children with APL. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

A scientometric and visualization analysis of studies on arsenic for acute promyelocytic leukemia

The use of arsenic for acute promyelocytic leukemia (APL) has a long history. However, a systematic scientometric study to describe these studies and to explore their research status and development trends has not been carried out. CNKI and Web of Science databases were searched from their inception to June 13, 2021 to identify suitable articles. Knowledge network maps of identified studies focusing on authors, institutions, keywords and their references were summmarised. 3095 articles published between 1996 and 2021 showed an overall fluctuating trend in growth of articles. Main institutions conducting research were Harbin Medical University and Shanghai Jiaotong University School of Medicine. The main research team working outside of China was located at the Sloan Kettering Cancer Center. Research hotspots included efficacy evaluation of arsenic alone or in combination with retinoic acid, mechanism study of apoptosis, RARα, activation, growth inhibition, expression etc. The current research hot topics were APL differentiation syndrome and drug resistance. Chinese patent medicine compound Huangdai tablets, arsenous acid and all-trans retinoic acid were the main drugs. The types of highly cited and burst studies were landmark case series, well-designed RCTs, comprehensive reviews, and authoritative APL guidelines. Articles on the use of arsenic for APL have fluctuated in growth since 1996. The themes have focused on clinical efficacy and mechanism of arsenic and its action. The APL differentiation syndrome and drug resistance are disease research hotspots. The compound Huangdai tablets, arsenious acid and all-trans retinoic acid are potentially the main focus for drugs now and in the future.

The role of adjuvant chemotherapy in the management of acute promyelocytic leukemia differentiation syndrome.

Acute Promyelocytic Leukemia (APL) is characterized by the t(15;17) chromosomal translocation resulting in a PML-RARA fusion protein. The all-trans-retinoic acid (ATRA) and Arsenic Trioxide (ATO) only regimens have demonstrated success in treating low- and intermediate-risk patients. However, induction with ATRA/ATO only regimens have been showing increased incidence of differentiation syndrome (DS), a potentially lethal complication, traditionally treated with dexamethasone. We conducted a three-institution retrospective study, aiming to evaluate the role of short-term adjuvant chemotherapy in managing moderate DS for patients with low- or intermediate-risk APL initially treated with ATRA/ATO only protocols. We evaluated the difference in incidence and duration of moderate DS in APL patients who were treated with ATRA/ATO with or without adjuvant chemotherapy. 57 low- or intermediate-risk APL patients were retrospectively identified and included for this study; 36 patients received ATRA/ATO only induction treatment, and 21 patients received ATRA/ATO/adjuvant chemotherapy combination induction therapy. Similar proportions of patients experienced DS in both groups (66.7% vs. 81.0%, P = 0.246). The median duration of DS resolution in patients receiving ATRA/ATO only was 17 days (n = 23), and in patients receiving combination therapy was 8 days (n = 16) (P = 0.0001). The lengths of hospital stay in patients receiving ATRO/ATO only was 38 days (n = 7), and in patients receiving combination therapy was 14 days (n = 17) (P = 0.0007). In conclusion, adding adjuvant chemotherapy to ATRA/ATO only protocol may reduce the duration of DS and the length of hospital stay during APL induction treatment.

THIS DYSPNEA FEELS DIFFERENT: A CASE OF DIFFERENTIATION SYNDROME

TOPIC: Pulmonary Manifestations of Systemic Disease TYPE: Medical Student/Resident Case Reports INTRODUCTION: Acute Promyelocytic Leukemia Differentiation Syndrome (DS) also known as Retinoic Acid Syndrome (RAS) is a potentially lethal complication of All-Trans Retinoic Acid (ATRA) treatment. Symptoms are initially nonspecific from dyspnea, weight gain, fever and weakness. Major findings seen in DS includes bilateral infiltrates on chest imaging with possible pleural and pericardial effusion. Patients respond favorably to steroids in the form of Dexamethasone while ATRA is being held. CASE PRESENTATION: A 70-year-old male presented to the hospital with dyspnea and body aches, with initial diagnosis of pneumonia and subsequently started on antibiotics. Chest X-Ray showed right lower lobe infiltrate. Labs also showed Pancytopenia which prompted Flow Cytometry and Bone marrow biopsy revealing Acute Promyelocytic Leukemia. Patient was started on chemotherapeutic agents including Arsenic Trioxide and Tretinoin. The following day, patient's dyspnea worsening requiring BiPAP, his CT chest revealed new bilateral infiltrates with pleural and pericardial effusions. His labs showed worsening leukocytosis of 61, increased creatinine to 1.6. Due to the symptoms mentioned above as well as a high clinical suspicion, patient was started on Dexamethasone. Patient's respiratory status drastically improved over the next 2-3 days. Patient was subsequently discharged to continue Tretinoin outpatient. DISCUSSION: Differentiation Syndrome has unknown epidemiology, however, there have been varying reports that it has an incidence between 2-48% of patients treated with ATRA. The pathogenesis of DS is unclear however the most widely accepted theory is massive cytokine release by blast cells leading to a systematic inflammatory response syndrome and increased vascular permeability leading to both hypotension and organ hypoperfusion. There is currently no universally accepted diagnostic criteria for DS, however common findings are dyspnea, unexplained fever, weight gain >5 kg and hypotension. Lab findings in DS are nonspecific and not pathognomonic, leukocytosis is often seen in approximately half the patient. The presence of 3 of the previous findings warrants empiric therapy with Dexamethasone. Prospective and retrospective studies show a mortality of 1% in patients with DS who are treated with steroids. CONCLUSIONS: Differentiation Syndrome is a potentially fatal complication of ATRA therapy with no universally accepted diagnostic criteria. A high clinical suspicion is required to diagnose and treat DS for a favorable outcome. REFERENCE #1: Stahl M, Tallman MS. Differentiation syndrome in acute promyelocytic leukaemia. Br J Haematol. 2019 Oct;187(2):157-162. doi: 10.1111/bjh.16151. Epub 2019 Aug 13. PMID: 31410848. DISCLOSURES: No relevant relationships by Sreevastav teja Kalangi, source=Web Response Owner/Founder relationship with Palaniandy K. Kogulan, M.D., PLLC Please note: since 2010 Added 05/13/2021 by Palaniandy Kogulan, source=Web Response, value=Salary No relevant relationships by Mohamed Mohamed, source=Web Response

Influence of Body Mass Index on Incidence and Prognosis of Acute Myeloid Leukemia and Acute Promyelocytic Leukemia: A Systematic Review and Meta-Analysis

Background: Previous studies have demonstrated an association between high body mass index (BMI) and acute myeloid leukemias (AML), particularly acute promyelocytic leukemia (APL). However, the effect of obesity and overweight on the incidence of AML is not supported by all studies, and the relationship between obesity and prognosis of AML and APL has not been established. Thus, we conducted a meta-analysis to determine the role of BMI on the risk and clinical outcome of AML, including APL.Methods: A literature search (last search updated to Dec. 4, 2016) was conducted in PubMed, EMBASE, Web of Science and the Cochrane Library for articles assessing the effect of overweight and obesity on the incidence and clinical outcome of AML. In all,twenty-six eligible studies enrolling 12,971 AML (including 866 APL) patients were retrieved and analyzed.Results: Both overweight and obesity was associated with an increased incidence of AML (for overweight, relative risk [RR], 1.10; 95% CI, 1.03-1.17; P=0.007; I2=43.1%; fixed effects; and for obesity, RR, 1.41; 95% CI, 1.24-1.61; P<0.001; I2=66.5%; random effects; Figure 1). High BMI did not significantly affect overall survival (OS) (for overweight, hazard ratio [HR], 0.86; 95% CI, 0.70-1.05; P=0.14; I2=59.5%; random effects; and for obesity, HR, 0.99; 95% CI, 0.93-1.07; P=0.281; I2=32.9%; fixed effects; Figure 2A and 2B) or disease-free survival (HR, 0.98; 95% CI, 0.88-1.10; P=0.755) in patients with non-APL AML patients. By contrast, APL patients with high BMI had shorter OS (HR, 1.77; 95% CI, 1.26-2.48; P=0.001, Figure 2C) and a higher risk of differentiation syndrome (HR, 1.53; 95% CI, 1.03-2.27, P=0.04).Conclusion: Our findings suggest that patients with overweight or obesity have a higher incidence of AML. While no significant effect was found on the clinical outcome of non-APL AML, high BMI indicates worse overall survival and higher risk of differentiation syndrome in APL.. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Interleukin-8 is not a predictive biomarker for the development of the acute promyelocytic leukemia differentiation syndrome

BackgroundDifferentiation syndrome (DS) is the main life-threatening adverse event that occurs in acute promyelocytic leukemia (APL) patients treated with all-trans retinoic acid (ATRA). Cytokine imbalances have been reported to play role during the developing of acute promyelocytic leukemia differentiation syndrome (APL-DS). However, the relationship between the plasma cytokine levels and their prognostic value for the prediction of DS developing in patients with APL during the treatment with ATRA and anthracyclines has not been previously reported.MethodsIn this study, we followed an APL cohort (n = 17) over 7 days of ATRA therapy in DS (n = 6) and non-DS groups (n = 11). Interleukin (IL)-1β, IL-6, IL-8, IL-10, IL-12p70 and TNF-α were measured in the peripheral blood plasma from 17 patients with APL and 11 healthy adult controls by using the cytometric bead array method.ResultsIn non-DS patients, IL-8 plasma levels were significantly reduced in the seventh day of ATRA treatment (34.16; 6.99 to 147.11 pg mL− 1 in D0 vs. 10.9; 0 to 26.81 pg mL− 1 in D7; p = 0.02) whereas their levels did not discriminate between DS and non-DS development during the entire induction period (all p > 0.05 in D0, D3, and D7). No significant differences were found in IL-6 levels between groups (p > 0.05 in D0-D7). Other cytokines tested were all undetectable in patients with APL or healthy controls.ConclusionsWe demonstrated that the modulation of IL-8 following ATRA treatment may occur regardless of the development of DS and, therefore, does not appear to be a predictive biomarker to monitor the APL-DS.

Autophagy: New Insights into Mechanisms of Action and Resistance of Treatment in Acute Promyelocytic leukemia.

Autophagy is one of the main cellular catabolic pathways controlling a variety of physiological processes, including those involved in self-renewal, differentiation and death. While acute promyelocytic leukemia (APL) cells manifest low levels of expression of autophagy genes associated with reduced autophagy activity, the introduction of all-trans retinoid acid (ATRA)—a differentiating agent currently used in clinical settings—restores autophagy in these cells. ATRA-induced autophagy is involved in granulocytes differentiation through a mechanism that involves among others the degradation of the PML-RARα oncoprotein. Arsenic trioxide (ATO) is another anti-cancer agent that promotes autophagy-dependent clearance of promyelocytic leukemia retinoic acid receptor alpha gene (PML-RARα) in APL cells. Hence, enhancing autophagy may have therapeutic benefits in maturation-resistant APL cells. However, the role of autophagy in response to APL therapy is not so simple, because some autophagy proteins have been shown to play a pro-survival role upon ATRA and ATO treatment, and both agents can activate ETosis, a type of cell death mediated by the release of neutrophil extracellular traps (ETs). This review highlights recent findings on the impact of autophagy on the mechanisms of action of ATRA and ATO in APL cells. We also discuss the potential role of autophagy in the development of resistance to treatment, and of differentiation syndrome in APL.

Acute promyelocytic leukemia: state-of-the-art management

Acute promyelocytic leukemia (APL) is driven by the promyelocytic leukemia (PML) -retinoic acid receptor (RAR) α fusion protein generated by the chromosomal translocation t (15;17) which affects both nuclear receptor signaling and PML nuclear body (NB) assembly. The advent of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) as molecular targeted therapies directed against PML-RARα has been a major breakthrough in APL treatment. ATRA and ATO target RARα and PML, respectively, and elicit PML-RARα degradation, leading to the reformation of normal NBs and cell differentiation. In several multicenter trials, more than 90% of newly diagnosed APL patients treated with ATRA and chemotherapy achieved complete remission, of whom 20%-30% subsequently relapsed; the overall survival was approximately 80% in these studies. However, several major clinical problems continue to account for treatment failure including early death due to hemorrhage, infection during consolidation, disease relapse, and secondary malignancies. These issues are associated mainly with anticancer agents used in combination with ATRA. Combination therapy using ATRA and ATO is the current standard therapy for untreated patients with APL in Western countries. The current problems in patients with APL treated with ATRA and ATO are APL differentiation syndrome and high risk of relapse in patients with an initial leukocyte count of more than 10×109/l.

In vitro studies on the role of recombinant human soluble thrombomodulin in the context of retinoic acid mediated APL differentiation syndrome

Recombinant human soluble thrombomodulin (rTM) is a newly developed anti-coagulant approved for treatment of disseminated intravascular coagulation (DIC) in Japan. rTM exerts anti-inflammatory and cytoprotective functions via its lectin-like and epidermal growth factor-like domains, respectively. In this study, we retrospectively reviewed the treatment of 21 consecutive patients with coagulopathy, complicated by acute promyelocytic leukemia (APL), with all-trans retinoic acid (ATRA) with or without combination with rTM. Surprisingly, none of the 14 rTM-treated patients developed retinoic acid (RA)-related differentiation syndrome (DS). The co-culture of vascular endothelial cell-derived EA.hy926 and APL-derived NB4 cells in the presence of RA increased production of tumor necrosis factor alpha (TNF-α) in culture media, in parallel with activation of p38 mitogen-activated protein kinase and increased levels of intracellular adhesion molecule 1 (ICAM1) in EA.hy926 cells. This was also associated with increased levels of the phosphorylated forms of VE-cadherin and enhanced vascular permeability of EA.hy926 monolayers. Importantly, addition of rTM to this co-culture system inhibited the RA-induced phosphorylation of p38 and VE-cadherin and decreased ICAM1 and vascular permeability in EA.hy926 cells, without a decrease inthe levels of TNF-α. Taken together, use of rTM may be a promising treatment strategy to prevent DS in APL patients who receive ATRA.

Single Agent Tamibarotene Has Activity in Acute Promyelocytic Leukemia Patients Previously Treated with ATRA and Arsenic Trioxide, but Does Not Produce Durable Responses

Background:Treatment of acute promyelocytic leukemia (APL) with arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) is highly effective as first-line therapy, although approximately 10% of patients relapse after treatment. Several mechanisms of ATRA resistance have been proposed including accelerated clearance of ATRA and increased levels of cellular retinoic acid-binding protein (CRABP), which induces retinoic acid metabolism. Tamibarotene is a synthetic retinoid that does not significantly bind CRABP, suggesting that it might be effective in APL patients with ATRA resistance. Tamibarotene has shown efficacy in APL patients with relapse after chemotherapy and ATRA, but has not been studied in relapse after treatment with ATO and ATRAMethods:We conducted a multicenter phase II clinical trial of tamibarotene in adult patients with relapsed or refractory APL after treatment with ATRA and ATO (concomitant or sequential). Participants were treated with single agent tamibarotene at a daily dose of 6 mg/m2 for up to 56 days during induction. Patients achieving a complete response were eligible to continue on consolidation treatment with tamibarotene at the same dose for a maximum of six 28 day cycles. The primary outcome for this trial was to determine the rate of durable complete response (CR) using tamibarotene as a single agent. Secondary outcomes included the rate of morphologic complete remission, partial response, cytogenetic complete response, molecular complete response as well as the safety profile and tolerability of this medication.Results:We enrolled 14 patients from March 2008 to October 2011 at 8 centers. The median age of the participants was 56 years (range 20-76). Twelve patients had relapsed APL and 2 had primary refractory disease. Patients had a median of 2 remissions (range 1-5) prior to enrollment with a median time from the most recent remission to study screening of 23 months (range 2-102). Twelve patients (86%) had received other treatments including stem cell transplant (n=4) in addition to ATO and ATRA prior to enrollment. Eight patients achieved a morphologic remission during treatment with tamibarotene and 2 had a partial response (>50% reduction in BM blasts). Three (21%) patients with complete morphologic remission had a CR, whereas 5 (36%) had a complete remission with incomplete hematologic recovery (CRi), without meeting pre-specified recovery of neutrophil (>1,000/μL) and platelet counts (>100,000/μL). Seven out of 8 patients who achieved CR or CRi relapsed after treatment. The median duration of response for patients achieving CR was 203 days (range 183-212). The median overall survival for the entire group was 233 days (95% CI 196-526 days). Thirteen patients reported treatment-emergent adverse events, although the majority were mild (Grade 1-2). The most frequently reported adverse events included rash (n=6, grade 1-3), headache (n=4, grade 1) and neutropenia (n=3, grade 3-4). Two patients experienced APL differentiation syndrome (grade 2). Two patients discontinued the study due to adverse events: one patient developed progressive multifocal leukoencephalopathy and the other developed pneumonia, although neither of these events was thought to be related to tamibarotene.Discussion:These results suggest that tamibarotene has activity in patients with relapsed APL after treatment with ATO and ATRA. Although the CR rate of 21% is lower than that reported in a previous trial using tamibarotene (58%; Tobita, 1997), the 24 patients in that study had received ATRA alone or in combination with chemotherapy, but not ATO. Thus, tamibarotene has significant clinical activity in this heavily pre-treated population with acceptable toxicity. Further studies using tamibarotene as initial therapy and in combination with ATO are warranted. DisclosuresLoCoco:Lundbeck: Consultancy, Speakers Bureau; Teva: Consultancy, Speakers Bureau. Cortes:CytRx: Research Funding.

Acute promyelocytic leukemia in patients aged >70years: the cure beyond the age.

All-trans retinoic acid (ATRA) has made acute promyelocytic leukemia (APL) a very curable disease also in patients aged >60years; however, there are only few case reports in very elderly APL patients. To address this issue, we reviewed treatment results in 13 patients aged >70years with newly diagnosed APL followed at our institution from January 1991 to December 2008. According to Sanz score, seven patients were at low risk, five at intermediate risk, and one at high risk. Induction therapy consisted of ATRA + idarubicin in nine patients (3/9 with reduced idarubicin dosage) and ATRA alone in four patients; in this latter group, however, 2/4 needed to add chemotherapy (CHT) due to hyperleukocytosis during ATRA treatment. All patients achieved both morphological and molecular complete remission (CR) after a median time of 51 [interquartile range (IR) 43-55] and 114 (IR 74-155) days, respectively. Infective complications were observed in 10/13 patients, APL differentiation syndrome in 3/13 patients. Twelve patients received consolidation therapy, followed by maintenance treatment in nine patients. Five patients relapsed after 7, 8, 11, 35, and 56months. At present, seven patients are still alive, five died due to disease progression (four) or senectus while in CR (one), and one was lost to follow-up while in CR. The 5-year event-free survival was 56.1% (95% CI, 26.0-86.2); the 5-year overall survival (OS) was 64.5% (95% CI, 35.6-93.4). ATRA-based treatment of APL is safe and effective also in very elderly patients, with long-lasting disease-free OS.

Nephrotic syndrome in acute promyelocytic leukemia.

A five-year-old boy presented (Day 0) with gingival bleeding and pancytopenia (white blood cells: 1.7 × 109/L; hemoglobin: 7.3 g/dL; platelets: 16 × 109/L). A coagulation panel was unremarkable. Peripheral blood smear revealed dysmorphic promyelocytes with red-blue granules, folded reniform nuclei and no Auer rods. Bone marrow examination showed immature myeloid cells (>60% promyelocytes) that were positive for myeloperoxidase (MPO), CD117, CD13 and CD33, and negative for CD34 and HLA-DR. Cytogenetic analysis showed a male karyotype with 46,XY, t(15;17)(q24;q21). Quantitative real-time polymerase chain reaction was positive for PML-RARα. A diagnosis of acute promyelocytic leukemia (APL) was established. Induction chemotherapy with daunorubicin (50 mg/m2 Days 1, 3 and 5), cytarabine (100 mg/m2 every 12 h, Days 1–10) and thioguanine (100 mg/m2 every 12 h, Days 1–10) along with all-trans retinoic acid (ATRA; 45 mg/m2 per day in two divided doses starting on Day 1) was initiated on admission Day 2. Prophylactic dexamethasone (0.1 mg/kg twice daily) was administered along with ATRA. On Day 9, the patient developed a hypertensive crisis, bilateral lower extremity edema, proteinuria (24-h urine protein 1000 mg) and hyperlipidemia (triglycerides: 525 mg/dL, total cholesterol: 275 mg/dL). His serum albumin at this time was 3.2 g/dL. Given the above presentation and the definition of nephrotic-range proteinuria in children (>40 mg/m2/h), a diagnosis of nephrotic syndrome (NS) (most likely minimal change disease) was established and steroids (prednisone 2 mg/kg/day) were initiated. Proteinuria and other manifestations of NS resolved on admission Day 26, after which steroids were quickly tapered and eventually discontinued. The patient has now completed the second course of DAT without signs or symptoms of NS. During the second course, he only received prophylactic doses of steroids. The association of NS with acute myeloid leukemia (AML) is rare, with only 10 cases reported previously (Table 1). There was a remarkable male predominance (80%), and the median age at diagnosis was 33 (range: 3–81) years. Surprisingly, 45% of all cases and all three pediatric cases were APL. NS was present before treatment in 45% of cases, suggesting a direct pathogenic role of leukemia. In other cases, anthracycline therapy was the main culprit. Histopathological findings on renal biopsy did not reveal a unique pattern and varied from minimal change disease (MCD) to focal segmental glomerulosclerosis (FSGS), immune complex deposition, macrophage infiltration, membranous glomerulonephritis, proliferative glomerulonephritis and detachment of epithelial cells from the glomerular basement membrane. From the nine patients who received some form of treatment for NS, steroids were the chosen treatment in seven patients, with a response rate of 86%; the other two patients were treated only with chemotherapy and NS responded to treatment in both. Table 1. Summary of previous reports on the association between AML and NS A number of mechanisms may explain the rare association between NS and AML. Disruption of podocyte integrity and function due to cytokine release has been proposed as a mechanism of nephrotic syndrome during ATRA-induced differentiation syndrome in APL [1]. A causal relationship between NS and AML is further supported by the response of proteinuria to chemotherapy for AML and the association between higher leukemia burden and more proteinuria [1, 2]. Anthracyclines have been proposed as a culprit in the development of NS following treatment of AML since they can cause acute renal tubulointerstitial toxicity [3, 4]. Also, adriamycin rapidly increases the expression of the ligands on podocytes for advanced glycation end products, leading to podocyte stress and glomerulosclerosis in mouse models [5]. Adriamycin is now often used to induce experimental FSGS [6, 7]. Finally, NS in AML may reflect a local immune complex-mediated process [8, 9]. Given the absence of proteinuria before AML treatment in our patient, we believe daunorubicin was the most likely cause of NS in the present case. However, a direct effect of ATRA (e.g. terminal differentiation of promyelocytes and toxic effects of the released granules) cannot be ruled out. He had no signs of recurrent NS after re-exposure to chemotherapy, suggesting re-challenge may be safe in drug-induced NS.

Feasibility of oral arsenic trioxide treatment for acute promyelocytic leukemia during hemodialysis

Dear Editor, Arsenic trioxide (As2O3) is a standard medication for relapsed acute promyelocytic leukemia (APL). However, high blood arsenic levels lead to potentially fatal arrhythmias. As2O3 is renal-excreted and considered contraindicated in renal failure. A 42-year-old man was referred for treatment of APL in first relapse, presenting with pancytopenia, impaired renal function, and septicemia. He was treated with all-trans retinoic acid (ATRA, 45 mg/m2/day) and oral As2O3 (10 mg/day) [1]. Progressive renal function derangement developed, necessitating reduction of oral As2O3 to 5 mg/day. On the third day, the leukocyte count increased to 8.9 × 109/L, associated with bilateral pulmonary infiltrates. Features were consistent with the APL differentiation syndrome, which with the underlying septicemia led to anuric acute renal failure. ATRA was stopped. Idarubicin (6 mg/m2/day × 5), dexamethasone (12 mg/day × 7), and alternate daily hemodialysis were administered. Oral As2O3 at 5 mg was given after each hemodialysis and was stopped after 9 days. At 4 weeks, marrow examination confirmed complete remission. He remained anuric, and hemodialysis was continued. Oral As2O3 was re-commenced at 2 mg after each hemodialysis. Two months later, continuous ambulatory peritoneal dialysis (CAPD) was started. A maintenance regimen for APL, comprising oral As2O3 (5 mg/day) and ATRA (20 mg twice daily) [2, 3], given 2 weeks every 2 months, was administered. At 6-month follow-up, he remained in remission and was negative for the PML-RARA fusion gene characteristic of APL. No cardiac arrhythmias were observed at any time. Serum elemental arsenic levels were assayed by inductively coupled plasma mass spectrometry [3, 4], on blood samples sent for creatinine measurement. At 4 days, there was a sudden increase of arsenic levels, as the cellular and third-space compartments became saturated and anuria prevented arsenic excretion (Fig. 1a). The arsenic level peaked at 4,240 nmol/L, outside the therapeutic range of 500–2,000 nmol/L typical of oral As2O3. The commencement of hemodialysis and cessation of oral As2O3 resulted in a fall of arsenic levels parallel to those of creatinine. After oral As2O3 was re-commenced, arsenic levels gradually increased to the therapeutic range (Fig. 1b). As arsenic clearance in oral As2O3 therapy during CAPD had been documented previously [3], arsenic assays were not performed after peritoneal dialysis was started. Fig. 1 a Blood arsenic levels during the first 3 weeks of hemodialysis. A rapid surge of arsenic levels occurred on day 5, in parallel with a rise in creatinine and further renal function deterioration. Oral arsenic trioxide was stopped on day 9, resulting ... As2O3 is a key medication for patients with relapsed APL. Intravenous (i.v.) As2O3, used in most reports, may lead to lethal arrhythmias due to QT prolongation, which is directly proportional to blood arsenic levels [5]. Because i.v. As2O3 leads to a rapid surge of blood arsenic levels, arrhythmia related to QT prolongation is an important adverse effect. Oral As2O3 is slowly absorbed and results in lower blood arsenic levels. Its bioavailability, estimated by area-under-the-curve pharmacokinetically, is comparable to that of i.v. As2O3 [6]. Hence, oral As2O3 has the same efficacy, but little risk of arrhythmia [5]. In one previous report, blood arsenic levels after i.v. As2O3 were measured in an APL patient on hemodialysis [7]. The peak level was 6,450 nmol/L, a toxic level that led to termination of i.v. As2O3 therapy. It was concluded that i.v. As2O3 was contraindicated in renal failure [7]. In our case, the sudden increase in blood arsenic levels was related to an unanticipated acute renal failure. Timely cessation of oral As2O3 and institution of hemodialysis prevented further increases in arsenic levels. Subsequently, with careful dose adjustment and meticulous monitoring, oral As2O3 was safely administered during hemodialysis. The blood arsenic levels were also kept within the therapeutic range. We have also previously demonstrated the safety of oral As2O3 during CAPD. Therefore, patients on renal replacement therapy are still eligible for oral As2O3 treatment.

How I treat hematologic emergencies in adults with acute leukemia

AbstractAcute 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.

Front Line Treatment of Elderly Patients with Acute Promyelocytic Leukemia: Long-Term Results of the German AML Cooperative Group

Abstract 425The introduction of all-trans-retinoic acid (ATRA) in front line therapy of acute promyelocytic leukemia (APL) has improved the outcome of all age groups. In the elderly patients (pts), multi-morbidity and higher vulnerability to chemotherapy-related toxicity are the main problems reducing the chance of cure. This has led to recommendations to reduce the intensity of therapy in elderly APL pts. We report on the long-term outcome of pts with newly diagnosed APL registered in two prospective studies of the German AML Cooperative Group (AMLCG) from December 1994 until June 2011. The therapy consisted of ATRA and anthracycline/ara-C-based induction and consolidation therapy (TAD/HAM–TAD) followed by maintenance therapy as reported previously in younger APL pts (Lengfelder et al. Leukemia 2009;23:2248–2258). In pts ≥60 years (y), the administration of the second induction cycle (HAM with an age adapted cumulative ara-C dose of 6g/sqm) was at the discretion of the treating physician. After December 2005, the pts were included in the ongoing APL protocol and randomized between the AMLCG strategy and the protocols of the Spanish PETHEMA. Among 295 adult pts with newly diagnosed APL, 83 pts (28%) were ≥60y of age. Seventeen elderly pts (20%) were not enrolled in the study, due to death before start of therapy, contraindications against chemotherapy or concomitant other malignancy. Eleven pts randomized in the PETHEMA arm were excluded from the present analysis to cover homogeneity of therapy. In 53 of 55 pts treated according to the AMLCG protocol, results are available. Median age was 67 y (range 60 to 83); 58% were male, 42% female; 68% had low/intermediate and 32% high risk according to Sanz score. Morphology was FAB M3 in 62%, M3v in 38%. Cytogenetics showed t(15;17) alone in 52%, and combination with other abnormalities in 48% of pts. The bcr1/bcr2 transcript of PML/RARA was found in 41% and the bcr3 transcript in 59% of pts. Forty-four pts (83%) achieved complete remission (CR). Early death (ED) occurred in 9 pts (17%). Median time to ED was 12 days (range 2 to 19) after start of therapy. Causes of ED were bleeding, multi-organ failure and sepsis. Manifest APL differentiation syndrome occurred in 25% of pts and WHO grade ’3 bleeding, fever/infection or cardiac failure in 8%, 43% and 17% of pts, respectively. After consolidation therapy, 96% of pts were in molecular remission. After a median follow up of 5.3 y (1 day to 12.8 y), the 6-year overall (OS), event free (EFS) and relapse free survival (RFS) and the cumulative incidence of relapse (CIR) were 45%, 41%, 50% and 26%, respectively. The outcome was further analyzed according to risk group, number of induction cycles, and age ≥60y to 69y and ≥70y. Pts with pretreatment white blood cell (WBC) count <10 × 109/L (low/intermediate risk; n=36) had a significantly superior outcome compared to pts with high WBC counts (high risk; n=17) resulting in a CR rate of 92% vs. 65% and ED rate of 8% vs. 35%, respectively (p=0.02). The 6-year OS, EFS, RFS and CIR of the low/intermediate risk pts was 56%, 53%, 60% and 14%, respectively, compared to 25%, 15%, 23% and 58% in high risk pts (p=0.006, p=0.0004; p=0.008; p<0.01). All 12 pts, who had received two induction cycles achieved CR, and no relapse occurred so far resulting in a significantly superior outcome compared to patients, who had received only one induction cycle (OS: p=0.007; EFS: p=0.0002; RFS: p=0.01). In the pts ’70y (n=17), 71% entered CR and 29% died from ED. Separated according to low and high WBC counts, the CR rate of this group was 83% vs. 40% and the ED rate 17% vs. 60% (p=0.07), respectively, resulting in an inferior OS (p=0.08) of the pts with high WBC count. Conclusions: Among our elderly pts, we found a high proportion of pts with high risk profile and a high rate of exclusion from the study due to death before the start of therapy or poor condition. In patients included in our study, high WBC count and advanced age are associated with a high risk of ED. The inferior outcome in pts, who received only one induction cycle, suggests that intensification of chemotherapy should be considered in elderly APL pts, if possible. The incorporation of arsenic trioxide might be an alternative, which could be investigated in future trials. Disclosures:No relevant conflicts of interest to declare.

Phase II Study of Single-Agent Arsenic Trioxide for the Front-Line Therapy of Acute Promyelocytic Leukemia

The long-term follow-up results of patients with acute promyelocytic leukemia (APL) treated with all-trans retinoic acid and chemotherapy show high cure rates. Several studies have shown high efficacy of single-agent arsenic trioxide in newly diagnosed APL. However, long-term follow-up results are needed. One hundred ninety-seven patients with newly diagnosed APL were treated with arsenic trioxide 0.15 mg/kg daily intravenous infusion until complete remission (CR). After achieving CR, the patients received one to four more courses of therapy with arsenic trioxide as consolidation and were observed with reverse-transcriptase polymerase chain reaction studies from peripheral blood (to detect of minimal residual disease) every 3 months or until relapse or death. The morphologic CR rate was 85.8%. The most common cause of remission failure was early death owing to APL differentiation syndrome (13.2%). The most important prognostic factor for early mortality was a high WBC count at presentation. The 5-year disease-free survival (DFS) rate was 66.7% ± 4% (SE). Relapse after 5 years in CR was rare. The 5-year overall survival (OS) rate by intention-to-treat analysis was 64.4% ± 4%. In patients who achieved CR, OS and DFS were identical. The long-term follow-up of newly diagnosed patients with APL treated with single-agent arsenic trioxide shows high rates of DFS and OS.

Does microgranular variant morphology of acute promyelocytic leukemia independently predict a less favorable outcome compared with classical M3 APL? A joint study of the North American Intergroup and the PETHEMA Group

AbstractFew studies have examined the outcome of large numbers of patients with the microgranular variant (M3V) of acute promyelocytic leukemia (APL) in the all-trans retinoic acid era. Here, the outcome of 155 patients treated with all-trans retinoic acid–based therapy on 3 clinical trials, North American Intergroup protocol I0129 and Programa para el Estudio de la Terapéutica en Hemopatía Maligna protocols LPA96 and LPA99, are reported. The complete remission rate for all 155 patients was 82%, compared with 89% for 748 patients with classical M3 disease. The incidence of the APL differentiation syndrome was 26%, compared with 25% for classical M3 patients, and the early death rate was 13.6% compared with 8.4% for patients with classical M3 morphology. With a median follow-up time among survivors of 7.6 years (range 3.6-14.5), the 5-year overall survival, disease-free survival, and cumulative incidence of relapse for patients with M3V were 70%, 73%, and 24%, respectively. With a median follow-up time among survivors of 7.6 years (range 0.6-14.3), the 5-year overall survival, disease-free survival, and cumulative incidence of relapse among patients with classical M3 morphology were 80% (P = .006 compared with M3V), 81% (P = .07), and 15% (P = .005), respectively. When outcomes were adjusted for the white blood cell count or the relapse risk score, none of these outcomes were significantly different between patients with M3V and classical M3 APL.