Salvage regimens using conventional chemotherapy agents for relapsed/refractory adult AML patients: a systematic literature review

Single cell RNA sequencing improves the next generation of approaches to AML treatment: challenges and perspectives

Acute myeloid leukemia (AML) is caused by altered maturation and differentiation of myeloid blasts, as well as transcriptional/epigenetic alterations, all leading to excessive proliferation of malignant blood cells in the bone marrow. Tumor heterogeneity due to the acquisition of new somatic alterations leads to a high rate of resistance to current therapies or reduces the efficacy of hematopoietic stem cell transplantation (HSCT), thus increasing the risk of relapse and mortality. Single-cell RNA sequencing (scRNA-seq) will enable the classification of AML and guide treatment approaches by profiling patients with different facets of the same disease, stratifying risk, and identifying new potential therapeutic targets at the time of diagnosis or after treatment. ScRNA-seq allows the identification of quiescent stem-like cells, and leukemia stem cells responsible for resistance to therapeutic approaches and relapse after treatment. This method also introduces the factors and mechanisms that enhance the efficacy of the HSCT process. Generated data of the transcriptional profile of the AML could even allow the development of cancer vaccines and CAR T-cell therapies while saving valuable time and alleviating dangerous side effects of chemotherapy and HSCT in vivo. However, scRNA-seq applications face various challenges such as a large amount of data for high-dimensional analysis, technical noise, batch effects, and finding small biological patterns, which could be improved in combination with artificial intelligence models.

Venetoclax Combined With FLAG-IDA in Refractory or Relapsed Acute Myeloid Leukemia

INTRODUCTION

The prognosis of patients with refractory or relapsed AML (R/R-AML) is very limited. To (re)achieve complete remission, there has recently been increasing evidence that the combination of venetoclax (VEN) with chemotherapy is associated with improved outcomes.

PATIENTS AND METHODS

Our retrospective, single-center study of 53 R/R-AML patients with a median follow-up time of 11.0 months compared standard salvage chemotherapy (FLAG-Ida or HAM in n = 35 patients) with a combination of venetoclax (VEN) and FLAG-Ida (FLAVIDA in n = 18 patients) concerning safety and efficacy.

RESULTS

Regarding the primary endpoints, there was a statistically significant increased event free survival (EFS) in the FLAVIDA group compared to patients with standard chemotherapy based on the univariate log-rank-test and in the multivariate Cox regression analysis (HR 0.22 [95% CI 0.05, 0.97]). There were no differences between the two groups in terms of patients developing febrile neutropenia CTCAE III° and IV° or a delay in hematological recovery. In addition, a clear trend towards an improved overall response rate (78% vs. 51%) was demonstrated in the FLAVIDA group.

CONCLUSIONS

The FLAVIDA regimen represents a promising treatment alternative for R/R AML patients with a high response rate and significantly improved EFS compared to standard chemotherapy.

Design and development of a series of 4-(piperazin-1-yl)pyrimidines as irreversible menin inhibitors

The interaction between menin and MLL1 protein plays an important role in AML with MLL rearrangement and NPM1 mutation. Blocking the formation of menin-MLL complex can inhibit proliferation and induce differentiation in these cancer subtypes. In development of anticancer drugs, irreversible inhibitors are gaining spotlight as they may have better activities than the reversible analogs. Therefore, we designed and developed a novel series of covalent menin inhibitors. Among these compounds, 37 emerges as a selective and potent inhibitor of MLL fusion protein-expressing leukemic cells. The cellular study indicates 37 has a distinct mechanism of action, in both reducing menin protein levels and downregulating MEN1 transcription. This effect of 37 is not involved in proteasomal degradation, and may directly affect the synthesis of menin protein, which offers a significant advantage in addressing acquired resistance to menin inhibitors. Further study showed that compound 37 has prolonged anti-leukemic action and exhibits promising in vivo efficacy, making it a valuable probe for further menin-MLL interaction studies.

Dose-Reduced FLA-IDA in Combination with Venetoclax Is an Effective and Safe Salvage Therapy in Relapsed and Refractory Acute Myeloid Leukemia (R/R AML)

BACKGROUND

Despite the development of targeted therapies in first-line AML, complete remissions (CR) cannot be achieved in 30-40%, and relapse rates remain high. In R/R AML the intensive treatment regimen of fludarabine, cytarabine, idarubicin combined with venetoclax (FLA-VIDA) showed improved remission rates compared to FLA-IDA. In this retrospective single-center analysis, we investigated the efficacy and safety of dose-reduced FLA-IDA with and without venetoclax to minimize the risk of infectious complications and excessive myelosuppression; Methods: Between 2011 and 2023, 89 R/R AML patients were treated with dose-reduced FLA-IDA (fludarabine 30 mg/m2 day 1-4, cytarabine 2000 mg/m2 day 1-4, idarubicin 10 mg/m2 day 1 + 4). From 2019 onwards, venetoclax was added (day 1 100 mg, day 2 200 mg, day 3-14 400 mg); Results: Significantly improved response rates were observed with 60.0% vs. 38.8% CR/CRi (p = 0.0297) and 74.5% vs. 47.3% (p = 0.032) CR/CRi/MLFS for FLA-VIDA vs. FLA-IDA. Further, with FLA-VIDA significantly improved event-free survival (EFS) was observed (p = 0.026). Overall survival (OS) was similar in FLA-VIDA and FLA-IDA treated patients. The most common treatment-related toxicities were hematological adverse events, but they were comparable between groups. The time to neutrophil and platelet recovery were similar in responding patients treated with FLA-VIDA vs. FLA-IDA; Conclusions: Dose-reduced FLA-VIDA significantly improved response rates without increases in toxicity, showing promise for an improved R/R AML treatment.

A phase ib clinical trial of oral ciprofloxacin and etoposide in subjects with resistant acute myeloid leukemia

A phase 1b study was conducted to evaluate the safety and feasibility of ciprofloxacin and etoposide combination treatment in subjects with relapsed and refractory acute myeloid leukemia. Eleven subjects were enrolled in the study. Utilizing the standard '3 + 3' design, escalating ciprofloxacin doses (750 mg, 1000 mg) twice daily on D1-D10 in combination with a fixed dose (200 mg) of etoposide on D2-D8 were administered. Maximum tolerated dose was determined to be 1000 mg of ciprofloxacin in combination with 200 mg of etoposide. Serious adverse events occurred in 54.5% (n = 6) subjects and 91% (n = 10) subjects reported ≥ grade 3 toxicities. Nine subjects completed treatment, one had a dose-limiting toxicity, and one withdrew. One subject achieved complete remission with a duration of 111 days and one subject achieved morphologic leukemia-free state after cycle 1. While the combination demonstrated safety and an acceptable toxicity profile, only modest hematologic and clinical benefits were observed.This trial was registered at www.clinicaltrials.gov as #NCT02773732.

High expression of ARHGEF5 predicts unfavorable prognosis in acute myeloid leukemia

Acute myeloid leukemia (AML) is a highly heterogeneous hematological neoplasm, highlighting the need for new molecular markers to improve prognosis prediction and therapeutic strategies. While Rho guanine nucleotide exchange factor 5 (ARHGEF5) is known to be overexpressed in various cancers, its role in AML is not well understood. This study investigates the correlation between ARHGEF5 expression and AML using data from the Cancer Genome Atlas (TCGA). ARHGEF5 expression levels in AML patients and normal samples were compared using the Wilcoxon rank-sum test. The Kaplan-Meier method and Cox regression analysis (CRA) assessed the association between ARHGEF5 expression and patient survival. A prognostic nomogram was constructed using CRA, incorporating patient age and cytogenetic risk.Our findings indicate significant overexpression of ARHGEF5 in AML compared to normal samples. Elevated ARHGEF5 levels were associated with poor prognosis, particularly in patients ≤ 60 years, those with NPM1 mutations, FLT3 mutation-positive, and wild-type RAS (P < 0.05). CRA confirmed that high ARHGEF5 expression independently predicts poor prognosis. Additionally, 412 differentially expressed genes (DEGs) were identified between high and low ARHGEF5 expression groups, with 216 genes upregulated and 196 downregulated. Pathway enrichment analyses using GO and KEGG, along with protein-protein interaction network and single sample gene set enrichment analyses, revealed key pathways and immune cell associations linked to ARHGEF5. These findings suggest that ARHGEF5 overexpression could serve as a biomarker for unfavorable outcomes in AML, providing insights into the underlying mechanisms of AML onset and progression.

Clinical Outcomes and Treatment Patterns in Adults With FLT3-ITDmut+ Acute Myeloid Leukemia Undergoing Allogeneic Hemopoietic Cell Transplantation in the United States and Canada

Allogeneic hematopoietic cell transplantation (alloHCT) is used to treat patients with acute myeloid leukemia (AML) with internal tandem duplication of the FMS-like tyrosine kinase 3 gene (FLT3-ITDmut+). However, the effect of different characteristics on outcomes after transplant is not fully understood. The aim of this study was to determine the impact of patient, disease, and transplant characteristics on clinical outcomes and trends in maintenance therapy for patients with FLT3-ITDmut+ AML who underwent their first alloHCT. This was an observational cohort study of adults ≥18 years who were recipients of human leukocyte antigen identical sibling, haploidentical, 8/8 or 7/8 unrelated, or cord blood donor alloHCT in the United States and Canada between 2014 and 2019. Patient, disease, and transplant characteristics were collected from Center for International Blood & Marrow Transplant Research between 2014 and 2022. Patients enrolled in the MORPHO clinical trial (NCT02997202) were excluded. Clinical outcomes were measured from the time of alloHCT by disease status: first complete remission (CR1), second or greater complete remission (≥CR2), or relapsed/refractory (R/R). The primary endpoints of this study were overall survival (OS) and leukemia-free survival (LFS). Key secondary endpoints included relapse after alloHCT, nonrelapse mortality (NRM), time from diagnosis to complete remission, time from complete remission to alloHCT, and maintenance therapy before and after alloHCT. Univariate analyses were conducted with Gray's test and log-rank test, while multivariable analyses were conducted using Cox proportional hazards models. A total of 3147 eligible patients (CR1, n = 2389; ≥CR2, n = 340; R/R, n = 418) were included. Most patient, disease, and transplant characteristics were similar between different disease statuses. In univariate analyses, disease status of CR1 compared with ≥CR2 or R/R was significantly (P < .001) associated with improved OS and LFS, and decreased probability of relapse; NRM likely differed across cohorts after alloHCT (P = .003). In multivariable analyses, patients with a disease status of ≥CR2 and R/R compared with CR1 had significantly shorter OS (hazard ratio [HR] 95% confidence interval [CI], 1.43 [1.19 to 1.72], P = .0001, and 2.14 [1.88 to 2.44], P < .0001, respectively). Patients with a disease status of CR1 at ≤2.6 months had better LFS compared with ≥CR2 and R/R (HR [95% CI], 2.03 [1.56 to 2.63], P < .0001 and 3.98 [3.07 to 5.17], P < .0001, respectively). Patients with a ≥CR2 or R/R disease status at ≤2.6 months had an increased likelihood of relapse compared with CR1 (HR [95% CI], 2.46 [1.82 to 3.33], P < .0001 and 4.68 [3.46 to 6.34], P < .0001, respectively). Disease status was not significantly associated with NRM. We also identified several additional patient, disease, and transplant characteristics that may have been associated with inferior OS and/or LFS and greater relapse and/or NRM. Maintenance therapy usage after alloHCT increased from 2014 to 2019 primarily due to increased FLT3 inhibitor use. In this largest study to date of patients from the United States and Canada with FLT3-ITDmut+ AML, disease status of CR1 at the time of alloHCT was associated with better clinical outcomes. Additional factors were identified that may also impact clinical outcomes, and in total, have the potential to inform clinical decision-making.

Results of a phase I trial with Haploidentical mbIL-21 ex vivo expanded NK cells for patients with multiply relapsed and refractory AML

Natural killer (NK)-cells have potent anti-tumor effects, yet it remains unclear if they are effective for patients with relapsed acute myeloid leukemia (AML). In a phase I clinical trial, we treated 12 patients (median age 60 years) with refractory AML (median 5 lines of prior therapy, median bone marrow blast count of 47%) with fludarabine/cytarabine followed by 6 infusions of NK-cells expanded from haploidentical donors using K562 feeder cells expressing membrane-bound IL21 and 4-1BBL. Patients received 106-107/kg/dose. No toxicity or graft-versus-host disease (GVHD) was observed and MTD was not reached. Seven patients (58.3%) responded and achieved a complete remission (CR) with/without count recovery. Median time to best response was 48 days. Five responding patients proceeded to a haploidentical transplant from the same donor. After a median follow-up of 52 months, 1-year overall survival (OS) for the entire group was 41.7%, better for patients who responded with CR/CRi (57.14%), and for patients who responded and underwent transplantation (60%). Persistence and expansion of donor-derived NK-cells were identified in patients' blood, and serum IFNγ levels rose concurrently with NK cell infusions. A higher count-functional inhibitory KIR was associated with higher likelihood of achieving CR/CRi. In conclusion, we observed a significant response to ex vivo expanded NK-cell administration in refractory AML patients without adverse effects.

Treating acute myelogenous leukemia in patients aged 70 and above: Recommendations from the International Society of Geriatric Oncology (SIOG)

Acute myeloid leukemia (AML) treatment is challenging in older patients. There is a lack of evidence-based recommendations for older patients ≥70, a group largely underrepresented in clinical trials. With new treatment options being available in recent years, recommendations are needed for these patients. As such the International Society of Geriatric Oncology (SIOG) assembled a task force to review the evidence specific to treatment and outcomes in this population of patients ≥70 years. Six questions were selected by the expert panel in domains of (1) baseline assessment, (2) frontline therapy, (3) post-remission therapy, (4) treatment for relapse, (5) targeted therapies, and (6) patient reported outcome/function and enhancing treatment tolerance. Information from current literature was extracted, combining evidence from systematic reviews/meta-analyses, decision models, individual trials targeting these patients, and subgroup data. Accordingly, recommendations were generated using a GRADE approach upon reviewing current evidence by consensus of the whole panel. It is our firm recommendation and hope that direct evidence should be generated for patients aged ≥70 as a distinct group in high need of improvement of their survival outcomes. Such studies should integrate information from a geriatric assessment to optimize external validity and outcomes.

Phase 1 study of selinexor in combination with salvage chemotherapy in Adults with relapsed or refractory Acute myeloid leukemia

Selinexor, an oral inhibitor of the nuclear transport protein Exportin-1, shows promising single-agent activity in clinical trials of relapsed/refractory (R/R) acute myeloid leukemia (AML) and preclinical synergy with topoisomerase (topo) IIα inhibitors. We conducted a phase 1, dose-escalation study of selinexor with mitoxantrone, etoposide, and cytarabine (MEC) in 23 patients aged < 60 years with R/R AML. Due to dose-limiting hyponatremia in 2 patients on dose level 2 (selinexor 40 mg/m2), the maximum tolerated dose was 30 mg/m2. The most common grade ≥ 3 treatment-related non-hematologic toxicities were febrile neutropenia, catheter-related infections, diarrhea, hyponatremia, and sepsis. The overall response rate was 43% with 6 patients (26%) achieving complete remission (CR), 2 (9%) with CR with incomplete count recovery, and 2 (9%) with a morphologic leukemia-free state. Seven of 10 responders proceeded to allogeneic stem cell transplantation. The combination of selinexor with MEC is a feasibile treatment option for patients with R/R AML.

Midostaurin plus daunorubicin or idarubicin for young and older adults with FLT3-mutated AML: a phase 3b trial

The pivotal RATIFY study demonstrated midostaurin (50 mg twice daily) with standard chemotherapy significantly reduced mortality in adult patients (<60 years) with newly diagnosed (ND) FLT3mut acute myeloid leukemia (AML). Considering that AML often present in older patients who show poor response to chemotherapy, this open-label, multicenter phase 3b trial was designed to further assess safety and efficacy of midostaurin plus chemotherapy in induction, consolidation, and maintenance monotherapy in young (≤60 years) and older (>60 years) patients with FLT3mut ND-AML. Compared with RATIFY, this study extended midostaurin treatment from 14 days to 21 days, substituted anthracyclines (idarubicin or daunorubicin), and introduced variation in standard combination chemotherapy dosing ("7+3" or "5+2" in more fragile patients). Total 301 patients (47.2% >60 years and 82.7% with FLT3-ITDmut) of median age 59 years entered induction phase. Overall, 295 patients (98.0%) had at least 1 adverse event (AE), including 254 patients (84.4%) with grade ≥3 AE. The grade ≥3 serious AEs occurred in 134 patients. No difference was seen in AE frequency between age groups, but grade ≥3AE frequency was higher in older patients. Overall, complete remission (CR) rate including incomplete hematologic recovery (CR + CRi) (80.7% [95% confidence interval, 75.74-84.98]) was comparable between age groups (≤60 years [83.5%]; >60 to ≤70 years [82.5%]; in patients >70 years [64.1%]) and the type of anthracycline used in induction. CR + CRi rate was lower in males (76.4%) than females (84.4%). Overall, the safety and efficacy of midostaurin remains consistent with previous findings, regardless of age, sex, or induction regimen. The trial is registered at www.clinicaltrials.gov as #NCT03379727.

Q-HAM: a multicenter upfront randomized phase II trial of quizartinib and high-dose Ara-C plus mitoxantrone in relapsed/refractory AML with FLT3-ITD

BACKGROUND

About 50% of older patients with acute myeloid leukemia (AML) fail to attain complete remission (CR) following cytarabine plus anthracycline-based induction therapy. Salvage chemotherapy regimens are based on high-dose cytarabine (HiDAC), which is frequently combined with mitoxantrone (HAM regimen). However, CR rates remain low, with less than one-third of the patients achieving a CR. FLT3-ITD has consistently been identified as an unfavorable molecular marker in both relapsed and refractory (r/r)-AML. One-quarter of patients who received midostaurin are refractory to induction therapy and relapse rate at 2 years exceeds 40%. The oral second-generation bis-aryl urea tyrosine kinase inhibitor quizartinib is a very selective FLT3 inhibitor, has a high capacity for sustained FLT3 inhibition, and has an acceptable toxicity profile.

METHODS

In this multicenter, upfront randomized phase II trial, all patients receive quizartinib combined with HAM (cytarabine 3g/m2 bidaily day one to day three, mitoxantrone 10mg/m2 days two and three) during salvage therapy. Efficacy is assessed by comparison to historical controls based on the matched threshold crossing approach with achievement of CR, complete remission with incomplete hematologic recovery (CRi), or complete remission with partial recovery of peripheral blood counts (CRh) as primary endpoint. During consolidation therapy (chemotherapy and allogeneic hematopoietic cell transplantation), patients receive either prophylactic quizartinib therapy or measurable residual disease (MRD)-triggered preemptive continuation therapy with quizartinib according to up-front randomization. The matched threshold crossing approach is a novel study-design to enhance the classic single-arm trial design by including matched historical controls from previous clinical studies. It overcomes common disadvantages of single-armed and small randomized studies, since the expected outcome of the observed study population can be adjusted based on the matched controls with a comparable distribution of known prognostic and predictive factors. Furthermore, balanced treatment groups lead to stable statistical models. However, one of the limitations of our study is the inability to adjust for unobserved or unknown confounders. Addressing the primary endpoint, CR/CRi/CRh after salvage therapy, the maximal sample size of 80 patients is assessed generating a desirable power of the used adaptive design, assuming a logistic regression is performed at a one-sided significance level α=0.05, the aspired power is 0.8, and the number of matching partners per intervention patient is at least 1. After enrolling 20 patients, the trial sample size will be recalculated in an interim analysis based on a conditional power argument.

CONCLUSION

Currently, there is no commonly accepted standard for salvage chemotherapy treatment. The objective of the salvage therapy is to reduce leukemic burden, achieve the best possible remission, and perform a hemopoietic stem-cell transplantation. Thus, in patients with FLT3-ITD mutation, the comparison of quizartinib with intensive salvage therapy versus chemotherapy alone appears as a logical consequence in terms of efficacy and safety.

ETHICS AND DISSEMINATION

Ethical approval and approvals from the local and federal competent authorities were granted. Trial results will be reported via peer-reviewed journals and presented at conferences and scientific meetings.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03989713; EudraCT Number: 2018-002675-17.

Cladribine, Cytarabine, and Etoposide-Based Regimens Are Safe and Tolerable In Relapsed and Refractory Acute Myeloid Leukemia Patients

Intensive treatment regimens for relapsed/refractory (R/R) acute myeloid leukemia (AML) generally include an anthracycline, cytarabine, with or without a purine analog. In patients who cannot tolerate an anthracycline due to comorbidities, one may consider using etoposide. Given the ongoing fludarabine shortage, it has prompted the switch to other purine analogs, such as cladribine, in combination with cytarabine and etoposide in patients who may be eligible for intensive chemotherapy but not able to tolerate an anthracycline due to comorbidities or cardiotoxicity risks. Here, we present 4 patients who received a cladribine, cytarabine, and etoposide (CCE) based regimen for R/R AML. There were no significant therapy-related adverse events, dose holds, or delays. Two out of 3 evaluable patients were successfully bridged to allogeneic transplant, and one is pending another cycle of chemotherapy as a bridge to transplant. The CCE regimen offers a potential option for patients with R/R AML in need of an anthracycline-free salvage regimen during a fludarabine shortage.

French Retrospective Database Analysis of Patient Characteristics and Treatment Patterns in Patients with R/R FLT3-Mutated AML: A Registry-Based Cohort Study

INTRODUCTION

There is a dearth of evidence to document treatment of FMS-like tyrosine kinase 3 (FLT3)-mutated acute myeloid leukemia (AML) in real-world settings before the introduction of FLT3 inhibitors. A retrospective cohort study was conducted to understand treatment practices prior to the availability of FLT3 inhibitors in patients with FLT3-mutated AML from two registries in France.

METHODS

Patient data from January 1, 2009 to December 31, 2017 were collected from the Hauts-de-France and Midi-Pyrénées registries. Patients aged ≥ 18 years at diagnosis with FLT3-mutated AML were included. Demographic and disease characteristics of patients with FLT3-mutated AML and relapsed or refractory (R/R) FLT3-mutated AML were documented. Treatment regimens, overall survival (OS), and event-free survival were assessed in patients with R/R FLT3-mutated AML who did not participate in clinical trials.

RESULTS

Overall, 819 and 1244 adult patients with AML from the Midi-Pyrénées and Hauts-de-France cohorts, respectively, underwent FLT3 mutation testing; 172 (21.0%) and 263 (21.1%) patients, respectively, had a FLT3 mutation. Primary R/R status was identified in 41.3% (n = 71/172) of the Midi-Pyrénées and 34.6% (n = 91/263) of the Hauts-de-France cohorts. Before R/R AML diagnosis, 82.0% and 97.5% of patients in the Midi-Pyrénées and Hauts-de-France cohorts, respectively, achieved complete remission (CR) or CR with incomplete hematologic recovery (CRi) following induction chemotherapy; after diagnosis of R/R AML, CR/CRi rates with salvage therapy were 33.3% and 28.1%, respectively. Median OS (interquartile range) in patients receiving salvage therapy (n = 49, n = 78) was 5.2 (2.3-11.1) and 6.1 (2.5-35.2) months, in the Midi-Pyrénées and Hauts-de-France cohorts, respectively. Across both cohorts, patients with R/R FLT3-mutated AML had low rates of CR/CRi with salvage therapy and a median OS of approximately 6 months.

CONCLUSION

Before FLT3 inhibitor availability, real-world treatment patterns and outcomes in French patients with R/R FLT3-mutated AML were consistent with clinical trial data, highlighting a poor prognosis and unmet need for effective treatment.

A case of high-risk AML in a patient with advanced systemic mastocytosis

Aggressive SM + AML has limited therapeutic options. Even a strong combination of decitabine-venetoclax-midostaurin has a transient effect on AML and a mitigated effect on SM. Larger series are required to identify the best therapeutic strategy.

Ritanserin suppresses acute myeloid leukemia by inhibiting DGKα to downregulate phospholipase D and the Jak-Stat/MAPK pathway

Refractory or relapsed (R/R) AML is the most challenging form of AML to treat. Due to frequent genetic mutations, therapy alternatives are limited. Here, we identified the role of ritanserin and its target DGKα in AML. Several AML cell lines and primary patient cells were treated with ritanserin and subjected to cell proliferation, apoptosis and gene analyses with CCK-8 assay, Annexin V/PI assay and Western blotting, respectively. We also evaluated the function of the ritanserin target diacylglycerol kinase alpha (DGKα) in AML by bioinformatics. In vitro experiments have revealed that ritanserin inhibits AML progression in a dose- and time-dependent manner, and it shows an anti-AML effect in xenograft mouse models. We further demonstrated that the expression of DGKα was elevated in AML and correlated with poor survival. Mechanistically, ritanserin negatively regulates SphK1 expression through PLD signaling, also inhibiting the Jak-Stat and MAPK signaling pathways via DGKα. These findings suggest that DGKα may be an available therapeutic target and provide effective preclinical evidence of ritanserin as a promising treatment for AML.

Incidence and Risk Factors for Development of Cardiac Toxicity in Adult Patients with Newly Diagnosed Acute Myeloid Leukemia

The incidence of cardiac morbimortality in acute myeloid leukemia (AML) is not well known. We aim to estimate the cumulative incidence (CI) of cardiac events in AML patients and to identify risk factors for their occurrence. Among 571 newly diagnosed AML patients, 26 (4.6%) developed fatal cardiac events, and among 525 treated patients, 19 (3.6%) experienced fatal cardiac events (CI: 2% at 6 months; 6.7% at 9 years). Prior heart disease was associated with the development of fatal cardiac events (hazard ratio (HR) = 6.9). The CI of non-fatal cardiac events was 43.7% at 6 months and 56.9% at 9 years. Age ≥ 65 (HR = 2.2), relevant cardiac antecedents (HR = 1.4), and non-intensive chemotherapy (HR = 1.8) were associated with non-fatal cardiac events. The 9-year CI of grade 1-2 QTcF prolongation was 11.2%, grade 3 was 2.7%, and no patient had grade 4-5 events. The 9-year CI of grade 1-2 cardiac failure was 1.3%, grade 3-4 was 15%, and grade 5 was 2.1%; of grade 1-2, arrhythmia was 1.9%, grade 3-4 was 9.1%, and grade 5 was 1%. Among 285 intensive therapy patients, median overall survival decreased in those experiencing grade 3-4 cardiac events (p < 0.001). We observed a high incidence of cardiac toxicity associated with significant mortality in AML.

OLFML2A Overexpression Predicts an Unfavorable Prognosis in Patients with AML

Background

Acute myeloid leukemia (AML) is a malignant clonal disease of the myeloid hematopoietic system. Clinically, standard treatment options include conventional chemotherapy as well as hematopoietic stem cell transplantation. Among them, chemotherapy has a remission rate of 60% to 80% and nearly 50% relapse in consolidation therapy. Some patients have a poor prognosis due to the presence of unfavorable factors such as advanced age, hematologic history, poor prognosis karyotype, severe infection, and organ insufficiency, which cannot tolerate or are not suitable for standard chemotherapy regimens, and scholars have tried to find new treatment strategies to improve this situation. In the pathogenesis and treatment of leukemia, epigenetics has received attention from experts and scholars.

Objective

To investigate the relationship between OLFML2A overexpression and AML patients.

Methods

From The Cancer Genome Atlas, researchers used the data of OLFML2A gene to analyze and study the pan-cancer using R language and then divided the high and low levels of this protein into two groups to study its relationship with the clinical characteristics of the disease. The relationship between the high levels of OLFML2A and various clinical features of the disease was studied with emphasis on the relationship between the high levels of OLFML2A and various clinical features of the disease. A multidimensional Cox regression analysis was also performed to study the factors affecting patient survival. The correlation between OLFML2A expression and immune infiltration through the immune microenvironment was analyzed. The researchers then conducted a series of studies to analyze the data collected in the study. The focus was on the relationship between the high levels of OLFML2A and immune infiltration. Gene ontology analysis was also performed to study the interactions between the different genes associated with this protein.

Results

According to the pan-cancer analysis, OLFML2A was differentially expressed in different tumors. More importantly, the analysis of OLFML2A in the TCGA-AML database revealed that OLFML2A was highly expressed in AML. The researchers found that the high levels of OLFML2A were associated with different clinical features of the disease, and that the expression of the protein was different in different groups. Those patients with the high levels of OLFML2A were found to have substantially longer survival times compared to those with low-protein levels.

Conclusions

The OLFML2A gene is able to act as a molecular indicator involved in the diagnosis, prognosis, and immune process of AML. It improves the molecular biology prognostic system of AML, provides help for the selection of AML treatment options, and provides new ideas for future biologically targeted therapy of AML.

Re-induction therapy in patients with acute myeloid leukemia not in complete remission after the first course of treatment

A standard salvage regimen for patients with acute myeloid leukemia (AML) who are not in complete remission (CR) after initial induction therapy does not exist. We retrospectively investigated re-induction therapy for 151 patients with AML who did not achieve CR after the initial course between January 2014 and March 2021. The re-induction regimen did not correlate with the CR rate after the second course, whereas patients had similar 5-year overall survival (OS) and event-free survival (EFS) based on different re-induction regimens. Multivariable analysis revealed that International European Leukaemia Net (ELN) risk stratification independently predicted both OS and EFS among patients not in CR after the first course, although the re-induction regimen did not predict prognosis. Urgent salvage alloHSCT may improve the prognosis of patients with refractory AML. In summary, our study showed that the re-induction regimen did not significantly predict the prognosis of patients with AML not in CR after the first course of treatment. The development and selection of an efficient treatment algorithm for the treatment of AML remains a pressing research challenge.

Gilteritinib (XOSPATA®) in Turkey: Early Access Program Results

Background And Objectives

Gilteritinib (XOSPATA®, Astellas) is a type I oral FLT3 inhibitor, a tyrosine kinase AXL inhibitor, involved in both c-Kit and FMS-like tyrosine kinase 3 (FLT3) resistance. In the phase 3 ADMIRAL trial, gilteritinib was compared with the standard of care in (R/R) acute myeloid leukemia (AML) patients who harbored any FLT3 mutation and showed superior efficacy with regard to response and survival.

Objectives

This research aimed to investigate the real-life efficacy and safety of gilteritinib in FLT3-positive R/R AML patients who were treated as a part of an early access program held in Turkey in April 2020 (NCT03409081).

Results

The research included 17 R/R AML patients who had received gilteritinib from seven centers. The overall response rate was 100%. The most common adverse events were anemia and hypokalemia (7 patients, 41.2%). Grade 4 thrombocytopenia was observed in one patient only (5.9%), leading to permanent treatment discontinuation. Patients with peripheral edema had a 10.47 (95% CI: 1.64-66.82) times higher risk of death than those without peripheral edema (p<0.05).

Conclusion

This research showed that patients with febrile neutropenia and peripheral edema were at a high risk of death when compared to patients without febrile neutropenia and peripheral edema.

Single-cell analysis reveals the chemotherapy-induced cellular reprogramming and novel therapeutic targets in relapsed/refractory acute myeloid leukemia

Chemoresistance and relapse are the leading cause of AML-related deaths. Utilizing single-cell RNA sequencing (scRNA-seq), we dissected the cellular states of bone marrow samples from primary refractory or short-term relapsed AML patients and defined the transcriptional intratumoral heterogeneity. We found that compared to proliferating stem/progenitor-like cells (PSPs), a subpopulation of quiescent stem-like cells (QSCs) were involved in the chemoresistance and poor outcomes of AML. By performing longitudinal scRNA-seq analyses, we demonstrated that PSPs were reprogrammed to obtain a QSC-like expression pattern during chemotherapy in refractory AML patients, characterized by the upregulation of CD52 and LGALS1 expression. Flow cytometric analysis further confirmed that the preexisting CD99⁺CD49d⁺CD52⁺Galectin-1⁺ (QSCs) cells at diagnosis were associated with chemoresistance, and these cells were further enriched in the residual AML cells of refractory patients. Interaction of CD52-SIGLEC10 between QSCs and monocytes may contribute to immune evading and poor outcomes. Furthermore, we identified that LGALS1 was a promising target for chemoresistant AML, and LGALS1 inhibitor could help eliminate QSCs and enhance the chemotherapy in patient-derived primary AML cells, cell lines, and AML xenograft models. Our results will facilitate a better understanding of the AML chemoresistance mechanism and the development of novel therapeutic strategies for relapsed/refractory AML patients.

Phase I study of alvocidib plus cytarabine/mitoxantrone or cytarabine/daunorubicin for acute myeloid leukemia in Japan

Therapeutic improvements are needed for patients with acute myeloid leukemia (AML), particularly those who have relapsed or who have treatment-refractory (R/R) AML or newly diagnosed patients with poor prognostic factors. Alvocidib (DSP-2033), a potent cyclin-dependent kinase 9 inhibitor, has previously demonstrated promising clinical activity for the treatment of AML. In this multicenter, open-label, uncontrolled, 3 + 3 phase I study, we investigated the safety and tolerability of alvocidib administered in combination with either cytarabine and mitoxantrone (ACM) for R/R AML or cytarabine/daunorubicin (A + 7 + 3) for newly diagnosed AML. Alvocidib was administered to all patients as a 30-min intravenous (i.v.) bolus (30 mg/m² /d), followed by a continuous i.v. infusion over 4 h on days 1-3 (60 mg/m² /d). A total of 10 patients were enrolled: six received ACM (at two dose levels of cytarabine and mitoxantrone) and four received A + 7 + 3. Alvocidib was tolerated and no dose-limiting toxicities were observed. All patients experienced adverse events, of which diarrhea was the most frequent (100%); hematologic events were also common. Alvocidib concentration peaked at the end of dosing (4.5 h after start of administration), plasma accumulation after repeated dosing was minimal and urinary excretion was negligible. The rate of complete remission/complete remission with incomplete hematologic recovery was 66.7% with the ACM regimen in R/R AML, including four complete remission (median duration 13.6 months), and 75% (three complete remission) with the A + 7 + 3 regimen. Further development of alvocidib in hematologic malignancies is warranted. The trial is registered with Clinicaltrials.gov, NCT03563560.

Outcome of salvage intra-arterial chemotherapy for recurrent retinoblastoma

PURPOSE

To examine the outcome of salvage intra-arterial chemotherapy (IAC) for patients with recurrent retinoblastoma after the initial course of IAC and determine the factors influencing clinical outcome.

METHODS

A total of 73 eyes of 71 patients with recurrent retinoblastoma undergoing salvage IAC after initial successfully IAC between May 2014 and May 2019 were retrospectively reviewed for clinical outcomes. Ocular survival and progression-free survival were used to examine the efficacy of salvage IAC. The factors influencing clinical outcomes were determined using univariate and multivariate analyses.

RESULTS

The salvage IAC was delivered at mean 9.4 months (median 7, range 2.1-38.3 months) following the last cycle of initial IAC. 86.5% (64/73) eyes relapsed 16 months after the initial IAC. After the salvage IAC, 57 eyes (78.1%) were salvaged, and no further-line therapies were required for 36 eyes (49.3%). The 2-year Kaplan-Meier ocular survival and progression-free survival estimates after salvage IAC were 66.4% (95% CI, 31.5-42.1%) and 38.2% (95% CI, 17.8-28.8%), respectively. Univariate and multivariate analyses showed that the ocular survival and progression-free survival after salvage IAC were significantly associated with the history of vitreous seeds (p = 0.02 and p = 0.03, respectively).

CONCLUSION

Salvage IAC is effective for the management of recurrent retinoblastoma after the initial successful IAC. Eyes with a history of vitreous seeds in the course of the disease are more likely to relapse and with worse ocular survival. A close follow-up strategy is imperative to treat the recurrent tumour after salvage IAC.

Updates on the Management of Acute Myeloid Leukemia

Acute myeloid leukemia is a heterogeneous disease defined by a large spectrum of genetic aberrations that are potential therapeutic targets. New targeted therapies have changed the landscape for a disease with poor outcomes. They are more effective than standard chemotherapy with a good safety profile. For "fit patients" in first-line, the combination of gemtuzumab ozogamicin or midostaurin with intensive chemotherapy or Vyxeos is now considered the "standard of care" for selected patients. On the other hand, for "unfit patients", azacitidine-venetoclax has been consolidated as a frontline treatment, while other combinations with magrolimab or ivosidenib are in development. Nevertheless, global survival results, especially in relapsed or refractory patients, remain unfavorable. New immunotherapies or targeted therapies, such as Menin inhibitors or sabatolimab, represent an opportunity in this situation. Future directions will probably come from combinations of different targeted therapies ("triplets") and maintenance strategies guided by measurable residual disease.

[Variables associated with hematological remission and survival in patients with acute myeloid leukemia after induction failure and relapse]

Objective: This study aimed to explore variables associated with remission rate and survival in patients with acute myeloid leukemia (AML) after induction failure and relapse. Methods: Data of 373 consecutive patients with AML were analyzed after induction failure and relapse. Binary logistics and the Cox model regression were used to identify variables associated with remission rate and outcomes. Results: In patients with AML after induction failure and relapse, the total CR+CRi rates were 50.6% and 40.3%, respectively; among those who achieved CR/CRi, the 3-year RFS rates were 34.4% and 30.4%, respectively, and the 3-year overall survival rates were 40.1% and 31.6%, respectively. In the multivariate analyses, using CLAG or FLAG regimen as a re-induction chemotherapy regimen, age <39 years and SWOG low-risk were significantly associated with higher remission rates in patients with induction failure. Male, secondary AML, SWOG high-risk, the interval from the first remission to relapse within 12 months, and bone marrow blasts ≥20% at the time of relapse were significantly associated with lower remission rates in relapsed patients. Transplantation was significantly associated with prolonged relapse-free survival and overall survival in patients achieving hematologic remission; the SWOG low-risk group was significantly associated with longer overall survival in those with induction failure; and achieving CR (not CRi) or having female gender was associated with longer RFS or overall survival in relapsed patients. Conclusion: Reinduction chemotherapy regimen, age, gender, SWOG risk, secondary AML, the interval from the first remission to relapse, and bone marrow blast percentage at the time of relapse were significantly associated with remission rates in the patients with AML after induction failure and relapse. Transplantation, SWOG low-risk, achieving CR, or female gender were associated with longer survivals in those achieving remission.

Homoharringtonine combined with cladribine and aclarubicin (HCA) in acute myeloid leukemia: A new regimen of conventional drugs and its mechanism

Objective

The prognosis of children with refractory acute myeloid leukemia (AML) is poor. Complete remission (CR) is not always achieved with current salvage chemotherapy regimens before transplantation, and some patients have no chance of transplantation. Here, we aimed to describe a new regimen of conventional chemotherapy drugs (homoharringtonine, cladribine , and aclarubicin (HCA)) for refractory AML and its mechanism in vitro.

Methods

We retrospectively collected the clinical data of 5 children with primary refractory AML using HCA as reinduction chemotherapy, and CR rates, adverse reactions, and disease-free survival (DFS) were analyzed. The effects of homoharringtonine, cladribine, and aclarubicin alone or in combination on the proliferation of HL60 and THP1 cells were analyzed by CCK-8 assay. Furthermore, CCK-8 was used to determine the effects of HCA, alone or in combination with apoptosis inhibitors, necroptosis inhibitors, ferroptosis inhibitors, or autophagy inhibitors, on the proliferation of HL60 and THP1 cells and to screen for possible HCA-mediated death pathways in AML cells. The pathway of HCA-mediated AML cell death was further verified by Hoechst/PI staining, flow cytometry, and Western blotting.

Results

After 2 cycles of conventional chemotherapy, none of the 5 children with AML achieved CR and were then treated with the HCA regimen for two cycles, 4 of 5 achieved CR, and another child achieved CR with incomplete hematological recovery (CRi). After CR, 3 children underwent hematopoietic stem cell transplantation (HSCT), and only 2 of them received consolidation therapy. As of the last follow-up, all 5 patients had been in DFS for a range of 23 to 28 months. The inhibition rate of homoharringtonine, cladribine, and aclarubicin in combination on HL60 and THP1 cells was significantly greater than that of a single drug or a combination of two drugs. We found that inhibitors of apoptosis and necroptosis were able to inhibit HCA-mediated cell death but not ferroptosis or autophagy inhibitors. Compared with the control group, the number of apoptotic cells in the HCA group was significantly increased and could be reduced by an apoptosis inhibitor. Western blot results showed that PARP, caspase-3, and caspase-8 proteins were activated and cleaved in the HCA group, the expression of Bax was upregulated and that of Bcl-2 was downregulated. The expression of apoptosis-related proteins could be reversed by apoptosis inhibition. Compared with the control group, the expression levels of the necroptosis-related proteins RIP1, RIP3, and MLKL were downregulated in the HCA group but were not phosphorylated. The necroptosis inhibitor increased the expression of RIP1 but caused no significant changes in RIP3 and MLKL, and none were phosphorylated.

Conclusions

HCA, as a new regimen of conventional drugs, was a safe and efficacious reinduction salvage strategy in children with refractory AML before HSCT. HCA exhibits the synergistic growth inhibition of AML cells and induces cell death mainly through apoptosis.

Acute cardiotoxicity after initiation of the novel tyrosine kinase inhibitor gilteritinib for acute myeloid leukemia

BACKGROUND

Gilteritinib is a novel FMS-like tyrosine kinase 3 inhibitor recently approved by the United States Food and Drug Administration in 2018 for relapsed or refractory acute myeloid leukemia. However, gilteritinib may be associated with underrecognized cardiotoxicities.

CASE PRESENTATION

This case describes a patient with a history significant for hyperlipidemia who was diagnosed with relapsed acute myeloid leukemia. After four doses of gilteritinib monotherapy, she abruptly developed acute systolic heart failure with global hypokinesis and septal wall motion abnormalities. Two days after discontinuation, cardiac magnetic resonance imaging showed partial recovery of her left ventricular ejection fraction as well as myocardial edema and non-ischemic fibrosis suggestive of inflammatory cardiomyopathy. She underwent intravenous diuresis and eventually started guideline-directed heart failure therapy. Follow-up cardiac magnetic resonance imaging five months later showed improved ejection fraction with mild non-ischemic fibrosis and resolution of myocardial edema and inflammation. She later received an allogeneic stem cell transplant from a matched unrelated donor.

CONCLUSIONS

Gilteritinib may be associated with early cardiotoxicities, including non-ischemic cardiomyopathy and myocarditis. Cardiac magnetic resonance imaging can be an important modality to help differentiate or diagnose early cardiotoxicities associated with novel targeted therapies.

Outcome of patients with relapsed or refractory acute myeloid leukemia treated with Mito-FLAG salvage chemotherapy

PURPOSE

Curative intended treatment is challenging in patients with relapsed or refractory acute myeloid leukemia (r/r AML) and associated with a dismal prognosis for long-term survival. Despite novel treatment options, the majority of patients are treated with chemotherapy-based regimens. Although widely used, little data exist on the combination of fludarabine, cytarabine, granulocyte colony stimulating factor (FLAG) and mitoxantrone as salvage strategy for r/r AML.

MATERIALS AND METHODS

Sixty-six patients receiving Mito-FLAG for r/r AML treated at a German tertiary care center between 2009 and 2019 were analyzed with regard to response rates, survival and safety profile.

RESULTS

Overall response rate was 75.8% with 56.1% of patients achieving complete remission (CR) and 19.7% partial remission (PR). After a median follow-up of 54 months, median overall survival (OS) was 13 months. Patients transitioned to allogeneic hematopoietic stem cell transplantation (alloHSCT) (75.8%) showed a significant improvement in OS with a median OS of 17 (95% CI 8.5-25.4) months vs 3 (95% CI 1.7-4.3) months (p < 0.001). 30- and 60-day mortality rates for all patients after the initial cycle of Mito-FLAG were 4.5% and 7.6%, respectively.

CONCLUSION

The Mito-FLAG salvage protocol represents an effective and feasible treatment regimen for r/r AML. Importantly, a high rate of transition to successful alloHSCT with the aim of long-term disease-free survival has been shown.

Allogeneic hematopoietic stem cell transplantation improves long-term outcome for relapsed AML patients across all ages: results from two East German Study Group Hematology and Oncology (OSHO) trials

Relapse of acute leukemia is a frequent complication with uncertain outcome and poorly defined risk factors. From 1621 patients entered into two prospective clinical trials (AML02; n = 740 and AML04; n = 881), 74.2% reached complete remission (CR) 1 after induction(s) and 59 patients after additional induction ± hematopoietic cell transplantation (HCT). Of the non-refractory patients, 48.4% with a median age of 63 (range 17-85) years relapsed. Relapses occurred within 6 months after CR in 46.5%, between 7 and 18 months in 38.7%, and after 18 months in 14.8% of patients. Relapse treatment resulted in CR2 in 39% of patients depending upon age (54.5% of ≤ 60 and 28.6% of > 60 years), duration of CR1, and treatment of relapse. Overall survival (OS) was 10.9 (7.4-16.2) %, but OS after HCT ± intensive chemotherapy (ICT) was 39.3% (31.8-48.6) at 5 years and not different in younger and older patients. Donor lymphocyte infusion ± chemotherapy and ICT alone resulted only in OS of 15.4% and of 5%, respectively. Independent favorable factors for OS were long CR1 duration, and HCT, while non-monosomal disease was beneficial for OS in elderly patients. Leukemia-free survival [LFS; 24.9 (19.5-31.7) % at 10 years] was affected by similar risk factors. In a competing risk model, the relapse incidence at 5 years was 53.5 ± 3.5% and the non-relapse mortality rate 21.7 ± 2.9%. Lower relapse incidence was observed in patents with HCT, long CR1 duration, and female gender. Risk factors for non-relapse mortality were HCT in younger and type of AML in elderly patients. In conclusion, allogeneic HCT ± IC improved the results in relapsed AML in younger and elderly patients. Increasing CR2 rates and HCT frequency will be the challenge for the next years. Relapse of the disease remains the major problem.

Recent advances of targeted therapy in relapsed/refractory acute myeloid leukemia

Despite advances in the understanding of disease pathobiology, treatment for relapsed or refractory acute myeloid leukemia (R/R AML) remains challenging. The prognosis of R/R AML remains extremely poor despite chemotherapy and bone marrow transplants. Discoveries on recurrent and novel genetic mutations, such as FLT3-ITD and IDH1/IDH2, critical signaling pathways, and unique molecular markers expressed on the surface of leukemic cells have been under investigation for the management of R/R AML. Other than monoclonal antibodies, diabodies, and triabodies are new targeted therapies developed in recent years and will be the new direction of immunotherapy. Targeted agents combined intensive regimens can be viable options for salvage therapy and as bridges to allogeneic transplant. Future directions will focus on novel, efficient and targeted combinations, low-toxicity maintenance, and individualized precision strategies. Here, we review the major recent advances of targeted therapies in the treatment of R/R AML.

Evolving patterns of care and outcomes in relapsed/refractory FLT3 mutated acute myeloid leukemia adult patients

We have analyzed treatment patterns and outcomes of relapsed/refractory(R/R) FLT3mut AML adult patients registered in our institutional data base between 1998 and 2018. Overall, 147 patients were evaluable: 34 from 1998 to 2009, 113 from 2010 to 2018. Salvage treatments were intensive chemotherapy (n = 25, 74%), and supportive care (n = 9, 26%) in the 1998-2009 period, and intensive chemotherapy (n = 63, 56%), hypomethylating agent (n = 7, 6%), low-dose cytarabine-based (n = 8, 7%), clinical trial (n = 16, 14%) and supportive care (n = 19, 17%) in the 2010-2018 period. Complete remission (CR) or with incomplete recovery (CRi) rate was 44%, 49% among patients treated intensively (vs 30% with non-intensive p = 0.005). Median overall survival since first R/R was 5.8 months, and 16.3 months in subjects receiving an allo-HSCT in CR/CRi after first salvage (vs 3.8 in the remaining patients p < 0.0001). Clinical outcomes of R/R FLT3mut AML remain unsatisfactory. Inclusion in clinical trials and expanding options could lead to improved outcomes.

RNAi prodrugs decrease elevated mRNA levels of Polo-like kinase 1 in ex vivo cultured primary cells from pediatric acute myeloid leukemia patients

Polo-like kinase 1 (Plk1) is an important regulator of the cell cycle and it is frequently overexpressed in cancer cells. Several small molecule inhibitors have been developed to target Plk1 and some of them have reached clinical trials in adults with acute myeloid leukemia (AML). Pediatric AML patients have a poor prognosis and survivors suffer from long-term side effects. As adult AML cells have an elevated expression of Plk1, AML is a disease candidate for Plk1 inhibition. However, the relative success of clinical trials have been hampered by adverse reactions. Herein, PLK1-targeting RNA interference (RNAi) prodrugs that enter cells without a transfection reagent are used to target PLK1 selectively in primary cells from pediatric AML patients. We show that PLK1 and PLK4 mRNA expression are significantly higher in pediatric AML patients when compared to healthy donors and that PLK1 is downregulated by on average 50% using RNAi prodrugs without a significant effect on other PLK family members. In addition, the RNAi prodrug-induced decrease in PLK1 can be used to potentiate the effect of cytarabine. In summary, PLK1-targeting RNAi prodrugs can decrease the elevated levels of PLK1 in primary cells from pediatric AML patients and sensitize pediatric AML cells to chemotherapeutics.

A phase I trial of selinexor plus FLAG-Ida for the treatment of refractory/relapsed adult acute myeloid leukemia patients

Prognosis for relapsed or refractory (R/R) acute myeloid leukemia (AML) despite salvage therapy is dismal. This phase I dose-escalation trial assessed the safety and preliminary clinical activity of selinexor, an oral exportin-1 (XPO1) inhibitor, in combination with FLAG-Ida in younger R/R AML patients. The aim was to find the recommended phase 2 dose (RP2D) and maximum tolerated dose (MTD). Fourteen patients were included, and selinexor dosage was 60 mg (3 patients), 80 mg (3 patients), and 100 mg (7 patients) weekly. No dose-limiting toxicities were reported. Grade ≥3 non-hematologic adverse events (AEs) occurred in 78.6% of patients. Two patients were non MTD evaluable due to early death, and overall, 3 out of 14 patients (21.4%) had fatal AEs. Five out of 12 (42%) response and MTD evaluable patients achieved a complete remission (CR; n=4) or CR with incomplete hematologic recovery (CRi, n=1), and 4 patients (33%) subsequently underwent allogeneic transplantation. The median overall survival (OS) and event-free survival (EFS) were 6.0 (range 0.9-19.3) and 1.1 months (range 0.7-19.3), respectively. Using selinexor 100 mg/weekly, CR/CRi rate of 66.7%, OS 13.6 months (range, 1.6-19.3), and EFS 10.6 months (range, 0.9-19.3). At last follow-up, 3 patients were alive. Selinexor 100 mg/weekly with FLAG-Ida combination in R/R AML showed acceptable tolerability and efficacy, establishing the RP2D of this regimen in future clinical trials. ClinicalTrials.gov Identifier: NCT03661515.

Venetoclax-Based Regimens for Relapsed/Refractory Acute Myeloid Leukemia in a Real-Life Setting: A Retrospective Single-Center Experience

Relapsed/refractory (R/R) acute myeloid leukemia (AML) is a largely unmet medical need, owing to the lack of standardized, effective treatment approaches, resulting in an overall dismal outcome. The only curative option for R/R AML patients is allogeneic hematopoietic stem cell transplantation (HSCT) which is only applicable in a fraction of patients due to the scarce efficacy and high toxicity of salvage regimens. Recently, a number of targeted agents with relatively favorable toxicity profiles have been explored in clinical trials for R/R AML patients. The Bcl-2 inhibitor venetoclax, in combination with hypomethylating agents or low dose cytarabine, has produced impressive results for newly diagnosed AML, while its role in R/R disease is not well defined yet. We retrospectively analyzed the clinical outcomes of 47 R/R AML patients treated with venetoclax-based regimens between March 2018 and December 2020 at our institution. Overall, we report a composite complete response rate of 55% with an overall acceptable toxicity profile. Outcomes were particularly favorable for NPM1 mutated patients, unlike for FLT3-ITD positive patients irrespective of NPM1 status. For patients treated with intention to transplant, the procedure could be finally performed in 54%. These findings suggest a role for venetoclax-based regimens in R/R AML patients and support the design of prospective studies.

Healthcare resource utilization in adult patients with relapsed/refractory FLT3 mutated acute myeloid leukemia: A retrospective chart review from Spain

BACKGROUND

Information regarding impact on healthcare systems of relapsed or refractory (R/R) FLT3 mutated (FLT3mut) acute myeloid leukemia (AML) is scarce.

OBJECTIVE

To assess the time and reimbursement associated with hospitalizations of patients with R/R FLT3mut AML in a tertiary Spanish hospital.

METHODS

Retrospective review of medical charts identified patients aged ≥ 18 years with R/R FLT3mut AML between 1998 and 2018. Data were collected from the date of first diagnosis of R/R FLT3mut AML (index) until death or loss to follow-up. The primary end point was duration and frequency of hospitalization, use of outpatient resources and transfusion burden. Reimbursement associated with hospitalizations (including associated chemotherapy) was also assessed.

RESULTS

Thirty-eight patients were eligible for inclusion. Their median age was 52 years, and 30 (79%) received intensive salvage chemotherapy; FLAG-IDA-based regimens were the most frequent (24 patients, 63%). Overall, there were 150 hospitalizations (mean 3.9/patient; mean duration 21 days). Patients spent a mean of 24% of the study period in hospital. Total mean reimbursement was €108 293 per patient; the majority (€89 834) attributable to inpatient stays (€22 576 /hospitalization). During chemotherapy period (prior to first alloHSCT), there were 73 hospitalizations (mean duration 22 days); mean reimbursement was €19 776 per hospitalization and €49 819 per patient. AlloHSCT (n = 16) involved 77 hospitalizations (mean duration 21 days), mean reimbursement €25 231/hospitalization and €131 515 per patient.

CONCLUSION

Data from this study suggest that there is a substantial healthcare resource utilization and cost burden on R/R FLT3mut AML patients in Spain receiving active treatments.

High Expression of CLEC11A Predicts Favorable Prognosis in Acute Myeloid Leukemia

Background

Acute myeloid leukemia (AML) is a heterogeneous disease of the hematopoietic system, for which identification of novel molecular markers is potentially important for clinical prognosis and is an urgent need for treatment optimization.

Methods

We selected C-type lectin domain family 11, member A (CLEC11A) for study via several public databases, comparing expression among a variety of tumors and normal samples as well as different organs and tissues. To investigated the relationship between CLEC11A expression and clinical characteristics, we derived an AML cohort from The Cancer Genome Atlas (TCGA); we also investigated the Bloodspot and HemaExplorer databases. The Kaplan-Meier method and log-rank test were used to evaluate the associations between CLEC11A mRNA expression, as well as DNA methylation, and overall survival (OS), event-free survival (EFS), and relapse-free survival (RFS). DNA methylation levels of CLEC11A from our own 28 de novo AML patients were assessed and related to chemotherapeutic outcomes. Bioinformatics analysis of CLEC11A was carried out using public databases.

Results

Multiple public databases revealed that CLEC11A expression was higher in leukemia. The TCGA data revealed that high CLEC11A expression was linked with favorable prognosis (OS p-value = 2e-04; EFS p-value = 6e-04), which was validated in GSE6891 (OS p-value = 0; EFS p-value = 0; RFS p-value = 2e-03). Methylation of CLEC11A was negatively associated with CLEC11A expression, and high CLEC11A methylation level group was linked to poorer prognosis (OS p-value = 1e-02; EFS p-value = 2e-02). Meanwhile, CLEC11A hypermethylation was associated with poor induction remission rate and dismal survival. Bioinformatic analysis also showed that CLEC11A was an up-regulated gene in leukemogenesis.

Conclusion

CLEC11A may be used as a prognostic biomarker, and could do benefit for AML patients by providing precise treatment indications, and its unique gene pattern should aid in further understanding the heterogeneous AML mechanisms.

Clinical Implications of Inflammation in Acute Myeloid Leukemia

Recent advances in the description of the tumor microenvironment of acute myeloid leukemia, including the comprehensive analysis of the leukemic stem cell niche and clonal evolution, indicate that inflammation may play a major role in many aspects of acute myeloid leukemia (AML) such as disease progression, chemoresistance, and myelosuppression. Studies on the mechanisms of resistance to chemotherapy or tyrosine kinase inhibitors along with high-throughput drug screening have underpinned the potential role of glucocorticoids in this disease classically described as steroid-resistant in contrast to acute lymphoblastic leukemia. Moreover, some mutated oncogenes such as RUNX1, NPM1, or SRSF2 transcriptionally modulate cell state in a manner that primes leukemic cells for glucocorticoid sensitivity. In clinical practice, inflammatory markers such as serum ferritin or IL-6 have a strong prognostic impact and may directly affect disease progression, whereas interesting preliminary data suggested that dexamethasone may improve the outcome for AML patients with a high white blood cell count, which paves the way to develop prospective clinical trials that evaluate the role of glucocorticoids in AML.

Improved outcome of children with relapsed/refractory acute myeloid leukemia by addition of cladribine to re-induction chemotherapy

Background

The preferred salvage treatment for children with relapsed/refractory acute myeloid leukemia (R/R‐AML) remains unclear. The combination of cladribine/Ara‐C/granulocyte‐colony stimulating factor and mitoxantrone (CLAG‐M) shown promising results in adult R/R‐AML. We aim to investigate the efficacy and safety of CLAG‐M versus mitoxantrone/etoposide/cytarabine (MEC) or idarubicin/etoposide/cytarabine (IEC) in R/R‐AML children.

Methods

Fifty‐five R/R‐AML children were analyzed. The overall response rate (ORR), overall survival (OS), and progression‐free survival (PFS) at 3‐year were documented. Karyotype or mutations status were summarized as different risk groups.

Results

The ORR was achieved in 80% (16/20) and 51% (18/35) of patients after one‐cycle of CLAG‐M and MEC/IEC treatment (p < 0.001). The CLAG‐M group's OS (66.8% ± 16.2% vs. 40.4% ± 10.9%, p = 0.019) and PFS (52.6% ± 13.7% vs. 34.9% ± 9.1%, p = 0.036) at 3‐year was significantly higher than the MEC/IEC group. In high‐risk patients, 33.3% experienced progression of disease (PD) and 22.2% dead in CLAG‐M group, while 50% experienced PD and 43.8% dead in MEC/IEC. When it comes to low‐risk group, none of them in CLAG‐M experienced PD or death, while up to 50% of patients received MEC/IEC suffered PD, and all of them died eventually. Similar results were also found in the intermediate‐risk group. Surprisingly, the presence of FLT3‐ITD was associated with poor outcome in both groups. The most common adverse events were hematologic toxicities, and the incidence was similar in both group.

Conclusions

CLAG‐M group demonstrated effective palliation along with acceptable toxicity in R/R‐AML patients. However, patients with FLT3‐ITD may benefit less from CLAG‐M, owing to higher PD rate and all‐cause mortality than other patients.

Dasatinib response in acute myeloid leukemia is correlated with FLT3/ITD, PTPN11 mutations and a unique gene expression signature

Novel targeted therapies demonstrate improved survival in specific subgroups (defined by genetic variants) of acute myeloid leukemia (AML) patients, validating the paradigm of molecularly targeted therapy. However, identifying correlations between AML molecular attributes and effective therapies is challenging. Recent advances in high-throughput in vitro drug sensitivity screening applied to primary AML blasts were used to uncover such correlations; however, these methods cannot predict the response of leukemic stem cells (LSCs). Our study aimed to predict in vitro response to targeted therapies, based on molecular markers, with subsequent validation in LSCs. We performed ex vivo sensitivity screening to 46 drugs on 29 primary AML samples at diagnosis or relapse. Using unsupervised hierarchical clustering analysis we identified group with sensitivity to several tyrosine kinase inhibitors (TKIs), including the multi-TKI, dasatinib, and searched for correlations between dasatinib response, exome sequencing and gene expression from our dataset and from the Beat AML dataset. Unsupervised hierarchical clustering analysis of gene expression resulted in clustering of dasatinib responders and non-responders. In vitro response to dasatinib could be predicted based on gene expression (AUC=0.78). Furthermore, mutations in FLT3/ITD and PTPN11 were enriched in the dasatinib sensitive samples as opposed to mutations in TP53 which were enriched in resistant samples. Based on these results, we selected FLT3/ITD AML samples and injected them to NSG-SGM3 mice. Our results demonstrate that in a subgroup of FLT3/ITD AML (4 out of 9) dasatinib significantly inhibits LSC engraftment. In summary we show that dasatinib has an anti-leukemic effect both on bulk blasts and, more importantly, LSCs from a subset of AML patients that can be identified based on mutational and expression profiles. Our data provide a rational basis for clinical trials of dasatinib in a molecularly selected subset of AML patients.

Murine double minute 2 inhibition alone or with cytarabine in acute myeloid leukemia: Results from an idasanutlin phase 1/1b study⋆

The prognosis remains poor for patients with relapsed or refractory (r/r) acute myeloid leukemia; thus, novel therapies are needed. We evaluated idasanutlin-a new, potent murine double minute 2 antagonist-alone or with cytarabine in patients with r/r acute myeloid leukemia, de novo untreated acute myeloid leukemia unsuitable for standard treatment or with adverse features, or secondary acute myeloid leukemia in a multicenter, open-label, phase 1/1b trial. Primary objectives were to determine the maximum tolerated dose (MTD) and recommended dose for expansion (RDE) and characterize the safety profile of idasanutlin monotherapy and combination therapy. Clinical activity and pharmacokinetics were secondary objectives. Two idasanutlin formulations were investigated: a microprecipitate bulk powder (MBP) and optimized spray-dried powder (SDP). Following dose escalation, patients (N = 122) received idasanutlin at the RDE in the extension cohorts. No formal MTD was identified. Idasanutlin was tolerable alone and in combination with cytarabine. The RDE was determined as 600 mg twice a day for the MBP formulation and 300 mg twice a day for the SDP formulation. Adverse events were mostly grade 1/2 (76.2 %). The most common any-grade adverse events were gastrointestinal (including diarrhea [90.2 %]). The early death rate across all patients was 14.8 %. Plasma idasanutlin exposure was dose related. In TP53 wild-type patients, composite complete remission rates were 18.9 % with monotherapy and 35.6 % with combination therapy. Based on these results, idasanutlin development continued with further investigation in the treatment of acute myeloid leukemia. ClinicalTrials.gov: NCT01773408.

Gilteritinib use in the treatment of relapsed or refractory acute myeloid leukemia with a FLT3 mutation

The prognosis of patients with relapsed or refractory acute myeloid leukemia (R/R AML) is dismal with salvage standard approaches, and mutations of FMS-like tyrosine kinase 3 (FLT3) gene, occurring in around 30% of AML patients may confer even poorer outcomes. Several targeted tyrosine kinase inhibitors have been developed to improve FLT3-mutated AML patient´s survival. Gilteritinib, a highly specific second-generation class I oral FLT3 inhibitor, has demonstrated superiority to salvage chemotherapy (SC) in R/R FLT3 mutated AML based on significantly longer OS in the gilteritinib arm than in the SC arm. Gilteritinib is generally well tolerated, but some clinically relevant adverse events should be monitored, especially myelosuppression, QTc prolongation and differentiation syndrome, usually manageable (dose reductions, interruption or discontinuation) and reversible. We discuss clinical development, efficacy, safety and mechanisms of resistance of gilteritinib in the treatment of R/R patients with FLT3 mutated AML.

A multi-institutional comparison of mitoxantrone, etoposide, and cytarabine vs high-dose cytarabine and mitoxantrone therapy for patients with relapsed or refractory acute myeloid leukemia

Relapsed or refractory acute myeloid leukemia (R/R AML) has a poor prognosis and is best treated with salvage chemotherapy as a bridge to allogeneic stem cell transplant (alloSCT). However, the optimal salvage therapy remains unknown. Here we compared two salvage regimens; mitoxantrone, etoposide, and cytarabine (MEC) and mitoxantrone and high-dose Ara-C (Ara-C couplets). We analyzed 155 patients treated at three academic institutions between 1998 and 2017; 87 patients received MEC and 68 received Ara-C couplets. The primary endpoint was overall response (OR). Secondary endpoints included progression-free survival (PFS), overall survival (OS), duration of hospitalization, hematologic and nonhematologic toxicities, and success in proceeding to alloSCT. Baseline characteristics of the cohorts were well matched, though patients receiving Ara-C couplets had more co-morbidities (48.5% vs 33%; P = .07). OR was achieved in 43.7% of MEC and 54.4% of Ara-C couplets patients (P = .10). Ara-C couplets patients also trended towards a longer OS and PFS, more frequently proceeded to alloSCT (31% vs 54.4%; P = .003), and experienced less febrile neutropenia (94% vs 72%; P < .001) and grade 3/4 gastrointestinal toxicities (17.2% vs 2.94%; P = .005). No significant differences in other toxicities or median duration of hospitalization were noted. This is the first multi-institutional study directly comparing these regimens in a racially diverse population of R/R AML patients. Although these regimens have equivalent efficacy in terms of achieving OR, Ara-C couplets use is associated with significant reductions in toxicities, suggesting it should be used more frequently in these patients.

Tandem Allogeneic Hematopoietic Stem Cell Transplantation for Salvage Treatment of Acute Myeloid Leukemia Refractory to Induction Chemotherapy: A Case Report

BACKGROUND

Primary refractory acute myeloid leukemia (AML) is associated with dismal prognosis. No standard treatment options are available, and it remains an unmet clinical need. Here, we report a case of a tandem allogeneic hematopoietic stem cell transplantation (allo-HSCT) performed in a patient who did not achieve remission after 2 courses of induction chemotherapy.

METHODS CASE REPORT

The treatment was approved by the Bioethical Commission of the Medical University of Warsaw and was performed in accordance with the Declaration of Helsinki. The patient gave informed consent.

RESULTS

A 41-year-old woman was diagnosed with AML, high cytogenetic risk, with concomitant skin and central nervous system involvement, bone marrow necrosis, and hemophagocytic lymphohistiocytosis. She received "3+7" induction and HAM (cytarabine, mitoxantrone) reinduction, after which she did not achieve remission and hematopoietic recovery. Tandem allo-HSCT was performed from the same HLA-identical brother---the first after reduced intensity conditioning (cladribine, cytarabine, mitoxantrone, melphalan) and the second after myeloablative conditioning (BuCy--busulphan, cyclophosphamide). The patient obtained complete remission after the first allo-HSCT and remains disease-free after the second for 5 years CONCLUSION: Tandem allo-HSCT may be a treatment option for primary refractory AML.