The differentiation syndrome in patients with acute promyelocytic leukemia: experience of the pethema group and review of the literature. Mediterr J Hematol Infect Dis. 2011;3:e2011059. [PMID: 22220256 PMCID: PMC3248336 DOI: 10.4084/mjhid.2011.059]

Differentiation syndrome associated with treatment with IDH2 inhibitor enasidenib: pooled analysis from clinical trials

ABSTRACT

Treatment with enasidenib, a selective mutant isocitrate dehydrogenase isoform 2 (IDH2) inhibitor, has been associated with the development of differentiation syndrome (DS) in patients with acute myeloid leukemia (AML). Studies on the incidence and clinical features of DS are limited in this setting, and diagnosis is challenging because of nonspecific symptoms. This study assessed the incidence, diagnostic criteria, risk factors, and correlation with clinical response of DS based on the pooled analysis of 4 clinical trials in patients with IDH2-mutated AML treated with enasidenib as monotherapy, or in combination with azacitidine or with chemotherapy. Across the total AML population, 67 of 643 (10.4%) had ≥1 any-grade DS event, with highest incidence in patients who received enasidenib plus azacitidine and lowest incidence in patients who received enasidenib plus chemotherapy (13/74 [17.6%] and 2/93 [2.2%]). The most common symptoms of DS were dyspnea/hypoxia (80.6%) and pulmonary infiltrate (73.1%). Median time to onset of first DS event across all studies was 32 days (range, 4-129). Most patients (88.1%) received systemic steroids for treatment of DS. Evaluation of baseline risk factors for DS identified higher levels of bone marrow blasts and lactate dehydrogenase as independent factors associated with increased grade 3 to 5 DS risk. Overall, these results suggest that DS associated with IDH inhibition is manageable, given the benefits of enasidenib treatment in IDH2-mutated AML. We further characterized enasidenib-related DS in these patients and identified risk factors, which could be used for DS management in clinical practice. These trials were registered at www.ClinicalTrials.gov as # NCT01915498, NCT02577406, NCT02677922, and NCT02632708.

A Race Against Time: Early-Onset Differentiation Syndrome Following All-Trans-Retinoic-Acid (ATRA) Therapy in Acute Promyelocytic Leukemia (AML-M3)

This study reports a case of differentiation syndrome, a rare complication of ATRA (all-trans-retinoic-acid) therapy, observed in a 20-year-old male with acute promyelocytic leukemia (APML). Following the initiation of ATRA therapy for APML, the patient presented with fever, bleeding gums, bloody stool, and mouth ulcers. After 36 hours, he developed respiratory distress, hypotension, tachycardia, and hypoxemia, leading to the diagnosis of differentiation syndrome. ATRA therapy was promptly discontinued, and the patient, exhibiting type 1 respiratory failure, necessitated intubation. The management included hydroxyurea, dexamethasone, vasopressors, intravenous fluids, and furosemide. After seven days, significant improvement was observed, underscoring the importance of recognizing and promptly addressing differentiation syndrome in APML patients undergoing ATRA therapy. This case emphasizes the necessity of ATRA discontinuation, coupled with the judicious use of steroids and hydroxyurea, in the effective management of differentiation syndrome.

IDH2 mutations in acute myeloid leukemia

Advances in the treatment of acute myeloid leukemia (AML) over the last 40 years have been limited. With an improved understanding of the pathophysiology of the disease, the advent of new treatment options has enriched the armamentarium of the physician to combat the disease. Mutations of the isocitrate dehydrogenase (IDHs) genes are common in AML and occur in 20-30% of cases. These mutations lead to DNA hypermethylation, aberrant gene expression, cell proliferation, and abnormal differentiation. Targeting mutant IDH, either as monotherapy or in combination with hypomethylating agents (HMAs) or BCL-2 inhibitors, has opened new avenues of therapy for these patients.This review will outline the function of IDHs and focus on the biological effects of IDH2 mutations in AML, their prognosis and treatment options.

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.

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.

Vitamin A regulates tissue-specific organ remodeling in diet-induced obesity independent of mitochondrial function

Background

Perturbed mitochondrial energetics and vitamin A (VitA) metabolism are associated with the pathogenesis of diet-induced obesity (DIO) and type 2 diabetes (T2D).

Methods

To test the hypothesis that VitA regulates tissue-specific mitochondrial energetics and adverse organ remodeling in DIO, we utilized a murine model of impaired VitA availability and high fat diet (HFD) feeding. Mitochondrial respiratory capacity and organ remodeling were assessed in liver, skeletal muscle, and kidney tissue, which are organs affected by T2D-associated complications and are critical for the pathogenesis of T2D.

Results

In liver, VitA had no impact on maximal ADP-stimulated mitochondrial respiratory capacity (VADP) following HFD feeding with palmitoyl-carnitine and pyruvate each combined with malate as substrates. Interestingly, histopathological and gene expression analyses revealed that VitA mediates steatosis and adverse remodeling in DIO. In skeletal muscle, VitA did not affect VADP following HFD feeding. No morphological differences were detected between groups. In kidney, VADP was not different between groups with both combinations of substrates and VitA transduced the pro-fibrotic transcriptional response following HFD feeding.

Conclusion

The present study identifies an unexpected and tissue-specific role for VitA in DIO that regulates the pro-fibrotic transcriptional response and that results in organ damage independent of changes in mitochondrial energetics.

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.

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 120 h 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, 120 h) 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.

Shifting gears to differentiation agents in acute promyelocytic leukemia with resource constraints-a cohort study

BACKGROUND

Treatment of acute promyelocytic leukaemia has emerged as a major success in hemato-oncology. While literature from the developed world boasts of outstanding outcomes, there is a paucity of data from the developing world. This study aimed to assess complications and outcomes of acute promyelocytic leukaemia in a resource-constrained setting.

METHODS

We retrospectively collected data from patients diagnosed with APL from January 2016 to December 2020.

RESULTS

Sixty-four patients were treated-32 in both the Sanz high and low-risk groups. In the Sanz low-risk group, 12.5% of patients received ATRA with daunorubicin and 81.25% received ATRA with ATO. In the Sanz high-risk group, 18.8% of patients received ATRA with daunorubicin, 34.3% received ATRA with daunorubicin and ATO while 40.6% received ATRA with ATO. 56.25% of patients developed differentiation syndrome. The incidence was higher in Sanz high-risk group as compared to Sanz low-risk group. 57.4% of patients had an infection at the time of presentation. 62.5% of patients developed neutropenic fever during treatment. 17.2% of patients developed pseudotumor cerebri. The 4-year EFS and OS were 71.25 and 73.13%, respectively. Sanz low-risk group had a better 4-year EFS and OS as compared to the Sanz high-risk group. Haemoglobin at presentation and Sanz high-risk group were associated with poorer outcomes with a hazard ratio of 0.8 and 3.1, respectively. Outcomes in high-risk patients were better with the use of ATRA + ATO + daunorubicin.

CONCLUSION

In the Indian population, APL patients have a high incidence of differentiation syndrome, pseudotumor cerebri, and infections during induction. CR, EFS, and OS compared to the developed world can be achieved with optimal therapy. Low haemoglobin at presentation and Sanz high-risk group were associated with poorer outcomes. ATRA, ATO, and daunorubicin combination is the preferred protocol for treating high-risk patients.

Rexinoids Modulate Effector T Cell Expression of Mucosal Homing Markers CCR9 and α4β7 Integrin and Direct Their Migration In Vitro

Altering T cell trafficking to mucosal regions can enhance immune responses towards pathogenic infections and cancers at these sites, leading to better outcomes. All-trans-retinoic acid (ATRA) promotes T cell migration to mucosal surfaces by inducing transcription of the mucosal-homing receptors CCR9 and α4β7 via binding to retinoic acid receptors (RARs), which heterodimerize with retinoid X receptors (RXRs) to function. However, the unstable nature and toxicity of ATRA limit its use as a widespread treatment modality for mucosal diseases. Therefore, identifying alternatives that could reduce or eliminate the use of ATRA are needed. Rexinoids are synthetically derived compounds structurally similar to ATRA. Originally named for their ability to bind RXRs, rexinoids can enhance RAR-mediated gene transcription. Furthermore, rexinoids are more stable than ATRA and possess an improved safety profile, making them attractive candidates for use in clinical settings. Here we show that select novel rexinoids act as ATRA mimics, as they cause increased CCR9 and α4β7 expression and enhanced migration to the CCR9 ligand, CCL25 in vitro, even in the absence of ATRA. Conversely, other rexinoids act synergistically with ATRA, as culturing cells with suboptimal doses of both compounds resulted in CCR9 expression and migration to CCL25. Overall, our findings show that rexinoids can be used independently or synergistically with ATRA to promote mucosal homing of T cells in vitro, and lends support for the prospective clinical use of these compounds in immunotherapeutic approaches for pathogenic infections or cancers at mucosal surfaces.

Hematological Malignancies and the Kidney

The incidence of hematologic malignancies is on the rise worldwide. Kidney disease is ubiquitous in patients with hematologic malignancies, encompassing a wide spectrum of disorders involving each kidney compartment, including the vasculature, tubules, interstitium, and glomerulus, and there is significant overlap of kidney involvement with each hematologic malignancy. Vascular disorders include both microvascular and macrovascular damage, via thrombotic microangiopathy, hyperleukocytosis, hyperviscosity, and cryoglobulinemia. The tubulointerstitial compartment may be affected by prerenal azotemia and acute tubular injury, but malignant infiltration, tumor lysis syndrome, extramedullary hematopoiesis, cast nephropathy, granulomatous interstitial nephritis, and lysozymuria should be considered in certain populations. Obstructive uropathy may occur due to nephrolithiasis or retroperitoneal fibrosis. Glomerular disorders, including membranoproliferative, membranous, minimal change, and focal segmental glomerulosclerosis, can rarely occur. By understanding how each compartment may be affected, care can best be optimized for these patients. In this review, we summarize the widely varied etiologies of kidney diseases stratified by kidney compartment and hematologic malignancy, focusing on demographics, pathology, pathophysiology, mechanism, and outcomes. We conclude with common electrolyte abnormalities associated with hematologic malignancies.

Diagnosis of Acute Promyelocytic Leukemia After Presentation to Neuro-Ophthalmology

BACKGROUND

Acute promyelocytic leukemia (APML) is a medical emergency that can initially present with neuro-ophthalmologic signs. Early recognition is crucial, and immediate treatment with all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) can be life-saving. The goal of this study was to describe patients who first presented to neuro-ophthalmology and were subsequently diagnosed with APML.

METHODS

We retrospectively reviewed consecutive patients seen at a tertiary neuro-ophthalmology centre. Patients with an unknown diagnosis of APML at presentation who subsequently went on to receive this diagnosis were included. Clinical characteristics, neuro-ophthalmologic findings, and outcome were retrieved.

RESULTS

A total of 3 patients (2 women and 1 men) with a mean age of 30.7 (range 24-33) years were included in the study. Neuro-ophthalmologic diagnoses at presentation were severe hemorrhagic papilledema related to dural venous sinus thrombosis, hemorrhagic bilateral optic disc edema, and left homonymous hemianopia related to an occipital lobe hemorrhage. At diagnosis, the average hemoglobin was 83.7g/L (range 78-104), and the platelet count was 39.3 × 109/L (range 15-77). All patients were treated with ATRA and ATO. One patient developed papilledema and sixth nerve palsies related to this treatment, which resolved with acetazolamide. Clinical follow-up ranged from 6 to 12 months, and all patients were in clinical remission about systemic APML.

CONCLUSION

Neuro-ophthalmologic symptoms may be the first manifestations of APML, and a complete blood count is an essential test in patients presenting with optic disc edema, especially if hemorrhagic.

Acute Respiratory Distress Syndrome in a Patient With Acute Promyelocytic Leukemia: Overlapping Between Differentiation Syndrome and COVID-19

Differentiation syndrome (DS) is a relatively common and severe complication in acute promyelocytic leukemia (APL) patients undergoing induction therapy with all-trans retinoic acid (ATRA) and/or arsenic trioxide (ATO). DS is a multisystem disorder with pulmonary involvement. The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is also a systemic disorder with similar pulmonary and other clinical manifestations as DS. Here, we report an APL case with overlapping between DS and COVID-19. After admission to the hospital, the patient was diagnosed with APL and underwent differentiation therapy with ATRA/ATO. In the meantime, COVID-19 was diagnosed with a positive polymerase chain reaction test of SARS-CoV-2 from an oropharyngeal swab. The patient developed acute respiratory distress syndrome, coagulopathy, and acute kidney injury, which fit the clinical pictures of both DS and COVID-19. The patient died at last and this complicate case imposed big challenges for clinicians due to the laboratory and imaging findings of DS disguised in the context of COVID-19. Therefore, comprehensive treatment strategy should be considered to balance the risk and benefit of differentiation therapy in the context of COVID-19.

Differentiation syndrome-induced Myopericarditis in the induction therapy of acute Promyelocytic leukemia: a case report

Background

All trans retinoic acid (ATRA) has revolutionized the treatment and outcomes of patients with Acute Promyelocytic Leukemia (APL). Induction therapy with ATRA is associated with the rare but potentially fatal complication of differentiation syndrome. While the presentation of this syndrome is varied, myopericarditis as a manifestation of differentiation syndrome is often fatal and rarely reported in literature. We present a case of myopericarditis as the sole manifestation of differentiation syndrome in a patient on induction therapy with ATRA and arsenic trioxide for APL.

Clinical presentation

A 62 year old woman with remote history of breast and uterine cancer presented to the hospital for expedited work up of easy bruising and expanding hematomas. She was diagnosed with APL with peripheral blood and bone marrow cytogenetics revealing t (15;17) translocation and initiated on induction therapy with ATRA and ATO as well as steroids for differentiation syndrome prophylaxis. Eighteen days into induction therapy, patient developed pleuritic chest pain, elevated cardiac biomarkers, ECG changes suggestive of pericarditis. Cardiac magnetic resonance imaging showed patchy multifocal sub-epicardial late gadolinium enhancement and elevated T2 signal consistent with acute myopericarditis. Given the timing of symptom onset and lack of other identifiable cause, patient was diagnosed with differentiation syndrome- induced myopericarditis and promptly initiated on high dose steroids with rapid improvement in symptoms, ECG, and cardiac biomarkers. Patient successfully resumed dose-reduced ATRA and arsenic trioxide without complication.

Conclusion

Myopericarditis can be the sole manifestation of differentiation syndrome and the presentation may be atypical owing to the use of prophylactic steroids as illustrated in our patient’s case. A high index of suspicion for differentiation syndrome, multimodality imaging, and prompt input from multidisciplinary providers is crucial for making the timely diagnosis and initiating life-saving treatment.

Selective Inhibition of JAK1 Primes STAT5-Driven Human Leukemia Cells for ATRA-Induced Differentiation

BACKGROUND

All-trans retinoic acid (ATRA), a derivate of vitamin A, has been successfully used as a therapy to induce differentiation in M3 acute promyelocytic leukemia (APML), and has led to marked improvement in outcomes. Previously, attempts to use ATRA in non-APML in the clinic, however, have been underwhelming, likely due to persistent signaling through other oncogenic drivers. Dysregulated JAK/STAT signaling is known to drive several hematologic malignancies, and targeting JAK1 and JAK2 with the JAK1/JAK2 inhibitor ruxolitinib has led to improvement in survival in primary myelofibrosis and alleviation of vasomotor symptoms and splenomegaly in polycythemia vera and myelofibrosis.

OBJECTIVE

While dose-dependent anemia and thrombocytopenia limit the use of JAK2 inhibition, selectively targeting JAK1 has been explored as a means to suppress inflammation and STAT-associated pathologies related to neoplastogenesis. The objective of this study is to employ JAK1 inhibition (JAK1i) in the presence of ATRA as a potential therapy in non-M3 acute myeloid leukemia (AML).

METHODS

Efficacy of JAK1i using INCB52793 was assessed by changes in cell cycle and apoptosis in treated AML cell lines. Transcriptomic and proteomic analysis evaluated effects of JAK1i. Synergy between JAK1i+ ATRA was assessed in cell lines in vitro while efficacy in vivo was assessed by tumor reduction in MV-4-11 cell line-derived xenografts.

RESULTS

Here we describe novel synergistic activity between JAK1i inhibition and ATRA in non-M3 leukemia. Transcriptomic and proteomic analysis confirmed structural and functional changes related to maturation while in vivo combinatory studies revealed significant decreases in leukemic expansion.

CONCLUSIONS

JAK1i+ ATRA lead to decreases in cell cycle followed by myeloid differentiation and cell death in human leukemias. These findings highlight potential uses of ATRA-based differentiation therapy of non-M3 human leukemia.

AXL receptor tyrosine kinase: a possible therapeutic target in acute promyelocytic leukemia

BACKGROUND

Acute promyelocytic leukemia (APL) is a subset of acute myeloid leukemia (AML) which is characterized by the fusion of promyelocytic leukemia PML and retinoic acid receptor- alpha (RAR-alpha) genes. All-trans retinoic acid (ATRA) and/or arsenic trioxide (ATO) have resulted in durable cytogenetic and molecular remissions in most APL patients and have altered the natural history of the disease. Most APL patients treated with ATRA and/or ATO are now anticipated to have a nearly normal life expectancy. Unfortunately, relapse and resistance to the current treatment occur in APL patients and the outcome remains dismal in these refractory patients. AXL receptor tyrosine kinase (AXL-RTK) has been shown to increase tumour burden, provide resistance to therapy and is critical to maintain cancer stem cells (CSCs) in chronic myeloid leukemia (CML) by stabilizing β-catenin in the Wnt/β-catenin signalling pathway. However, the role of AXL-RTK has not been explored in PML/RARα-positive APL. This study aimed to explore the role of AXL-RTK receptor in PML/RARα-positive APL.

METHODS AND RESULTS

By using biochemical and pharmacological approaches, here we report that targeting of AXL-RTK is related to the down-regulation of β-catenin target genes including c-myc (p < 0.001), AXIN2 (p < 0.001), and HIF1α (p < 0.01) and induction of apoptosis in PML/RARα-positive APL cell line. Resistance to all-trans retinoic acid (ATRA) was also overcomed by targeting AXL-RTK with R428 in APL (p < 0.05).

CONCLUSION

Our results provide clear evidence of the involvement of AXL-RTK in leukemogenic potential of PML/RARα-positive APL and suggest targeting of AXL-RTK in the treatment of therapy resistant APL patients.

Differentiation syndrome with lower-intensity treatments for acute myeloid leukemia

Differentiation Syndrome (DS) has been identified in a subset of patients undergoing treatment with novel classes of differentiating therapies for acute myeloid leukemia (AML) such as IDH and FLT3 inhibitors. While DS is a well-known treatment-related complication in acute promyelocytic leukemia (APL), efforts are still ongoing to standardize diagnostic and treatment parameters for DS in AML. Though the rates of incidence vary, many of the signs and symptoms of DS are common between APL and AML. So, DS can lead to fatal complications in AML, but prompt management is usually effective and rarely necessitates interruption or discontinuation of AML therapy.

Myelomonocytic differentiation of leukemic blasts accompanied by differentiation syndrome in a case of FLT3-ITD-positive AML treated with gilteritinib

Fms-like tyrosine kinase 3 (FLT3) is one of the most frequently mutated genes in acute myelogenous leukemia (AML) and the mutation is associated with poor prognosis of patients. Two distinct types of activating mutations have been identified in AML samples. One is internal tandem duplications in the juxtamembrane domain (FLT3-ITD) and the other is point mutations in the tyrosine kinase domain (FLT3-TKD). Gilteritinib is a FLT3 inhibitor that inhibits both FLT3-ITD and FLT3-TKD. It was reported that differentiation of leukemic blasts accompanied by differentiation syndrome occurs in some patients treated with gilteritinib. However, information about the precise clinical course is limited, and appropriate management of differentiation syndrome has not been established. We report a case of relapsed AML with FLT3-ITD that was treated with gilteritinib. Analysis of the FLT3-ITD variant allele frequency (VAF) revealed that FLT3-ITD VAF was not decreased despite achievement of complete remission with incomplete hematologic recovery. Remarkable increases of monocytes and granulocytes accompanied by differentiation syndrome were observed at 6 months after the initiation of gilteritinib treatment. Intermittent chemotherapy with low-dose cytarabine and mitoxantrone was effective for reducing myelomonocytosis and resolving differentiation syndrome.

Multidisciplinary corroboration in differentiation syndrome: a case report

Background

Differentiation syndrome (DS) is a life-threatening complication that may be seen in patients with acute promyelocytic leukaemia undergoing induction therapy with all-trans retinoic acid or arsenic trioxide. It can lead to severe inflammatory response syndrome and shock if adequate measures are not taken immediately. The radiological features of lung nodules with changes in ground-glass opacity can represent DS. The principal unique feature of the case reported here is that the diagnosis of DS was based on imaging results in the absence of a low total leukocyte count.

Case presentation

A 14-year-old Indian girl diagnosed with acute promyelocytic leukaemia currently undergoing a chemotherapy regimen that included all-trans retinoic acid/arsenic trioxide was sent to the radiology department for investigation of respiratory distress which she had developed soon after the initiation of chemotherapy. Her chest radiograph showed bilateral lower zone lung infiltrates. Computed tomography (CT) revealed changes in ground-glass opacity in the lower lobes with multiple lung nodules. Differential diagnosis included bacterial, viral or fungal infections, leukemic infiltrates, drug toxicity, pulmonary haemorrhage or leukostasis. She was started on dexamethasone immediately after stopping the chemotherapy with all-trans retinoic acid/arsenic trioxide and given ventilatory support. Her condition subsequently improved and her follow-up chest radiograph and CT scan showed a significant reduction of abnormal lung findings. Based on the clinical improvement and the resolution of findings on imaging following the withdrawal of all-trans retinoic acid/arsenic trioxide, we made the diagnosis of DS.

Conclusions

Though a rather unusual possibility, the treatment history of the patient enabled a rather crucial diagnosis in the nick of time and imaging played a pivotal role. This case further iterates the importance of keeping DS in mind when dealing with similar patients in the future.

IDH1/IDH2 Inhibition in Acute Myeloid Leukemia

Recently, the discovery of biological and clinical properties of mutated isoforms 1 and 2 mutations of isocitrate dehydrogenases (IDH) 1 and 2, affecting approximately 20% of patients with acute myeloid leukemia (AML), lead to the development of an individualized treatment strategy. Promoting differentiation and maturation of the malignant clone targeting IDH is an emerging strategy to promote clinical responses in AML. Phase I/II trials have shown evidence of safety, tolerability, and encouraging evidence of efficacy of two small molecule inhibitors targeting IDH2 and IDH1 gene mutations, respectively enasidenib and ivosidenib. In this review, the contribution of IDH1/IDH2 mutations in leukemogenesis and progress of targeted therapeutics in AML will be highlighted.

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.

Isotretinoin is active in the initial management of acute pro-myelocytic leukemia

Pro-myelocytic acute leukemia (APL) is characterized by the proliferation of cells blocked at promyelocytic stage and ATRA is the choice of initial treatment because of the APL sensitivity to this compound. In this case study we report a 28-year-old man who presented to the Emergency Department with epistaxis, petechial rash, and fever. Laboratory tests revealed the presence of high white blood cell count with 60% blasts and evidence of coagulopathy. The diagnosis was confirmed later as APL. Because of the delayed transfer to the reference center and unavailability of ATRA initial treatment, the patient received isotretinoin, a related compound. The treatment was successfully implemented in the initial management of acute pro-myelocytic leukemia as patient condition improved. isotretinoin could be used as an alternative therapy for ATRA whenever the latter is not available. further research is needed to establish the appropriate doses and to assess the potential risk of differentiation syndromes.

Differentiation Syndrome Mimicking COVID-19 Pneumonia

Introduction: SARS-CoV-2 infection is spreading worldwide, and due to multi-organ involvement, it could mimic other well-known diseases. Case Presentation: Herein, we describe the case of a pediatric patient with acute promyelocytic leukemia (APL), who developed severe respiratory illness with diffuse pulmonary involvement after consuming all-transretinoic acid during the COVID-19 pandemic. Conclusions: All-transretinoic acid syndrome is a very similar condition to COVID-19 both in clinical presentations and radiologic findings; thus, the treatment of such patients may be challenging.

Thyroiditis: A Rare Manifestation of Enasidenib-Induced Differentiation Syndrome

Enasidenib is an FDA-approved isocitrate dehydrogenase 2 (IDH2) inhibitor, which is used in the treatment of acute myeloid leukemia (AML). We present a case of AML with an IDH2 mutation treated with a regimen of enasidenib and 5-azacitidine, where thyroiditis was noted to be a part of differentiation syndrome. The patient is a 77-year-old woman with IDH2-mutated AML who had initially been started on 100 mg of enasidenib and then presented with dyspnea and was diagnosed with pleural effusion - a common presentation with enasidenib - but was also noted to have thyroiditis. She was started on steroids, but due to continued hyperbilirubinemia and thyroiditis, her dose of enasidenib was reduced to half, which resulted in clinical improvement. This case demonstrates thyroiditis as one of the rare manifestations in the treatment of AML with enasidenib-induced differentiation syndrome.

Tannic acid ameliorates arsenic trioxide-induced nephrotoxicity, contribution of NF-κB and Nrf2 pathways

BACKGROUND AND PURPOSE

Tannic acid (TA), a group of polyphenolic compounds, has multiple anticancer, antimutagenic, antioxidant and anti-inflammatory activities. However, the effects of TA on arsenic trioxide (ATO)-induced nephrotoxicity are still relatively unknown. This study investigated the protective effects and potential mechanisms of TA on ATO-induced nephrotoxicity in rats.

METHODS

Rats were intragastrically administered TA with concurrent ATO infused intraperitoneally over 10 days. Renal morphology changes were observed through light microscopy. The levels of antioxidants and pro-inflammatory factors were measured in the serum and renal tissue, respectively. Further, expression of B-cell lymphoma-2, B-cell lymphoma-extra large, p53, and Bcl-2-associated X protein were measured using an immunohistochemical method. The protein expression of nuclear factor kappa B (NF-κB), nuclear factor-erythroid-2-related factor 2 (Nrf2), and kelch-like ECH-associated protein 1 (Keap1) were measured by Western blot.

RESULTS

The data showed that ATO exposure significantly increased the serum nephritic, oxidative stress, apoptosis and inflammatory markers in the renal tissue of rats. Conversely, pretreatment with TA reversed these changes. Furthermore, TA treatment caused a significant decrease in NF-κB expression (P < 0.05), while increasing Nrf2 and Keap1 expressions (P < 0.05).

CONCLUSION

TA ameliorates ATO-induced nephrotoxicity, which is related to the inhibition of oxidative stress, inflammation and apoptosis, potentially through the NF-κB/Nrf2 pathway.

Myositis Induced by Isotretinoin: A Case Report and Literature Review

Patient: Male, 45-year-old

Final Diagnosis: Myositis induced by isotretinoin

Symptoms: Muscle pain in the upper limbs with marked functional limitation associated by coluria

Medication: —

Clinical Procedure: —

Specialty: Rheumatology

A rare case of perimyocarditis induced by all-trans retinoic acid administration during induction treatment of acute promyelocytic leukemia

Treatment by All-Trans Retinoic Acid (ATRA) combined with an Anthracycline Chemotherapy has been shown to improve disease-free survival in patients with Acute Promyelocytic Leukemia (APL). Although ATRA is generally well tolerated, occurrence of Retinoic Acid Syndrome (RAS) during the induction chemotherapy in some patients is recognized as a distinct complication and a potential life-threatening side effect.

Isolated myocarditis as a result of RAS related to ATRA administration is uncommon and has been rarely reported in the literature.

We report a very rare case of ATRA-induced perimyocarditis accompanied by hemodynamic compromise. There was complete resolution of the signs and symptoms of peri-myocarditis when ATRA was temporary suspended. Finally, ATRA was safely resumed.

Differentiation Syndrome Associated With Enasidenib, a Selective Inhibitor of Mutant Isocitrate Dehydrogenase 2: Analysis of a Phase 1/2 Study

Importance

Enasidenib mesylate, a mutant isocitrate dehydrogenase 2 (IDH2) protein inhibitor that promotes differentiation of leukemic myeloblasts, was recently approved by the US Food and Drug Administration for use in relapsed/refractory (R/R) mutant IDH2 acute myeloid leukemia (AML). During the first study of enasidenib in humans, a minority of patients with advanced myeloid neoplasms experienced unexpected signs/symptoms of a differentiation syndrome (DS), a potentially lethal entity.

Objective

To characterize IDH-inhibitor-associated DS (IDH-DS) and its effective management.

Design, Setting, and Participants

Using data obtained from a multicenter, open-label, pivotal phase 1/2 study of enasidenib, a differentiation syndrome review committee retrospectively evaluated potential cases of IDH-DS in enasidenib-treated patients with R/R AML. Data were collected between August 27, 2013, and October 14, 2016. The committee identified and agreed on signs and symptoms characteristic of IDH-DS and developed an algorithm for identification and treatment. Among 281 patients with R/R AML enrolled in the trial, the committee identified 72 patients for review based on investigator-reported cases of DS (n = 33) or reported adverse events or signs and symptoms characteristic of IDH-DS.

Interventions

Treatment with enasidenib at a dosage of 50 to 650 mg/d was evaluated during the dose-escalation phase, and a dosage of 100 mg/d was used in the phase 1 expansion and phase 2, all in continual 28-day cycles.

Main Outcomes and Measures

Unexpected adverse events of IDH-DS during the phase 1/2 study.

Results

Thirty-three of the 281 patients (11.7%) were identified as having possible or probable IDH-DS. Median age of those 33 patients was 70 years (range, 38-80 years); 20 (60.6%) were male. The most frequent manifestations were dyspnea, fever, pulmonary infiltrates, and hypoxia. Median time to onset was 30 days (range, 7-129 days). Patients who experienced IDH-DS were less likely to have less than 20% bone marrow blasts (6% vs 22%, P = .04) and more likely to have undergone fewer previous anticancer regimens (median, 1.0 [range, 1-4] vs 2.0 [range, 1-14], P = .05) at study entry than those who did not. Thirteen patients (39.4%) had concomitant leukocytosis. Isocitrate dehydrogenase differentiation syndrome was effectively managed with systemic corticosteroids. The enasidenib regimen was interrupted for 15 patients (45.5%), but permanent discontinuation of treatment was not required.

Conclusions and Relevance

Isocitrate dehydrogenase differentiation syndrome is a recognizable and potentially lethal clinical entity, occurring in approximately 12% of enasidenib-treated patients with mutant-IDH2 R/R AML. It requires prompt recognition and management. As use of mutant IDH inhibitors increases, these findings and recommendations are increasingly germane to care of patients with mutant-IDH neoplasms.

Trial Registration

clinicaltrials.gov Identifier: NCT01915498.

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.

Ivosidenib: IDH1 Inhibitor for the Treatment of Acute Myeloid Leukemia

There is no standard therapy for refractory acute myeloid leukemia (AML), but several salvage therapies are available (National Comprehensive Cancer Network [NCCN], 2018). Recently, there have been major developments in the treatment of AML focusing on the development of targeted and novel therapies. Ivosidenib is the first approved oral, targeted, small-molecule inhibitor of the isocitrate dehydrogenase 1 (IDH1) mutation seen in AML. IDH1 mutations have been associated with significantly worse outcomes in disease-free survival, relapse-free survival, and overall survival (NCCN, 2018). This article reviews the clinical trials and dose escalation studies that led to the U.S. Food & Drug Administration approval for ivosidenib in patients with relapsed or refractory AML with a susceptible IDH1 mutation. Patient counseling and monitoring, including dosing and administration, are important steps that advanced practitioners should be aware of. The mechanism of action and pharmacokinetic information for ivosidenib is discussed, as well as recommendations for drug-drug interaction management. Adverse events and monitoring parameters are addressed in detail, as well as how to interrupt and resume treatment due to adverse events.

Mutant Isocitrate Dehydrogenase Inhibitors as Targeted Cancer Therapeutics

The identification of heterozygous neomorphic isocitrate dehydrogenase (IDH) mutations across multiple cancer types including both solid and hematologic malignancies has revolutionized our understanding of oncogenesis in these malignancies and the potential for targeted therapeutics using small molecule inhibitors. The neomorphic mutation in IDH generates an oncometabolite product, 2-hydroxyglutarate (2HG), which has been linked to the disruption of metabolic and epigenetic mechanisms responsible for cellular differentiation and is likely an early and critical contributor to oncogenesis. In the past 2 years, two mutant IDH (mutIDH) inhibitors, Enasidenib (AG-221), and Ivosidenib (AG-120), have been FDA-approved for IDH-mutant relapsed or refractory acute myeloid leukemia (AML) based on phase 1 safety and efficacy data and continue to be studied in trials in hematologic malignancies, as well as in glioma, cholangiocarcinoma, and chondrosarcoma. In this review, we will summarize the molecular pathways and oncogenic consequences associated with mutIDH with a particular emphasis on glioma and AML, and systematically review the development and preclinical testing of mutIDH inhibitors. Existing clinical data in both hematologic and solid tumors will likewise be reviewed followed by a discussion on the potential limitations of mutIDH inhibitor monotherapy and potential routes for treatment optimization using combination therapy.

Vitamin A signaling and homeostasis in obesity, diabetes, and metabolic disorders

Much evidence has accumulated in the literature over the last fifteen years that indicates vitamin A has a role in metabolic disease prevention and causation. This literature proposes that vitamin A can affect obesity development and the development of obesity-related diseases including insulin resistance, type 2 diabetes, hepatic steatosis and steatohepatitis, and cardiovascular disease. Retinoic acid, the transcriptionally active form of vitamin A, accounts for many of the reported associations. However, a number of proteins involved in vitamin A metabolism, including retinol-binding protein 4 (RBP4) and aldehyde dehydrogenase 1A1 (ALDH1A1, alternatively known as retinaldehyde dehydrogenase 1 or RALDH1), have also been identified as being associated with metabolic disease. Some of the reported effects of these vitamin A-related proteins are proposed to be independent of their roles in assuring normal retinoic acid homeostasis. This review will consider both human observational data as well as published data from molecular studies undertaken in rodent models and in cells in culture. The primary focus of the review will be on the effects that vitamin A per se and proteins involved in vitamin A metabolism have on adipocytes, adipose tissue biology, and adipose-related disease, as well as on early stage liver disease, including non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH).

Transglutaminase 2 programs differentiating acute promyelocytic leukemia cells in all-trans retinoic acid treatment to inflammatory stage through NF-κB activation

Differentiation syndrome (DS) is a life-threatening complication arising during retinoid treatment of acute promyelocytic leukemia (APL). Administration of all-trans retinoic acid leads to significant changes in gene expression, among the most induced of which is transglutaminase 2, which is not normally expressed in neutrophil granulocytes. To evaluate the pathophysiological function of transglutaminase 2 in the context of immunological function and disease outcomes, such as excessive superoxide anion, cytokine, and chemokine production in differentiated NB4 cells, we used an NB4 transglutaminase knock-out cell line and a transglutaminase inhibitor, NC9, which inhibits both transamidase- and guanosine triphosphate-binding activities, to clarify the contribution of transglutaminase to the development of potentially lethal DS during all-trans retinoic acid treatment of APL. We found that such treatment not only enhanced cell-surface expression of CD11b and CD11c but also induced high-affinity states; atypical transglutaminase 2 expression in NB4 cells activated the nuclear factor kappa (κ)-light-chain-enhancer of the activated B-cell pathway, driving pathogenic processes with an inflammatory cascade through the expression of numerous cytokines, including tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), and monocyte chemoattractant protein 1. NC9 decreased the amount of transglutaminase 2, p65/RelA, and p50 in differentiated NB4 cells and their nuclei, leading to attenuated inflammatory cytokine synthesis. NC9 significantly inhibits transglutaminase 2 nuclear translocation but accelerates its proteasomal breakdown. This study demonstrates that transglutaminase 2 expression induced by all-trans retinoic acid treatment reprograms inflammatory signaling networks governed by nuclear factor κ-light-chain-enhancer of activated B-cell activation, resulting in overexpression of TNF-α and IL-1β in differentiating APL cells, suggesting that atypically expressed transglutaminase 2 is a promising target for leukemia treatment.

A complex translocation (1;17;15) with spliced short-type PML-RARA fusion transcripts in acute promyelocytic leukemia: A case report

The promyelocytic leukemia (PML)-retinoic acid receptor α (RARA) fusion is hypothesized to serve a vital role in the pathogenesis of acute promyelocytic leukemia (APL), which results from a reciprocal translocation between chromosomes 15 and 17, t(15;17)(q24;q21). A minority of APL cases lack the classical t(15;17) and have been identified to have cryptic or masked t(15;17) or complex translocations. The present study reports on a case of a 37-year-old male with APL harboring a complex three-way translocation t(1;17;15)(q21;q21;q24). This karyotypic interpretation was further confirmed by fluorescence in situ hybridization, and 98% of the bone marrow cells analyzed were positive for the PML-RARA fusion gene. After combined treatment with all-trans retinoic acid and arsenic trioxide, the patient achieved complete remission with no recurrence for 3 years to date. To the best of our knowledge, the present study is the first to report on the novel variant of t(15;17) involving the breakpoint 1q21.

Successful treatment of disseminated intravascular coagulation by recombinant human soluble thrombomodulin in patients with acute myeloid leukemia

Disseminated intravascular coagulation (DIC) is a life-threatening condition that frequently occurs in patients with hematologic malignancies. Currently, recombinant human soluble thrombomodulin (rTM) is a therapeutic DIC drug that is manufactured and sold in Japan only. We evaluated the efficacy of rTM compared to that of gabexate mesilate (GM), which was previously used routinely for treating DIC in Japan, in patients with acute myeloid leukemia (AML). This retrospective study enrolled 43 AML patients, including 17 with acute promyelocytic leukemia (APL), that was complicated with DIC. DIC resolution rates in non-APL AML and rTM-treated APL patients were 68.4% and 81.8%, respectively. In non-APL AML patients, the duration of rTM administration was significantly shorter than that of GM (7 vs 11 days), suggesting that rTM could improve DIC earlier than GM, although rTM was used in patients with more severe DIC. Moreover, treatment with rTM significantly improved DIC score, fibrinogen, fibrin/fibrinogen degradation product (FDP), and prothrombin time (PT) ratio. Conversely, treatment with GM only improved the DIC score and FDP. In APL patients, the duration of rTM administration was also significantly shorter than that of GM. No severe side effects associated with the progression of bleeding were observed during rTM administration. These findings suggest that rTM is safe, and its anti-DIC effects are more prompt than GM for treating AML patients with DIC.

DNA Methylation Predicts the Response of Triple-Negative Breast Cancers to All-Trans Retinoic Acid

All-trans retinoic acid (atRA) regulates gene expression and is used to treat acute promyelocytic leukemia. Attempts to use atRA in breast cancer without a stratification strategy have resulted in limited overall effectiveness. To identify biomarkers for the treatment of triple-negative breast cancer (TNBC) with atRA, we characterized the effects of atRA on the tumor growth of 13 TNBC cell lines. This resulted in a range of effects that was not predictable based on previously hypothesized predictors of response, such as the levels of atRA nuclear shuttling proteins fatty acid binding protein 5 (FABP5) and cellular retinoic acid binding protein 2 (CRABP2). Transcriptional profiling revealed that atRA induced distinct gene expression changes in the sensitive versus resistant cell lines that were mostly independent of the presence of retinoic acid response elements (RAREs) or peroxisome proliferator response elements (PPREs). Given the importance of DNA methylation in regulating gene expression, we hypothesized that differential DNA methylation could predict the response of TNBCs to atRA. We identified over 1400 sites that were differentially methylated between atRA resistant and sensitive cell lines. These CpG sites predicted the response of four TNBC patient-derived xenografts to atRA, and we utilized these xenografts to refine the profile and identified that as many as 17% of TNBC patients could benefit from atRA treatment. These data illustrate that differential methylation of specific CpGs may be useful biomarkers for predicting the response of patient tumors to atRA treatment.

Evolving Treatment Strategies for Elderly Leukemia Patients with IDH Mutations

Acute myeloid leukemia (AML) is a debilitating and life-threatening condition, especially for elderly patients who account for over 50% of diagnoses. For over four decades, standard induction therapy with intensive cytotoxic chemotherapy for AML had remained unchanged. However, for most patients, standard therapy continues to have its shortcomings, especially for elderly patients who may not be able to tolerate the complications from intensive cytotoxic chemotherapy. New research into the development of targeted and alternative therapies has led to a new era in AML therapy. For the nearly 20% of diagnoses harboring a mutation in isocitrate dehydrogenase 1 or 2 (IDH1/2), potential treatment options have undergone a paradigm shift away from intensive cytotoxic chemotherapy and towards targeted therapy alone or in combination with lower intensity chemotherapy. The first FDA approved IDH2 inhibitor was enasidenib in 2017. In addition, IDH1 inhibitors are in ongoing clinical studies, and the oral BCL-2 inhibitor venetoclax shows preliminary efficacy in this subset of patients. These new tools aim to improve outcomes and change the treatment paradigm for elderly patients with IDH mutant AML. However, the challenge of how to best incorporate these agents into standard practice remains.

Two cases of differentiation syndrome with ocular manifestations in patients with acute promyelocytic leukaemia treated with all-trans retinoic acid and arsenic trioxide

Purpose

To describe two cases of differentiation syndrome presenting with ocular manifestations including bilateral chorioretinopathy in patients with acute promyelocytic leukaemia treated with all-trans retinoic acid and arsenic trioxide differentiation therapy.

Observations

This observational case series identifies two patients at a single tertiary institution diagnosed with differentiation syndrome with associated ophthalmic involvement. Both patients reported bilateral reduction in visual acuity at days fourteen and ten respectively following initiation of differentiation therapy in addition to developing other systemic manifestations of differentiation syndrome. Both patients received the same chemotherapeutic regimen including both all-trans retinoic acid and arsenic trioxide as well as ten days of routine differentiation syndrome prophylaxis with oral prednisolone. Case 1 presented with bilateral pale yellow sub-retinal lesions concentrated at the posterior poles with ocular coherence tomography (OCT) evidence of bilateral multifocal areas of focal RPE elevation and adhesion to the thickened outer retina with interspersed sub-retinal fluid. Fluorescein angiography revealed areas of early hyperflouresence corresponding to the yellow chorioretinal lesions with late diffuse leakage of fluid into the subretinal space. Case 2 presented with a similar characteristic retinal findings on fundoscopy and optical coherence tomography. Both patients experienced rapid improvement in the visual symptoms and marked resolution of the sub-retinal fluid within seven to fourteen days of onset with excellent long-term visual outcome. Both patients achieved molecular remission after induction and received standard consolidation and maintenance therapy without visual disturbance.

Conclusion and importance

Ocular manifestations of differentiation syndrome have been only recently recognised. We present a case series of two patients with differentiation syndrome with ocular involvement. Common to both presentations was the presence of bilateral reduction in visual acuity with multifocal serous retinal detachment secondary to chorioretinopathy. The visual outcome from both presentations was excellent with rapid normalisation of visual acuity and resolution of the sub-retinal fluid with only the first case having their differentiation therapy temporarily withheld during the acute phase of illness.

Enasidenib, a targeted inhibitor of mutant IDH2 proteins for treatment of relapsed or refractory acute myeloid leukemia

Mutations in IDH2 genes (mIDH2) occur in approximately 12% of patients with acute myeloid leukemia. Enasidenib is an oral, small-molecule inhibitor of mIDH2 proteins. Enasidenib is shown to suppress the oncometabolite, 2-hydroxyglutarate, and promote differentiation of leukemic bone marrow blasts. In a Phase I dose-escalation and expansion study, 40.3% of patients with relapsed/refractory acute myeloid leukemia responded to enasidenib monotherapy, including 19.3% who achieved complete remission and 11% who proceeded to transplant. Median overall survival was 9.3 months. 2-hydroxyglutarate suppression did not predict response and mIDH2 clearance was possible, but not required for response. Patients with ≥6 co-mutations or NRAS co-mutations were less likely to attain a response. Enasidenib was safe and well tolerated with low rates of treatment-related adverse events.

[Formula: see text]

Molecular and hematologic relapses in adult patients with acute promyelocytic leukemia: a cohort study

OBJECTIVE

To evaluate factors predictive for relapse in a cohort of adult patients with acute promyelocytic leukemia monitored by molecular methods during consolidation and during at least one month of maintenance therapy.

METHODS

The charts and laboratory data of 65 adult patients with acute promyelocytic leukemia treated according to the International Consortium on Acute Promyelocytic Leukemia 2006 protocol were reviewed. The identification of the promyelocytic leukemia-retinoic acid receptor-alpha gene rearrangement at diagnosis, post-induction, post-consolidation and during maintenance treatment was performed by qualitative and quantitative reverse transcription polymerase chain reaction.

RESULTS

Eighty-nine patients were diagnosed with acute promyelocytic leukemia over a seven-year period and of these 65 were eligible for treatment with the protocol. Among the 45 patients who received consolidation and maintenance treatment, six (13%) relapsed, three of whom presented hematologic and three presented molecular relapse. The first relapses occurred at a median of 39 months. Relapsed patients were from all risk groups (low, intermediate and high) and both morphological types (M3 and M3variant) were found. Three of these patients are alive and in molecular remission after salvage treatment. There were no statistically significant differences regarding gender, age, risk group, morphology, promyelocytic leukemia breakpoint cluster region, use of all-trans retinoic acid, development of differentiation syndrome and number of days to complete remission between the patients who relapsed and those who did not.

CONCLUSION

Our results reinforce the importance of prolonged monitoring of acute promyelocytic leukemia patients using molecular methods to detect relapse early.

Role of Vitamin A/Retinoic Acid in Regulation of Embryonic and Adult Hematopoiesis

Vitamin A is an essential micronutrient throughout life. Its physiologically active metabolite retinoic acid (RA), acting through nuclear retinoic acid receptors (RARs), is a potent regulator of patterning during embryonic development, as well as being necessary for adult tissue homeostasis. Vitamin A deficiency during pregnancy increases risk of maternal night blindness and anemia and may be a cause of congenital malformations. Childhood Vitamin A deficiency can cause xerophthalmia, lower resistance to infection and increased risk of mortality. RA signaling appears to be essential for expression of genes involved in developmental hematopoiesis, regulating the endothelial/blood cells balance in the yolk sac, promoting the hemogenic program in the aorta-gonad-mesonephros area and stimulating eryrthropoiesis in fetal liver by activating the expression of erythropoietin. In adults, RA signaling regulates differentiation of granulocytes and enhances erythropoiesis. Vitamin A may facilitate iron absorption and metabolism to prevent anemia and plays a key role in mucosal immune responses, modulating the function of regulatory T cells. Furthermore, defective RA/RARα signaling is involved in the pathogenesis of acute promyelocytic leukemia due to a failure in differentiation of promyelocytes. This review focuses on the different roles played by vitamin A/RA signaling in physiological and pathological mouse hematopoiesis duddurring both, embryonic and adult life, and the consequences of vitamin A deficiency for the blood system.