Effective treatment of acute promyelocytic leukemia with all-trans-retinoic acid, arsenic trioxide, and gemtuzumab ozogamicin

Dasatinib synergizes with ATRA to trigger granulocytic differentiation in ATRA resistant acute promyelocytic leukemia cell lines via Lyn inhibition-mediated activation of RAF-1/MEK/ERK

All-trans retinoic acid (ATRA) resistance has been a critical problem in acute promyelocytic leukemia (APL) relapsed patients. In this study, dasatinib synergized with ATRA to trigger differentiation in ATRA-resistant APL cell lines. The combined treatment activated RAF-1, MEK and ERK as well as enhanced ATRA-promoted up-regulation of the protein level of PU.1, C/EBPβ and C/EBPε. U0126 (MEK specific inhibitor) and sorafenib tosylate (RAF-1 specific inhibitor) suppressed the combined treatment-induced differentiation, ERK phosphorylation and the up-regulation of C/EBPs and PU.1. Sorafenib tosylate also attenuated the MEK activity. However, the combined treatment did not enhance Ras activity and Ras inhibitor neither blocked MEK activation nor inhibited differentiation. Therefore, the combined treatment induced differentiation via Ras independent RAF-1/MEK/ERK. Earlier than RAF-1 activation, dasatinib suppressed Lyn activity, the predominant activated Src family kinase (SFK) and dephosphorylated RAF-1 at S259. Furthermore, SFK inhibitor, PP2 did suppress Lyn activity and mimicked the effect of dasatinib on ATRA-induced differentiation as well as decreased phosphorylation of RAF-1 at S259. Thus, it was suggested that Lyn inhibition might activate RAF-1 by the dephosphorylation of RAF at S259 and lead to differentiation. In conclusion, the combination of dasatinib and ATRA could overcome ATRA resistance through Lyn inhibition-mediated activation of RAF-1/MEK/ERK.

The triple-negative (CD34-/HLA-DR-/CD11b-) profile rapidly and specifically identifies an acute promyelocytic leukemia

INTRODUCTION

The genetic testing to confirm or rule out an acute promyelocytic leukemia (APL) typically takes a minimum of 24-72 hours. Flow cytometric immunophenotyping (FCI) on the other hand provides rapid and objective information to differentiate APL from non-APL.

METHODS

FCI features, with single-tube 8-color combination using CD45, CD34, HAL-DR, CD11b, CD13, CD33, and CD117 and CD64, were compared for the 30 consecutive APL and 30 non-APL acute myeloid leukemia (AML) cases which morphologically mimicked an APL. The diagnosis was confirmed by cytogenetic or molecular genetic testing in the form of t (15:17) (q22; q21)/variant translocations or PML-RARA fusion transcript analysis.

RESULTS

The APL cells lacked CD34, HLA-DR, and CD11b in 90%, 90%, and 93.3% cases, respectively. Myeloid antigens such as CD33, CD13, CD117, and CD64 were expressed in 96.7%, 96.7%, 76.7%, and 70% cases, respectively. The dual negative profiles, CD34-/HLA-DR- or HLA-DR-/CD11b-, were noted in 90% and 93.3% cases. The triple-negative (CD34-/HLA-DR-/CD11b-) profile was noted in 90% of the cases. The sensitivity, specificity, and positive predictive value (PPV) of CD34-/HLA-DR- and HLA-DR-/CD11b- profiles for the diagnosis of APL were found to be 90%, 80% & 81.1% and 93.3%, 86.7%& 87.5%, respectively. Combining the above two profiles resulted in a triple-negative profile (CD34-, HLA-DR- and CD11b-), which had a better specificity (93.3%) and positive predictive value (93.1%), with similar sensitivity.

CONCLUSION

FCI is a rapid and reliable modality for the diagnosis of an APL. The triple-negative profile (CD34-/HLA-DR-/CD11b-) rapidly and specifically identifies an APL case.

Effectivity of a modified Sanz risk model for early death prediction in patients with newly diagnosed acute promyelocytic leukemia

Early death is the main obstacle for the cure of patients with acute promyelocytic leukemia (APL). We have analyzed risk factors of early death from 526 consecutive newly diagnosed APL patients between 2004 and 2016. The overall incidence of early death was 7.2% (38/526). The peak hazard of early death occurred in the first 0-3 days. Multivariate logistic analysis demonstrated white blood cell (WBC) counts [odds ratio (OR) = 1.039; 95% confidence interval (CI): 1.024-1.055; P < 0.001], age (OR = 1.061; 95% CI: 1.025-1.099; P = 0.001) and platelet counts (OR = 0.971; 95% CI: 0.944-0.999; P = 0.038) were independent risk factors for early death. Furthermore, receiver-operator characteristic (ROC) curve analyses revealed a simple WBC/platelet ratio was significantly more accurate in predicting early death [areas under the ROC curve (AUC) = 0.842, 95% CI: 0.807-0.872) than WBC counts (AUC = 0.793; 95% CI: 0.756-0.827) or Sanz score (AUC = 0.746; 95% CI: 0.706-0.783). We stratified APL patients into four risk subgroups: low risk (WBC ≤ 10 × 10⁹/L, platelet >40 × 10⁹/L), intermediate risk (WBC/platelet <0.2 and age ≤ 60, not in low risk), high risk (WBC/platelet ≥0.2 or age > 60, not in low and ultra-high risk) and ultra-high risk (WBC > 50 × 10⁹/L), the early death rates were 0, 0.6, 12.8, and 41.2%, respectively. In conclusion, we proposed a modified Sanz risk model as a useful predictor of early death risk in patients with APL.

Molecularly targeted drug combinations demonstrate selective effectiveness for myeloid- and lymphoid-derived hematologic malignancies

Translating the genetic and epigenetic heterogeneity underlying human cancers into therapeutic strategies is an ongoing challenge. Large-scale sequencing efforts have uncovered a spectrum of mutations in many hematologic malignancies, including acute myeloid leukemia (AML), suggesting that combinations of agents will be required to treat these diseases effectively. Combinatorial approaches will also be critical for combating the emergence of genetically heterogeneous subclones, rescue signals in the microenvironment, and tumor-intrinsic feedback pathways that all contribute to disease relapse. To identify novel and effective drug combinations, we performed ex vivo sensitivity profiling of 122 primary patient samples from a variety of hematologic malignancies against a panel of 48 drug combinations. The combinations were designed as drug pairs that target nonoverlapping biological pathways and comprise drugs from different classes, preferably with Food and Drug Administration approval. A combination ratio (CR) was derived for each drug pair, and CRs were evaluated with respect to diagnostic categories as well as against genetic, cytogenetic, and cellular phenotypes of specimens from the two largest disease categories: AML and chronic lymphocytic leukemia (CLL). Nearly all tested combinations involving a BCL2 inhibitor showed additional benefit in patients with myeloid malignancies, whereas select combinations involving PI3K, CSF1R, or bromodomain inhibitors showed preferential benefit in lymphoid malignancies. Expanded analyses of patients with AML and CLL revealed specific patterns of ex vivo drug combination efficacy that were associated with select genetic, cytogenetic, and phenotypic disease subsets, warranting further evaluation. These findings highlight the heuristic value of an integrated functional genomic approach to the identification of novel treatment strategies for hematologic malignancies.

Recent advances in acute promyelocytic leukaemia

Acute promyelocytic leukaemia (APML) is a subtype of leukaemia arising from a distinct reciprocal translocation involving chromosomes 15 and 17, which results in the PML-RARA fusion gene. Over the past three decades, APML has been transformed from a highly fatal disease to a highly curable one. This drastic improvement is because of the introduction of a new treatment strategy with all-trans retinoic acid and, more recently, arsenic trioxide. The revolutionary treatment of APML has also paved the way for a new cancer treatment, which is genetically targeted therapy. In this review, we look into this amazing journey of transformation and provide recent advances in the management of APML.

Tumour growth-suppressive effect of arsenic trioxide in squamous cell lung carcinoma

Lung squamous cell carcinoma (SCC) is the second most common subtype of non-small cell lung carcinoma. The anticancer effects of arsenic trioxide (ATO) in lung adenocarcinoma and small-cell lung cancer have previously been reported; however its effects in SCC remain unclear. An MTT assay and western blot analysis were performed to determine cell viability and protein expression, respectively, in the SK-MES-1 and SW900 SCC cell lines following treatment with ATO. Phosphatidylserine externalization, mitochondrial membrane depolarization and cell cycle distribution were studied using flow cytometry and the in vivo effects of ATO on tumour growth were investigated with a xenograft model. The results demonstrated that SK-MES-1 and SW900 SCC cells were sensitive to clinically relevant concentrations of ATO. ATO induced apoptosis, mitochondrial membrane depolarization and G₂/M arrest. In addition, treatment with ATO resulted in the downregulation of X-linked inhibitor of apoptosis, B-cell lymphoma-2 (Bcl-2), E2F transcription factor 1 (E2F1), thymidylate synthase and ribonucleotide reductase M1 in addition to the upregulation of Bcl-2 antagonist/killer protein, cleaved poly ADP-ribose polymerase and cleaved caspase 3 in a cell-line specific manner. In the SW900 xenograft model, tumour growth was inhibited by ATO with the formation of apoptotic bodies and downregulation of Bcl-2 and E2F1. In conclusion, ATO suppresses the growth of SCC in vitro and in vivo.

Maintenance therapy with all-trans retinoic acid and arsenic trioxide improves relapse-free survival in adults with low- to intermediate-risk acute promyelocytic leukemia who have achieved complete remission after consolidation therapy

BACKGROUND

Currently, the optimal maintenance therapy for patients with acute promyelocytic leukemia (APL) who have achieved complete remission (CR) after completing consolidation chemotherapy remains controversial. The comparative effectiveness of the all-trans retinoic acid (ATRA) plus arsenic trioxide (As₂O₃) maintenance strategy with classic ATRA plus chemotherapy has not been evaluated. In this study, we compared the efficacy and toxicity of maintenance therapy with ATRA plus As₂O₃ and classic ATRA plus chemotherapy in low- to intermediate-risk APL patients reaching the first CR after induction and consolidation therapy.

METHODS

A retrospective review of 58 adult patients diagnosed with APL was conducted. After receiving consolidation therapy and achieving CR, 30 patients were administered maintenance therapy with an ATRA plus As₂O₃ regimen (ATRA+As₂O₃ group), whereas 28 patients were administered 3-monthly cycles of an ATRA plus chemotherapy regimen (ATRA+chemotherapy group).

RESULTS

Grade 3-4 neutropenia was significantly more frequent in the ATRA+chemotherapy group (N=9, 32.1%) than in the ATRA+As₂O₃ group (N=0) (P=0.001). At a median follow-up of 49.1 months (range: 9.7-97.4 months) from the completion of consolidation, no relapses were observed in the ATRA+As₂O₃ group, whereas seven relapses occurred in the ATRA+chemotherapy group. The risk of relapse in the patients administered ATRA+As₂O₃ maintenance was significantly lower than that in those administered ATRA+chemotherapy maintenance (P=0.004). Based on log-rank analysis, only maintenance therapy with ATRA and As₂O₃ was associated with a significantly higher relapse-free survival (P=0.0159).

CONCLUSION

Maintenance therapy with ATRA and As₂O₃ was beneficial in low- to intermediate-risk APL patients who were effectively treated to achieve CR. Further clinical trials with reliable designs are needed to confirm these observations.

Retinoic acid and arsenic trioxide in the treatment of acute promyelocytic leukemia: current perspectives

Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia (AML) with a unique morphological appearance, associated coagulopathy and canonical balanced translocation of genetic material between chromosomes 15 and 17. APL was first described as a distinct subtype of AML in 1957 by Dr Leif Hillestad who recognized the pattern of an acute leukemia associated with fibrinolysis, hypofibrinogenemia and catastrophic hemorrhage. In the intervening years, the characteristic morphology of APL has been described fully with both classical hypergranular and variant microgranular forms. Both are characterized by a balanced translocation between the long arms of chromosomes 15 and 17, [t(15;17)(q24;q21)], giving rise to a unique fusion gene PML-RARA and an abnormal chimeric transcription factor (PML-RARA), which disrupts normal myeloid differentiation programs. The success of current treatments for APL is in marked contrast to the vast majority of patients with non-promyelocytic AML. The overall prognosis in non-promyelocytic AML is poor, and although there has been an improvement in overall survival in patients aged <60 years, only 30%-40% of younger patients are still alive 5 years after diagnosis. APL therapy has diverged from standard AML therapy through the empirical discovery of two agents that directly target the molecular basis of the disease. The evolution of treatment over the last 4 decades to include all-trans retinoic acid and arsenic trioxide, with chemotherapy limited to patients with high-risk disease, has led to complete remission in 90%-100% of patients in trials and rates of overall survival between 86% and 97%.

Improved Outcomes With Retinoic Acid and Arsenic Trioxide Compared With Retinoic Acid and Chemotherapy in Non–High-Risk Acute Promyelocytic Leukemia: Final Results of the Randomized Italian-German APL0406 Trial

Purpose

The initial results of the APL0406 trial showed that the combination of all- trans-retinoic acid (ATRA) and arsenic trioxide (ATO) is at least not inferior to standard ATRA and chemotherapy (CHT) in first-line therapy of low- or intermediate-risk acute promyelocytic leukemia (APL). We herein report the final analysis on the complete series of patients enrolled onto this trial.

Patients and Methods

The APL0406 study was a prospective, randomized, multicenter, open-label, phase III noninferiority trial. Eligible patients were adults between 18 and 71 years of age with newly diagnosed, low- or intermediate-risk APL (WBC at diagnosis ≤ 10 × 109/L). Overall, 276 patients were randomly assigned to receive ATRA-ATO or ATRA-CHT between October 2007 and January 2013.

Results

Of 263 patients evaluable for response to induction, 127 (100%) of 127 patients and 132 (97%) of 136 patients achieved complete remission (CR) in the ATRA-ATO and ATRA-CHT arms, respectively ( P = .12). After a median follow-up of 40.6 months, the event-free survival, cumulative incidence of relapse, and overall survival at 50 months for patients in the ATRA-ATO versus ATRA-CHT arms were 97.3% v 80%, 1.9% v 13.9%, and 99.2% v 92.6%, respectively ( P < .001, P = .0013, and P = .0073, respectively). Postinduction events included two relapses and one death in CR in the ATRA-ATO arm and two instances of molecular resistance after third consolidation, 15 relapses, and five deaths in CR in the ATRA-CHT arm. Two patients in the ATRA-CHT arm developed a therapy-related myeloid neoplasm.

Conclusion

These results show that the advantages of ATRA-ATO over ATRA-CHT increase over time and that there is significantly greater and more sustained antileukemic efficacy of ATO-ATRA compared with ATRA-CHT in low- and intermediate-risk APL.

Tailored Approaches to Induction Therapy for Acute Promyelocytic Leukemia

The Oncology Grand Rounds series is designed to place original reports published in the Journal into clinical context. A case presentation is followed by a description of diagnostic and management challenges, a review of the relevant literature, and a summary of the authors’ suggested management approaches. The goal of this series is to help readers better understand how to apply the results of key studies, including those published in Journal of Clinical Oncology, to patients seen in their own clinical practice.

Long-term outcome of acute promyelocytic leukemia treated with all-trans-retinoic acid, arsenic trioxide, and gemtuzumab

The combination of all-trans-retinoic acid (ATRA) plus arsenic trioxide (ATO) has been shown to be superior to ATRA plus chemotherapy in the treatment of standard-risk patients with newly diagnosed acute promyelocytic leukemia (APL). A recent study demonstrated the efficacy of this regimen with added gemtuzumab ozogamicin (GO) in high-risk patients. We examined the long-term outcome of patients with newly diagnosed APL treated at our institution on 3 consecutive prospective clinical trials, using the combination of ATRA and ATO, with or without GO. For induction, all patients received ATRA (45 mg/m² daily) and ATO (0.15 mg/kg daily) with a dose of GO (9 mg/m² on day 1) added to high-risk patients (white blood cell count, >10 × 10⁹/L), as well as low-risk patients who experienced leukocytosis during induction. Once in complete remission, patients received 4 cycles of ATRA plus ATO consolidation. One hundred eighty-seven patients, including 54 with high-risk and 133 with low-risk disease, have been treated. The complete remission rate was 96% (52 of 54 in high-risk and 127 of 133 in low-risk patients). Induction mortality was 4%, with only 7 relapses. Among low-risk patients, 60 patients (45%) required either GO or idarubicin for leukocytosis. Median duration of follow-up was 47.6 months. The 5-year event-free, disease-free, and overall survival rates are 85%, 96%, and 88%, respectively. Late hematological relapses beyond 1 year occurred in 3 patients. Fourteen deaths occurred beyond 1 year; 12 were related to other causes. This study confirms the durability of responses with this regimen.

Frontline treatment of acute myeloid leukemia in adults

Recent years have highlighted significant progress in understanding the underlying genetic and epigenetic signatures of acute myeloid leukemia(AML). Most importantly, novel chemotherapy and targeted strategies have led to improved outcomes in selected genetic subsets. AML is a remarkably heterogeneous disease, and individualized therapies for disease-specific characteristics (considering patients' age, cytogenetics, and mutations) could yield better outcomes. Compared with the historical 5-to 10-year survival rate of 10%, the survival of patients who undergo modern treatment approaches reaches up to 40-50%, and for specific subsets, the improvements are even more dramatic; for example, in acute promyelocytic leukemia, the use of all-trans retinoic acid and arsenic trioxide improved survival from 30 to 40% up to 80 to 90%. Similar progress has been documented in core-binding-factor-AML, with an increase in survival from 30% to 80% upon the use of high-dose cytarabine/fludarabine/granulocyte colony-stimulating factor combination regimens. AML treatment was also recently influenced by the discovery of the superiority of regimens with higher dose Ara-C and nucleoside analogues compared with the "7+3"regimen, with about a 20% improvement in overall survival. Despite these significant differences, most centers continue to use the "7+3" regimen, and greater awareness will improve the outcome. The discovery of targetable molecular abnormalities and recent studies of targeted therapies (gemtuzumab ozagomycin, FLT3 inhibitors, isocitrate dehydrogenase inhibitors, and epigenetic therapies), future use of checkpoint inhibitors and other immune therapies such as chimeric antigen receptor T-cells, and maintenance strategies based on the minimal residual disease evaluation represent novel, exciting clinical leads aimed to improve AML outcomes in the near future.

Mutations in AML: prognostic and therapeutic implications

Acute myeloid leukemia (AML) is a heterogeneous hematologic malignancy characterized by the proliferation and aberrant differentiation of immature clonal myeloid cells. The prognosis of AML is variable, based on clinical features such as patient age, performance status, and comorbidities, as well as leukemia-specific genetic features including cytogenetics and molecular classification. The modern application of next-generation sequencing technology has uncovered marked heterogeneity and genomic complexity within AML, based on the presence or absence of cooperating mutations within functional categories such as epigenetic regulators, cell signaling and proliferation pathways, and master hematopoietic transcription factors. Although the treatment of AML has hitherto changed little in the past 40 years, the enhanced scientific understanding of AML pathophysiology and leukemogenesis has led to the recent development of multiple targeted and selective treatment approaches, and our increasing awareness of functional AML subsets will be evermore used to inform rational and personalized treatment strategies.

Current first- and second-line treatment options in acute promyelocytic leukemia

Outcome of acute promyelocytic leukemia (APL) has remarkably improved during the last 30 years, especially after the identification of PML-RARA oncogene as a key in the pathogenesis of APL and all-trans retinoic acid as therapeutic agent. Arsenic trioxide has been recently demonstrated to be the most effective single antileukemic agent and it has also showed synergistic action when combined with all-trans retinoic acid, decreasing relapse rate especially in low/intermediate-risk settings. Therapeutic advances led to complete remission rates of more than 90%, modifying disease history. In relapse setting, arsenic trioxide-based regimens showed efficacy for the achievement of second molecular complete remission. The most challenging issue in APL management remains the significant early deaths rate, nowadays the principal reason for treatment failure.

Future prospects of therapeutic clinical trials in acute myeloid leukemia

Acute myeloid leukemia (AML) is a markedly heterogeneous hematological malignancy that is most commonly seen in elderly adults. The response to current therapies to AML is quite variable, and very few new drugs have been recently approved for use in AML. This review aims to discuss the issues with current trial design for AML therapies, including trial end points, patient enrollment, cost of drug discovery and patient heterogeneity. We also discuss the future directions in AML therapeutics, including intensification of conventional therapy and new drug delivery mechanisms; targeted agents, including epigenetic therapies, cell cycle regulators, hypomethylating agents and chimeric antigen receptor T-cell therapy; and detail of the possible agents that may be incorporated into the treatment of AML in the future.

Arsenic Trioxide and Tretinoin (AsO/ATRA) for Acute Promyelocytic Leukemia (APL)

The complexity of cancer chemotherapy requires pharmacists be familiar with the complicated regimens and highly toxic agents used. This column reviews various issues related to preparation, dispensing, and administration of antineoplastic therapy, and the agents, both commercially available and investigational, used to treat malignant diseases. Questions or suggestions for topics should be addressed to Dominic A. Solimando, Jr., President, Oncology Pharmacy Services, Inc., 4201 Wilson Blvd #110-545, Arlington, VA 22203, e-mail: OncRxSvc@comcast.net; or J. Aubrey Waddell, Professor, University of Tennessee College of Pharmacy; Oncology Pharmacist, Pharmacy Department, Blount Memorial Hospital, 907 E. Lamar Alexander Parkway, Maryville, TN 37804, e-mail: waddfour@charter.net.

Fabrication of water-soluble polymer-encapsulated As4S4 to increase oral bioavailability and chemotherapeutic efficacy in AML mice

Realgar (As4S4) has been demonstrated to be effective for the treatment of acute myeloid leukemia (AML); it has the advantages of no drug resistance and oral administration. Nevertheless, its poor solubility has been an obstacle to its bioavailability, requiring high-dose administration over a long period. We investigated whether crushing realgar crystals to the nanoscale and encapsulating the particles in a water-soluble polymer in one step using hot-melt extrusion would increase the bioavailability of As4S4. Raw As4S4 (r-As4S4) and water-soluble polymer were processed via co-rotating twin screw extrusion. The resulting product (e-As4S4) was characterized by SEM, XRD, and DLS. The cytotoxicity and therapeutic effects of e-As4S4 were evaluated in vivo and in vitro. The results show that e-As4S4 dissolved rapidly in water, forming a stable colloid solution. The average size of e-As4S4 particles was 680 nm, which was reduced by more than 40-fold compared with that of r-As4S4. The bioavailability of e-As4S4 was up to 12.6-fold higher than that of r-As4S4, and it inhibited the proliferation of HL-60 cells much more effectively than did r-As4S4, inducing apoptosis and significantly reducing the infiltration of HL-60 cells into the bone marrow, spleen, and liver. This in turn prolonged the survival of AML mice.

Disseminated intravascular coagulation observed following treatment with gemtuzumab ozogamicin for relapsed/refractory acute promyelocytic leukemia

Gemtuzumab ozogamicin (GO) is a recombinant humanized immunoglobulin G4 anti-cluster of differentiation (CD)33 monoclonal antibody conjugated to N-acetyl-γ calicheamicin dimethylhydrazide, a naturally potent antibiotic. It has been introduced for the treatment of acute promyelocytic leukemia (APL), since large quantities of CD33 are commonly expressed on the surface of APL cells. The present study reported two cases with prominent disseminated intravascular coagulation (DIC), which was transiently observed following treatment with GO with relapsed/refractory APL. Very limited information exists regarding DIC occurring following GO, and its mechanism remains to be elucidated. In the present study, recombinant human soluble thrombomodulin was used for DIC treatment, and the patients recovered promptly. Since DIC is the most serious adverse event associated with GO treatment, elucidation of its mechanism and establishment of a treatment strategy are warranted.

Current management of newly diagnosed acute promyelocytic leukemia

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

Acute myeloid leukemia--major progress over four decades and glimpses into the future

In this Review, the progress in research and therapy of acute myeloid leukemia is detailed.

The evolution of arsenic in the treatment of acute promyelocytic leukemia and other myeloid neoplasms: Moving toward an effective oral, outpatient therapy

The therapeutic potential of arsenic derivatives has long been recognized and was recently rediscovered in modern literature. Early studies demonstrated impressive activity of this compound in patients with relapsed acute promyelocytic leukemia (APL). Over the last 2 decades, intravenous arsenic trioxide has been used successfully, both alone and in combination with other agents, for the treatment of APL and, with some success, of other myeloid neoplasms. Arsenic trioxide is currently part the standard of care for patients with APL. More recently, oral formulations of this compound have been developed and are entering clinical practice. In this review, the authors discuss the evolution of arsenic in the treatment of APL and other myeloid neoplasms.

Current standard treatment of adult acute promyelocytic leukaemia

The outcome of patients with acute promyelocytic leukaemia (APL) has dramatically improved over the last two decades, due to the introduction of combined all-trans retinoic acid (ATRA) and chemotherapy regimens and, more recently, to the advent of arsenic trioxide (ATO). ATRA and anthracycline-based chemotherapy remains a widely used strategy, providing cure rates above 80%, but it is associated with risk of severe infections and occurrence of secondary leukaemias. ATO is the most effective single agent in APL and, used alone or in combination with ATRA or ATRA and reduced-intensity chemotherapy, results in greater efficacy with considerably less haematological toxicity. The toxic profile of ATO includes frequent, but manageable, QTc prolongation and increase of liver enzymes. Two large randomized studies have shown that ATRA + ATO is superior to ATRA + chemotherapy for newly diagnosed low-risk APL resulting in 2-4 year event-free survival rates above 90% and very few relapses. According to real world data, the spectacular progress in APL outcomes reported in clinical trials has not been paralleled by a significant improvement in early death rates, this remains the most challenging issue for the final cure of the disease.

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

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

Pseudotumor Cerebri in Acute Promyelocytic Leukemia Patients on Intergroup Protocol 0129: Clinical Description and Recommendations for New Diagnostic Criteria

BACKGROUND

Multiple randomized trials have demonstrated a benefit for all-trans retinoic acid (ATRA) in patients with acute promyelocytic leukemia (APL). Pseudotumor cerebri (PTC) is an infrequently reported adverse effect of ATRA.

METHODS

We examined the incidence, clinical course, and outcomes of patients with APL treated on Intergroup Protocol 0129 (I0129) who developed PTC. This trial evaluated the role of ATRA alone during induction and/or as maintenance therapy.

RESULTS

Of the patients on trial, 240 received ATRA during induction, maintenance, or both; 8 had a clinical suspicion for PTC. Upon review of individual cases, this was felt to be "probable" in 4 patients, "possible" in 1 and "unlikely" in 3 due to lack of diagnostic criteria or presence of a more likely alternate diagnosis.

CONCLUSIONS

"Probable" PTC occurred in 1.7% of patients who received ATRA during induction and/or maintenance therapy. In agreement with previous reports, the incidence of PTC in APL patients receiving ATRA was higher in the pediatric population. Here, we discuss the method for diagnosing PTC in the setting of ATRA therapy and management strategies.

Antioxidant Intake and Antitumor Therapy: Toward Nutritional Recommendations for Optimal Results

The role of the induction of oxidative stress as the mechanism of action of many antitumor drugs is acquiring an increasing interest. In such cases, the antitumor therapy success may be conditioned by the antioxidants present in our own body, which can be synthesized de novo (endogenous) or incorporated through the diet and nutritional supplements (exogenous). In this paper, we have reviewed different aspects of antioxidants, including their classification, natural sources, importance in diet, consumption of nutritional supplements, and the impact of antioxidants on health. Moreover, we have focused especially on the study of the interaction between antioxidants and antitumor therapy, considering both radiotherapy and chemotherapy. In this regard, we found that the convenience of administration of antioxidants during cancer treatment still remains a very controversial issue. In general terms, antioxidants could promote or suppress the effectiveness of antitumor treatment and even protect healthy tissues against damage induced by oxidative stress. The effects may depend on many factors discussed in the paper. These factors should be taken into consideration in order to achieve precise nutritional recommendations for patients. The evidence at the moment suggests that the supplementation or restriction of exogenous antioxidants during cancer treatment, as appropriate, could contribute to improving its efficiency.

Molecular Monitoring as a Path to Cure Acute Promyelocytic Leukemia

Acute promyelocytic leukemia (APL) is a molecularly well-defined disease, characterized by a specific chromosomal translocation; the improvement in biologic and clinical knowledge and subsequent introduction of molecularly targeted therapies have transformed the management of APL, with survival rates now exceeding 80%. Minimal residual disease (MRD) assessment in APL is the most important tool for its treatment; the prognostic role of the molecular detection of promyelocytic leukemia retinoic acid receptor α (PML-RARα) transcript after consolidation therapy in the early identification of the following hematologic relapse is now well established and guides preemptive therapy. First experiences performed with a qualitative polymerase chain reaction (PCR) approach were replaced with more accurate real-time quantitative PCR (RQ-PCR), which guarantees a numeric quantification of MRD. The identification of arsenic trioxide (ATO) as a valid therapy not only in relapsed patients but also as an alternative to standard therapy alone or in association with all-trans-retinoic acid enlarges the setting of validation of MRD evaluation in APL patients, considering a possible different clearance of PML-RARα with innovative therapy different from the standard ones. MRD monitoring demonstrated its validity also in the setting of relapsed patients with interesting results in the autologous and allogeneic stem cell transplantation setting or with the use of other biological agents. The aim of this review is to report and discuss the actual state of the art of MRD in APL.

Arsenic trioxide and all-trans retinoic acid treatment for acute promyelocytic leukaemia in all risk groups (AML17): results of a randomised, controlled, phase 3 trial

BACKGROUND

Acute promyelocytic leukaemia is a chemotherapy-sensitive subgroup of acute myeloid leukaemia characterised by the presence of the PML-RARA fusion transcript. The present standard of care, chemotherapy and all-trans retinoic acid (ATRA), results in a high proportion of patients being cured. In this study, we compare a chemotherapy-free ATRA and arsenic trioxide treatment regimen with the standard chemotherapy-based regimen (ATRA and idarubicin) in both high-risk and low-risk patients with acute promyelocytic leukaemia.

METHODS

In the randomised, controlled, multicentre, AML17 trial, eligible patients (aged ≥16 years) with acute promyelocytic leukaemia, confirmed by the presence of the PML-RARA transcript and without significant cardiac or pulmonary comorbidities or active malignancy, and who were not pregnant or breastfeeding, were enrolled from 81 UK hospitals and randomised 1:1 to receive treatment with ATRA and arsenic trioxide or ATRA and idarubicin. ATRA was given to participants in both groups in a daily divided oral dose of 45 mg/m(2) until remission, or until day 60, and then in a 2 weeks on-2 weeks off schedule. In the ATRA and idarubicin group, idarubicin was given intravenously at 12 mg/m(2) on days 2, 4, 6, and 8 of course 1, and then at 5 mg/m(2) on days 1-4 of course 2; mitoxantrone at 10 mg/m(2) on days 1-4 of course 3, and idarubicin at 12 mg/m(2) on day 1 of the final (fourth) course. In the ATRA and arsenic trioxide group, arsenic trioxide was given intravenously at 0·3 mg/kg on days 1-5 of each course, and at 0·25 mg/kg twice weekly in weeks 2-8 of course 1 and weeks 2-4 of courses 2-5. High-risk patients (those presenting with a white blood cell count >10 × 10(9) cells per L) could receive an initial dose of the immunoconjugate gemtuzumab ozogamicin (6 mg/m(2) intravenously). Neither maintenance treatment nor CNS prophylaxis was given to patients in either group. All patients were monitored by real-time quantitative PCR. Allocation was by central computer minimisation, stratified by age, performance status, and de-novo versus secondary disease. The primary endpoint was quality of life on the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30 global health status. All analyses are by intention to treat. This trial is registered with the ISRCTN registry, number ISRCTN55675535.

FINDINGS

Between May 8, 2009, and Oct 3, 2013, 235 patients were enrolled and randomly assigned to ATRA and idarubicin (n=119) or ATRA and arsenic trioxide (n=116). Participants had a median age of 47 years (range 16-77; IQR 33-58) and included 57 high-risk patients. Quality of life did not differ significantly between the treatment groups (EORTC QLQ-C30 global functioning effect size 2·17 [95% CI -2·79 to 7·12; p=0·39]). Overall, 57 patients in the ATRA and idarubicin group and 40 patients in the ATRA and arsenic trioxide group reported grade 3-4 toxicities. After course 1 of treatment, grade 3-4 alopecia was reported in 23 (23%) of 98 patients in the ATRA and idarubicin group versus 5 (5%) of 95 in the ATRA and arsenic trioxide group, raised liver alanine transaminase in 11 (10%) of 108 versus 27 (25%) of 109, oral toxicity in 22 (19%) of 115 versus one (1%) of 109. After course 2 of treatment, grade 3-4 alopecia was reported in 25 (28%) of 89 patients in the ATRA and idarubicin group versus 2 (3%) of 77 in the ATRA and arsenic trioxide group; no other toxicities reached the 10% level. Patients in the ATRA and arsenic trioxide group had significantly less requirement for most aspects of supportive care than did those in the ATRA and idarubicin group.

INTERPRETATION

ATRA and arsenic trioxide is a feasible treatment in low-risk and high-risk patients with acute promyelocytic leukaemia, with a high cure rate and less relapse than, and survival not different to, ATRA and idarubicin, with a low incidence of liver toxicity. However, no improvement in quality of life was seen.

Identification of a novel fusion gene, IRF2BP2-RARA, in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is characterized by the fusion of retinoic acid receptor alpha (RARA) with promyelocytic leukemia (PML) or, rarely, other gene partners. This report presents a patient with APL with a novel fusion between RARA and the interferon regulatory factor 2 binding protein 2 (IRF2BP2) genes. A bone marrow examination in a 19-year-old woman who presented with ecchymoses and epistaxis showed morphologic and immunophenotypic features consistent with APL. PML oncogenic domain antibody was positive. Results of fluorescence in situ hybridization, conventional cytogenetics, reverse transcription-polymerase chain reaction (RT-PCR), and oligonucleotide microarray for PML-RARA and common APL variant translocations were negative. Next-generation RNA-sequencing analysis followed by RT-PCR and direct sequencing revealed distinct breakpoints within IRF2BP2 exon 2 and RARA intron 2. The patient received all-trans retinoic acid, arsenic, and gemtuzumab ozogamicin, and achieved complete remission. However, the disease relapsed 10 months later, 2 months after consolidation therapy. This is the first report showing involvement of IRF2BP2 in APL, and it expands the list of novel RARA partners identified in APL.

Use of arsenic trioxide in remission induction and consolidation therapy for acute promyelocytic leukaemia in the Australasian Leukaemia and Lymphoma Group (ALLG) APML4 study: a non-randomised phase 2 trial

BACKGROUND

Initial treatment of acute promyelocytic leukaemia traditionally involves tretinoin (all-trans retinoic acid) combined with anthracycline-based risk-adapted chemotherapy, with arsenic trioxide being the treatment of choice at relapse. To try to reduce the relapse rate, we combined arsenic trioxide with tretinoin and idarubicin in induction therapy, and used arsenic trioxide with tretinoin as consolidation therapy.

METHODS

Patients with previously untreated genetically confirmed acute promyelocytic leukaemia were eligible for this study. Eligibilty also required Eastern Cooperative Oncology Group performance status 0-3, age older than 1 year, normal left ventricular ejection fraction, Q-Tc interval less than 500 ms, absence of serious comorbidity, and written informed consent. Patients with genetic variants of acute promyelocytic leukaemia (fusion of genes other than PML with RARA) were ineligible. Induction comprised 45 mg/m(2) oral tretinoin in four divided doses daily on days 1-36, 6-12 mg/m(2) intravenous idarubicin on days 2, 4, 6, and 8, adjusted for age, and 0·15 mg/kg intravenous arsenic trioxide once daily on days 9-36. Supportive therapy included blood products for protocol-specified haemostatic targets, and 1 mg/kg prednisone daily as prophylaxis against differentiation syndrome. Two consolidation cycles with tretinoin and arsenic trioxide were followed by maintenance therapy with oral tretinoin, 6-mercaptopurine, and methotrexate for 2 years. The primary endpoints of the study were freedom from relapse and early death (within 36 days of treatment start) and we assessed improvement compared with the 2 year interim results. To assess durability of remission we compared the primary endpoints and disease-free and overall survival at 5 years in APML4 with the 2 year interim APML4 data and the APML3 treatment protocol that excluded arsenic trioxide. This study is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12605000070639.

FINDINGS

124 patients were enrolled between Nov 10, 2004, and Sept 23, 2009, with data cutoff of March 15, 2012. Four (3%) patients died early. After a median follow-up of 4·2 years (IQR, 3·2-5·2), the 5 year freedom from relapse was 95% (95% CI 89-98), disease-free survival was 95% (89-98), event-free survival was 90% (83-94), and overall survival was 94% (89-97). The comparison with APML3 data showed that hazard ratios were 0·23 (95% CI 0·08-0·64, p=0·002) for freedom from relapse, 0·21 (0·07-0·59, p=0·001) for disease-free survival, 0·34 (0·16-0·69, p=0·002) for event-free survival, and 0·35 (0·14-0·91, p=0·02) for overall survival.

INTERPRETATION

Incorporation of arsenic trioxide in initial therapy induction and consolidation for acute promyelocytic leukaemia reduced the risk of relapse when compared with historical controls. This improvement, together with a non-significant reduction in early deaths and absence of deaths in remission, translated into better event-free and overall survival.

FUNDING

Phebra.

Tamibarotene in patients with acute promyelocytic leukaemia relapsing after treatment with all-trans retinoic acid and arsenic trioxide

Treatment of acute promyelocytic leukaemia (APL) with arsenic trioxide (ATO) and all-trans retinoic acid (ATRA) is highly effective first-line therapy, although approximately 5-10% of patients relapse. Tamibarotene is a synthetic retinoid with activity in APL patients who relapse after chemotherapy and ATRA, but has not been studied in relapse after treatment with ATO and ATRA. We report on a phase II study of tamibarotene in adult patients with relapsed or refractory APL after treatment with ATRA and ATO (n = 14). Participants were treated with tamibarotene (6 mg/m(2) /d) during induction and for up to six cycles of consolidation. The overall response rate was 64% (n = 9), the rate of complete cytogenetic response was 43% (n = 6) and the rate of complete molecular response was 21% (n = 3). Relapse was frequent with 7 of 9 responders relapsing after a median of 4·6 months (range 1·6-26·8 months). The median event-free survival (EFS) was 3·5 months [95% confidence interval (CI) 0-8·6 months] and the median overall survival (OS) was 9·5 months (95% CI 5·9-13·1 months). These results demonstrate that tamibarotene has activity in relapsed APL after treatment with ATO and ATRA and further studies using tamibarotene as initial therapy and in combination with ATO are warranted.

Prognostic factors of patients with newly diagnosed acute promyelocytic leukemia treated with arsenic trioxide-based frontline therapy

Prognostic factors for patients with acute promyelocytic leukemia (APL) treated in the context of arsenic trioxide (ATO)-based frontline regimes have not been established clearly. We retrospectively analyzed the clinical features, immunophenotypes, Fms-like tyrosine kinase-3 internal tandem duplication (FLT3-ITD), and outcomes of 184 consecutive newly diagnosed APL patients treated by intravenous ATO-based therapy. The median age was 40 years (14-77 years). The early death rate was 4.9% (9/184 patients). With a median follow-up time of 36 months (9-74 months), the 3-year relapse-free survival (RFS) and overall survival (OS) were 93.3% and 92.2%, respectively. Interestingly, there was no meaningful association between 3-year RFS and initial white blood cell count, FLT3-ITD status, or type of PML-RARA isoforms. In multivariable analysis, the CD56 expression was the only independent risk factor in terms of RFS (hazard ratio, 4.70; P=0.005). These results suggested that ATO-based therapy may ameliorate the unfavorable influence of previously known high-risk features; moreover, CD56 expression remains to be a potentially unfavorable prognostic factor in APL patients.

Association of serum retinoic acid with hepatic steatosis and liver injury in nonalcoholic fatty liver disease

BACKGROUND

Retinoic acid (RA), an active metabolite of vitamin A (retinol), has been implicated in the regulation of lipid metabolism and hepatic steatosis in animal models. However, the relation between RA and liver histology in patients with nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) is unknown.

OBJECTIVE

This study aimed at examining the association of RA with NAFLD and NASH in Chinese subjects.

DESIGN

Serum RA concentration was determined by ELISA in 41 control subjects, 45 patients with NAFLD, and 38 patients with NASH. The associations of RA with adiposity, serum glucose, lipid profiles, and markers of liver damage were studied. Moreover, both mRNA and protein levels of retinoic X receptor α (RXRα) in the liver were analyzed in subjects with different degrees of hepatic steatosis.

RESULTS

Serum RA concentrations in patients with NAFLD (1.42 ± 0.47 ng/mL) and NASH (1.14 ± 0.26 ng/mL) were significantly lower than those in control subjects (2.70 ± 0.52 ng/mL) (P < 0.01). Furthermore, serum RA concentrations were significantly different between subjects with normal glucose tolerance and those with type 2 diabetes in control [2.87 ± 0.52 (n = 28) vs. 2.32 ± 0.44 ng/mL (n = 13)], NAFLD [1.61 ± 0.37 (n = 29) vs. 1.28 ± 0.41 ng/mL (n = 16)], and NASH [1.35 ± 0.34 (n = 24) vs. 1.07 ± 0.29 ng/mL (n = 14)] groups. In human liver tissue, RXRα mRNA expression was inversely correlated with the exacerbation of hepatic steatosis. Both serum RA concentrations and RXRα mRNA levels were inversely correlated with intrahepatic triglyceride content (r = -0.700, P < 0.001, and r = -0.611, P = 0.002, respectively). Compared with grade 0 severity, the concentration of RXRα protein was lower in more severe grades in patients with NAFLD.

CONCLUSION

These results show that circulating RA concentrations were lower in subjects with NAFLD and were associated with hepatic lipid metabolism and insulin resistance. This trial was registered at clinicaltrials.gov as NCT01940263.

New strategies in acute promyelocytic leukemia: moving to an entirely oral, chemotherapy-free upfront management approach

Incorporation of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) into the management paradigms of acute promyelocytic leukemia (APL) has markedly improved outcomes. Significant progress occurred in understanding the molecular pathogenesis of APL. ATO, in contrast with ATRA, is capable of eradicating the APL-initiating cells and can result in cure. Preclinical and clinical data confirmed the synergy of ATO and ATRA, and the ATRA-ATO combination was proved noninferior to a standard ATRA-chemotherapy regimen in patients with non-high-risk APL. Oral formulations of arsenic exhibited excellent activity in advanced clinical testing and their combinations with ATRA offer an opportunity for a completely oral, chemotherapy-free regimen for curing APL. Nonetheless, significant challenges remain. Reducing early death due to bleeding complications is an important area of unmet need. Data suggest that delays in initiation of ATRA upon suspecting APL continue to occur in the community and contribute to early mortality. Questions remain about the optimal place and schedule of arsenic in the therapeutic sequence and the role of the oral formulations. Refining the role of minimal residual disease in directing treatment decisions is important. Development of novel targeted agents to treat relapsed disease requires deeper understanding of the secondary resistance mechanisms to ATRA and ATO.

Retinoic acid and arsenic trioxide trigger degradation of mutated NPM1, resulting in apoptosis of AML cells

RA/arsenic induces proteasomal degradation of mutant NPM1, yielding AML growth arrest and apoptosis. RA/arsenic treatment restored nucleolar localization of NPM1 and significantly reduced bone marrow blasts in NPM1 mutant AML patients.

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

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

Targeting of leukemia-initiating cells in acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia (AML) with peculiar molecular, phenotypic and clinical features and unique therapeutic response to specific treatments. The disease is characterized by a single, pathognomonic molecular event, consisting of the translocation t(15;17) which gives rise to the PML/retinoic acid receptor α (RARα) hybrid protein. The development of this leukemia is mainly related to the fusion oncoprotein PML/RARα, acting as an altered RAR mediating abnormal signalling and repression of myeloid differentiation, with consequent accumulation of undifferentiated promyelocytes. The prognosis of APL has dramatically been improved with the introduction in therapy of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). The main effect of these two drugs is linked to the targeting of either RAR moiety of the PML/RARα molecule and induction of cell differentiation (ATRA) or of the PML moiety of the fusion protein and induction of leukemic cell apoptosis, including leukemic progenitors (mostly induced by ATO). These two drugs exhibited excellent synergism and determine a very high rate of durable remissions in low/intermediate-risk APLs, when administered in the absence of any chemotherapeutic drug. The strong synergism and the marked clinical efficacy of these two agents when administered together seem to be related to their capacity to induce PML/RARα degradation and complete eradication of leukemia stem cells.

Insights into the All-trans-Retinoic Acid and Arsenic Trioxide Combination Treatment for Acute Promyelocytic Leukemia: A Meta-Analysis

BACKGROUND

This study aimed to compare the curative effects of the combination therapy of all-trans-retinoic acid (ATRA) and arsenic trioxide (ATO, As₂O₃) with ATRA monotherapy on newly diagnosed acute promyelocytic leukemia (APL).

METHODS

The studies were retrieved from PubMed, EMBASE, Cochrane Library, ChinaInfo and China National Knowledge Infrastructure (CNKI) databases from the inception to June 20, 2014. Thereafter, the eligible studies were selected based on the predefined criteria, and the literature quality was assessed. The meta-analysis was conducted using Review Manager 5.2 software. The pooled effect size was relative risk (RR) and its 95% confidence interval (CI).

RESULTS

A total of 8 studies containing 480 cases were included, among which 264 were assigned to the ATRA + ATO group and the other 216 to the ATRA group. The meta-analysis showed that ATRA + ATO combination therapy significantly improved the complete remission (CR) rate (RR = 1.09, 95% CI = 1.03-1.16, p = 0.004), decreased the early mortality rate (RR = 0.42, 95% CI = 0.20-0.9, p = 0.03) and relapse rate (RR = 0.17, 95% CI = 0.07-0.42, p < 0.0001), but increased the high risk of liver dysfunction (RR = 2.43, 95% CI = 1.72-3.41, p < 0.00001), comparing with ATRA monotherapy.

CONCLUSIONS

The ATRA + ATO combination therapy may be more effective for newly diagnosed APL with a higher CR rate but lower early mortality rate and relapse rate. However, the risks of liver damage should be of concern.

Acute promyelocytic leukemia: where did we start, where are we now, and the future

Historically, acute promyelocytic leukemia (APL) was considered to be one of the most fatal forms of acute leukemia with poor outcomes before the introduction of the vitamin A derivative all-trans retinoic acid (ATRA). With considerable advances in therapy, including the introduction of ATRA initially as a single agent and then in combination with anthracyclines, and more recently by development of arsenic trioxide (ATO)-containing regimens, APL is now characterized by complete remission rates of 90% and cure rates of ∼80%, even higher among low-risk patients. Furthermore, with ATRA-ATO combinations, chemotherapy may safely be omitted in low-risk patients. The disease is now considered to be the most curable subtype of acute myeloid leukemia (AML) in adults. Nevertheless, APL remains associated with a significant incidence of early death related to the characteristic bleeding diathesis. Early death, rather than resistant disease so common in all other subtypes of AML, has emerged as the major cause of treatment failure.

The clinical activity of arsenic trioxide, ascorbic acid, ifosfamide and prednisone combination therapy in patients with relapsed and refractory multiple myeloma

This study aimed to investigate the activity of arsenic trioxide (As2O3) combined with ascorbic acid, ifosfamide, and prednisone chemotherapy in patients with repeatedly relapsed and refractory multiple myeloma (MM). Here, we retrospectively analyzed medical data of 30 MM patients showing progressive disease after receiving at least two previous lines of treatment including an immunomodulatory agent (thalidomide or lenalidomide) and a proteasome inhibitor. There were 19 men and eleven women, aged 54-73 (median 65) years, in this study. The distribution of different isotypes included immunoglobulin G(IgG) (12 patients), IgA (six patients), IgD (three), and light chain (nine patients). All the patients were Durie-Salmon stage III and had relapsed at least three times; the median cycles of prior therapies was 15 (range 10-18). The patients were treated with As2O3, ascorbic acid, and CP (ifosfamide 1 g on day 1, day 3, day 5, and day 7; prednisone 30 mg taken orally for 2 weeks). As2O3 was administered as an intravenous infusion at a dose of 10 mg/d and ascorbic acid at a dose of 2 g/d for 14 days of each 4-week cycle. The results showed that after 2 cycles of therapy, there were five patients that attained partial response, 15 had minimal response, five had no change, and five had progressive disease. The overall response rate was 66.7% (20/30 cases), 50% (10/20 cases), and 40% (2/5 cases), respectively, after 2, 4, and 6 cycles of the therapy. But there were no patients that attained complete remission. The median time of overall survival and progression-free survival were 48 (29-120) and 6 (2-8) months, respectively. The most common treatment-related adverse events included neutropenia, fatigue, anemia, thrombocytopenia, and infection that could be tolerated. The results showed that As2O3 combined with ascorbic acid, ifosfamide, and prednisone chemotherapy may be a choice treatment for repeatedly relapsed and refractory MM patients.