Maintenance therapy in AML: The past, the present and the future

FLT3-PROTACs for combating AML resistance: Analytical overview on chimeric agents developed, challenges, and future perspectives

The urgent and unmet medical demand of acute myeloid leukemia (AML) patients has driven the drug discovery process for expansion of the landscape of AML treatment. Despite the several agents developed for treatment of AML, more than 60 % of treated patients undergo relapse again after re-emission, thus, no complete cure for this complex disease has been reached yet. Targeted oncoprotein degradation is a new paradigm that can be employed to solve drug resistance, disease relapse, and treatment failure in complex diseases as AML, the most lethal hematological malignancy. AML is an aggressive blood cancer form and the most common type of acute leukemia, with bad outcomes and a very poor 5-year survival rate. FLT3 mutations occur in about 30 % of AML cases and FLT3-ITD is associated with poor prognosis of this disease. Prevalent FLT3 mutations include internal tandem duplication and point mutations (e.g., D835) in the tyrosine kinase domain, which induce FLT3 kinase activation and result in survival and proliferation of AML cells again. Currently approved FLT3 inhibitors suffer from limited clinical efficacy due to FLT3 reactivation by mutations, therefore, alternative new treatments are highly needed. Proteolysis-targeting chimera (PROTAC) is a bi-functional molecule that consists of a ligand of the protein of interest, FLT3 inhibitor in our case, that is covalently linked to an E3 ubiquitin ligase ligand. Upon FLT3-specific PROTAC binding to FLT3, the PROTAC can recruit E3 for FLT3 ubiquitination, which is subsequently subjected to proteasome-mediated degradation. In this review we tried to address the question if PROTAC technology has succeeded in tackling the disease relapse and treatment failure of AML. Next, we explored the latest FLT3-targeting PROTACs developed in the past few years such as quizartinib-based PROTACs, dovitinib-based PROTACs, gilteritinib-based PROTACs, and others. Then, we followed with a deep analysis of their advantages regarding potency improvement and overcoming AML drug resistance. Finally, we discussed the challenges facing these chimeric molecules with proposed future solutions to circumvent them.

Epigenetic alterations in AML: Deregulated functions leading to new therapeutic options

Acute myeloid leukemia (AML) results in disruption of the hematopoietic differentiation process. Crucial progress has been made, and new therapeutic strategies for AML have been developed. Induction chemotherapy, however, remains the main option for the majority of AML patients. Epigenetic dysregulation plays a central role in AML pathogenesis, supporting leukemogenesis and maintenance of leukemic stem cells. Here, we provide an overview of the intricate interplay of altered epigenetic mechanisms, including DNA methylation, histone modifications, and chromatin remodeling, in AML development. We explore the role of epigenetic regulators, such as DNMTs, HMTs, KDMs, and HDACs, in mediating gene expression patterns pushing towards leukemic cell transformation. Additionally, we discuss the impact of cytogenetic lesions on epigenomic remodeling and the potential of targeting epigenetic vulnerabilities as a therapeutic strategy. Understanding the epigenetic landscape of AML offers insights into novel therapeutic avenues, including epigenetic modifiers and particularly their use in combination therapies, to improve treatment outcomes and overcome drug resistance.

Interleukin-2 mediated associations between gut microbiota and acute myeloid leukemia: A population-based mediation Mendelian randomization study

The relationship between the gut microbiota and acute myeloid leukemia (AML) has been established, but the exact role of interleukin (IL) in mediating this relationship has remained unclear. This study aimed to utilize whether interleukins mediate the relationships between gut microbiota and AML, thereby identifying potential novel targets for future AML treatment. Mendelian randomization (MR) is a method for finding the causality of exposure and outcome. Final instrumental variables were selected based on MR assumptions, and used to judge validity of the results. Our study identified risk and protective factors for AML, and interleukin-related gut microbiota. Finally, mediation MR analyses resulted in Interleukin-2 (IL-2) mediated associations between Clostridiaceae 1, Clostridium sensu stricto 1 and AML, with IL-2 respectively explaining 13.96 % and 12.11 % of the total effect of the aforementioned gut microbiota on AML. Our results successfully identified causal effects between specific gut microbiota, AML, and interleukins, while also elucidating the mediating role of IL-2 in these associations using MR analysis. These findings provide valuable insights into potential therapeutic targets for AML treatment.

Alternative polyadenylation quantitative trait loci contribute to acute myeloid leukemia risk genes regulation

Acute myeloid leukemia (AML) is a hematopoietic malignancy with a high relapse rate and progressive drug resistance. Alternative polyadenylation (APA) contributes to post-transcriptional dysregulation, but little is known about the association between APA and AML. The APA quantitative trait locus (apaQTL) is a powerful method to investigate the relationship between APA and single nucleotide polymorphisms (SNPs). We quantified APA usage in 195 Chinese AML patients and identified 4922 cis-apaQTLs related to 1875 genes, most of which were newly reported. Cis-apaQTLs may modulate the APA selection of 115 genes through poly(A) signals. Colocalization analysis revealed that cis-apaQTLs colocalized with cis-eQTLs may regulate gene expression by affecting miRNA binding sites or RNA secondary structures. We discovered 207 cis-apaQTLs related to AML risk by comparing genotype frequency with the East Asian healthy controls from the 1000 Genomes Project. Genes with cis-apaQTLs were associated with hematological phenotypes and tumor incidence according to the PHARMGKB and MGI databases. Collectively, we profiled an atlas of cis-apaQTLs in Asian AML patients and found their association with APA selection, gene expression, AML risk, and complex traits. Cis-apaQTLs may provide insights into the regulatory mechanisms related to APA in AML occurrence, progression, and prognosis.

Azacitidine maintenance therapy for blastic plasmacytoid dendritic cell neoplasm allograft: A case report

BACKGROUND

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare, highly invasive malignant neoplasm. There is no universally accepted standard of care because of its rarity and the dearth of prospective research. It is still challenging for some patients to achieve persistent clinical remission or cure, despite the success of allogeneic hematopoietic stem cell transplantation (allo-HSCT), indicating that there is still a significant recurrence rate. We report a case of prevention of BPDCN allograft recurrence by azacitidine maintenance therapy and review the relevant literature.

CASE SUMMARY

We report a 41-year-old man with BPDCN who was admitted to hospital due to skin sclerosis for > 5 mo' duration. BPDCN was diagnosed by combined clinical assessment and laboratory examinations. Following diagnosis, the patients underwent induction consolidation chemotherapy to achieve the first complete remission, followed by bridging allo-HSCT. Post-transplantation, azacitidine (75 mg/m2 for 7 d) was administered as maintenance therapy, with repeat administration every 4-6 wk and appropriate extension of the chemotherapy cycle. After 10 cycles, the patient has been disease free for 26 mo after transplantation. Regular assessments of bone marrow morphology, minimal residual disease, full donor chimerism, Epstein-Barr virus, and cytomegalovirus all yielded normal results with no abnormalities detected.

CONCLUSION

Azacitidine may be a safe and effective maintenance treatment for BPDCN following transplantation because there were no overt adverse events during the course of treatment.

Blastic Plasmacytoid Dendritic Cell Neoplasm in Long-Term Complete Remission After Venetoclax Monotherapy

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive hematological malignancy associated with a poor prognosis and limited treatment options. Although allogeneic hematopoietic stem cell transplantation or intensive chemotherapy prolongs overall survival in patients with BPDCN, intensive chemotherapy is inappropriate for older or unfit patients. Venetoclax (VEN), an oral BCL2 inhibitor, is approved for use in patients with acute myeloid leukemia (AML). BPDCN cells require BCL2 protein and are uniformly sensitive to VEN in vivo. Moreover, patients with AML who have achieved complete remission after induction therapy are reportedly considered to receive VEN monotherapy as maintenance therapy, especially older patients. However, the efficacy of VEN monotherapy as a maintenance therapy for patients with BPDCN remains controversial. Recently, BPDCN has been classified into MYC+ and MYC- subtypes, which show clinical differences. Hence, BPDCN treatment strategies based on the MYC classification may be necessary. Here, we report a case of MYC- BPDCN in an older patient in long-term complete remission after VEN monotherapy following VEN and azacitidine induction chemotherapy.

[Clinical analysis of allogeneic hematopoietic stem cell transplantation for seven cases of acute myeloid leukemia with BCR::ABL1 fusion]

Objective: To explore the efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in acute myeloid leukemia (AML) patients with BCR::ABL1 fusion. Methods: The clinical data of seven AML patients with BCR::ABL1 fusion from November 2012 to January 2022 were retrospectively analyzed, and their survival status was followed up. Results: The median age of patients at the time of diagnosis was 35 years. Four cases (57.1%) were diagnosed with high leukocyte counts. All cases were assayed as BCR::ABL1 positive and accompanied by four types of gene mutations (NPM1, RUNX1, ASXL1, PHF6) . Seven patients received tyrosine kinase inhibitor (TKI) combined with induction chemotherapy and bridged to allo-HSCT, and six patients received maintenance therapy with TKI. Before allo-HSCT, six patients achieved complete remission, and four patients achieved complete molecular remission (CMR) . After allo-HSCT, the three remaining cases also achieved CMR. All patients were in remission post-allo-HSCT. One case died of infection, and the remaining cases survived without relapse. The 3-year cumulative overall survival rate was (80.0±17.9) %. Conclusions: TKI combined with traditional chemotherapy could achieve a high response rate in AML patients with BCR::ABL1 fusion. In addition, allo-HSCT could enhance the molecular response rate. Maintenance therapy post-HSCT with TKI could improve prognosis.

Patient and Physician Preferences for Acute Myeloid Leukemia Maintenance Treatments Following Hematopoietic Stem Cell Transplantation

Purpose

This study assessed and compared preferences for treatment attributes of maintenance therapies post-hematopoietic stem cell transplantation (HSCT) in patients with acute myeloid leukemia (AML) and in physicians who treat these patients.

Patients and Methods

Patients with AML post HSCT and physicians from the United States, United Kingdom, Canada, and Australia (physicians only) completed a web-based discrete choice experiment (DCE). The DCE used inputs identified via a targeted literature review and qualitative interviews to ascertain relevant treatment attributes and associated levels. Six treatment attributes were selected (chance of 2-year relapse-free survival, quality of life [QoL], risk of serious infections, risk of nausea, chance of achieving transfusion independence, and duration of hospitalization annually), each with three or four levels. The experimental design included 36 choice tasks that presented a pair of hypothetical treatment profiles with varying attribute levels; participants chose a preferred treatment for each choice task. Choice tasks were divided into three blocks of 12 tasks each in the patient survey and 4 blocks of 9 tasks each in the physician survey; survey participants were randomly assigned to one of the blocks. Random parameter logit regression models were used to assess the impact of stated attributes on preferences for maintenance treatment post HSCT.

Results

Surveys from 84 patients and 149 physicians were assessed. For patients, QoL was the most important attribute, followed by duration of hospitalization and chance of 2-year relapse-free survival. For physicians, chance of 2-year relapse-free survival was the most important attribute, followed by QoL and risk of serious infections.

Conclusion

Differences in how patients and physicians valued post-HSCT maintenance treatment attributes were identified. These differences suggest that patient-centered decision-making may help physicians choose maintenance treatments for patients with AML post HSCT that better meet their treatment needs and improve their treatment satisfaction.

MiR-409-3p regulates the proliferation and apoptosis of THP-1 through targeting Rab10

Acute myeloid leukemia cytogenetics and molecular subtypes are connected with microRNAs, although it is unclear how miRNAs affect AML pathogenesis. miR-409-3p expression is downregulated in bone marrows, as we have previously demonstrated in our team. Nevertheless, the tumor-suppressing activities and molecular mechanisms of miR-409-3p remain unknown. Hence, in this study, we investigate at the functional significance of miR-409-3p in the development of AML. We found that a significant decrease in miR-409-3p expression was observed in THP-1 cell. The expression of miR-409-3p was altered in THP-1 by transfecting with agomiR-409-3p and agomiR-409-3p NC. A series of experiments showed that overexpression of miR-409-3p expression significantly suppressed proliferation and increased the apoptosis of THP-1. Moreover, Rab10 was confirmed as a direct target gene of miR-409-3p and was negatively modulated by miR-409-3p. Rab10 downregulation imitated the suppressed proliferation and increased the apoptosis of THP-1. Furthermore, miR-409-3p overexpression or Rab10 knockdown obviously down-regulated the expression levels of Bcl-2, but up-regulated Bax expression. In a xenograft mouse model, miR-409-3p-overexpressed THP-1 cells resulted in much less tumor weight and size in the mice bearing the cells as compared to the mock-transfected mice. Collectively, our findings demonstrated that miR-409-3p exerted tumor suppressor gene effects in AML by directly targeting Rab10, which might provide a promising therapeutic target for AML.

Economic burden during remission and after relapse among older patients with newly diagnosed acute myeloid leukemia without hematopoietic stem cell transplant: A retrospective study using the SEER-Medicare database

Acute myeloid leukemia (AML) is associated with a substantial clinical and economic burden. This study characterized the magnitude of this burden following initial treatment with standard or less intensive therapies (hypomethylating agents [HMAs]) and throughout different treatment phases post-remission. The Surveillance, Epidemiology, and End Results (SEER) cancer registry (2007-2016) linked with Medicare beneficiary claims (2007-2015) was analyzed. Patients were ≥ 65 years old with AML who initiated chemotherapy or HMAs and achieved remission. Outcomes included baseline characteristics, treatment patterns, clinical outcomes, healthcare resource utilization (HRU), and costs (2019 United States dollar). Economic impacts were stratified by treatment phase (initial treatment, early post-remission, late post-remission, and post-relapse). Early and late post-remission were defined as treatment initiated ≤ 60 days and > 60 days following initial treatment, respectively. A subgroup analysis of patients receiving only HMAs as initial treatment was also conducted. Overall, 530 patients were included (mean age: 74.1 years; 53.6 % male). In the overall analysis, 68.1 % of patients received post-remission treatment; 31.9% had no post-remission treatment. Mean monthly per patient healthcare costs by treatment phase were $45,747 (initial treatment), $30,248 (early post-remission), $23,173 (late post-remission), and $37,736 (post-relapse), driven predominantly by inpatient visits. The HMA subgroup analysis comprised 71 patients (mean age: 78.8 years; 50.7 % male); mean monthly per patient healthcare costs were highest post-relapse. The economic burden of AML among older patients is substantial across all treatment phases. AML treatments that induce and prolong remission may reduce HRU and the economic burden of disease.

LNS8801 inhibits Acute Myeloid Leukemia by Inducing the Production of Reactive Oxygen Species and Activating the Endoplasmic Reticulum Stress Pathway

Despite recent therapeutic advances, the 5-year survival rate for adults with acute myeloid leukemia (AML) is poor and standard-of-care chemotherapy is associated with significant toxicity, highlighting the need for new therapeutic approaches. Recent work from our group and others established that the G protein-coupled estrogen receptor (GPER) is tumor suppressive in melanoma and other solid tumors. We performed a preliminary screen of human cancer cell lines from multiple malignancies and found that LNS8801, a synthetic pharmacologic agonist of GPER currently in early phase clinical trials, promoted apoptosis in human AML cells. Using human AML cell lines and primary cells, we show that LNS8801 inhibits human AML in preclinical in vitro models, while not affecting normal mononuclear cells. Although GPER is broadly expressed in normal and malignant myeloid cells, this cancer-specific LNS8801-induced inhibition appeared to be independent of GPER signaling. LNS8801 induced AML cell death primarily through a caspase-dependent apoptosis pathway. This was independent of secreted classical death receptor ligands, and instead required induction of reactive oxygen species (ROS) and activation of endoplasmic reticulum (ER) stress response pathways including IRE1α. These studies demonstrate a novel activity of LNS8801 in AML cells and show that targeting ER stress with LNS8801 may be a useful therapeutic approach for AML.

Significance

Previous work demonstrated that LNS8801 inhibits cancer via GPER activation, especially in solid tumors. Here we show that LNS8801 inhibits AML via GPER-independent mechanisms that include ROS induction and ER activation.

Azacitidine Post-Remission Therapy for Elderly Patients with AML: A Randomized Phase-3 Trial (QoLESS AZA-AMLE)

This phase-3 randomized multicenter trial evaluated the efficacy of subcutaneous azacitidine (AZA) post-remission therapy vs. best supportive care (BSC) in elderly acute myeloid leukemia (AML) patients. The primary endpoint was the difference in disease-free survival (DFS) from complete remission (CR) to relapse/death. Patients with newly diagnosed AML aged ≥61 years received two courses of induction chemotherapy ("3+7" daunorubicin and cytarabine) followed by consolidation (cytarabine). At CR, 54 patients were randomized (1:1) to receive BSC (N = 27) or AZA (N = 27) at a dose of 50 mg/m² for 7 days every 28 days and the dose increased after the 1st cycle to 75 mg/m² for a further 5 cycles, followed by cycles every 56 days for 4.5 years. At 2 years, median DFS was 6.0 (95% CI: 0.2-11.7) months for patients receiving BSC vs. 10.8 months (95% CI: 1.9-19.6, p = 0.20) months for AZA. At 5 years, DFS was 6.0 (95% CI: 0.2-11.7) months in the BSC arm vs. 10.8 (95% CI: 1.9-19.6, p = 0.23) months in the AZA arm. Significant benefit was afforded by AZA on DFS at 2 and 5 years in patients aged >68 years (HR = 0.34, 95% CI: 0.13-0.90, p = 0.030 and HR = 0.37, 95% CI: 0.15-0.93, p = 0.034, respectively). No deaths occurred prior to leukemic relapse. Neutropenia was the most frequent adverse event. There were no differences in patient-reported outcome measures between study arms. In conclusion, AZA post-remission therapy was found to provide benefit in AML patients aged >68 years.

Efficacy and safety of anlotinib as maintenance therapy after induction chemotherapy in extensive-stage small-cell lung cancer

Anlotinib has been approved as the third-line or beyond treatment regimen for patients with extensive-stage small-cell lung cancer (ES-SCLC). However, it is indistinct whether there are survival benefits of anlotinib in the maintenance therapy of ES-SCLC. Therefore, this study aims to evaluate the efficacy and safety of anlotinib monotherapy as maintenance therapy after induction chemotherapy for patients with ES-SCLC. The median progression-free survival (mPFS) was considered to be the pivotal symbol as the primary endpoint. The median overall survival (mOS) and safety were recognized as the second endpoints. Eligible patients in stable status after first-line chemotherapy would subsequently accept oral anlotinib (12 mg/d, d1-d14, every 21 days as a course). The maintenance method was continued until disease progression or unmanageable toxicity occurred. The mPFS was 7.7 months (95% CI, 7.20-8.20 months) and the mOS was 11.0 months (95% CI, 9.19-12.82 months), respectively. The most common treatment-related adverse events were hypertension ( n = 9; 64.3%), fatigue ( n = 6; 42.9%), followed by decreased appetite ( n = 5; 35.7%), nausea ( n = 5; 35.7%), weight decrease ( n = 4; 28.6%), and rash ( n = 4; 28.6%). There were no patients who required dose reduction because of severe adverse events. Anlotinib achieved prospective efficacy and manageable safety in the maintenance treatment of ES-SCLC. These above outcomes demonstrated that anlotinib was a tolerable and potent maintenance treatment option after induction chemotherapy in ES-SCLC.

Lycorine induces apoptosis of acute myeloid leukemia cells and inhibits triglyceride production via binding and targeting FABP5

Acute myeloid leukemia (AML) is the most common hematopoietic malignancy with abnormal lipid metabolism. However, currently available information on the involvement of the alterations in lipid metabolism in AML development is limited. In this study, we demonstrate that FABP5 expression facilitates AML cell viability, protects AML cells from apoptosis, and maintains triglyceride production. Our bioinformatics analysis revealed that FABP5 expression was upregulated and correlated with unfavorable overall survival of AML patients. FABP5 expression may be used to distinguish normal and AML with high accuracy. FABP5-based risk score was an independent risk factor for AML patients. AML patients with highly expressed FABP5 predicted resistance to drugs. In vitro study showed that FABP5 expression was remarkably elevated in primary AML blasts and an AML cell line. Silencing FABP5 expression attenuated AML cell viability, reduced triglyceride production and lipid droplet accumulation, and induced apoptosis. We utilized AutoDock online tool to identify lycorine as an FABP5 inhibitor by binding FABP5 at amino acid residues Ile54, Thr56, Thr63, and Arg109. Lycorine treatment downregulated the expression levels of FABP5 and its target PPARγ, impaired AML cell viability, triggered apoptosis, and reduced triglyceride production in AML cells. These results demonstrate that FABP5 is critical for AML cell survival and highlight a novel metabolic vulnerability for AML.

Landscape and clinical impact of NOTCH mutations in newly diagnosed acute myeloid leukemia

BACKGROUND

NOTCH mutations (NOTCH^mut ) are recognized as major oncogenic drivers associated with controversial clinical impact on T-cell acute lymphoblastic leukemia (T-ALL), whereas their clinical value on acute myeloid leukemia (AML) is poorly defined.

METHODS

A study involving 878 consecutive newly diagnosed patients with AML was undertaken in an institution with available clinical data to unravel the impact of NOTCH^mut on prognosis.

RESULTS

In the study, NOTCH^mut were discovered in 3.6% (32/878) of included patients with AML and composed substitution-missense, frameshift mutation, substitution-nonsense, and insertion-in frame. These mutations were more commonly associated with low platelet (29 vs 42 × 10⁹ /L, p = .024) count and coexisted with BCOR/BCORL1 (15.6% vs 3.2%, p = .001), DNMT3A (28.1% vs 12.5%, p = .021), and MPL (9.4% vs 0.8%, p = .004) mutations compared with NOTCH wild-type (NOTCH^wt ). No significant difference was observed in treatment responses between NOTCH^mut and NOTCH^wt . The presence of NOTCH^mut was associated with worse overall survival ([OS], 1 year-OS: 68.0% vs 84.2%; 3 year-OS: 48.3% vs 59.6%; p = .059) and relapse-free survival ([RFS], 1 year-RFS: 78.3% vs 85.4%; 3 year-RFS: 54.5% vs 76.9%; p = .018), especially within the European Leukemia Net 2017 intermediate-risk group. Furthermore, allogeneic hematopoietic stem cell transplantation might abrogate the dismal impact of NOTCH^mut on RFS. In multivariate analysis, NOTCH^mut were found to be an independent factor negatively influencing RFS (hazard ratio, 2.153; 95% CI, 1.166-3.975; p = .014).

CONCLUSION

This study suggests that NOTCH^mut may serve as an indicator for poor prognosis of AML.

PLAIN LANGUAGE SUMMARY

Although NOTCH mutations (NOTCH^mut ) are well studied in T-cell acute lymphoblastic leukemia (T-ALL), less is known about their incidence and prognostic implications in acute myeloid leukemia (AML). A total of 878 newly diagnosed patients with AML was retrospectively analyzed; it was found that the frequency of NOTCH^mut was relatively low but was associated with an adverse prognosis.

Chidamide-based 3-drug combination regimen reverses molecular relapse post transplantation in AML1-ETO-positive acute myeloid leukemia

Objective: We aimed to explore a new method to reverse early relapse in patients with AML1-ETO-positive acute myeloid cell transplantation. Methods: A chidamide-based 3-drug combination regimen was used in our center to treat patients with AML1-ETO-positive AML post transplantation but negative flow cytometry results. A retrospective analysis was performed of the survival rate and possible influencing factors of patients with relapse treated with this regimen in our center from January 2018 to January 2022. Results: The overall response rate was 95.8% (23/24), and the median number of treatment courses was 4 (range, 3-12 courses). The total molecular complete response (MCR) was 79.1% (19/24) after all treatments, and the molecular complete response was 37.5% (9/24) after one cycle of treatment but reached 58.3% (14/24) after four cycles; overall, the proportion of MCR increased gradually with the increase in treatment cycles. The projected 5-year overall survival rate was 73.9%. The projected 5-year leukemia-free survival rate was 64.8%, and the projected 1-year cumulative relapse rate was 35.5%. The incidence of grade II-IV graft-versus-host diseases (GVHD) was 29.2% (7/24), and that of grade III-IV GVHD was 20.8% (5/24), which could be effectively controlled by glucocorticoid therapy combined with calcineurin inhibitors The total incidence of chronic GVHD was 29.2% (7/24), and all cases were localized chronic GVHD. The total infection rate was 33.3% (8/24), mainly involving bacterial and fungal infections, and the incidence of life-threatening infections was 4.17% (1/24). The treatment-related mortality rate was 0%; and the total mortality rate was 20.8% (5/24). Nausea and vomiting, thrombocytopenia, and neutropenia were common adverse reactions, all of which were Common Terminology Criteria for Adverse Events grade 2-3 events and reversible after drug withdrawal. In terms of immunity, Th1 cell counts gradually increased, Th17 cell counts gradually decreased, and the Th1/Th17 ratio gradually increased after treatment. The CD8⁺ T lymphocyte count increased gradually, while the CD4⁺ T lymphocyte count did not change significantly. Conclusion: Our chidamide-based 3-drug combination regimen led to a high remission rate and tolerable adverse reactions in patients with AML1-ETO-positive post-transplant relapse, and most patients can achieve long-term survival with this regimen.

Treating CD33-Positive de novo Acute Myeloid Leukemia in Pediatric Patients: Focus on the Clinical Value of Gemtuzumab Ozogamicin

Although survival in pediatric acute myeloid leukemia (AML) has increased considerably over the past decades, refractory disease and relapse rates remain high. Refractory and relapsed disease are difficult to treat, with overall survival rates less than 40-50%. Preventing relapse should, therefore, be one of the highest priorities. Current conventional chemotherapy regimens are hard to intensify due to associated toxic complications, hence more effective therapies that do not increase toxicity are needed. A promising targeted agent is the CD33-directed antibody-drug conjugate gemtuzumab ozogamicin (GO). Because CD33 is highly expressed on leukemic cells in the majority of AML patients, GO can be useful for a broad range of patients. Better relapse-free survival (RFS) after therapy including GO has been reported in several pediatric clinical trials; however, ambiguity about the clinical value of GO in newly diagnosed children remains. Treatment with GO in de novo AML patients aged ≥1 month, in combination with standard chemotherapy is approved in the United States, whereas in Europe, GO is only approved for newly diagnosed patients aged ≥15 years. In this review, we aimed to clarify the clinical value of GO for treatment of newly diagnosed pediatric AML patients. Based on current literature, GO seems to have additional value, in terms of RFS, and acceptable toxicity when used in addition to chemotherapy during initial treatment. Moreover, in KMT2A-rearranged patients, the clinical value of GO was even more evident. Also, we addressed predictors of response, being CD33 expression and SNPs, PgP-1 and Annexin A5. The near finalized intent-to-file clinical trial in the MyeChild consortium investigates whether fractionated dosing has additional value for pediatric AML, which may pave the way for a broader application of GO in pediatric AML.

SOHO State of the Art Updates and Next Questions |The Role of Maintenance Therapy in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is an aggressive disease predominantly affecting the elderly population. Although, up to 65% of patients with AML achieve a complete remission with standard induction chemotherapy, the majority of patients will relapse and succumb to the disease. Although maintenance therapy is a component of standard management for various hematological malignancies, such as acute lymphoblastic leukemia (ALL), acute promyelocytic leukemia (APL) or multiple myeloma, past studies investigating the role of maintenance therapy in AML were unable to demonstrate an advantage in overall survival, and therefore, it has not been an established practice in the treatment of AML. For patients, who are not candidates for stem cell transplant, effective AML maintenance therapies are needed in order to reduce the risk of relapse. Over the past decades, many investigators have examined the role of various maintenance strategies in AML; with the intention to prolong remission and overall survival. This review will provide an overview of prior and ongoing approaches and strategies to maintenance therapy for AML.

Indirect treatment comparison of oral versus injectable azacitidine as maintenance therapy for acute myeloid leukemia

Aim: Evaluate the relative efficacy of oral versus injectable azacitidine (AZA) maintenance therapy in acute myeloid leukemia (AML) after complete remission. Materials & methods: Systematic literature review identified QUAZAR AML-001, HOVON 97 AML, UK NCRI AML16 and QoLESS-AZA-AMLE (sensitivity analysis) trials. Network meta-analysis and matching-adjusted indirect comparisons assessed survival outcomes. Results: In the network meta-analysis, combining the HOVON 97 and UK NCRI trials, oral AZA (QUAZAR) was associated with significantly improved overall survival (OS) versus injectable AZA (hazard ratio: 0.744; 95% credible interval: 0.557-0.998). After matching-adjusted indirect comparisons, to address differences in patient characteristics across trials, OS improvements were maintained with oral versus injectable AZA (hazard ratio: 0.753; credible interval: 0.563-0.998). Conclusion: In AML, maintenance therapy with oral AZA was associated with improved OS versus injectable AZA.

Harnessing the power of sphingolipids: Prospects for acute myeloid leukemia

Acute myeloid leukemia (AML) is an aggressive, heterogenous malignancy characterized by clonal expansion of bone marrow-derived myeloid progenitor cells. While our current understanding of the molecular and genomic landscape of AML has evolved dramatically and opened avenues for molecularly targeted therapeutics to improve upon standard intensive induction chemotherapy, curative treatments are elusive, particularly in older patients. Responses to current AML treatments are transient and incomplete, necessitating the development of novel treatment strategies to improve outcomes. To this end, harnessing the power of bioactive sphingolipids to treat cancer shows great promise. Sphingolipids are involved in many hallmarks of cancer of paramount importance in AML. Leukemic blast survival is influenced by cellular levels of ceramide, a bona fide pro-death molecule, and its conversion to signaling molecules such as sphingosine-1-phosphate and glycosphingolipids. Preclinical studies demonstrate the efficacy of therapeutics that target dysregulated sphingolipid metabolism as well as their combinatorial synergy with clinically-relevant therapeutics. Thus, increased understanding of sphingolipid dysregulation may be exploited to improve AML patient care and outcomes. This review summarizes the current knowledge of dysregulated sphingolipid metabolism in AML, evaluates how pro-survival sphingolipids promote AML pathogenesis, and discusses the therapeutic potential of targeting these dysregulated sphingolipid pathways.

CD44v6 chimeric antigen receptor T cell specificity towards AML with FLT3 or DNMT3A mutations

Background

Chimeric antigen receptor T‐cell (CAR‐T) therapy for acute myeloid leukaemia (AML) has thus far been elusive, in part due to target restriction and phenotypic heterogeneity of AML cells. Mutations of the FMS‐like tyrosine kinase 3 (FLT3) and DNA methyltransferase 3A (DNMT3A) genes are common driver mutations that present with a poor prognosis in AML patients. We found that AML patients with FLT3 or DNMT3A mutations had higher expression of CD44 isoform 6 (CD44v6) compared to normal specimens. Therefore, we intended to demonstrate CD44v6 could be a specific option for AML with FLT3 or DNMT3A mutations.

Methods

Internal tandem duplication (ITD) mutations of FLT3 (FLT3/ITD) knock‐in clone and DNMT3A‐R882H mutant clones of SKM‐1 cells were generated using CRISPR/Cas9 and lentiviral transfection, respectively. CD44v6 CAR‐T cells were constructed by transfecting T cells with lentivirus containing CD44v6 CAR. CD44v6 expression in AML cell lines, AML patients and healthy donors was evaluated by flow cytometry. DNA methylation assays were used to analyse the mechanisms of FLT3 and DNMT3A mutations affecting CD44v6 expression.

Results

Aberrant overexpression of CD44v6 was observed in AML cell lines with FLT3 or DNMT3A mutations compared to the wild‐type SKM‐1 or K562 cells. AML patients with FLT3 or DNMT3A mutations had higher expression of CD44v6 compared to normal specimens. Then we constructed CD44v6 CAR‐T cells and found that CD44v6 CAR‐T specifically lysed CD44v6⁺ cells, accompanied by cytokines release. No significant killing effect was observed from CD44v6^‐ AML cells and normal cells after co‐culture with CD44v6 CAR‐T. These results were also observed in vivo. Furthermore, we found that FLT3 or DNMT3A mutations induced CD44v6 overexpression by downregulating the CpG methylation of CD44 promoter.

Conclusions

Collectively, CD44v6 is a promising target of CAR‐T for AML patients with FLT3 or DNMT3A mutations.

Novel Mechanisms for Post-Transplant Maintenance Therapy in Acute Myeloid Leukemia

Allogeneic stem cell transplantation has improved survival for patients with acute myeloid leukemia (AML), especially for patients with disease at high risk of relapse. However, relapse remains the most common cause of treatment failure and death in the post-transplant period. Maintenance therapy, an extended course of treatment after achieving remission to reduce the rate of relapse, is an important component of the treatment of various hematologic malignancies; however, its role in the treatment of AML is far less well-defined. Recently, there has been significant interest in the use of novel therapeutic agents as maintenance therapy after allogeneic stem cell transplant, utilizing new mechanisms of treatment and more favorable toxicity profiles. In this review, we will discuss the mechanistic and clinical data for post-transplant maintenance therapies in AML. Then, we will review several emergent and current clinical trials which aim to incorporate novel agents into maintenance therapy regimens.

Enhanced stimulation of antigen-specific immune responses against nucleophosmin 1 mutated acute myeloid leukaemia by an anti-programmed death 1 antibody

Nucleophosmin1 (NPM1) is one of the most commonly mutated genes in AML and is often associated with a favourable prognosis. Immune responses play an increasing role in AML treatment decisions; however, the role of immune checkpoint inhibition is still not clear. To address this, we investigated specific immune responses against NPM1, and three other leukaemia-associated antigens (LAA), PRAME, Wilms' tumour 1 and RHAMM in AML patients. We investigated T cell responses against leukaemic progenitor/stem cells (LPC/LSC) using colony-forming immunoassays and flow cytometry. We examined whether immune checkpoint inhibition with the anti-programmed death 1 antibody increases the immune response against stem cell-like cells, comparing cells from NPM1 mutated and NPM1 wild-type AML patients. We found that the anti-PD-1 antibody, nivolumab, increases LAA stimulated cytotoxic T lymphocytes and the cytotoxic effect against LPC/LSC. The effect was strongest against NPM1^mut cells when the immunogenic epitope was derived from the mutated region of NPM1 and these effects were enhanced through the addition of anti-PD-1. The data suggest that patients with NPM1 mutated AML could be treated with the immune checkpoint inhibitor anti-PD-1 and that this treatment combined with NPM1-mutation specific directed immunotherapy could be even more effective for this unique group of patients.

Comprehensive Analysis of N6-Methyladenosine-Related Long Noncoding RNA Prognosis of Acute Myeloid Leukemia and Immune Cell Infiltration

N6-Methyladenosine-related long noncoding RNAs play an essential role in many cancers’ development. However, the relationship between m6A-related lncRNAs and acute myelogenous leukemia (AML) prognosis remains unclear. We systematically analyzed the association of m6A-related lncRNAs with the prognosis and tumor immune microenvironment (TME) features using the therapeutically applicable research to generate effective treatment (TARGET) database. We screened 315 lncRNAs associated with AML prognosis and identified nine key lncRNAs associated with m6A by the LASSO Cox analysis. A model was established based on these nine lncRNAs and the predictive power was explored in The Cancer Genome Atlas (TCGA) database. The areas under the ROC curve of TARGET and TCGA databases for ROC at 1, 3, and 5 years are 0.701, 0.704, and 0.696, and 0.587, 0.639, and 0.685, respectively. The nomogram and decision curve analysis (DCA) showed that the risk score was more accurate than other clinical indicators in evaluating patients’ prognoses. The clusters with a better prognosis enrich the AML pathways and immune-related pathways. We also found a close correlation between prognostic m6A-related lncRNAs and tumor immune cell infiltration. LAG3 expression at the immune checkpoint was lower in the worse prognostic cluster. In conclusion, m6A-related lncRNAs partly affected AML prognosis by remodeling the TME and affecting the anticarcinogenic ability of immune checkpoints, especially LAG3 inhibitors. The prognostic model constructed with nine key m6A-related lncRNAs can provide a method to assess the prognosis of AML patients in both adults and children.

Cost-effectiveness analysis of azacitidine maintenance therapy in patients with acute myeloid leukemia

BACKGROUND

The QUAZAR AML-001 trial (NCT01757535) showed survival benefits with the maintenance treatment of oral azacitidine(CC-486) for acute myeloid leukemia(AML) in first complete remission. We conducted a cost-effectiveness analysis to explore the costs and benefits of oral azacitidine in AML from the perspective of payers in the United States.

METHODS

We constructed a Markov model to evaluate the economic value of oral azacitidine. The model was conducted with a 10-year time horizon. The health utility scores and until prices of medical costs were acquired from previous studies and GoodRX. The transition probabilities were derived from the survival curves of the QUAZAR AML-001 study. Outcomes were measured in quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratio (ICER).

RESULTS

Compared with placebo, oral azacitidine improved 0.39 QALY, with an increasing cost of $458928.66. The ICER of oral azacitidine is $1176740.15, higher than the willingness to pay (P < 0.05). Deterministic sensitivity analysis showed that the price of oral azacitidine has a significant impact on ICERs (P < 0.05). Probability sensitivity analysis showed that the probability of cost-effectiveness for oral azacitidine is 0.

CONCLUSION

In the United States, oral azacitidine is unlikely to be cost-effective for AML patients at current prices.

CLINICAL TRIAL REGISTRATION

The trial is registered at ClinicalTrials.gov (CT.gov identifier: NCT01757535).

Targeting the NRF2/HO-1 Antioxidant Pathway in FLT3-ITD-Positive AML Enhances Therapy Efficacy

Acute myeloid leukemia (AML) is a molecularly heterogenous hematological malignancy, with one of the most common mutations being internal tandem duplication (ITD) of the juxtamembrane domain of the fms-like tyrosine kinase receptor-3 (FLT3). Despite the development of FLT3-directed tyrosine kinase inhibitors (TKI), relapse and resistance are problematic, requiring improved strategies. In both patient samples and cell lines, FLT3-ITD raises levels of reactive oxygen species (ROS) and elicits an antioxidant response which is linked to chemoresistance broadly in AML. NF-E2–related factor 2 (NRF2) is a transcription factor regulating the antioxidant response including heme oxygenase -1 (HO-1), a heat shock protein implicated in AML resistance. Here, we demonstrate that HO-1 is elevated in FLT3-ITD-bearing cells compared to FLT3-wild type (WT). Transient knockdown or inhibitor-based suppression of HO-1 enhances vulnerability to the TKI, quizartinib, in both TKI-resistant and sensitive primary AML and cell line models. NRF2 suppression (genetically or pharmacologically using brusatol) results in decreased HO-1, suggesting that TKI-resistance is dependent on an active NRF2-driven pathway. In AML-patient derived xenograft (PDX) models, brusatol, in combination with daunorubicin, reduces leukemia burden and prolongs survival. Cumulatively, these data encourage further development of brusatol and NRF2 inhibition as components of combination therapy for refractory AML.

Lysosomes in Stem Cell Quiescence: A Potential Therapeutic Target in Acute Myeloid Leukemia

Lysosomes are cellular organelles that regulate essential biological processes such as cellular homeostasis, development, and aging. They are primarily connected to the degradation/recycling of cellular macromolecules and participate in cellular trafficking, nutritional signaling, energy metabolism, and immune regulation. Therefore, lysosomes connect cellular metabolism and signaling pathways. Lysosome's involvement in the critical biological processes has rekindled clinical interest towards this organelle for treating various diseases, including cancer. Recent research advancements have demonstrated that lysosomes also regulate the maintenance and hemostasis of hematopoietic stem cells (HSCs), which play a critical role in the progression of acute myeloid leukemia (AML) and other types of cancer. Lysosomes regulate both HSCs' metabolic networks and identity transition. AML is a lethal type of blood cancer with a poor prognosis that is particularly associated with aging. Although the genetic landscape of AML has been extensively described, only a few targeted therapies have been produced, warranting the need for further research. This review summarizes the functions and importance of targeting lysosomes in AML, while highlighting the significance of lysosomes in HSCs maintenance.

Azacitidine maintenance in AML post induction and posttransplant

PURPOSE OF REVIEW

Disease relapse remains the most common cause of death among patients with acute myeloid leukemia (AML) following induction therapy and allogeneic hematopoietic cell transplant (allo-HCT). Prolonging the duration of remission with minimal nonrelapse mortality risk is an area of unmet need for AML patients.

RECENT FINDINGS

In QUAZAR AML-001 study, the oral azacitidine analogue CC-486 demonstrated an overall survival (OS) benefit when given as postremission therapy (PRT) for patients in CR1 that were ineligible to proceed to allo-HCT. Used as maintenance post allo-HCT, CC-486 has also shown safety with encouraging disease-free survival (DFS). Although a recent randomized trial of parenteral azacitidine vs. placebo post allo-HCT failed to show relapse reduction, a subsequent meta-analysis of maintenance studies posttransplant has shown good utility with this approach. Such conflicting results emphasize the need for robust study designs to identify subsets of patients that derive maximal benefits using latest tools to risk stratify relapse risk.

SUMMARY

PRT with hypomethylating agents is feasible and in select population, there is a survival advantage with CC-486. Better understanding of distinct epigenetic and immunomodulatory properties of azacitidine, holds significant promise to synergize pharmacologic and cellular drivers of disease control as PRT in future AML trials.

Oral Azacitidine (CC-486) for the Treatment of Myeloid Malignancies

Epigenetic dysregulation leads to aberrant DNA hypermethylation and is common in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). A large number of clinical trials in AML, MDS, and other hematologic malignancies have assessed hypomethylating agents (HMAs), used alone or in combination with other drugs, in the frontline, maintenance, relapsed/refractory, and peritransplant settings. Effective maintenance therapy has long been a goal for patients with AML in remission. Previous large, randomized clinical trials of maintenance with HMAs or other agents had not shown meaningful improvement in overall survival. Oral azacitidine (Oral-AZA [CC-486]) is approved in the United States, Canada, and European Union for treatment of adult patients with AML in first complete remission (CR) or CR with incomplete blood count recovery (CRi) following intensive induction chemotherapy who are ineligible for hematopoietic cell transplant. Regulatory approvals of Oral-AZA were based on outcomes from the randomized, phase III QUAZAR AML-001 trial, which showed a median overall survival advantage of 9.9 months with Oral-AZA versus placebo. Oral-AZA allows convenient extended AZA dosing for 14 days per 28-day treatment cycle, which is not feasible with injectable AZA. Focusing on AML and MDS, this report reviews the rationale for the use of orally bioavailable AZA and its potential use in all-oral combination therapy regimens; the unique pharmacokinetic and pharmacodynamic profile of Oral-AZA compared with injectable AZA; the clinical safety and efficacy of Oral-AZA maintenance therapy in patients with AML in first remission and for treatment of patients with active MDS; and ongoing Oral-AZA clinical trials.

Development and validation of a novel survival model for acute myeloid leukemia based on autophagy-related genes

Background

Acute myeloid leukemia (AML) is one of the most common blood cancers, and is characterized by impaired hematopoietic function and bone marrow (BM) failure. Under normal circumstances, autophagy may suppress tumorigenesis, however under the stressful conditions of late stage tumor growth autophagy actually protects tumor cells, so inhibiting autophagy in these cases also inhibits tumor growth and promotes tumor cell death.

Methods

AML gene expression profile data and corresponding clinical data were obtained from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, from which prognostic-related genes were screened to construct a risk score model through LASSO and univariate and multivariate Cox analyses. Then the model was verified in the TCGA cohort and GEO cohorts. In addition, we also analyzed the relationship between autophagy genes and immune infiltrating cells and therapeutic drugs.

Results

We built a model containing 10 autophagy-related genes to predict the survival of AML patients by dividing them into high- or low-risk subgroups. The high-risk subgroup was prone to a poorer prognosis in both the training TCGA-LAML cohort and the validation GSE37642 cohort. Univariate and multivariate Cox analysis revealed that the risk score of the autophagy model can be used as an independent prognostic factor. The high-risk subgroup had not only higher fractions of CD4 naïve T cell, NK cell activated, and resting mast cells but also higher expression of immune checkpoint genes CTLA4 and CD274. Last, we screened drug sensitivity between high- and low-risk subgroups.

Conclusion

The risk score model based on 10 autophagy-related genes can serve as an effective prognostic predictor for AML patients and may guide for patient stratification for immunotherapies and drugs.

Management Approach to Acute Myeloid Leukemia Leveraging the Available Resources in View of the Latest Evidence: Consensus of the Saudi Society of Blood and Marrow Transplantation

Acute myeloid leukemia (AML) is the most prevalent acute leukemia in adults and is responsible for the majority of cancer-related mortality. In Saudi Arabia, leukemia is ranked the fifth most prevalent type of malignancy in adults. Our aim is to review existing epidemiologic data in Saudi Arabia and develop consensus guidelines for management of AML.

Maintenance therapies in acute myeloid leukemia: the renaissance of an old therapeutic concept

PURPOSE OF REVIEW

Disease relapse remains the major cause of death in patients with acute myeloid leukemia (AML) and is driven by the persistence of leukemic cells following induction chemotherapy or allogeneic hematopoietic cell transplant (allo-HCT). Maintenance therapies to extend the duration of remission and to improve survival have been proposed for several years with mixed results but have experienced a renaissance recently.

RECENT FINDINGS

The oral hypomethylating agent CC-486 has been the first agent to show an overall survival (OS) benefit compared with observation in AML patients in remission following intensive chemotherapy who are not proceeding to allo-HCT. In the realm of postallo-HCT maintenance therapy, the FLT3 inhibitor sorafenib has yielded superior results in terms of OS and relapse-free survival in randomized trials compared with observation. Several open questions remain regarding patient selection, timing, duration and safety of maintenance therapies. Various targeted agents are currently tested in clinical trials and could potentially enable an even more individualized therapeutic approach.

SUMMARY

Maintenance therapies following intensive chemotherapy or allo-HCT offer a new therapeutic paradigm for an increasing number of AML patients and have been shown to result in an OS benefit in selected patients.

Long-term results of low-intensity chemotherapy with clofarabine or cladribine combined with low-dose cytarabine alternating with decitabine in older patients with newly diagnosed acute myeloid leukemia

The treatment of older patients with newly diagnosed acute myeloid leukemia (AML) using intensive chemotherapy is associated with treatment intolerance and poor survival. We evaluated two new lower-intensity regimens with clofarabine (n = 119) or cladribine (n = 129) combined with low-dose cytarabine (LDAC) alternating with decitabine. We reviewed response rates by subgroup and long term outcomes of 248 patients with newly diagnosed non core-binding-factor AML treated on two clinical trials investigating double nucleoside-analogue therapy (DNT) alternating with HMA from October, 2008 to April, 2018. Of 248 patients with a median age of 69 years (range, 49-85 years), 102 patients (41%) were ≥ 70 years, and 108 (44%) had adverse karyotype. Overall, 164 patients (66%) responded: 147 (59%) complete remission (CR) and 17 (7%) CR with incomplete count recovery (CRi). With a median follow up of 60 months, median relapse-free and overall survival (OS) were 10.8 and 12.5 months, respectively. The 2-year OS was 29%. Among patients with normal karyotype, the CR/CRi rate was 79% and the median OS 19.9 months. High response rates and OS were observed in patients with mutations in NPM1, FLT3, IDH2, and RUNX1. The 4- and 8-week mortality rates were 2% and 11%, respectively. The backbone of clofarabine or cladribine and LDAC alternating with decitabine was effective and safe for the treatment of older patients with newly diagnosed AML. Incorporating targeted therapies could extend the efficacy of this approach and provide more curative therapeutic options in this AML population.

Differential Effect of Graft-versus-Host Disease on Survival in Acute Leukemia according to Donor Type

PURPOSE

The anti-leukemic activity of allogeneic hematopoietic cell transplantation (HCT) depends on both the intensity of conditioning regimen and the strength of the graft-versus-leukemia (GVL) effect. However, it is unclear whether the sensitivity of the GVL effects differs between donor type and graft source.

EXPERIMENTAL DESIGN

We retrospectively evaluated the effect of acute and chronic graft-versus-host disease (GVHD) on transplant outcomes for adults with acute leukemia (n = 6,548) between 2007 and 2017 using a Japanese database. In all analyses, we separately evaluated three distinct cohorts based on donor type [(8/8 allele-matched sibling donor, 8/8 allele-matched unrelated donor, and unrelated single-cord blood (UCB)].

RESULTS

The multivariate analysis, in which the development of GVHD was treated as a time-dependent covariate, showed a reductive effect of grade I-II acute GVHD on treatment failure (defined as 1-leukemia-free survival; P < 0.001), overall mortality (OM; P < 0.001), relapse (P < 0.001), and non-relapse mortality (NRM; P < 0.001) in patients receiving from UCB. A reductive effect of limited chronic GVHD on treatment failure (P < 0.001), OM (P < 0.001), and NRM (P < 0.001) was also shown in patients receiving from UCB. However, these effects were not always shown in patients receiving from other donors. The beneficial effects of mild acute and chronic GVHD after UCB transplantation on treatment failure were noted relatively in subgroups of patients with acute myelogenous leukemia and a non-remission status.

CONCLUSIONS

These data suggested that the development of mild GVHD could improve survival after UCB transplantation for acute leukemia.

Bispecific T cell engagers: an emerging therapy for management of hematologic malignancies

Harnessing the power of immune cells, especially T cells, to enhance anti-tumor activities has become a promising strategy in clinical management of hematologic malignancies. The emerging bispecific antibodies (BsAbs), which recruit T cells to tumor cells, exemplified by bispecific T cell engagers (BiTEs), have facilitated the development of tumor immunotherapy. Here we discussed the advances and challenges in BiTE therapy developed for the treatment of hematologic malignancies. Blinatumomab, the first BiTE approved for the treatment of acute lymphocytic leukemia (ALL), is appreciated for its high efficacy and safety. Recent studies have focused on improving the efficacy of BiTEs by optimizing treatment regimens and refining the molecular structures of BiTEs. A considerable number of bispecific T cell-recruiting antibodies which are potentially effective in hematologic malignancies have been derived from BiTEs. The elucidation of mechanisms of BiTE action and neonatal techniques used for the construction of BsAbs can improve the treatment of hematological malignancies. This review summarized the features of bispecific T cell-recruiting antibodies for the treatment of hematologic malignancies with special focus on preclinical experiments and clinical studies.

Pathogenic and therapeutic roles of cytokines in acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogeneous disease with high mortality that accounts for the most common acute leukemia in adults. Despite all progress in the therapeutic strategies and increased rate of complete remission, many patients will eventually relapse and die from the disease. Cytokines as molecular messengers play a pivotal role in the immune system. The imbalance release of cytokine has been shown to exert a significant influence on the progression of hematopoietic malignancies including acute myeloid leukemia. This article aimed to summarize current knowledge about cytokines and their critical roles in the pathogenesis, treatment, and survival of AML patients.

HDAC8 promotes daunorubicin resistance of human acute myeloid leukemia cells via regulation of IL-6 and IL-8

The chemoresistance is one of the major challenges for acute myeloid leukemia (AML) treatment. We found that the expression of histone deacetylase 8 (HDAC8) was increased in daunorubicin (DNR) resistant AML cells, while targeted inhibition of HDAC8 by its specific siRNA or inhibitor can restore sensitivity of DNR treatment . Further, targeted inhibition of HDAC8 can suppress expression of interleukin 6 (IL-6) and IL-8. While recombinant IL-6 (rIL-6) and rIL-8 can reverse si-HDAC8-resored DNR sensitivity of AML cells. Mechanistical study revealed that HDAC8 increased the expression of p65, one of key components of NF-κB complex, to promote the expression of IL-6 and IL-8. It might be due to that HDAC8 can directly bind with the promoter of p65 to increase its transcription and expression. Collectively, our data suggested that HDAC8 promotes DNR resistance of human AML cells via regulation of IL-6 and IL-8.

AML and the art of remission maintenance

Relapse in acute myeloid leukemia (AML) is common, especially in older patients, and there is currently no standard of care maintenance therapy for those who achieve complete remission. Finding effective, tolerable maintenance therapy to prolong remission has been a goal for decades, but early clinical trials testing a variety of agents demonstrated disappointing results with no overall survival benefit. CC-486, an oral hypomethylating agent, was recently approved in the United States for maintenance treatment in patients with AML in first remission following chemotherapy. A number of ongoing studies are assessing various therapeutics in the maintenance setting, including other hypomethylating agents, targeted small-molecule inhibitors, monoclonal antibodies, and immunomodulators. New strategies are needed to identify patients most likely to benefit from maintenance therapy, including those for whom a preemptive approach reliant on monitoring of measurable residual disease would be advantageous.

Single cord blood transplantation for acute myeloid leukemia patients aged 60 years or older: a retrospective study in Japan

The availability of alternative donor sources could allow elderly patients to receive allogeneic hematopoietic cell transplantation (HCT). We retrospectively evaluated the outcomes of single-unit cord blood transplantation (CBT) in 1577 patients aged ≥60 years with acute myeloid leukemia (AML) in Japan between 2002 and 2017. In total, 990 (63%) patients were not in complete remission (CR) at the time of CBT. A myeloablative conditioning regimen (52%) and calcineurin inhibitor (CI) + mycophenolate mofetil (MMF)-based graft-versus-host disease (GVHD) prophylaxis (45%) were more commonly used. With a median follow-up for survivors of 31 months, the probability of overall survival and the cumulative incidence of leukemia-related mortality at 3 years was 31% and 29%, respectively. The cumulative incidence of non-relapse mortality (NRM) at 100 days and 3 years were 24% and 41%, respectively. The cumulative incidences of grade II-IV and grade III-IV acute GVHD at 100 days and extensive chronic GVHD at 2 years were 44%, 16%, and 14%, respectively. The cumulative incidence of neutrophil engraftment was 80% at 42 days. Results of multivariate analysis indicated that the following factors were significantly associated with higher overall mortality: performance status ≥1, hematopoietic cell transplantation-specific comorbidity index ≥3, adverse cytogenetics, extramedullary disease at diagnosis, and non-CR status at CBT. By contrast, female sex, HLA disparities ≥2, mycophenolate mofetil-based GVHD prophylaxis, and recent CBT were significantly associated with lower overall mortality. In conclusion, single CBT offers a curative option for AML patients aged ≥60 years with careful patient selection.

Single Cord Blood Transplantation Versus Unmanipulated Haploidentical Transplantation for Adults with Acute Myeloid Leukemia in Complete Remission

Allogeneic hematopoietic cell transplantation (HCT) is a potentially curative post-remission therapy for adult patients with acute myeloid leukemia (AML) in complete remission (CR). The availability of alternative human leukocyte antigen (HLA)-mismatched donors, such as cord blood and haploidentical related donors, could allow patients to receive allogeneic HCT who are without an HLA-matched sibling or unrelated donor. The use of these alternative donors is preferable for patients with advanced disease due to the rapid availability. However, comparative data for cord blood transplantation (CBT) and haploidentical related donor transplantation (haplo-HCT) are limited for adult patients with AML in CR. We sought to compare overall survival (OS); leukemia-free survival (LFS); graft-versus-host disease (GVHD)-free, relapse-free survival (GRFS); and chronic GVHD-free, relapse-free survival (CRFS) between single-unit CBT (SCBT) and haplo-HCT recipients for adult patients with intermediate- or poor-risk AML in CR. We retrospectively analyzed and compared the results of allogeneic hematopoietic cell transplantation in 1313 adult patients with intermediate- or poor-risk AML in CR who received either SCBT (n = 1102) or unmanipulated haplo-HCT (n = 211) between 2007 and 2018 in Japan. Among the whole cohort, the cumulative incidences of neutrophil and platelet recovery were significantly lower in SCBT recipients compared with those in haplo-HCT recipients (P < .001 for neutrophil, P < .001 for platelet). SCBT was significantly associated with a higher incidence of grade II to IV acute GVHD and lower incidence of extensive chronic GVHD compared to haplo-HCT (P = .013 for grades II to IV acute GVHD; P = .006 for extensive chronic GVHD). Haplo-HCT recipients developed a higher incidence of cytomegalovirus (CMV) antigenemia compared to SCBT recipients (P = .004). In the multivariate analysis, there were no significant differences for grades III or IV acute GVHD (hazard ratio [HR], 1.17; 95% confidence interval [CI], .88 to 1.57; P = .26), relapse incidence (HR, 1.09; 95% CI, .76 to 1.58; P = .61), non-relapse mortality (HR, .83; 95% CI, .58 to 1.18; P = .32), OS (HR, .92; 95% CI, .70 to 1.20; P = .56), LFS (HR, .94; 95% CI, .73 to 1.21; P = .67), GRFS (HR, 1.12; 95% CI, .90 to 1.40; P = .27), or CRFS (HR, 1.15; 95% CI, .92 to 1.44; P = .19) between the two donor types. In the propensity score matching analysis, which identified 180 patients in each cohort, there were no significant differences in transplant outcomes between the two donor types, except for delayed neutrophil (P < .001) and platelet recovery (P < .001) and a higher incidence of grades II to IV acute GVHD (P = .052) in SCBT. SCBT and unmanipulated haplo-HCT had similar survival outcomes for adult patients with AML in CR despite the lower hematopoietic recovery and higher grade II to IV acute GVHD in SCBT recipients and the higher CMV antigenemia in haplo-HCT recipients.

Phase 2 study of lenalidomide maintenance for patients with high-risk acute myeloid leukemia in remission

BACKGROUND

New drug combinations have led to significant improvements in remission rates for patients with acute myeloid leukemia (AML). However, many patients with high-risk AML who respond to their initial treatment and are not candidates for allogeneic stem cell transplantation (ASCT) will eventually relapse with poor outcomes.

METHODS

In this phase 2 trial, the efficacy of lenalidomide maintenance was evaluated in patients with high-risk AML who had achieved their first or second remission after induction chemotherapy and at least 1 consolidation cycle and who were not candidates for immediate ASCT. Lenalidomide was given orally at 10 to 20 mg daily on days 1 to 28 of a 28-day cycle for up to 24 cycles.

RESULTS

A total of 28 patients were enrolled in this study with a median age of 61 years (range, 24-87 years). The median number of cycles was 8 (range, 1-24 cycles). Ten patients (36%) completed 24 months of maintenance treatment. With a median follow-up of 22.5 months (range, 2.6-55 months), 12 patients (43%) relapsed after a median of 3 months (range, 0.7-23 months). The median duration of remission for all patients was 18.7 months (range, 0.7-55.1 months). The 2-year overall survival and relapse-free survival rates from the time of enrollment were 63% and 50%, respectively. Overall, lenalidomide was well tolerated; serious adverse events of grade 3 or 4, including rash (n = 5), thrombocytopenia (n = 4), neutropenia (n = 4), and fatigue (n = 2), were observed in 13 patients (46%).

CONCLUSIONS

Lenalidomide is a safe and feasible maintenance strategy in patients with high-risk AML who are not candidates for ASCT, and it has beneficial effects for patients with negative measurable residual disease.

Maintenance therapy in acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation

Relapse remains the main cause of treatment failure in acute myeloid leukemia (AML) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). Emerging evidence has demonstrated that AML patients might benefit from maintenance therapy post-transplantation, especially for high-risk AML patients. In this mini-review, we will summarize targeted drugs, such as hypomethylating agents, FLT3 inhibitors and isocitrate dehydrogenase inhibitors, as maintenance therapy post-transplantation in AML patients undergoing allo-HSCT.

Lysosomes in acute myeloid leukemia: potential therapeutic targets?

Lysosomes, since their discovery, have been primarily known for degrading cellular macromolecules. However, in recent studies, they have begun to emerge as crucial regulators of cell homeostasis. They are at the crossroads of catabolic and anabolic pathways and are intricately involved in cellular trafficking, nutrient signaling, energy metabolism, and immune regulation. Their involvement in such essential cellular functions has renewed clinical interest in targeting the lysosome as a novel way to treat disease, particularly cancer. Acute myeloid leukemia (AML) is an aggressive blood cancer with a low survival probability, particularly in older patients. The genomic landscape of AML has been extensively characterized but few targeted therapies (with the exception of differentiation therapy) can achieve a long-term cure. Therefore, there is an unmet need for less intensive and more tolerable therapeutic interventions. In this review, we will give an overview on the myriad of functions performed by lysosomes and their importance in malignant disease. Furthermore, we will discuss their relevance in hematopoietic cells and different ways to potentially target them in AML.

Oral Azacitidine Maintenance Therapy for Acute Myeloid Leukemia in First Remission

BACKGROUND

Although induction chemotherapy results in remission in many older patients with acute myeloid leukemia (AML), relapse is common and overall survival is poor.

METHODS

We conducted a phase 3, randomized, double-blind, placebo-controlled trial of the oral formulation of azacitidine (CC-486, a hypomethylating agent that is not bioequivalent to injectable azacitidine), as maintenance therapy in patients with AML who were in first remission after intensive chemotherapy. Patients who were 55 years of age or older, were in complete remission with or without complete blood count recovery, and were not candidates for hematopoietic stem-cell transplantation were randomly assigned to receive CC-486 (300 mg) or placebo once daily for 14 days per 28-day cycle. The primary end point was overall survival. Secondary end points included relapse-free survival and health-related quality of life.

RESULTS

A total of 472 patients underwent randomization; 238 were assigned to the CC-486 group and 234 were assigned to the placebo group. The median age was 68 years (range, 55 to 86). Median overall survival from the time of randomization was significantly longer with CC-486 than with placebo (24.7 months and 14.8 months, respectively; P<0.001). Median relapse-free survival was also significantly longer with CC-486 than with placebo (10.2 months and 4.8 months, respectively; P<0.001). Benefits of CC-486 with respect to overall and relapse-free survival were shown in most subgroups defined according to baseline characteristics. The most common adverse events in both groups were grade 1 or 2 gastrointestinal events. Common grade 3 or 4 adverse events were neutropenia (in 41% of patients in the CC-486 group and 24% of patients in the placebo group) and thrombocytopenia (in 22% and 21%, respectively). Overall health-related quality of life was preserved during CC-486 treatment.

CONCLUSIONS

CC-486 maintenance therapy was associated with significantly longer overall and relapse-free survival than placebo among older patients with AML who were in remission after chemotherapy. Side effects were mainly gastrointestinal symptoms and neutropenia. Quality-of-life measures were maintained throughout treatment. (Supported by Celgene; QUAZAR AML-001 ClinicalTrials.gov number, NCT01757535.).

Individualizing Treatment for Newly Diagnosed Acute Myeloid Leukemia

OPINION STATEMENT

There is increasing awareness that AML is a widely heterogeneous disease, not only based on clinical characteristics and demographics of the patients we treat but also based on the genomics of the disease. Wider accessibility to next-generation DNA sequencing in AML has identified recurrent genetic abnormalities that drive disease biology, define overall prognosis, and predict for response to newly developed target-specific therapies. This knowledge has allowed the field to move away from a "one-size-fits-all" approach in newly diagnosed AML, to a more thoughtful, individualized approachy based on these factors. The first steps in realizing this new approach involve developing systems to efficiently obtain and analyze patient- and disease-related factors prior to starting therapy and having available clinical trials to address each subtype.

Jujuboside B promotes the death of acute leukemia cell in a RIPK1/RIPK3/MLKL pathway-dependent manner

Initiation of necroptosis has been considered as a promising strategy for anticancer therapies, especially for eradicating apoptosis-resistant malignant cells. Jujubisode B is a natural saponins extracted from the seeds of Zizyphi Spinosi Semen, and possesses multiple pharmacological activities, including antianxiety, anti-inflammation, antiplatelet aggregation and induction of apoptosis. This study aims to explore the effect of jujuboside B on acute leukemic cells and the underlying mechanisms. Our results showed that jujuboside B inhibited leukemia cell growth in a dose-dependent manner and attenuated the clonogenic ability of U937 cells, concomitant with activation of RIPK1/RIPK3/MLKL pathway; these phenomena were evidently blocked by necroptosis inhibitor (Nec-1). With the help of Molecular Operating Environment (MOE) program, we identified that RIPK1, RIPK3 and MLKL are potential targets of jujuboside B. To the best of our knowledge, this is the first study to provide evidence that jujuboside B possesses antileukemic activity via a mechanism involving activation of RIPK1/RIPK3/MLKL pathway.

Is outcome of older people with acute myeloid leukemia improving with new therapeutic approaches and stem cell transplantation?

Introduction: The clinical outcome of older patients with acute myeloid leukemia (AML) is still poor, especially for those who are unfit to treatments aimed at altering the natural course of the disease. Hypomethylating agents (HMA) offer an important therapeutic opportunity to a consistent number of patients, but long-term results are largely unsatisfactory.Area covered: Recently, a number of new agents have been registered for AML, some of which selectively available for older patient population, with promising results in terms of response rate and survival. Furthermore, the upper age limit for allogeneic stem cell transplantation is constantly increasing, so that this procedure is offered and actually given to an increasing number of older patients with AML. A literature review was conducted of the PubMed database for articles published in English as well as for abstracts from most important and recent hematology meetings on AML in older patients.Expert opinion: Appropriate selection among different options on the basis of clinical fitness and molecular findings at diagnosis as well as at relapse would result in improvement of therapeutic results, sparing unnecessary toxicity and optimizing health systems resources.