Venetoclax Combined With FLAG-IDA Induction and Consolidation in Newly Diagnosed and Relapsed or Refractory Acute Myeloid Leukemia

Clinical features and outcomes of patients with acute myeloid leukemia: the single-center experience of 668 patients in China

OBJECTIVE

To investigate efficacy and prognostic factors in the treatment of adult newly-diagnosed acute myeloid leukemia (AML) with or without allogeneic hematopoietic stem cell transplantation (Allo-HSCT).

METHODS

We retrospectively analyzed 668 patients with newly-diagnosed AML (non-M3 type) in the Department of Hematology at Shanghai Changhai Hospital from January 2012 to December 2021. Based on different induction chemotherapy regimens, patients were categorized into an IA (idarubicin, IDA + cytarabine, Ara-C) (3 + 7, regimen) group (n = 303) and a DA (daunorubicin, DNR + cytarabine, Ara-C) (3 + 7, regimen) group (n = 365) with or without allo-HSCT. Minimal residual disease (MRD), complete response (CR), overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and adverse effects (AE) were analyzed and compared. Characteristics significantly associated with overall or progression-free survival (OS or PFS) upon univariate analysis were subsequently included in a Cox proportional hazard model.

RESULTS

This study used data from 668 AML patients. After induction therapy, the CR rate in the IA group was 70.63% and ORR was 79.87%, which were significantly higher than those in the DA group (with a CR rate of 56.99% and an ORR of 70.14%) (P = 0.0002 and P = 0.0035, respectively). There were no significant differences in drug safety between the two chemotherapy regimens used in IA and DA (P > 0.05). The recurrence rate was lower in patients with an MRD < 0.001 than in patients with an MRD ≥ 0.001. A continuous negative MRD during the period is significant because it is associated with prolonged OS and PFS of AML patients. Data from 100 patients in the two groups who underwent allo-HSCT were analyzed using univariate analysis and the Cox proportional hazards model. From the multivariate analysis, MRD was found to be the only independent predictor of OS (P = 0.042; HR 1; 95%CI 0.00-0.76).

CONCLUSION

In the treatment of adult AML patients, IA regimen is associated with a high CR rate and ORR rate and does not increase treatment-related toxicity. IA regimen prolongs OS and PFS in AML patients and reduces the likelihood of leukemia cells' subsequent infiltration into the central nervous system. There is a high correlation between the level of MRD after treatment and the patient's bone marrow recurrence. To obtain superior treatment effects for patients undergoing allo-HSCT, the MRD should be reduced to less than 0.001 before pretreatment. A negative MRD before allo-HSCT can prolong OS in patients with AML. We examined the clinical characteristics and outcomes of AML patients in China, finding novel information on prognostic factors and primary treatment of AML that may be applicable in routine clinical practice.

Increased Th17 and Treg levels in peripheral blood positively correlate with minimal residual disease in acute myeloid leukaemia

PURPOSE

Immune dysregulation plays a key role in acute myeloid leukemia (AML). We aimed to explore the correlation between T helper cell 17 (Th17) and the regulatory cells (Tregs) in the peripheral blood of patients with newly diagnosed (ND) AML and bone marrow blast cells, as well as minimal residual disease (MRD) before and after treatment.

METHODS

Changes in Th17 and Treg cells in the peripheral blood of 32 patients with ND AML were observed before and after induction chemotherapy with cytarabine for seven days and anthracycline for three days. The levels of inflammatory cytokines were measured using an enzyme-linked immunosorbent assay. Correlation analysis between bone marrow blast cells and Th17 and Treg cell frequencies was performed using the Pearson's correlation test. Frequencies of Th17 and Treg cells and MRD were assessed using flow cytometry.

RESULTS

IL-6, IL-10, IL-17A, and GM-CSF levels gradually increased in patients with ND AML and CR and NR patients. The percentages of Th17 and Treg cells positively correlated with those of blast cells. In addition, the frequencies of Th17 and Treg cells in MRD-positive patients were higher than those in MRD-negative patients at the initial induction and after three months of chemotherapy. The frequencies of Tregs and Th17 cells positively correlated with MRD onset.

CONCLUSION

Increased Th17 and Treg cell levels were positively correlated with onset of AML, poor remission, and MRD.

Relapse and resistance in acute myeloid leukemia post venetoclax: improving second lines therapy and combinations

INTRODUCTION

The combined use of the BCL-2 inhibitor venetoclax with azacitidine now is the standard of care for patients with acute myeloid leukemia (AML) unfit for intensive chemotherapy with outcomes exceeding those achieved with hypomethylating agents alone. Venetoclax in combination with intensive chemotherapy is also increasingly used both as frontline as well as salvage therapy. However, resistance to and relapse after venetoclax-based therapies are of major concern and outcomes after treatment failure remain poor.

AREAS COVERED

A comprehensive search was performed using PubMed database (up to April 2024). Studies evaluating venetoclax-based combination treatments in AML and studies assessing markers of response and resistance to venetoclax were investigated. We summarize the status of venetoclax-based therapies in the frontline and relapsed/refractory setting with focus on the main mechanisms of resistance to BCL-2 inhibition. Further, strategies to overcome resistance including combinatorial regimens of hypomethylating agent (HMA) + venetoclax + inhibitors targeting actionable mutations like IDH1/2 or FLT3-ITD and the introduction of novel agents like menin-inhibitors are addressed.

EXPERT OPINION

Although venetoclax is reshaping the treatment of unfit and fit AML patients, prognosis of patients after HMA/VEN failure remains dismal, and strategies to abrogate primary and secondary resistance are an unmet clinical need.

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.

Cell death pathways: molecular mechanisms and therapeutic targets for cancer

Cell death regulation is essential for tissue homeostasis and its dysregulation often underlies cancer development. Understanding the different pathways of cell death can provide novel therapeutic strategies for battling cancer. This review explores several key cell death mechanisms of apoptosis, necroptosis, autophagic cell death, ferroptosis, and pyroptosis. The research gap addressed involves a thorough analysis of how these cell death pathways can be precisely targeted for cancer therapy, considering tumor heterogeneity and adaptation. It delves into genetic and epigenetic factors and signaling cascades like the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathways, which are critical for the regulation of cell death. Additionally, the interaction of the microenvironment with tumor cells, and particularly the influence of hypoxia, nutrient deprivation, and immune cellular interactions, are explored. Emphasizing therapeutic strategies, this review highlights emerging modulators and inducers such as B cell lymphoma 2 (BCL2) homology domain 3 (BH3) mimetics, tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), chloroquine, and innovative approaches to induce ferroptosis and pyroptosis. This review provides insights into cancer therapy's future direction, focusing on multifaceted approaches to influence cell death pathways and circumvent drug resistance. This examination of evolving strategies underlines the considerable clinical potential and the continuous necessity for in-depth exploration within this scientific domain.

Ven the dose matters: Venetoclax dosing in the frontline treatment of AML

Older/unfit adults with AML have worse outcomes and fewer treatment options than their younger/fit counterparts. In vitro studies have found a synergistic effect of hypomethylating agents (HMA) with venetoclax (VEN) on AML cells and since the phase 3 VIALE-A trial demonstrated a survival benefit, HMA + VEN has become the standard of care in the frontline setting for older/unfit adults with AML. Unfortunately, the standard 28-day cycle of VEN is associated with a high degree of myelosuppression leading to treatment delays and dose modifications. Many small retrospective studies have successfully shown comparable outcomes to VIALE-A with reduced dose/duration of VEN. Furthermore, low dose metronomic dosing of HMA + VEN has shown clinical benefit while minimizing myelotoxicity. Future trials are vital to understand the appropriate dose of VEN in combination with HMA, to evaluate HMA + VEN compared to intensive therapy for younger/fit patients, and to explore its utility in the relapsed/refractory setting.

Anti-PD-1 combined with hypomethylating agent and CAG regimen bridging to allogeneic hematopoietic stem cell transplantation: a novel strategy for relapsed/refractory acute myeloid leukemia

Introduction

The prognosis of relapsed/refractory acute myeloid leukemia (r/rAML) is dismal, and allogeneic hematopoietic stem cell transplant (allo-HSCT) is a potential cure. Combining anti-PD-1, hypomethylating agent (HMA), and CAG (cytarabine, aclarubicin/idarubicin, granulocyte colony-stimulating factor) regimen has showed primary efficacy in r/rAML. However, pre-transplant exposure to anti-PD-1 may lead to severe graft-versus-host disease (GVHD). This preliminary study aimed to evaluate the safety and efficacy of allo-HSCT in r/rAML patients receiving the anti-PD-1+HMA+CAG regimen.

Methods

Fifteen r/rAML patients (12 related haploidentical donors [HIDs], 2 matched siblings, 1 unrelated donor) received this regimen and subsequent peripheral blood HSCT.

Results

Four patients with HIDs received a GVHD prophylaxis regimen consisted of Anti-thymocyte globulin and a reduced-dose of post-transplant cyclophosphamide. The median follow-up was 20.9 months (range, 1.2-34.2). The cumulative incidences of acute GVHD grade 2-4 and grade 3-4 were 40% and 13.3%, respectively. The 2-year incidence of moderate-to-severe chronic GVHD, non-relapse mortality, and relapse were 10%, 22.3%, and 22.5%, respectively. The 2-year overall survival and GVHD-free/relapse-free survival rates were 54% and 48.6%, respectively. No death or relapse was observed in the PTCy group.

Conclusion

The anti-PD-1+HMA+CAG regimen bridging to allo-HSCT for r/r AML was tolerable with promising efficacy. GVHD prophylaxis with PTCy for HID-HSCT showed preliminary survival advantage.

Venetoclax for pediatric patients with newly diagnosed acute myeloid leukemia

This retrospective study at the University of Texas MD Anderson Cancer Center evaluated frontline venetoclax combination therapy in 11 pediatric/adolescent patients with acute myeloid leukemia (AML). Despite the small sample size and retrospective nature, the treatment demonstrated safety and potential efficacy, with most patients achieving early complete remission. Adverse events were consistent with other AML therapies, and no discontinuations due to toxicity occurred. While acknowledging study limitations, including selection bias and diverse concurrent therapies, this research underscores the promising role of venetoclax in pediatric AML. Further investigation is crucial to validate its long-term efficacy in this population.

Outcomes of adults with refractory or relapsed acute myeloid leukemia treated with azacitidine and venetoclax compared to other therapies: a multicenter retrospective study

This study reports characteristics and outcomes of adults who received Azacitidine-Venetoclax (AZA-VEN) compared to other salvage therapies (NO-AZA-VEN) as first salvage therapy for acute myeloid leukemia (AML). The clinical data of 81 patients with a diagnosis of relapsed or refractory AML were analyzed. The ORR was comparable for both groups (55% vs 57%, p = 0.852). Median OS (6.8 vs 11.2 months, p = 0.053) and median RFS (6.9 vs 11.2 months, p = 0.488) showed a trend in favor of the NO-AZA-VEN group. OS was significantly longer with NO-AZA-VEN for ELN 2022 risk category sub-group, patients under 60 years old, primary AML and for patients who underwent allo-hematopoietic stem cell transplant after salvage therapy. There was no statistical difference in complications of treatment such as febrile neutropenia, intensive care unit stay, septic shock and total parenteral nutrition. Those results do not support the preferential use of AZA-VEN over other regimens in R/R acute myeloid leukemia.

Homoharringtonine synergizes with venetoclax in early T cell progenitor acute lymphoblastic leukemia: Bench and bed

BACKGROUND

Early T cell precursor acute lymphoblastic leukemia (ETP-ALL) is a distinct subtype of T-ALL with a poor prognosis. To find a cure, we examined the synergistic effect of homoharringtonine (HHT) in combination with the BCL-2 inhibitor venetoclax (VEN) in ETP-ALL.

METHODS

Using in vitro cellular assays and ETP-ALL xenograft models, we first investigated the synergistic activity of HHT and VEN in ETP-ALL. Next, to explore the underlying mechanism, we employed single-cell RNA sequencing of primary ETP-ALL cells treated with HHT or VEN alone or in combination and validated the results with western blot assays. Based on the promising preclinical results and given that both drugs have been approved for clinical use, we then assessed this combination in clinical practice.

FINDINGS

Our results showed that HHT synergizes strongly with VEN both in vitro and in vivo in ETP-ALL. Mechanistic studies demonstrated that the HHT/VEN combination concurrently downregulated key anti-apoptotic proteins, i.e., MCL1, leading to enhanced apoptosis. Importantly, the clinical results were very promising. Six patients with ETP-ALL with either refractory/relapsed (R/R) or newly diagnosed disease were treated with an HHT/VEN-based regimen. All patients achieved complete remission (CR) after only one cycle of treatment.

CONCLUSIONS

Our findings demonstrate that a combination of HHT/VEN is effective on ETP-ALL and represents the "backbone" of a promising and safe regimen for newly diagnosed and R/R patients with ETP-ALL.

FUNDING

This work was funded by the National Cancer Institute, Gehr Family Foundation, George Hoag Family Foundation, National Natural Science Foundation of China, and Key Research and Development Program of Zhejiang Province of China.

Patients with TP53-Mutated Acute Myeloid Leukemia Receiving Intensive Induction Therapy Have Superior Outcomes Due to a Higher Rate of Salvage Therapy: A Single Institution, Retrospective Study

BACKGROUND

TP53 mutations (TP53m) define the most treatment-refractory acute myeloid leukemia (AML) subtype. Optimal treatment approaches have not been established in this setting. We reviewed our institutional experience to identify therapy sequencing, treatment response, and survival patterns in these patients.

METHODS

This study was a single-center, retrospective cohort analysis.

RESULTS

Our cohort includes 86 TP53m and 337 TP53 wild-type (TP53wt) adult AML patients. TP53m AML patients presented with lower bone marrow and peripheral blasts; none presented with hyperleukocytosis. Patients who received intensive treatment up front demonstrated superior overall survival (OS) over those receiving first-line non-intensive therapy (2-year OS 22% versus 7%; p = 0.02). However, the complete remission (CR) rates among the first-line intensive and non-intensive therapy groups were comparable (21.9% and 29.4%, respectively, p = 0.49). The improved OS is therefore attributed to superior cumulative CR in the intensive group. First-line intensively treated patients were more likely to receive and respond to salvage, leading to a cumulative CR rate of 65.7% (versus 29.4%, p = 0.003). Achieving CR at any point is strongly associated with superior survival outcomes with 2-year OS of 31% versus 0% for those not achieving CR ever (p < 0.01).

CONCLUSIONS

We find that TP53m AML rarely presents with oncological emergencies, suggesting that clinical trial enrollment is feasible in this group. Additionally, in our cohort, intensive induction therapies lead to superior survival outcomes attributed to successful salvage therapy. These data suggest that strategic therapy sequencing and salvage therapy may be important in optimizing outcomes for TP53m AML patients.

Molecular Features and Treatment Paradigms of Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a common hematologic malignancy that is considered to be a disease of aging, and traditionally has been treated with induction chemotherapy, followed by consolidation chemotherapy and/or allogenic hematopoietic stem cell transplantation. More recently, with the use of next-generation sequencing and access to molecular information, targeted molecular approaches to the treatment of AML have been adopted. Molecular targeting is gaining prominence, as AML mostly afflicts the elderly population, who often cannot tolerate traditional chemotherapy. Understanding molecular changes at the gene level is also important for accurate disease classification, risk stratification, and prognosis, allowing for more personalized medicine. Some mutations are well studied and have an established gene-specific therapy, including FLT3 and IDH1/2, while others are being investigated in clinical trials. However, data on most known mutations in AML are still minimal and therapeutic studies are in pre-clinical stages, highlighting the importance of further research and elucidation of the pathophysiology involving these genes. In this review, we aim to highlight the key molecular alterations and chromosomal changes that characterize AML, with a focus on pathophysiology, presently available treatment approaches, and future therapeutic options.

Venetoclax-based treatment in acute myeloid leukemia: an unexpected bonus on the path to allogeneic hematopoietic stem cell transplant?

Despite the approval of new drugs, the inclusion of -omics-derived data and the integration of machine learning in both the diagnostic and therapeutic process, the prognosis of acute myeloid leukemia (AML) remains dismal. The curative path is still aimed at achieving a successful allogeneic hematopoietic stem cell transplant (HSCT) in most patients. Nevertheless, access to this procedure is limited to eligible patients. Moreover, post-HSCT outcomes are influenced by AML heterogeneity and patient-related factors. The rise of venetoclax (VEN)-based combinations as standard of care in the treatment of older or unfit AML patients, together with their peculiar management profile, has led researchers to evaluate the feasibility of this approach in patients proceeding toward HSCT. We reviewed the available evidence to weigh up the advantages and pitfalls of this new therapeutic strategy.

Combination therapy with novel agents for acute myeloid leukaemia: Insights into treatment of a heterogenous disease

The treatment landscape of acute myeloid leukaemia (AML) is evolving rapidly. Venetoclax in combination with intensive chemotherapy or doublets or triplets with targeted or immune therapies is the focus of numerous ongoing trials. The development of mutation-targeted therapies has greatly enhanced the treatment armamentarium, with FLT3 inhibitors and isocitrate dehydrogenase inhibitors improving outcomes in frontline and relapsed/refractory (RR) AML, and menin inhibitors showing efficacy in RR NPM1mut and KMT2A-rearranged AML. With so many new drugs approved, the number of potential combinatorial approaches to leverage the maximal benefit of these agents has increased dramatically, while at the same time introducing clinical challenges, such as key preclinical and clinical data supporting the development of combinatorial therapy, how to optimally combine or sequence these novel agents, how to optimise dose and duration to maintain safety while enhancing efficacy, the optimal duration of therapy and the role of measurable residual disease in decision-making in both intensive and low-intensity therapy settings. In this review, we will outline the evidence leading to the approval of key agents in AML, their on-label current approvals and how they may be optimally combined in a safe and deliverable fashion to further improve outcomes in AML.

Intensive Reinduction Chemotherapy Followed by Early Allogeneic Hematopoietic Cell Transplantation for Relapsed/Refractory High-Grade Myeloid Neoplasms

Outcomes for adults with relapsed/refractory (R/R) high-grade myeloid neoplasms remain poor, with allogeneic hematopoietic cell transplantation (HCT) the sole therapy likely to result in cure. We conducted the present study to determine the feasibility of early HCT-within 60 days of beginning reinduction chemotherapy-to see whether getting patients to HCT in an expeditious manner would expand the number of patients being offered this curative option. In this proof-of-principle feasibility study, we included adults age 18 to 75 years with R/R myeloid malignancies with ≥10% blood/marrow blasts at diagnosis who were eligible for a reduced-intensity HCT. Subjects received reinduction chemotherapy with cladribine, cytarabine, mitoxantrone, and filgrastim (CLAG-M) and proceeded to HCT with reduced-intensity conditioning (fludarabine/ melphalan). We enrolled 30 subjects, all of whom received CLAG-M reinduction, although only 9 underwent HCT within 60 days (<15, the predetermined threshold for feasibility "success"), with a median time to HCT of 48 days (range, 42 to 60 days). Eleven additional subjects received HCT beyond the target 60 days (off-study), with a median time to transplantation of 83 days (range, 53 to 367 days). Barriers to early HCT included infection, physician preference, lack of an HLA-matched donor, logistical delays, and disease progression, all of which may limit the real-world uptake of such early-to-transplantation protocols.

The Immunotherapy of Acute Myeloid Leukemia: A Clinical Point of View

The potential of the immune system to eradicate leukemic cells has been consistently demonstrated by the Graft vs. Leukemia effect occurring after allo-HSCT and in the context of donor leukocyte infusions. Various immunotherapeutic approaches, ranging from the use of antibodies, antibody-drug conjugates, bispecific T-cell engagers, chimeric antigen receptor (CAR) T-cells, and therapeutic infusions of NK cells, are thus currently being tested with promising, yet conflicting, results. This review will concentrate on various types of immunotherapies in preclinical and clinical development, from the point of view of a clinical hematologist. The most promising therapies for clinical translation are the use of bispecific T-cell engagers and CAR-T cells aimed at lineage-restricted antigens, where overall responses (ORR) ranging from 20 to 40% can be achieved in a small series of heavily pretreated patients affected by refractory or relapsing leukemia. Toxicity consists mainly in the occurrence of cytokine-release syndrome, which is mostly manageable with step-up dosing, the early use of cytokine-blocking agents and corticosteroids, and myelosuppression. Various cytokine-enhanced natural killer products are also being tested, mainly as allogeneic off-the-shelf therapies, with a good tolerability profile and promising results (ORR: 20-37.5% in small trials). The in vivo activation of T lymphocytes and NK cells via the inhibition of their immune checkpoints also yielded interesting, yet limited, results (ORR: 33-59%) but with an increased risk of severe Graft vs. Host disease in transplanted patients. Therefore, there are still several hurdles to overcome before the widespread clinical use of these novel compounds.

Monocytic Differentiation in Acute Myeloid Leukemia Cells: Diagnostic Criteria, Biological Heterogeneity, Mitochondrial Metabolism, Resistance to and Induction by Targeted Therapies

We review the importance of monocytic differentiation and differentiation induction in non-APL (acute promyelocytic leukemia) variants of acute myeloid leukemia (AML), a malignancy characterized by proliferation of immature myeloid cells. Even though the cellular differentiation block is a fundamental characteristic, the AML cells can show limited signs of differentiation. According to the French-American-British (FAB-M4/M5 subset) and the World Health Organization (WHO) 2016 classifications, monocytic differentiation is characterized by morphological signs and the expression of specific molecular markers involved in cellular communication and adhesion. Furthermore, monocytic FAB-M4/M5 patients are heterogeneous with regards to cytogenetic and molecular genetic abnormalities, and monocytic differentiation does not have any major prognostic impact for these patients when receiving conventional intensive cytotoxic therapy. In contrast, FAB-M4/M5 patients have decreased susceptibility to the Bcl-2 inhibitor venetoclax, and this seems to be due to common molecular characteristics involving mitochondrial regulation of the cellular metabolism and survival, including decreased dependency on Bcl-2 compared to other AML patients. Thus, the susceptibility to Bcl-2 inhibition does not only depend on general resistance/susceptibility mechanisms known from conventional AML therapy but also specific mechanisms involving the molecular target itself or the molecular context of the target. AML cell differentiation status is also associated with susceptibility to other targeted therapies (e.g., CDK2/4/6 and bromodomain inhibition), and differentiation induction seems to be a part of the antileukemic effect for several targeted anti-AML therapies. Differentiation-associated molecular mechanisms may thus become important in the future implementation of targeted therapies in human AML.

Navigating Treatment Options and Communication in Relapsed Pediatric AML

Despite improved outcomes in newly diagnosed pediatric AML, relapsed disease remains a therapeutic challenge. Factors contributing to slow progress in improving outcomes include inherent challenges in pediatric clinical trial accrual and the scarcity of novel targeted/immunotherapy agents available for pediatric development. This paradigm is changing, however, as international collaboration grows in parallel with the development of promising targeted agents. In this review, we discuss the therapeutic landscape of relapsed pediatric AML, including conventional chemotherapy, targeted therapies, and the challenges of drug approvals in this patient population. We highlight current efforts to improve communication among academia, industry, and regulatory authorities and discuss the importance of international collaboration to improve access to new therapies. Among the therapeutic options, we highlight the approach to second hematopoietic stem cell transplant (HSCT) and discuss which patients are most likely to benefit from this potentially curative intervention. Importantly, we acknowledge the challenges in providing these high-risk interventions to our patients and their families and the importance of shared communication and decision making when considering early-phase clinical trials and second HSCT.

Venetoclax plus cytarabine and azacitidine in relapsed/refractory AML: An open-label, single-arm, phase 2 study

BACKGROUND

The outcome of relapsed/refractory (R/R) acute myeloid leukemia (AML) remains extremely poor. Venetoclax (VEN)-based regimens have shown promise in treating R/R AML.

OBJECTIVE

This phase 2 study aimed to systematically evaluate the efficacy and safety of the VAA regimen (VEN plus Cytarabine and Azacitidine) in R/R AML patients.

METHODS

Thirty R/R AML patients were enrolled. The study adopted a stepwise ramp-up of VEN dosing, starting with 100 mg on day 1, escalating to 200 mg on day 2, and reaching 400 mg from day 3 to day 9. Cytarabine (10 mg/m2, q12h) was administered intravenously twice daily from days 1 to 10, and Azacitidine (75 mg/m2) was administered via subcutaneous injection once daily from days 1-7. The primary efficacy endpoint was the composite complete remission rate (CRc), including complete response (CR) and complete response with incomplete blood count recovery (CRi). Secondary endpoints included overall survival (OS), duration of response (DOR), and safety analysis.

RESULTS

The CRc rate was 63.3% (19/30), with CR in 36.7% of patients and CRi in 26.7%. Notably, 14 (73.7%) of 19 patients achieving CRc showed undetectable measurable residual disease by flow cytometry. With a median follow-up of 10.7 months, the median OS had not been reached, and the median DOR was 18.3 months. The most common grade 3-4 adverse events (AEs) were neutropenia (100%), anemia (96.7%), thrombocytopenia (90.0%), and leukopenia (90.0%). Infections, with pneumonia being the most prevalent (43.3%), were observed, including one fatal case of Pseudomonas aeruginosa septicemia. There were no treatment-related deaths.

CONCLUSION

The VAA regimen is an effective and safe option for patients with R/R AML, demonstrating a high CRc rate and manageable safety profile.

Remission induction versus immediate allogeneic haematopoietic stem cell transplantation for patients with relapsed or poor responsive acute myeloid leukaemia (ASAP): a randomised, open-label, phase 3, non-inferiority trial

BACKGROUND

Whether high-dose cytarabine-based salvage chemotherapy, administered to induce complete remission in patients with poor responsive or relapsed acute myeloid leukaemia scheduled for allogeneic haematopoietic stem-cell transplantation (HSCT) after intensive conditioning confers a survival advantage, is unclear.

METHODS

To test salvage chemotherapy before allogeneic HSCT, patients aged between 18 and 75 years with non-favourable-risk acute myeloid leukaemia not in complete remission after first induction or untreated first relapse were randomly assigned 1:1 to remission induction with high-dose cytarabine (3 g/m2 intravenously, 1 g/m2 intravenously for patients >60 years or with a substantial comorbidity) twice daily on days 1-3 plus mitoxantrone (10 mg/m2 intravenously) on days 3-5 or immediate allogeneic HSCT for the disease control group. Block randomisation with variable block lengths was used and patients were stratified by age, acute myeloid leukaemia risk, and disease status. The study was open label. The primary endpoint was treatment success, defined as complete remission on day 56 after allogeneic HSCT, with the aim to show non-inferiority for disease control compared with remission induction with a non-inferiority-margin of 5% and one-sided type 1 error of 2·5%. The primary endpoint was analysed in both the intention-to-treat (ITT) population and in the per-protocol population. The trial is completed and was registered at ClinicalTrials.gov, NCT02461537.

FINDINGS

281 patients were enrolled between Sept 17, 2015, and Jan 12, 2022. Of 140 patients randomly assigned to disease control, 135 (96%) proceeded to allogeneic HSCT, 97 (69%) after watchful waiting only. Of 141 patients randomly assigned to remission induction, 134 (95%) received salvage chemotherapy and 128 (91%) patients subsequently proceeded to allogeneic HSCT. In the ITT population, treatment success was observed in 116 (83%) of 140 patients in the disease control group versus 112 (79%) of 141 patients with remission induction (test for non-inferiority, p=0·036). Among per-protocol treated patients, treatment success was observed in 116 (84%) of 138 patients with disease control versus 109 (81%) of 134 patients in the remission induction group (test for non-inferiority, p=0·047). The difference in treatment success between disease control and remission induction was estimated as 3·4% (95% CI -5·8 to 12·6) for the ITT population and 2·7% (-6·3 to 11·8) for the per-protocol population. Fewer patients with disease control compared with remission induction had non-haematological adverse events grade 3 or worse (30 [21%] of 140 patients vs 86 [61%] of 141 patients, χ2 test p<0·0001). Between randomisation and the start of conditioning, with disease control two patients died from progressive acute myeloid leukaemia and zero from treatment-related complications, and with remission induction two patients died from progressive acute myeloid leukaemia and two from treatment-related complications. Between randomisation and allogeneic HSCT, patients with disease control spent a median of 27 days less in hospital than those with remission induction, ie, the median time in hospital was 15 days (range 7-64) versus 42 days (27-121, U test p<0·0001), respectively.

INTERPRETATION

Non-inferiority of disease control could not be shown at the 2·5% significance level. The rate of treatment success was also not statistically better for patients with remission induction. Watchful waiting and immediate transplantation could be an alternative for fit patients with poor response or relapsed acute myeloid leukaemia who have a stem cell donor available. More randomised controlled intention-to-transplant trials are needed to define the optimal treatment before transplantation for patients with active acute myeloid leukaemia.

FUNDING

DKMS and the Gert and Susanna Mayer Stiftung Foundation.

AML treatment: conventional chemotherapy and emerging novel agents

Acute myeloid leukemia (AML) is driven by complex mutations and cytogenetic abnormalities with profound tumoral heterogeneity, making it challenging to treat. Ten years ago, the 5-year survival rate of patients with AML was only 29% with conventional chemotherapy and stem cell transplantation. All attempts to improve conventional therapy over the previous 40 years had failed. Now, new genomic, immunological, and molecular insights have led to a renaissance in AML therapy. Improvements to standard chemotherapy and a wave of new targeted therapies have been developed. However, how best to incorporate these advances into frontline therapy and sequence them in relapse is not firmly established. In this review, we highlight current treatments of AML, targeted agents, and pioneering attempts to synthesize these developments into a rational standard of care (SoC).

Allogeneic Stem Cell Transplantation in Refractory Acute Myeloid Leukaemia

Refractory acute myeloid leukaemia is very difficult to treat and represents an unmet clinical need. In recent years, new drugs and combinations of drugs have been tested in this category, with encouraging results. However, all treated patients relapsed and died from the disease. The only curative option is allogeneic transplantation through a graft from a healthy donor immune system. Using myeloablative conditioning regimens, the median overall survival regimens is 19%. Several so-called sequential induction chemotherapies followed by allogeneic transplantation conditioned by reduced intensity regimens have been developed, improving the overall survival to 25-57%. In the allogeneic transplantation field, continuous improvements in practices, particularly regarding graft versus host disease prevention, infection prevention, and treatment, have allowed us to observe improvements in survival rates. This is true mainly for patients in complete remission before transplantation and less so for refractory patients. However, full myeloablative regimens are toxic and carry a high risk of treatment-related mortality. In this review, we describe the results obtained with the different modalities used in more recent retrospective and prospective studies. Based on these findings, we speculate how allogeneic stem cell transplantation could be modified to maximise its therapeutic effect on refractory acute myeloid leukaemia.

Efficacy and safety of mitoxantrone, etoposide, and cytarabine for treatment of relapsed or refractory acute myeloid leukemia

BACKGROUND/RATIONALE

Most patients with acute myeloid leukemia (AML) develop relapsed or refractory (R/R) disease after receiving initial induction chemotherapy. Salvage chemotherapy followed by allogeneic hematopoietic stem cell transplantation (alloHSCT) is the only curative therapy for R/R AML. Mitoxantrone, etoposide, and cytarabine (MEC) is the current standard of care salvage regimen for R/R AML at Cleveland Clinic. The primary objective was to determine the overall remission rate (ORR: defined as patients achieving complete remission (CR) or complete remission with incomplete hematologic recovery (CRi)) in R/R AML patients who received MEC.

METHODS

Adult patients with R/R AML treated with MEC between July 1, 2014 and September 30, 2022 were included. ORR and its association with baseline characteristics were determined. Secondary outcomes included overall survival (OS), event-free survival (EFS), relapse-free survival (RFS), and safety.

RESULTS

Sixty patients were evaluated. The ORR was 51.7% (33.3% CR and 18.3% CRi). The median time from receipt of MEC to CR/CRi was 7.7 weeks. Patients with bone marrow blasts ≤20% and peripheral blood blasts ≤30% at MEC initiation were more than twice as likely to achieve CR/CRi compared to those with a higher blast burden. The median OS was 6.3 months. Twenty-four (40.0%) patients proceeded to alloHSCT. Twenty-one (35.0%) patients were transferred to the intensive care unit (ICU) during their admission.

CONCLUSIONS

MEC is an effective salvage regimen for patients with R/R AML, especially among those with low disease burden at initiation. Febrile neutropenia, infections, and severe oral mucositis were common with MEC administration.

Venetoclax resistance in acute myeloid leukaemia-Clinical and biological insights

Venetoclax, an oral BCL-2 inhibitor, has been widely incorporated in the treatment of acute myeloid leukaemia. The combination of hypomethylating agents and venetoclax is the current standard of care for elderly and patient's ineligible for aggressive therapies. However, venetoclax is being increasingly used with aggressive chemotherapy regimens both in the front line and in the relapse setting. Our growing experience and intensive research demonstrate that certain genetic abnormalities are associated with venetoclax sensitivity, while others with resistance, and that resistance can emerge during treatment leading to disease relapse. In the current review, we provide a summary of the known mechanisms of venetoclax cytotoxicity, both regarding the inhibition of BCL-2-mediated apoptosis and its effect on cell metabolism. We describe how these pathways are linked to venetoclax resistance and are associated with specific mutations. Finally, we provide the rationale for novel drug combinations in current and future clinical trials.

Simultaneous occurrence of multiple myeloma and acute myeloid leukemia: Case report and literature review

Multiple myeloma (MM) and acute myeloid leukemia (AML) are malignant clonal diseases of cells in different lineages. It remains very rare to have both diseases at first diagnosis. Only 24 cases of this situation were reported from 1971 to 2021, and poor prognosis in most cases. However, here we describe a case of de novo MM and AML occurring simultaneously in a 65-year-old woman. We have successfully used individualized treatment regimens to allow the patient to survive 1.5 years to date, which has exceeded 80 % of statistical cases.

Advancements and Challenges in the Treatment of AML

The therapeutic arsenal for the management of AML has expanded significantly in recent years. Before 2017, newly diagnosed AML was treated with either standard cytarabine- and anthracycline-based induction chemotherapy (for all fit patients) or a single-agent hypomethylating agent (in unfit patients or those 75 years and older). While assessing patient fitness remains important, characterizing the disease biology has become critical to select the optimal initial therapy for each patient with more options available. FLT3 inhibitors, gemtuzumab ozogamicin, and CPX-351 have been shown to improve outcomes for specific subsets of patients. Venetoclax (VEN) with a hypomethylating agent (HMA) is the standard-of-care frontline regimen for most older patients, except perhaps for those with an IDH1 mutation where ivosidenib with azacitidine may also be considered. On the basis of the success seen with HMA/VEN in older patients, there is now increasing interest in incorporating VEN into frontline regimens in younger patients, with promising data from multiple early phase studies. This article focuses on recent updates and ongoing challenges in the management of AML, with a particular focus on the ongoing challenge of secondary AML and considerations regarding the selection of initial therapy in younger patients. An overview of common side effects and toxicities associated with targeted therapies is also presented here, along with recommended strategies to mitigate these risks.

The RTK-RAS signaling pathway is enriched in patients with rare acute myeloid leukemia harboring t(16;21)(p11;q22)/FUS::ERG

Acute myeloid leukemia (AML) with t(16;21)(p11;q22)/FUS::ERG is a rare AML subtype associated with poor prognosis. However, its clinical and molecular features remain poorly defined. We determined the clinicopathological, genomic, and transcriptomic characteristics and outcomes of patients with AML harboring FUS::ERG at our center. Thirty-six AML patients harboring FUS::ERG were identified, with an incidence rate of 0.3%. These patients were characterized by high lactate dehydrogenase levels (median: 838.5 U/L), elevated bone marrow blast counts (median: 71.5%), and a CD56-positive immunophenotype (94.3%). Notably, we found that RTK-RAS GTPase (RAS) pathway genes, including NRAS (33%) and PTPN11 (24%), were frequently mutated in this subtype. Transcriptome analysis revealed enrichment of the phosphatidylinositol-3-kinase-Akt (PI3K-Akt), mitogen-activated protein kinase (MAPK), and RAS signaling pathways and upregulation of BCL2, the target of venetoclax, in FUS::ERG AML compared to RUNX1::RUNX1T1 AML, a more common AML subtype with good prognosis. The median event-free survival in patients with FUS::ERG AML was 11.9 (95% confidence interval [CI]: 9.0-not available [NA]) months and the median overall survival was 18.2 (95% CI: 12.4-NA) months. Allogeneic hematopoietic stem cell transplantation failed to improve outcomes. Overall, the high incidence of RTK-RAS pathway mutations and high expression of BCL2 may indicate promising therapeutic targets in this high-risk AML subset.

Myelomonocytic and monocytic acute myeloid leukemia demonstrate comparable poor outcomes with venetoclax-based treatment: a monocentric real-world study

Venetoclax (VEN), a BCL-2 inhibitor, has transformed treatment strategies for elderly and unfit acute myeloid leukemia (AML) patients by significantly improving response rates and survival. However, the predictive factors for VEN efficacy differ from traditional chemotherapy. The clinical relevance of the FAB (French-American-British) monocytic subtype, including M4 and M5, has been debated as a marker for VEN resistance. This real-world study examined 162 newly diagnosed (ND) and 85 relapsed/refractory (R/R) AML patients who received VEN-based therapy at West China Hospital, Sichuan University, from January 2019 to January 2023. We retrospectively collected clinical and treatment data from electronic medical records. The median age of the cohort was 55.5 years (range: 16.5-83.5). The composite complete remission (cCR) rate in the entire cohort was 60.7%. Specifically, among newly diagnosed (ND) patients, FAB monocytic subtypes exhibited lower cCR compared to non-monocytic subtypes (55.1% vs. 76.3%, P = 0.007). Additionally, there were no significant differences observed between M4 and M5 subtypes, both in the ND group (61.7% vs. 40.9%, p = 0.17) and the R/R group (38.2% vs. 40%, p > 0.9). Furthermore, the median follow-up was 238 (range: 7-1120) days. ND patients with monocytic subtypes had shorter overall survival compared to non-monocytic subtypes (295 days vs. not reached, p = 0.0017). Conversely, R/R patients showed no such difference (204 vs. 266 days, p = 0.72). In summary, our study suggests that the FAB monocytic subtype can predict VEN resistance and shorter survival in ND AML patients. Moreover, there is no significant distinction between M4 and M5 subtypes.

Prognostic value of European LeukemiaNet 2022 criteria and genomic clusters using machine learning in older adults with acute myeloid leukemia

This study aimed to validate the new European Leukemia Net (ELN) 2022 criteria for genetic risk stratification in older adults with acute myeloid leukemia (AML) and to determine the most likely set of clusters of similar cytogenetic and mutation properties correlated with survival outcomes in three treatment groups: intensive chemotherapy (IC), hypomethylating agents (HMA) alone, and HMA plus venetoclax (HMA/VEN). The study included 279 patients (aged ≥60 years) who received IC (N=131), HMA (N=76), and HMA/VEN (N=72) between July 2017 and October 2021. No significant differences were observed in survival among the groups according to ELN 2022 risk stratification. Unsupervised hierarchical clustering analysis identified nine genomic clusters (C1-9) with varying survival outcomes depending on treatment type. For example, C4 (predominant for core binding factor-AML) displayed a favorable prognosis in the IC group, but not in the HMA or HMA/VEN groups. The HMA/VEN group had better outcomes than the HMA group in many clusters (C1, 2, 3, and 5); however, the addition of VEN to HMA or IC did not improve the survival outcomes compared with those of HMA alone in C7 and C9 (predominant for -5, del(5q), -7, -17/abn(17p), complex karyotypes, and mutated TP53). The study highlights the limitations of ELN genetic risk stratification in older adults with AML. It emphasizes the need for a more comprehensive approach that considers co-occurring somatic mutations to guide treatment selection in older adults with AML.

FLAG/FLAG-Ida Regimen in Secondary and Relapsed/Refractory Acute Myeloid Leukemia-Even in the Era of New Treatment Modalities Still a Significant Player

(1) Background: Relapsed/refractory (r/r) and secondary acute myeloid leukemia are highlighted by chemoresistance and poor outcomes. The aim of the study was to assess the efficacy and toxicity of fludarabine, cytarabine, and granulocyte-colony stimulation factor (FLAG) with or without idarubicin (-Ida) and to discuss novel therapies in this setting. (2) Methods: Clinical and cytogenetic data on 130 consecutive patients with r/r and secondary AML treated at our center were retrospectively analyzed. (3) Results: There were 48, 56, and 26 patients with relapsed, refractory, and secondary AML, respectively. The median age was 60 years. The overall response was achieved in 70% of patients. The median overall survival (OS) time for the whole group was 9.4 months. In total, 47% of patients proceeded to allogeneic hematopoietic stem cell transplantation (aHSCT) and these patients had significantly prolonged OS compared to the others (63 months vs. 4.2 months; p < 0.001). Among the variables, including age, FLT3 mutation status, European LeukemiaNet (ELN) 2022 classification risk, FLAG vs. FLAG-Ida, and aHSCT, a multivariate analysis revealed that only aHSCT significantly influenced overall survival. (4) Conclusions: FLAG(-Ida) chemotherapy remains an effective salvage chemotherapy for patients with r/r and secondary AML with a plan of proceeding to aHSCT.

Venetoclax plus daunorubicin and cytarabine in newly diagnosed acute myeloid leukemia patients: A propensity score-matched analysis

Venetoclax plus 3 + 7 daunorubicin and cytarabine chemotherapy (DAV) has shown safety and efficacy in eligible patients with newly diagnosed acute myeloid leukemia (AML). However, there are no direct comparisons between DAV and 3 + 7 daunorubicin and cytarabine chemotherapy (DA) alone. We performed a propensity score-matched analysis to compare the outcomes of DAV group with historical DA group and identify the clinical and molecular characteristics of patients who might benefit from the DAV regimen. The DAV group had a higher Complete remission (CR) rate than the DA group (90% vs. 55%, p = 0.008). 25 (96%) patients in the DAV group had a higher MRD-negative CRc rate compared with 13 (62%) patients in the DA group (p = 0.006). After a median follow-up duration of 19.15 (IQR 17.13-21.67) months, the DAV group had an improved overall survival (p = 0.001) and event-free survival (p = 0.069), but not disease-free survival (p = 0.136). Collectively, DAV regimen induced high CR rates and deep MRD-negative CRc rates after one cycle of induction therapy, as well as prolonged the overall survival, in young adult patients with AML who were eligible for intensive chemotherapy. The addition of venetoclax to intensive chemotherapy should be considered in the future to achieve better survival advantages in eligible AML patients.

Comprehensive characterization of IFNγ signaling in acute myeloid leukemia reveals prognostic and therapeutic strategies

Interferon gamma (IFNγ) is a critical cytokine known for its diverse roles in immune regulation, inflammation, and tumor surveillance. However, while IFNγ levels were elevated in sera of most newly diagnosed acute myeloid leukemia (AML) patients, its complex interplay in AML remains insufficiently understood. We aim to characterize these complex interactions through comprehensive bulk and single-cell approaches in bone marrow of newly diagnosed AML patients. We identify monocytic AML as having a unique microenvironment characterized by IFNγ producing T and NK cells, high IFNγ signaling, and immunosuppressive features. IFNγ signaling score strongly correlates with venetoclax resistance in primary AML patient cells. Additionally, IFNγ treatment of primary AML patient cells increased venetoclax resistance. Lastly, a parsimonious 47-gene IFNγ score demonstrates robust prognostic value. In summary, our findings suggest that inhibiting IFNγ is a potential treatment strategy to overcoming venetoclax resistance and immune evasion in AML patients.

A phase 1/2 study of mini-hyper-CVD plus venetoclax in patients with relapsed/refractory acute lymphoblastic leukemia

ABSTRACT

Preclinical studies suggest that Bcl-2 inhibition with venetoclax has antileukemic activity in acute lymphoblastic leukemia (ALL) and may synergize with conventional chemotherapy. We designed a phase 1/2 clinical trial to evaluate the safety and efficacy of low-intensity chemotherapy in combination with venetoclax in adults with relapsed or refractory ALL. Patients received the mini-hyper-CVD regimen (dose-attenuated hyperfractionated cyclophosphamide, vincristine, and dexamethasone alternating with methotrexate and cytarabine) in combination with venetoclax (200 mg or 400 mg daily) on days 1 to 14 in cycle 1 and on days 1 to 7 in consolidation cycles. Twenty-two patients were treated. The median number of prior therapies was 2 (range, 1-6). Thirteen patients (59%) had undergone prior allogeneic stem cell transplant (allo-SCT), and 7 of 18 patients (39%) with B-cell ALL had previously received both inotuzumab ozogamicin and blinatumomab. The recommended phase 2 dose of venetoclax in the combination regimen was 400 mg daily. The composite complete remission (CR) and CR with incomplete hematologic recovery (CRi) rate was 57% (CR, 43%; CRi, 14%), and 45% of responders achieved measurable residual disease negativity by multiparameter flow cytometry. Four patients proceeded to allo-SCT. The median duration of response was 6.3 months. The median overall survival was 7.1 months, and the 1-year overall survival rate was 29%. The most common grade ≥3 nonhematologic adverse events were infection in 17 patients (77%) and febrile neutropenia in 4 patients (18%). Overall, the combination of mini-hyper-CVD plus venetoclax was active in heavily pretreated relapsed/refractory ALL. Further development of venetoclax-based combinations in ALL is warranted. This trial is registered at www.clinicaltrials.gov as #NCT03808610.

Sorafenib plus triplet therapy with venetoclax, azacitidine and homoharringtonine for refractory/relapsed acute myeloid leukemia with FLT3-ITD: A multicenter phase 2 study

BACKGROUND

Patients with relapsed or refractory acute myeloid leukemia (R/R AML) and FLT3-internal tandem duplication (FLT3-ITD) respond infrequently to salvage chemotherapy.

OBJECTIVE

To investigate the efficacy of sorafenib plus triplet therapy with venetoclax, azacitidine, and homoharringtonine (VAH) as a salvage therapy in this population.

METHODS

This multicenter, single-arm, phase 2 study was conducted at 12 hospitals across China. Eligible patients had R/R AML with FLT3-ITD (aged 18-65 years) who were treated with VAH. The primary endpoint was composite complete remission (CRc) after two cycles. Secondary outcomes included the overall response rate (ORR), safety, and survival.

RESULTS

Between July 9, 2020, and March 19, 2022, 58 patients were assessed for eligibility, 51 of whom were enrolled. The median patient age was 47 years (interquartile range [IQR] 31-57). CRc was 76.5% with ORR of 82.4%. At a median follow-up of 17.7 months (IQR, 8.7-24.7), the median duration of CRc was not reached (NR), overall survival was 18.1 months (95% confidence interval [CI], 11.8-NR) and event-free survival was 11.4 months (95% CI, 5.6-NR). Grade 3 or 4 adverse events occurring in ≥10% of patients included neutropenia in 47 (92.2%), thrombocytopenia in 41 (80.4%), anemia in 35 (68.6%), febrile neutropenia in 29 (56.9%), pneumonia in 13 (25.5%), and sepsis in 6 (11.8%) patients. Treatment-related death occurred in two (3.9%) patients.

CONCLUSIONS

The sorafenib plus VAH regimen was well tolerated and highly active against R/R AML with FLT3-ITD. This regimen may be a suitable therapeutic option for this population, but larger population trials are needed to be explored.

TRIAL REGISTRATION

Clinical Trials Registry: NCT04424147.

Smart Conditioning with Venetoclax-Enhanced Sequential FLAMSA + RIC in Patients with High-Risk Myeloid Malignancies

Up to 50% of patients with high-risk myeloid malignancies die of relapse after allogeneic stem cell transplantation. Current sequential conditioning regimens like the FLAMSA protocol combine intensive induction therapy with TBI or alkylators. Venetoclax has synergistic effects to chemotherapy. In a retrospective survey among German transplant centers, we identified 61 patients with myeloid malignancies that had received FLAMSA-based sequential conditioning with venetoclax between 2018 and 2022 as an individualized treatment approach. Sixty patients (98%) had active disease at transplant and 74% had genetic high-risk features. Patients received allografts from matched unrelated, matched related, or mismatched donors. Tumor lysis syndrome occurred in two patients but no significant non-hematologic toxicity related to venetoclax was observed. On day +30, 55 patients (90%) were in complete remission. Acute GvHD II°-IV° occurred in 17 (28%) and moderate/severe chronic GvHD in 7 patients (12%). Event-free survival and overall survival were 64% and 80% at 1 year as well as 57% and 75% at 2 years, respectively. The off-label combination of sequential FLAMSA-RIC with venetoclax appears to be safe and highly effective. To further validate these insights and enhance the idea of smart conditioning, a controlled prospective clinical trial was initiated in July 2023.

Venetoclax-based low intensity therapy in molecular failure of NPM1-mutated AML

ABSTRACT

Molecular failure in NPM1-mutated acute myeloid leukemia (AML) inevitably progresses to frank relapse if untreated. Recently published small case series show that venetoclax combined with low-dose cytarabine or azacitidine can reduce or eliminate measurable residual disease (MRD). Here, we report on an international multicenter cohort of 79 patients treated for molecular failure with venetoclax combinations and report an overall molecular response (≥1-log reduction in MRD) in 66 patients (84%) and MRD negativity in 56 (71%). Eighteen of 79 patients (23%) required hospitalization, and no deaths were reported during treatment. Forty-one patients were bridged to allogeneic transplant with no further therapy, and 25 of 41 were MRD negative assessed by reverse transcription quantitative polymerase chain reaction before transplant. Overall survival (OS) for the whole cohort at 2 years was 67%, event-free survival (EFS) was 45%, and in responding patients, there was no difference in survival in those who received a transplant using time-dependent analysis. Presence of FLT3-ITD mutation was associated with a lower response rate (64 vs 91%; P < .01), worse OS (hazard ratio [HR], 2.50; 95% confidence interval [CI], 1.06-5.86; P = .036), and EFS (HR, 1.87; 95% CI, 1.06-3.28; P = .03). Eighteen of 35 patients who did not undergo transplant became MRD negative and stopped treatment after a median of 10 months, with 2-year molecular relapse free survival of 62% from the end of treatment. Venetoclax-based low intensive chemotherapy is a potentially effective treatment for molecular relapse in NPM1-mutated AML, either as a bridge to transplant or as definitive therapy.

Venetoclax Combined with Intensive Chemotherapy: A New Hope for Refractory and/or Relapsed Acute Myeloid Leukemia?

Background. Primary resistance of acute myeloid leukemia (AML) to the conventional 3 + 7 intensive chemotherapy and relapses after first-line chemotherapy are two highly challenging clinical scenarios. In these cases, when allogeneic stem cell transplantation is feasible, patients are usually retreated with other chemotherapeutic regimens, as transplantation is still considered, nowadays, the only curative option. Methods. We discuss the mechanisms behind resistance to chemotherapy and offer a comprehensive review on current treatments of refractory/relapsed AML with a focus on novel approaches incorporating the BCL-2 inhibitor venetoclax. Results. Alas, complete remission rates after salvage chemotherapy remain relatively low, between 30 and 60% at best. More recently, the BCL-2 inhibitor venetoclax was combined either with hypomethylating agents or chemotherapy in refractory/relapsed patients. In particular, its combination with chemotherapy offered promising results by achieving higher rates of remission and bridging a substantial number of patients to transplantation. Conclusions. Venetoclax-based approaches might become, in the near future, the new standard of care for refractory/relapsed AML.

Fludarabine, Cytarabine, Granulocyte Colony-Stimulating Factor, and Idarubicin With Gemtuzumab Ozogamicin Improves Event-Free Survival in Younger Patients With Newly Diagnosed AML and Overall Survival in Patients With NPM1 and FLT3 Mutations

PURPOSE

To determine the optimal induction chemotherapy regimen for younger adults with newly diagnosed AML without known adverse risk cytogenetics.

PATIENTS AND METHODS

One thousand thirty-three patients were randomly assigned to intensified (fludarabine, cytarabine, granulocyte colony-stimulating factor, and idarubicin [FLAG-Ida]) or standard (daunorubicin and Ara-C [DA]) induction chemotherapy, with one or two doses of gemtuzumab ozogamicin (GO). The primary end point was overall survival (OS).

RESULTS

There was no difference in remission rate after two courses between FLAG-Ida + GO and DA + GO (complete remission [CR] + CR with incomplete hematologic recovery 93% v 91%) or in day 60 mortality (4.3% v 4.6%). There was no difference in OS (66% v 63%; P = .41); however, the risk of relapse was lower with FLAG-Ida + GO (24% v 41%; P < .001) and 3-year event-free survival was higher (57% v 45%; P < .001). In patients with an NPM1 mutation (30%), 3-year OS was significantly higher with FLAG-Ida + GO (82% v 64%; P = .005). NPM1 measurable residual disease (MRD) clearance was also greater, with 88% versus 77% becoming MRD-negative in peripheral blood after cycle 2 (P = .02). Three-year OS was also higher in patients with a FLT3 mutation (64% v 54%; P = .047). Fewer transplants were performed in patients receiving FLAG-Ida + GO (238 v 278; P = .02). There was no difference in outcome according to the number of GO doses, although NPM1 MRD clearance was higher with two doses in the DA arm. Patients with core binding factor AML treated with DA and one dose of GO had a 3-year OS of 96% with no survival benefit from FLAG-Ida + GO.

CONCLUSION

Overall, FLAG-Ida + GO significantly reduced relapse without improving OS. However, exploratory analyses show that patients with NPM1 and FLT3 mutations had substantial improvements in OS. By contrast, in patients with core binding factor AML, outcomes were excellent with DA + GO with no FLAG-Ida benefit.

How I treat refractory and relapsed acute myeloid leukemia

ABSTRACT

Most patients with acute myeloid leukemia (AML) develop refractory/relapsed (R/R) disease even in the presence of novel and targeted therapies. Given the biological complexity of the disease and differences in frontline treatments, there are therapies approved for only subgroups of R/R AML, and enrollment in clinical trials should be first priority. Allogeneic hematopoietic cell transplantation (HCT) is the only potentially curative strategy for most patients. Therapeutic approaches, including allogeneic HCT, triggered by the presence of measurable residual disease (MRD), have recently evolved to prevent overt hematologic relapse. Salvage therapy with chemotherapy or targeted therapy is frequently administered before HCT to reduce the leukemic burden. Gilteritinib is approved by the Food and Drug Administration and European Medicines Agency for patients with relapsed FLT3 mutated AML, whereas targeted therapy for relapsed IDH1/2 mutated AML has only FDA approval. Patients who are R/R after azacitidine and venetoclax (AZA/VEN) have a dismal outcome. In this setting, even available targeted therapies show unsatisfactory results. Examples of ongoing developments include menin inhibitors, a targeted therapy for patients with mutated NPM1 or KMT2A rearrangements, antibodies targeting the macrophage immune checkpoint CD47, and triple combinations involving AZA/VEN. The latter cause significant myelosuppressive effects, which make it challenging to find the right schedule and dose.

Fludarabine, cytarabine, and idarubicin with or without venetoclax in patients with relapsed/refractory acute myeloid leukemia

Treatment options for relapsed and refractory acute myeloid leukemia patients (R/R AML) are limited. This retrospective cohort study compares safety and efficacy of fludarabine, cytarabine, and idarubicin (FLA-IDA) without or with venetoclax (FLAVIDA) in patients with R/R AML. Thirty-seven and 81 patients received one course FLA-IDA with or without a 7-day course of venetoclax, respectively. The overall response rate (ORR) was significantly higher in FLAVIDA compared to FLAIDA- treated patients (78% vs. 47%; P=0.001), while measurable residual disease was negative at a similar proportion in responding patients (50% vs. 57%), respectively. Eighty-one percent and 79% of patients proceeded to allogeneic hematopoietic cell transplantation or donor lymphocyte infusion after FLAVIDA and FLA-IDA, respectively. Event-free and overall survival were similar in FLAVIDA- and FLA-IDA-treated patients. Refractory patients could be salvaged more successfully after FLA-IDA compared to FLAVIDA pretreatment. Neutrophil and platelet recovery times were similar in the venetoclax and the control group. In conclusion, short-term venetoclax in combination with FLA-IDA represents an effective treatment regimen in R/R AML identifying chemosensitive patients rapidly and inducing measurable residual disease-negative remission in a high proportion of R/R AML patients.

SOHO State of the Art Updates and Next Questions: Understanding and Overcoming Venetoclax Resistance in Hematologic Malignancies

The discovery of Venetoclax (VEN) has transformed the therapeutic landscape of acute myeloid leukemia (AML) and chronic lymphocytic leukemia (CLL). However, the response is heterogeneous with 10% to 50% of newly diagnosed AML patients not responding to hypomethylating agent (HMA) and VEN. Furthermore, up to 40% of responding patients relapse shortly. This review discusses the mechanism of action of Venetoclax and the major mechanisms of inherent and acquired resistance to VEN. VEN is highly specific to BCL-2 binding, as such other antiapoptotic proteins in BCL-2 family induce resistance. These antiapoptotic proteins can also be upregulated via a number of compensatory cell signaling pathways including PI3K/AKT/mTOR, the MAPK/ERK pathway, and mutant FLT3-ITD. Mutations can occur in BCL-2 and BAX proteins, or they can be silenced by TP53 mutations and other epigenetic changes. Changes to mitochondrial structure and metabolism can induce resistance. Key metabolic regulators include OXPHOS and alternative amino acid metabolism. Finally microenvironmental factors can influence VEN responses. This paper evaluates subsets of AML by differentiation, histology, cytogenetics and molecular markers and their different responses to VEN; with spliceosome mutations, ASXL1, NPM1 and IDH1/2 being favorable while others such as FLT3, TP53 and BCL-2 mutations being less responsive. Currently intensive multiagent chemotherapy and Venetoclax combinations such as 7+3+VEN are favored in fit younger AML patients. However, with resistant patients' subsets targeted combination therapies are becoming an increasingly attractive option. We explore the incorporation of non-BCL-2 inhibitors, next-generation BCL-2 and multi-protein agents, other inhibitors most prominently FLT-3 inhibitors in addition to Venetoclax, and other novel approaches for resolving Venetoclax resistance.

Clinical and genetic characteristics predict outcomes of acute myeloid leukemia patients with FLT3 mutations receiving venetoclax-based therapy

BACKGROUND

Acute myeloid leukemia (AML) is a heterogeneous disease, and its heterogeneity is associated with treatment response. Despite the demonstrated success of venetoclax (VEN)-based therapy for AML, the effect of FLT3 mutations on the efficacy of the therapy is poorly understood. We aimed to compare the efficacy of VEN-based therapy between FLT3-mutated (FLT3mut ) and FLT3 wild-type (FLT3wt ) patients and identify the predictors of efficacy in FLT3mut patients.

METHODS

A total of 266 AML patients (127 newly diagnosed [ND] and 139 refractory/relapsed [R/R]) receiving VEN-based regimens were enrolled in this study. A retrospective analysis was performed, and the treatment responses and overall survival (OS) of FLT3mut and FLT3wt patients were compared. Logistic regression and Cox proportional hazards model were applied to examine the clinical and genetic predictors of outcomes.

RESULTS

With a median of two cycles of VEN-based therapy, for the ND AML cohort, the FLT3mut group had a comparable composite complete remission (CRc) rate with the FLT3wt group (79.3% vs. 61.2%, p = 0.072). For the R/R AML cohort, the FLT3mut group exhibited a lower CRc rate than the FLT3wt group. With a median follow-up of 8.6 months (95% confidence interval [CI], 8.0-10), the median OS observed in the FLT3mut and FLT3wt groups for both cohorts were close (14.0 vs. 19.9 months, p = 0.356; 10.0 vs. 11.9 months, p = 0.680). For the ND AML cohort, in FLT3mut patients, MRD-positive and RNA-splicing mutation predicted inferior survival (hazard ratio [HR], 10.3; 95% CI: 2.0-53.8; p = 0.006; HR 11.3; 95% CI: 1.2-109.3; p = 0.036, respectively). For the R/R AML cohort, in FLT3mut patients, adverse ELN risk was associated with an inferior response (odds ratio [OR], 0.2; 95% CI: 0.1-0.8; p = 0.025), whereas NPM1 co-mutation was associated with a superior response (57.1%; OR, 6.7; 95% CI: 1.5-30.1; p = 0.014). CR/CRi predicted a better survival (HR 0.2; 95% CI: 0.1-0.8; p = 0.029), while DNMT3A mutation predicted an inferior survival (HR, 4.6; 95% CI: 1.4-14.9; p = 0.011).

CONCLUSIONS

FLT3 mutations may influence response to VEN-based therapy in R/R AML patients but not in ND AML patients. Furthermore, clinical and genetic characteristics could predict outcomes of FLT3mut patients receiving VEN-based therapy.

Venetoclax: A Game Changer in the Treatment of Younger AML Patients?

The combination approach based on venetoclax (VEN) with azacytidine (AZA) has significantly improved outcomes for elderly patients with acute myeloid leukemia (AML). This innovative approach has led to higher rates of overall response, measurable residual disease (MRD)-negative remissions, and overall survival compared with AZA monotherapy. As a result, this combination has emerged as the gold-standard treatment for elderly or unfit patients with AML who are not eligible for intensive therapy. In younger, fit patients with AML, intensive induction and consolidation chemotherapy is commonly used as a first-line approach; however, relapse continues to be the main reason for treatment failure in approximately 30-40% of patients. Efforts to improve MRD-negative response rates and to facilitate the transition to allogeneic hematopoietic stem cell transplantation, particularly in high-risk AML, have inspired trials exploring the combination of intensive chemotherapy with targeted agents. VEN, a first-in-class anti-BCL2 agent, combined with intensive chemotherapy regimens has shown deep MRD-negative remissions, producing prolonged event-free survival and enhancing the transition to allogeneic transplant in first-complete-remission patients. These benefits support the incremental advantages of adding VEN to intensive chemotherapy approaches across ELN risk subcategories, and provides a robust benchmark to design future trials. In this review, we will discuss current studies assessing the efficacy of frontline regimens integrating VEN into intensive chemotherapy in younger patients with AML and specific molecularly defined subgroups.

Emerging and Future Targeted Therapies for Pediatric Acute Myeloid Leukemia: Targeting the Leukemia Stem Cells

Acute myeloid leukemia (AML) is a rare subtype of acute leukemia in the pediatric and adolescent population but causes disproportionate morbidity and mortality in this age group. Standard chemotherapeutic regimens for AML have changed very little in the past 3-4 decades, but the addition of targeted agents in recent years has led to improved survival in select subsets of patients as well as a better biological understanding of the disease. Currently, one key paradigm of bench-to-bedside practice in the context of adult AML is the focus on leukemia stem cell (LSC)-targeted therapies. Here, we review current and emerging immunotherapies and other targeted agents that are in clinical use for pediatric AML through the lens of what is known (and not known) about their LSC-targeting capability. Based on a growing understanding of pediatric LSC biology, we also briefly discuss potential future agents on the horizon.

Early Mortality as a Quality Indicator in Frontline and Salvage Acute Myeloid Leukemia

BACKGROUND

Early mortality is a historical measure of the quality of care incorporated into many quality measure algorithms that mostly account for patient comorbidities but do not incorporate disease characteristics and treatment status which independently increase early mortality. This is particularly significant in leukemia, especially in the refractory and salvage settings.

STUDY AIM

To define the independent adverse effect of leukemia salvage vs. frontline therapy on early mortality in acute myeloid leukemia (AML) after accounting for the pretreatment independent adverse effects associated with early mortality.

PATIENTS AND METHODS

A total of 4151 patients with AML were analyzed, 2893 newly diagnosed and 1258 in salvage. Univariate and multivariate analyses (MVA) were conducted to determine the independent adverse effects associated with 8-week mortality.

RESULTS

The 8-week mortality was 13% in frontline therapy and 18% in salvage therapy. By MVA, older age; therapy-related AML; prior history of myelodysplastic syndrome; poorer performance status; high white blood cell count; lower platelet count; higher percent of peripheral blasts; lower albumin levels; higher bilirubin, creatinine, and lactate dehydrogenase levels; and adverse cytogenetic risk groups were independently associated with a higher 8-week mortality rate. Adding treatment status after accounting for the independent adverse variables still selected salvage status as significantly adverse for 8-week mortality (hazard ratio 1.954; P-value < .001).

CONCLUSIONS

Quality measure algorithms should incorporate a risk mortality index related to leukemia vs. other tumors and benign conditions and a risk mortality index related to the treatment status of leukemia (salvage vs. frontline therapy).

Addition of venetoclax to myeloablative conditioning regimens for allogeneic hematopoietic stem cell transplantation in high-risk AML

BACKGROUND

Venetoclax monotherapy is an effective option for patients with acute myeloid leukemia (AML). Venetoclax has also been used in non-myeloablative conditioning allogeneic hematopoietic stem cell transplantation (allo-HSCT) for high-risk AML with a tolerable toxicity profile. However, the efficacy and safety of a venetoclax-containing myeloablative conditioning (MAC) allo-HSCT regimen for high-risk AML have not been evaluated.

OBJECTIVE

To evaluate the safety and efficacy of a MAC regimen containing venetoclax for high-risk AML.

STUDY DESIGN

From 25 February 2021 to 4 September 2022, a total of 31 patients with high-risk AML who underwent allo-HSCT and a MAC regimen with venetoclax were analyzed.

RESULTS

At the time of transplantation, 21 patients were in first complete remission (CR1), 4 were in a second complete remission (CR2), and 6 in non-remission (NR). Twenty-four patients (77.4%) were minimal residual disease (MRD)-positive before transplant. The FLT3-ITD gene mutation was present in 51.6% of patients. NUP98 rearrangement, MLL rearrangement or MLL-PTD and DEK::CAN fusion genes were found in 5 (16.1%), 7(22.6%) and 2 (6.5%) patients, respectively. Twenty-nine (93.6%) patients underwent haploidentical allo-HSCT. The median follow-up time was 278 days (range: 52-632 days). The 100-day cumulative incidence of grade 3 to 4 acute graft-versus-host disease (aGVHD) was 16.1% (95%CI, 7.2-36.0%). The 180-day cumulative incidence of moderate to severe chronic graft-versus-host disease (cGVHD) was 7.1% (95%CI, 1.9-26.9%). Cumulative incidence of 100-day cytomegalovirus (CMV) viraemia and 100-day Epstein-Barr virus (EBV) viraemia was 61.6% (95%CI, 46.5-81.4%) and 3.2% (95%CI, 0.4-22.2%), respectively. The 600-day overall survival (OS) and leukemia-free survival (LFS) were 80.9% (95%CI, 63.5-93.6%) and 81.3% (95%CI, 64.2-93.7%), respectively. The 600-day relapse incidence (RI) and non-relapse mortality (NRM) was 6.9% (95%CI, 1.8-26.3%) and 11.7% (95%CI, 3.9-35.0%).

CONCLUSION

Our study shows that the addition of venetoclax to a MAC allo-HSCT was feasible, safe and effective for high-risk AML patients.