Curability of patients with acute myeloid leukemia who did not undergo transplantation in first remission

Acute Myeloid Leukemia: 2025 Update on Diagnosis, Risk-Stratification, and Management

DISEASE OVERVIEW

Acute myeloid leukemia (AML) is a bone marrow stem cell cancer that is often fatal despite available treatments. Diagnosis, risk assessment, monitoring, and therapeutic management of AML have changed dramatically in the last decade due to increased pathophysiologic understanding, improved assessment technology, and the addition of at least 12 approved therapies.

DIAGNOSIS

The diagnosis is based on the presence of immature leukemia cells in the blood, and/or bone marrow or less often in extra-medullary tissues. New biological insights have been integrated into recent classification systems.

RISK ASSESSMENT

The European Leukemia Network has published risk classification algorithms for both intensively and non-intensively treated patients based on cytogenetic and on molecular findings. Prognostic factors may differ based on the therapeutic approach.

MONITORING

Our increasing ability to quantify lower levels of measurable residual disease (MRD) potentially allows better response assessment, as well as dynamic monitoring of disease status. The incorporation of MRD findings into therapeutic decision-making is rapidly evolving.

RISK ADAPTED THERAPY

The availability of 12 newly approved agents has been welcomed; however, optimal strategies incorporating newer agents into therapeutic algorithms are debated. The overarching approach integrates patient and caregiver goals of care, comorbidities, and disease characteristics.

Allogeneic stem cell transplantation in de novo core-binding factor acute myeloid leukemia in active disease: a study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

Core-binding factor acute myeloid leukemia (CBF-AML) generally has a favorable prognosis, with allogeneic hematopoietic stem cell transplantation (allo-SCT) recommended for relapsed/ refractory (R/R) cases achieving second complete remission (CR). However, clinical outcomes remain suboptimal for patients who relapse or fail to achieve CR following induction chemotherapy. Allo-SCT in non-CR is a potential strategy for such patients, though supporting evidence in CBF-AML is limited. To assess outcomes and prognostic factors of allo-SCT in R/R CBF-AML with active disease, we conducted a retrospective analysis of 610 patients with CBF-AML in non-CR undergoing allo-SCT from 2010 to 2021 across 174 centers within the European Society for Blood and Marrow Transplantation. Graft sources included matched sibling (MSD, n = 151), unrelated (UD, n = 368), and haploidentical donors (Haplo, n = 91). Among patients, 124 had inv(16), and 486 had t(8;21). Two-year overall survival (OS) and leukemia-free survival (LFS) were 53.6% and 42.7%, respectively. Haplo-SCT showed inferior OS compared to MSD (HR 1.79, p = 0.003) and UD (HR 1.64, p = 0.004) and reduced chronic graft-versus-host disease. Patients with t(8;21) exhibited higher relapse incidence (HR 2.04, p = 0.002) and poorer survival outcomes than those with inv(16). These findings confirm the therapeutic role of allo-SCT in R/R CBF-AML in non-CR, supporting its favorable risk profile.

Cost-effectiveness of Enasidenib versus conventional care for older patients with IDH2-mutant refractory/relapsed AML

In the randomized phase III IDHENTIFY trial, the IDH2 inhibitor enasidenib (ENA) showed improvement in event-free but not overall survival compared with conventional care regimens (CCR) among patients with relapsed/refractory (R/R), IDH2-mutant AML. We constructed a partitioned survival model to evaluate the cost-effectiveness of enasidenib for the treatment of older patients with R/R, and IDH2-mutant AML. In the base-case scenario, ENA exhibited an incremental effectiveness of 0.234quality-adjusted life-years (QALYs) compared to CCR, and an incremental cost of $126,800, leading to an incremental cost-effectiveness ratio of $540,300/QALY(95% CI: $197,800-$4,777,000/QALY). In probabilistic sensitivity analysis, CCR was favored in 99.8% of simulations. The cost of ENA would need to be decreased by 72% to be cost-effective at a willingness-to-pay threshold of $150,000/QALY. Our findings suggest that ENA is unlikely to be a cost-effective treatment for older patients with IDH2-mutant R/R AML under current pricing.

Molecular relapse after first-line intensive therapy in patients with CBF or NPM1-mutated acute myeloid leukemia - a FILO study

Patients with Core-Binding Factor (CBF) and NPM1-mutated acute myeloid leukemia (AML) can be monitored by quantitative PCR after having achieved first complete remission (CR) to detect morphologic relapse and drive preemptive therapy. How to best manage these patients is unknown. We retrospectively analyzed 303 patients with CBF and NPM1-mutated AML, aged 18-60 years, without allogeneic hematopoietic cell transplantation (HCT) in first CR, with molecular monitoring after first-line intensive therapy. Among these patients, 153 (51%) never relapsed, 95 (31%) had molecular relapse (53 received preemptive therapy and 42 progressed to morphologic relapse at salvage therapy), and 55 (18%) had upfront morphologic relapse. Patients who received preemptive therapy had higher OS than those who received salvage therapy after having progressed from molecular to morphologic relapse and those with upfront morphologic relapse (three-year OS: 78% vs. 51% vs. 51%, respectively, P = 0.01). Preemptive therapy included upfront allogeneic HCT (n = 19), intensive chemotherapy (n = 21), and non-intensive therapy (n = 13; three-year OS: 92% vs. 79% vs. 58%, respectively, P = 0.09). Although not definitive due to the non-randomized allocation of patients to different treatment strategies at relapse, our study suggests that molecular monitoring should be considered during follow-up to start preemptive therapy before overt morphologic relapse.

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.

Engineering the best transplant outcome for high-risk acute myeloid leukemia: the donor, the graft and beyond

Allogeneic hemopoietic cell transplantation remains the goal of therapy for high-risk acute myeloid leukemia (AML). However, treatment failure in the form of leukemia relapse or severe graft-versus-host disease remains a critical area of unmet need. Recently, significant progress has been made in the cell therapy-based interventions both before and after transplant. In this review, the Stem Cell Engineering Committee of the International Society for Cell and Gene Therapy summarizes the literature regarding the identification of high risk in AML, treatment approaches before transplant, optimal transplant platforms and measures that may be taken after transplant to ideally prevent, or, if need be, treat AML relapse. Although some strategies remain in the early phases of clinical investigation, they are built on progress in pre-clinical research and cellular engineering techniques that are already improving outcomes for children and adults with high-risk malignancies.

Duocarmycin SA Reduces Proliferation and Increases Apoptosis in Acute Myeloid Leukemia Cells In Vitro

Acute myeloid leukemia (AML) is a hematological malignancy that is characterized by an expansion of immature myeloid precursors. Despite therapeutic advances, the prognosis of AML patients remains poor and there is a need for the evaluation of promising therapeutic candidates to treat the disease. The objective of this study was to evaluate the efficacy of duocarmycin Stable A (DSA) in AML cells in vitro. We hypothesized that DSA would induce DNA damage in the form of DNA double-strand breaks (DSBs) and exert cytotoxic effects on AML cells within the picomolar range. Human AML cell lines Molm-14 and HL-60 were used to perform 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT), DNA DSBs, cell cycle, 5-ethynyl-2-deoxyuridine (EdU), colony formation unit (CFU), Annexin V, RNA sequencing and other assays described in this study. Our results showed that DSA induced DNA DSBs, induced cell cycle arrest at the G2M phase, reduced proliferation and increased apoptosis in AML cells. Additionally, RNA sequencing results showed that DSA regulates genes that are associated with cellular processes such as DNA repair, G2M checkpoint and apoptosis. These results suggest that DSA is efficacious in AML cells and is therefore a promising potential therapeutic candidate that can be further evaluated for the treatment of AML.

A Markov analysis of azacitidine and venetoclax vs induction chemotherapy for medically fit patients with AML

ABSTRACT

Although induction chemotherapy (IC) is the standard of care in medically fit patients with newly diagnosed acute myeloid leukemia (AML), limited retrospective data indicate that patients at adverse-risk may benefit from azacytidine and venetoclax (aza-ven). Our goal was to perform a Markov decision analysis to determine whether IC or aza-ven is the optimal induction regimen in this population. Using the TreeAge software, Markov models were created for adverse-risk and intermediate-risk cohorts. A systematic review of the literature informed the transition probabilities and utilities included in the analyses. Our primary outcome was quality-adjusted life years (QALYs) gained over 5 years after diagnosis. Overall, patients at adverse risk treated with IC gained 1.4 QALYs, compared with 2.0 QALYs in patients treated with aza-ven. Patients at adverse risk treated with IC and allogeneic stem cell transplantation (allo-SCT), IC, aza-ven and allo-SCT, or aza-ven gained 2.1, 1.5, 3.0, and 1.9 QALYs, respectively. Meanwhile, patients at intermediate risk treated with IC gained 2.0 QALY, compared with 1.7 QALY in patients treated with aza-ven. Patients at intermediate risk treated with IC and allo-SCT, IC, aza-ven and allo-SCT, and aza-ven gained 2.7, 2.3, 2.6, and 1.8 QALYs, respectively. We have demonstrated that medically fit patients with newly diagnosed adverse-risk AML may benefit from treatment with aza-ven over those treated with IC, whereas IC remains the preferred approach for patients at intermediate risk. Our work challenges the use of the European LeukemiaNet risk classification for patients treated with aza-ven and highlights the need for prospective investigation into aza-ven as induction therapy for medically fit patients.

The core concepts of core binding factor acute myeloid leukemia: Current considerations for prognosis and treatment

Core binding factor acute myeloid leukemia (CBF AML), defined by t(8;21) or inv(16), is a subset of favorable risk AML. Despite its association with a high complete remission rate after induction and relatively good prognosis overall compared with other subtypes of AML, relapse risk after induction chemotherapy remains high. Optimizing treatment planning to promote recurrence free survival and increase the likelihood of survival after relapse is imperative to improving outcomes. Recent areas of research have included evaluation of the role of gemtuzumab in induction and consolidation, the relative benefit of increased cycles of high dose cytarabine in consolidation, the utility of hypomethylating agents and kinase inhibitors, and the most appropriate timing of stem cell transplant. Surveillance with measurable residual disease testing is increasingly being utilized for monitoring disease in remission, and ongoing investigation seeks to determine how to use this tool for early identification of patients who would benefit from proceeding to transplant. In this review, we outline the current therapeutic approach from diagnosis to relapse while highlighting the active areas of investigation in each stage of treatment.

Gilteritinib as Bridging and Posttransplant Maintenance for Relapsed Acute Myeloid Leukemia with FLT3-ITD Mutation Accompanied by Extramedullary Disease in Elderly

A 69-year-old woman was diagnosed with acute myeloid leukemia (AML) with an FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) mutation. Complete remission (CR) was achieved after induction therapy, but AML resulted in a hematological relapse two months after the consolidation chemotherapy. Relapse was accompanied by multiple skin lesions that demonstrated leukemic cell infiltration as well as a drooping right eyelid with extroversion of the eye due to right oculomotor palsy. Gilteritinib was started as salvage therapy, and bone marrow blasts decreased to 0.8% after one month. Two months later, the eye symptoms improved, and the patient underwent cord blood transplantation (CBT). The skin lesions disappeared after the conditioning regimen, and the patient achieved CR status with complete donor chimerism at day 28. Gilteritinib was restarted as posttransplant maintenance therapy on day 53 of CBT. No adverse events other than mild hepatotoxicity were observed, and the patient was alive and in CR status, while continuing gilteritinib at one year and seven months after CBT. Bridging and posttransplant maintenance therapy with gilteritinib may be a promising therapeutic option for relapsed AML with the FLT3-ITD mutation in elderly patients.

Effectiveness of chemotherapy using bortezomib combined with homoharringtonine and cytarabine in refractory or relapsed acute myeloid leukemia: a phase II, multicenter, prospective clinical trial

Background

Refractory/relapsed acute myeloid leukemia (R/R AML) has unsatisfactory outcomes even after allogeneic hematopoietic stem cell transplantation. Long-term survival is mainly influenced by complete remission (CR) rates after induction therapies.

Objectives

To investigate CR/CR with incomplete hematologic recovery (CRi) rates and adverse events with a new induction therapy (bortezomib, homoharringtonine, and cytarabine [BHA]) for patients with R/R AML.

Methods

We enrolled 21 patients with R/R AML (median age, 42 [range, 30-62] years), who received BHA for remission induction (bortezomib, 1.3 mg/m2/day on days 1 and 4; homoharringtonine, 4 mg/m2/day for 5 days, and cytarabine, 1.5 g/m2/day for 5 days). CR and adverse events were assessed.

Results

After one course of BHA, the CR/CRi and partial remission rates were 38.1% and 14.3%, respectively, with an overall response rate (ORR) of 52.4% in 21 patients. 9 of 21 patients harbored FLT3-ITD or FLT3-TKD mutations, and achieved either CR/CRi or ORR of 66.7% (P=0.03) by comparison with that in R/R AML without FLT3 mutation. After induction therapy, consolidation chemotherapy or allogeneic hematopoietic stem cell transplantation led to a one-year overall survival of 27.8% in all patients. One-year relapse-free survival was 50% in 8 patients who had achieved CR/CRi after one course of BHA. During induction, non-hematologic adverse events (grade 3/4) commonly were infection (90.5%), hypokalemia (14.4%), hypocalcemia (14.3%), and mucositis (9.5%). In patients achieving CR, the median time to neutrophil count >0.5×109/L and time to platelet count >20×109/L were 15 (13-17) days and 13 (13-18) days, respectively.

Conclusion

BHA chemotherapy regimen was safe and tolerable to serve as an induction therapy for R/R AML, particularly with FLT3 mutation. The higher CR/CRi rate will give a clue to determine a potentialeffectiveness of BHA for AML patients carrying FLT3 mutation in a further investigation.

Clinical trial registration

https://www.chictr.org.cn/, identifier ChiCTR2000029841.

Cardiac Interventions in Patients With Active, Advanced Solid and Hematologic Malignancies: JACC: CardioOncology State-of-the-Art Review

Invasive cardiac interventions are recommended to treat ST-segment elevation myocardial infarction, non-ST-segment elevation acute coronary syndromes, multivessel coronary disease, severe symptomatic aortic stenosis, and cardiomyopathy. These recommendations are based on randomized controlled trials that historically included few individuals with active, advanced malignancies. Advanced malignancies represent a significant competing risk for mortality, and there is limited evidence to inform the risks and benefits of invasive cardiac interventions in affected patients. We review the benefit conferred by invasive cardiac interventions; the periprocedural considerations; the contemporary survival expectations of patients across several types of active, advanced malignancy; and the literature on cardiovascular interventions in these populations. Our objective is to develop a rational framework to guide clinical recommendations on the use of invasive cardiac interventions in patients with active, advanced cancer.

A venetoclax and azacitidine bridge-to-transplant strategy for NPM1-mutated acute myeloid leukaemia in molecular failure

NPM1-mutated acute myeloid leukaemia (NPM1mut AML) represents a mostly favourable/intermediate risk disease that benefits from allogeneic haematopoietic stem cell transplantation (HSCT) in case of measurable residual disease (MRD) relapse or persistence after induction chemotherapy. Although the negative prognostic role of pre-HSCT MRD is established, no recommendations are available for the management of peri-transplant molecular failure (MF). Based on the efficacy data of venetoclax (VEN)-based treatment in NPM1mut AML older patients, we retrospectively analysed the off-label combination of VEN plus azacitidine (AZA) as bridge-to-transplant strategy in 11 NPM1mut MRD-positive fit AML patients. Patients were in MRD-positive complete remission (CRMRDpos ) at the time of treatment: nine in molecular relapse and two in molecular persistence. After a median number of two cycles (range 1-4) of VEN-AZA, 9/11 (81.8%) achieved CRMRD -negative (CRMRDneg ). All 11 patients proceeded to HSCT. With a median follow-up from treatment start of 26 months, and a median post-HSCT follow-up of 19 months, 10/11 patients are alive (1 died from non-relapse mortality), and 9/10 patients are in MRDneg status. This patient series highlights the efficacy and safety of VEN-AZA to prevent overt relapse, achieve deep responses and preserve patient fitness before HSCT, in patients with NPM1mut AML in MF.

Matched related versus unrelated versus haploidentical donors for allogeneic transplantation in AML patients achieving first complete remission after two induction courses: a study from the ALWP/EBMT

We compared transplants (HSCT) from matched related siblings (MSD) with those from matched 10/10 and mismatched 9/10 unrelated (UD) and T-replete haploidentical (Haplo) donors in acute myeloid leukemia (AML) in first complete remission (CR1) achieved after two inductions, a known poor prognostic factor. One thousand two hundred and ninety-five patients were included: MSD (n = 428), UD 10/10 (n = 554), UD 9/10 (n = 135), and Haplo (n = 178). Acute GVHD II-IV was higher in all groups compared to MSD. Extensive chronic (c) GVHD was significantly higher in UD 9/10 (HR = 2.52; 95% CI 1.55-4.11, p = 0.0002) and UD 10/10 (HR = 1.48; 95% CI 1.03-2.13, p = 0.036) and cGVHD all grades were higher in UD 9/10 vs MSD (HR = 1.77; 95% CI 1.26-2.49, p = 0.0009). Non-relapse mortality was higher in all groups compared to MSD. Relapse incidence, leukemia-free, and overall survival did not differ significantly between donor types. Finally, GVHD-free relapse-free survival was lower in HSCT from UD 9/10 (HR = 1.56, 95% CI 1.20-2.03, p = 0.0009) but not in those from UD 10/10 (HR = 1.13, p = 0.22) and Haplo donors (HR = 1.12, p = 0.43) compared to MSD. In conclusion, in AML patients undergoing HSCT in CR1 achieved after two induction courses 10/10 UD and Haplo but not 9/10 UD donors are comparable alternatives to MSD.

Acute Myeloid Leukemia Stem Cells in Minimal/Measurable Residual Disease Detection

Acute myeloid leukemia (AML) is a hematological malignancy characterized by an abundance of incompletely matured or immature clonally derived hematopoietic precursors called leukemic blasts. Rare leukemia stem cells (LSCs) that can self-renew as well as give rise to leukemic progenitors comprising the bulk of leukemic blasts are considered the cellular reservoir of disease initiation and maintenance. LSCs are widely thought to be relatively resistant as well as adaptive to chemotherapy and can cause disease relapse. Therefore, it is imperative to understand the molecular bases of LSC forms and functions during different stages of disease progression, so we can more accurately identify these cells and design therapies to target them. Irrespective of the morphological, cytogenetic, and cellular heterogeneity of AML, the uniform, singularly important and independently significant prognosticator of disease response to therapy and patient outcome is measurable or minimal residual disease (MRD) detection, defined by residual disease detection below the morphology-based 5% blast threshold. The importance of LSC identification and frequency estimation during MRD detection, in order to make MRD more effective in predicting disease relapse and modifying therapeutic regimen is becoming increasingly apparent. This review focuses on summarizing functional and cellular composition-based LSC identification and linking those studies to current techniques of MRD detection to suggest LSC-inclusive MRD detection as well as outline outstanding questions that need to be addressed to improve the future of AML clinical management and treatment outcomes.

Venetoclax: A New Partner in the Novel Treatment Era for Acute Myeloid Leukemia and Myelodysplastic Syndrome

BACKGROUND

Acute Myeloid Leukemia (AML) and Myelodysplastic Syndrome (MDS) are two closely related blood cancers that are more frequent in older adults. AML is the most common type of adult acute leukemia, and MDS is characterized by ineffective blood cell production and abnormalities in the bone marrow and blood. Both can be resistant to treatment, often due to dysfunction in the process of apoptosis, the body's natural mechanism for cell death. Venetoclax, an orally-administered medication that selectively targets the BCL-2 protein, has shown promise in enhancing treatment sensitivity in some hematological malignancies by reducing the apoptotic threshold. This review aims to evaluate the effectiveness of venetoclax in treating AML and MDS, as well as potential mechanisms of resistance to the medication.

METHODS

A literature search was conducted utilizing PUBMED to capture all relevant research articles on the use of venetoclax as a therapy for both diseases. The MeSH terms "acute myeloid leukemia", "myelodysplastic syndrome" and "venetoclax" were searched. Furthermore, Clinicaltrials.gov was accessed to ensure the inclusion of all ongoing clinical trials.

RESULTS

Although Venetoclax showed modest results as a single-agent therapy in AML, venetoclax-based combination therapies? mainly with hypomethylating agents or low-dose cytarabine? yielded significantly positive results. Preliminary results oN the use of venetoclax-based combination therapy with HMA, mainly azacitidine, in unfit high-risk MDS also yielded optimistic results. Identification of mutations for which various drugs have been approved has spurred active investigation of venetoclax in combination trials.

CONCLUSION

Venetoclax-based combination therapies have been shown to induce rapid responses and increase overall survival in AML patients unfit for intensive chemotherapy. These therapies are also yielding positive preliminary results in high-risk MDS patients in phase I trials. Resistance to venetoclax and drug-related toxicity are two main obstacles that need to be overcome to reap the full benefits of this therapy.

Acute myeloid leukemia: 2023 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Acute myeloid leukemia (AML) is a frequently fatal bone marrow stem cell cancer characterized by unbridled proliferation of malignant marrow stem cells with associated infection, anemia, and bleeding. An improved understanding of pathophysiology, improvements in measurement technology and at least 10 recently approved therapies have led to revamping the diagnostic, prognostic, and therapeutic landscape of AML.

DIAGNOSIS

One updated and one new classification system were published in 2022, both emphasizing the integration of molecular analysis into daily practice. Differences between the International Consensus Classification and major revisions from the previous 2016 WHO system provide both challenges and opportunities for care and clinical research.

RISK ASSESSMENT AND MONITORING

The European Leukemia Net 2022 risk classification integrates knowledge from novel molecular findings and recent trial results, as well as emphasizing dynamic risk based on serial measurable residual disease assessment. However, how to leverage our burgeoning ability to measure a small number of potentially malignant myeloid cells into therapeutic decision making is controversial.

RISK ADAPTED THERAPY

The diagnostic and therapeutic complexity plus the availability of newly approved agents requires a nuanced therapeutic algorithm which should integrate patient goals of care, comorbidities, and disease characteristics including the specific mutational profile of the patient's AML. The framework we suggest only represents the beginning of the discussion.

An 8-year pragmatic observation evaluation of the benefits of allogeneic HCT in older and medically infirm patients with AML

We designed a prospective, observational study enrolling patients presenting for treatment of acute myeloid leukemia (AML) at 13 institutions to analyze associations between hematopoietic cell transplantation (HCT) and survival, quality of life (QOL), and function in: the entire cohort, those aged ≥65 years, those with high comorbidity burden, intermediate cytogenetic risk, adverse cytogenetic risk, and first complete remission with or without measurable residual disease. Patient were assessed 8 times over 2 years. Time-dependent regression models were used. Among 692 patients that were evaluable, 46% received HCT with a 2-year survival of 58%. In unadjusted models, HCT was associated with reduced risks of mortality most of the subgroups. However, after accounting for covariates associated with increased mortality (age, comorbidity burden, disease risks, frailty, impaired QOL, depression, and impaired function), the associations between HCT and longer survival disappeared in most subgroups. Although function, social life, performance status, and depressive symptoms were better for those selected for HCT, these health advantages were lost after receiving HCT. Recipients and nonrecipients of HCT similarly ranked and expected cure as main goal of therapy, whereas physicians had greater expectations for cure than the former. Accounting for health impairments negates survival benefits from HCT for AML, suggesting that the unadjusted observed benefit is mostly owing to selection of the healthier candidates. Considering patients' overall expectations of cure but also the QOL burdens of HCT motivate the need for randomized trials to identify the best candidates for HCT. This trial was registered at www.clinicaltrials.gov as #NCT01929408.

How to improve the outcomes of elderly acute myeloid leukemia patients through allogeneic hematopoietic stem cell transplantation

In recent years, with the gradual advancement of haploidentical transplantation technology, the availability of donors has increased significantly, along with the widespread use of reduced-intensity conditioning and the improvement of nursing techniques, giving more elderly acute myeloid leukemia (AML) patients the chance to receive allogeneic hematopoietic stem cell transplantation. We have summarized the classic and recently proposed pre-transplant assessment methods and assessed the various sources of donors, conditioning regimens, and post-transplant complication management based on the outcomes of large-scale clinical studies for elderly AML patients.

The mythological chimera and new era of relapse prediction post-transplant

Allogeneic hemopoietic stem cell transplantation is the treatment of choice for high-risk or relapsed acute leukemia. However, unfortunately, relapse post-transplant continues to be the most common cause of treatment failure with 20-80% of patients relapsing based on disease risk and status at transplant. Advances in molecular profiling of different hematological malignancies have enabled us to monitor low level disease before and after transplant and develop a more personalized approach to the management of these disease including early detection post-transplant. While, in general, detectable disease by morphology remains the gold standard to diagnosing relapse, multiple approaches have allowed detection of cancer cells earlier, using peripheral blood-based methods with sensitivities as high as 1:10⁶, together called minimal/measurable residual disease (MRD) detection. However, a in significant number of patients with acute leukemia where no such molecular markers exist it remains challenging to detect early relapse. In such patients who receive transplantation, chimerism monitoring remains the only option. An increase in mixed chimerism in post allogeneic HCT patients has been correlated with relapse in multiple studies. However, chimerism monitoring, while commonly accepted as a tool for assessing engraftment, has not been routinely used for relapse detection, at least in part because of the lack of standardized, high sensitivity, reliable methods for chimerism detection. In this paper, we review the various methods employed for MRD and chimerism detection post-transplant and discuss future trends in MRD and chimerism monitoring from the viewpoint of the practicing transplant physician.

Real-world clinical outcomes with enasidenib in relapsed or refractory acute myeloid leukemia

Enasidenib was approved by the Food and Drug Administration in 2017 for the treatment of patients with relapsed or refractory (RR) acute myeloid leukemia (AML) with an isocitrate dehydrogenase-2 (IDH2) mutation. Given limited data in clinical practice, this study assessed real-world clinical outcomes and healthcare resource use in patients with RR AML. Physicians performed chart abstraction of patients with RR IDH2-mutated AML treated with enasidenib (between 1/2018 and 6/2019) or other first-line (1 L) RR therapy (between 1/2016 and 7/2017). Progression-free survival (PFS) and overall survival (OS) were estimated by the Kaplan-Meier method, and adjusted risk of progression and death were estimated by multivariable Cox proportional hazard models. Among 124 patients treated with enasidenib and 76 patients treated with other 1 L RR therapy, overall response rate was higher among patients treated with enasidenib vs. other 1 L RR therapies (77% vs. 52%, p < 0.01). After a median follow-up of 9 and 6 months, median PFS was 8 months in enasidenib-treated patients and 5 months in patients receiving other 1 L RR therapy, respectively (adjusted HR=0.36, 95% CI: 0.23-0.57, p < 0.01). Median OS was 11 and 6 months in enasidenib-treated patients and patients receiving other 1 L RR therapy, respectively (adjusted HR=0.37, 95% CI: 0.22-0.60, p < 0.01). Fewer enasidenib-treated patients were hospitalized during 1 L RR therapy vs. those receiving other therapies (14% vs. 46%, p < 0.01). Results from this real-world study confirm the effectiveness of enasidenib among patients with IDH2-mutated RR AML and demonstrate that hospitalizations were significantly lower vs. other 1 L RR treatment in clinical practice.

Retrospective comparison of survival and responses to Fludarabine, Cytarabine, GCSF (FLAG) in combination with gemtuzumab ozogamicin (GO) or Idarubicin (IDA) in patients with newly diagnosed core binding factor (CBF) acute myelogenous leukemia: MD Anderson experience in 174 patients

Fludarabine, cytarabine, GCSF (FLAG)-based induction/consolidation results in high remission rates in core binding factor (CBF) acute myelogenous leukemia. We treated 174 consecutive patients with newly diagnosed CBF-AML in a prospective clinical trial of FLAG-based induction/consolidation in combination with gemtuzumab ozogamicin (FLAG-GO; N = 65) or in combination with idarubicin (FLAG-IDA; N = 109). The 5 year RFS in the FLAG-GO cohort was significantly better than the FLAG-IDA cohort, 78% versus 59%, respectively (p-value = .02). In multivariate analysis for RFS, age (p = .0001), FLAG-GO regimen (p = .04), 4 log reduction in CBF-related fusion transcript by quantitative polymerase chain reaction (qPCR) in bone marrow samples at end of consolidation therapy (p = .03), and additional cytogenetic abnormalities (p = .03) were significant variables. Lower age (p = .0001) and 3 log or more transcript reduction at end of induction (p = .04) were significant variables predicting for better overall survival (OS), while there was strong trend for better OS with FLAG-GO (p = .06) regimen. FLAG-GO regimen was superior in optimal disease specific fusion transcript reduction at end of induction (p = .002), mid-consolidation (p < .01), and end of consolidation (p < .001) therapy. Induction/consolidation with FLAG-GO regimen results in better clinical outcomes in newly diagnosed patients with CBF-AML compared to FLAG-IDA and achieves deeper molecular clearance by qPCR assessment of the fusion transcripts.

Venetoclax combined with FLAG-IDA induction and consolidation in newly diagnosed acute myeloid leukemia

Multi-agent induction chemotherapy (IC) improves response rates in younger patients with acute myeloid leukemia (AML); however, relapse remains the principal cause of treatment failure. Improved induction regimens are needed. A prospective single-center phase Ib/II study evaluating fludarabine, cytarabine, G-CSF, and idarubicin combined with venetoclax (FLAG-IDA + VEN) in patients with newly diagnosed (ND) or relapsed/refractory AML. The primary efficacy endpoint was assessment of overall activity (overall response rate [ORR]: complete remission [CR] + CR with partial hematologic recovery [CRh] + CR with incomplete hematologic recovery [CRi] + morphologic leukemia free state + partial response). Secondary objectives included additional assessments of efficacy, overall survival (OS), and event-free survival (EFS). Results of the expanded ND cohort with additional follow-up are reported. Forty-five patients (median age: 44 years [range 20-65]) enrolled. ORR was 98% (N = 44/45; 95% credible interval 89.9%-99.7%). Eighty-nine percent (N = 40/45) of patients attained a composite CR (CRc + CRh + CRi) including 93% (N = 37/40) who were measurable residual disease (MRD) negative. Twenty-seven (60%) patients transitioned to allogeneic stem cell transplant (alloHSCT). Common non-hematologic adverse events included febrile neutropenia (44%; N = 20), pneumonia (22%, N = 10), bacteremia (18%, N = 8), and skin/soft tissue infections (44%, N = 20). After a median follow-up of 20 months, median EFS and OS were not reached. Estimated 24-month EFS and OS were 64% and 76%, respectively. FLAG-IDA + VEN is an active regimen in ND-AML capable of producing high MRD-negative remission rates and enabling transition to alloHSCT when appropriate in most patients. Toxicities were as expected with IC and were manageable. Estimated 24-month survival appears favorable compared to historical IC benchmarks.

Pediatric acute myeloid leukemia patients with KMT2A rearrangements: a single-center retrospective study

PURPOSE

Pediatric acute myeloid leukemia (AML) with KMT2A rearrangements has a very different prognosis. Poor outcomes cannot be avoided even after hematopoietic stem cell transplantation. In order to investigate the prognosis and efficacy, we conducted a retrospective analysis.

PATIENTS AND METHODS

We retrospectively analyzed a total of 32 children with KMT2A rearrangements AML treated in our hospital between January 2015 and February 2021.

RESULTS

The proportion of patients with KMT2A-rearranged in the medium-risk group of overall survival (OS) and event-free survival (EFS) was 100%. No differences in OS, EFS and cumulative incidence of relapse (CIR) were detected between the haploidentical hematopoietic stem cell transplantation (haplo-HSCT) and full matched HSCT (P = 0.289, P = 0.303, P = 0.303). Acute graft-versus-host disease (aGVHD) was often detected in the haplo-HSCT cohort, while full matched HSCT had no obvious aGVHD, assessed as≤1 grade (P < 0.05). Patients in the medium-risk pediatric group could acquire 100% OS and EFS only after chemotherapy. There was no significant difference in OS, EFS and CIR between full matched HSCT and haploidentical transplantation in pediatric AML with KMT2A rearrangements, but full matched HSCT seemed to have a lower death rate. The severity of aGVHD in the full matched HSCT was less than that in the haploidentical transplantation group.

CONCLUSION

The primary choice of donor can be HLA-matched sibling donors or matched unrelated donors for children with AML with KMT2A rearrangements, and the secondary choice can be haploid donors.

Impact of the MRD status in AML patients undergoing allogeneic stem cell transplantation in first vs second remission

Allogeneic hematopoietic stem cell transplantation (HSCT) offers the best chance for relapse-free survival to most acute myeloid leukemia (AML) patients. It might be performed in complete remission or delayed until after first relapse due to relevant treatment-related morbidity and mortality. The measurable residual disease (MRD) status at HSCT adds refined prognostic information to the assigned European LeukemiaNet (ELN) 2017 genetic risk at diagnosis. We analyzed 580 AML patients receiving allogeneic HSCT in either first (79%) or second (21%) remission. Although - due to common treatment strategies - some adverse risk characteristics, such as monosomal or complex karyotypes were less frequent in patients transplanted in second remission, they had worse outcomes compared to patients transplanted in first remission. The MRD status at HSCT was an independent prognostic factor irrespective of the number of remission at HSCT. Noteworthy, MRDpos patients transplanted in first remission and MRDneg patients transplanted in second remission had similar outcomes. In the clinically highly relevant group of ELN2017 intermediate risk individuals, the MRD status provided the highest prognostic value with very dismal outcomes of patients transplanted in MRDpos second remission. The adverse outcomes of MRDpos patients and individuals transplanted in second remission should be considered when planning consolidation treatment, to avert an allogeneic HSCT in MRDpos second remission when possible.

Cytogenetic risk classification maintains its prognostic significance in transplanted FLT3-ITD mutated acute myeloid leukemia patients: On behalf of the acute leukemia working party/European society of blood and marrow transplantation

FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) mutational status is a pivotal prognosticator in acute myeloid leukemia (AML) patients and significantly increases the risk of disease relapse. However, it remains unclear whether in FLT3-ITD patients referred for allogeneic stem cell transplantation (allo-SCT), baseline cytogenetics significantly impacts clinical outcome. Using the European Society of Blood and Marrow Transplantation registry, we performed a retrospective analysis of 1631 FLT3-ITD AML patients who underwent allo-SCT with the aim of determining the influence of cytogenetic risk category on patient outcomes. Median patient age was 49 years and median follow-up duration was 36 months. Two-year leukemia-free survival (LFS) and incidence of relapse were 54% and 31.6%, respectively. Non-relapse mortality was experienced by 14.4% with a 2-year overall survival (OS) of 60.1%. On multivariate analysis, LFS was significantly lower in patients with intermediate and adverse risk cytogenetics compared with those with favorable risk cytogenetics, (hazard ratio [HR] = 1.48, 95% confidence interval [CI], 1.06-2.06; p = .02), and (HR = 01.65, 95% CI, 1.13-2.40; p = .009), respectively. OS was significantly lower in patients with adverse risk cytogenetics compared with patients with favorable risk cytogenetics (HR = 1.74, 95% CI, 1.16-2.61; p = .008) with a trend toward lower OS in patients with intermediate risk cytogenetics compared to those with favorable risk cytogenetics (HR = 1.43, 95% CI, 1.00-2.05; p = .052). In addition, adverse risk patients and intermediate risk patients experienced higher relapse rates compared with favorable risk patients (HR = 1.83, 95% CI, 1.13-2.94; p = .013 and HR = 1.82, 95% CI, 1.19-2.77; p = .005). Overall, cytogenetic studies aid in refinement of risk stratification in transplanted FLT3-ITD AML patients.

Chemotherapy or Allogeneic Stem Cell Transplantation as Salvage Therapy for Patients with Refractory Acute Myeloid Leukemia: A Multicenter Analysis

Introduction

The overall outcome of patients with refractory AML (rAML) remains poor. Though allogeneic hematopoietic stem cell transplantation (allo-HSCT) is considered as the only curative therapy, it is routinely recommended only for patients after remission with salvage chemotherapy.

Objective

In this study, we evaluated the impact of salvage chemotherapy or allo-HSCT on the overall outcome in rAML.

Methods

We collected the clinical data of 220 patients from 4 medical centers and performed retrospective analysis of prognosis factors, including salvage chemotherapy, intensity of chemotherapy, and allo-HSCT.

Results

A total of 29 patients received allo-HSCT directly without salvage chemotherapy, 26 patients achieved complete remission (CR) or complete remission with incomplete hematological recovery (CRi) after transplantation and 4-year leukemia-free survival (LFS) and overall survival (OS) were 45.0 ± 10.7 and 51.0 ± 10.6%, respectively. Another 191 patients received salvage chemotherapy and 81 (42.2%) achieved CR or CRi. Thirty-four patients among them underwent subsequent allo-HSCT with 4-year LFS and OS of 46.0 ± 8.8 and 46.2 ± 9.0%. The 4-year LFS and OS in 26 patients who failed to obtain CR or CRi but received allo-HSCT with active disease were 32.9 ± 10.0 and 36.9 ± 10.8%, respectively. For patients who received salvage chemotherapy but not allo-HSCT, few of them became long-term survivors. In multivariate analysis, salvage chemotherapy and the intensity of chemotherapy failed to have significant impact on both OS and LFS. Allo-HSCT was the only prognostic factor for improved OS and LFS in multivariate analysis.

Conclusions

These results indicate the benefit of allo-HSCT in patients with rAML and direct allo-HSCT without salvage chemotherapy could be treatment option.

Allogeneic Stem Cell Transplantation with Sequential Melphalan-Based Conditioning in AML: Residual Morphological Blast Count Determines the Risk of Relapse

Introduction

Allogeneic hematopoietic cell transplantation (HCT) during chemotherapy-induced aplasia may offer long-term survival in acute myeloid leukemia (AML) with otherwise poor prognosis including ELN adverse risk, relapsed or refractory disease. However, the value of residual morphologic disease prior HCT in this context has not been conclusively settled until yet. Therefore, we aimed to investigate variables predicting outcome in this unique setting of sequential conditioning therapy, with a focus on pretreatment morphologic blast count. In contrast to the most popular FLAMSA-RIC protocol, we used a melphalan-based conditioning regimen during aplasia.

Methods

We retrospectively analyzed data from 173 AML patients who underwent a sequential melphalan-based conditioning therapy between 2003 and 2015 at our centre. All patients participated either in the prospective Phase 2 BRIDGE trial (NCT01295307), the Phase 3 AML2003 study (NCT00180102) or were treated according to this protocol and underwent allogeneic HCT after melphalan-based conditioning in treatment-induced aplasia.

Results

Median bone marrow blast count prior to conditioning was 10% (range, 0–96%). Four year probabilities of EFS and OS were 34% (95% CI, 28–43%) and 43% (95% CI, 36–52%), respectively. In multivariate analysis, blast count >20% was associated with worse EFS (HR = 1.93; p = 0.009) and OS (HR = 1.80; p = 0.026). This effect was not significant anymore for HCT during 1st line therapy.

Conclusion

Allogeneic HCT in aplasia with a melphalan-based conditioning regimen has the potential to cure a subset of adverse risk AML patients, even with persistent morphological disease prior HCT. However, a high pre-transplant blast count still indicates patients with a dismal prognosis, especially in the relapsed patient group, for whom post-transplant strategies should be considered to further optimize post HCT outcome.

Impact of NK Cell Activating Receptor Gene Variants on Receptor Expression and Outcome of Immunotherapy in Acute Myeloid Leukemia

Natural killer cells are important effector cells in the immune response against myeloid malignancies. Previous studies show that the expression of activating NK cell receptors is pivotal for efficient recognition of blasts from patients with acute myeloid leukemia (AML) and that high expression levels impact favorably on patient survival. This study investigated the potential impact of activating receptor gene variants on NK cell receptor expression and survival in a cohort of AML patients receiving relapse-preventive immunotherapy with histamine dihydrochloride and low-dose IL-2 (HDC/IL-2). Patients harboring the G allele of rs1049174 in the KLRK1 gene encoding NKG2D showed high expression of NKG2D by CD56^bright NK cells and a favorable clinical outcome in terms of overall survival. For DNAM-1, high therapy-induced receptor expression entailed improved survival, while patients with high DNAM-1 expression before immunotherapy associated with unfavorable clinical outcome. The previously reported SNPs in NCR3 encoding NKp30, which purportedly influence mRNA splicing into isoforms with discrete functions, did not affect outcome in this study. Our results imply that variations in genes encoding activating NK cell receptors determine receptor expression and clinical outcome in AML immunotherapy.

A Phase II Trial of the Double Epigenetic Priming Regimen Including Chidamide and Decitabine for Relapsed/Refractory Acute Myeloid Leukemia

Objective

To explore the role of chidamide, decitabine plus priming regimen in the salvage treatment of relapsed/refractory acute myeloid leukemia.

Methods

A clinical trial was conducted in relapsed/refractory acute myeloid leukemia patients using chidamide, decitabine, cytarabine, idarubicin, and granulocyte-colony stimulating factor, termed CDIAG, a double epigenetic priming regimen.

Results

Thirty-five patients were recruited. Three patients received 2 treatment cycles. In 32 evaluable patients and 35 treatment courses, the completed remission rate (CRR) was 42.9%. The median OS time was 11.7 months. The median OS times of responders were 18.4 months, while those of nonresponders were 7.4 months (P = 0.015). The presence of RUNX1 mutations was associated with a high CRR but a short 2-year OS (P = 0.023) and PFS (P = 0.018) due to relapse after treatment. The presence of IDH mutations had no effect on the remission rate (80.0% vs. 73.3%), but showed a better OS (2-year OS rate: 100.0% vs. 28.9%). Grade 3/4 nonhematological adverse events included pneumonia, hematosepsis, febrile neutropenia, skin and soft tissue infection and others.

Conclusion

The double epigenetic priming regimen (CDIAG regimen) showed considerably good antileukemia activity in these patients. Adverse events were acceptable according to previous experience. The study was registered as a clinical trial.

Clinical Trial Registration

https://clinicaltrials.gov/, identifier:NCT03985007

Thrombopoietin-based CAR-T cells demonstrate in vitro and in vivo cytotoxicity to MPL positive acute myelogenous leukemia and hematopoietic stem cells

While targeting CD19+ hematologic malignancies with CAR T cell therapy using single chain variable fragments (scFv) has been highly successful, novel strategies for applying CAR T cell therapy with other tumor types are necessary. In the current study, CAR T cells were designed using a ligand binding domain instead of an scFv to target stem-like leukemia cells. Thrombopoietin (TPO), the natural ligand to the myeloproliferative leukemia protein (MPL) receptor, was used as the antigen binding domain to engage MPL expressed on hematopoietic stem cells (HSC) and erythropoietic and megakaryocytic acute myeloid leukemias (AML). TPO-CAR T cells were tested in vitro against AML cell lines with varied MPL expression to test specificity. TPO-CAR T cells were specifically activating and cytotoxic against MPL+ leukemia cell lines. Though the TPO-CAR T cells did not extend survival in vivo, it successfully cleared the MPL+ fraction of leukemia cells. As expected, we also show the TPO-CAR is cytotoxic against MPL expressing bone marrow compartment in AML xenograft models. The data collected demonstrate preclinical potential of TPO-CAR T cells for stem-like leukemia through assessment of targeted killing of MPL+ cells and may facilitate subsequent HSC transplant under reduced intensity conditioning regimens.

Characteristics and outcome of patients with core-binding factor acute myeloid leukemia and FLT3-ITD: results from an international collaborative study

The aim of this study was to evaluate the prognostic impact of FLT3-ITD in core-binding factor acute myeloid leukemia (CBFAML) in an international, multicenter survey of 97 patients of whom 52% had t(8;21)(q22;q22) and 48% had inv(16)(p13q22)/t(16;16)(p13;q22). The median age of the patients was 53 years (range, 19-81). Complete remission after anthracycline-based induction (n=86) and non-intensive therapy (n=11) was achieved in 97% and 36% of the patients, respectively. The median follow-up was 4.43 years (95% confidence interval [95% CI]: 3.35-7.39 years). The median survival after intensive and non-intensive treatment was not reached and 0.96 years, respectively. Among intensively treated patients, inv(16) with trisomy 22 (n=11) was associated with a favorable 4-year relapse-free survival rate of 80% (95% CI: 59-100%) as compared to 38% (95% CI: 27-54%; P=0.02) in all other patients with CBFAML/ FLT3-ITD (n=75). Overall, 24 patients underwent allogeneic hematopoietic cell transplantation (HCT), 12 in first complete remission and 12 after relapse. Allogeneic HCT in first complete remission was not beneficial (P=0.60); however, allogeneic HCT seemed to improve median survival in relapsed patients compared to that of patients treated with chemotherapy (not reached vs. 0.6 years, respectively; P=0.002). Excluding patients with inv(16) with trisomy 22, our data indicate that compathe outcome of CBF-AML patients with FLT3-ITD may be inferior to that of patients without FLT3-ITD (based on previously published data), suggesting that prognostically CBF-AML patients with FLT3-ITD should not be classified as favorable-risk. FLT3-inhibitors may improve the outcome of these patients.

A Pilot Study of Allogeneic Hematopoietic Stem Cell Transplantation for Intermediated-risk Acute Myeloid Leukemia Patients

BACKGROUND/AIM

For intermediate risk acute myeloid leukemia patients, allogeneic hematopoietic stem cell transplantation (alloSCT) and chemotherapy are equally recommended as consolidation after first complete remission (CR1). In real-world, alloSCT might not be readily available, but there is paucity of data on the optimal timing of alloSCT for these patients.

PATIENTS AND METHODS

In this pilot study, we compared the outcomes of 13 patients undergoing alloSCT in CR1 with 13 patients undergoing alloSCT after relapse (non-CR1) to examine whether upfront alloSCT yields a better prognosis.

RESULTS

There were no differences between the two groups with regards to relapse-free survival (p=0.507) and overall survival (p=0.798). There were more chronic graft-versus-host-disease (GVHD) in the CR1 group compared to the non-CR group (p=0.001), but no difference in acute GVHD.

CONCLUSION

The outcome of alloSCT after relapse is not inferior to that of alloSCT in CR1, supporting the role of alloSCT after relapse in the setting of limited donors and resources.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The effect of the detection of minimal residual disease for the prognosis and the choice of post-remission therapy of intermediate-risk acute myeloid leukemia without FLT3-ITD, NPM1 and biallelic CEBPA mutations

BACKGROUND

Intermediate-risk acute myeloid leukemia (IR-AML) without FLT3-ITD, NPM1 and biallelic CEBPA mutations (here referred to as NPM1^mut-negCEBPA^dm-negFLT3-ITD^neg AML) is a clinically heterogeneous disease. The optimal post-remission therapy (PRT) is unclear for patients with NPM1^mut-negCEBPA^dm-negFLT3-ITD^neg AML who achieved first complete response (CR1). This study aims to explore clinical and molecular factors that can help determine the prognosis of those patients and their choice of PRT.

METHODS

We retrospectively analyzed 28 patients with NPM1^mut-negCEBPA^dm-negFLT3-ITD^neg AML who received induction chemotherapy and achieved CR1. For PRT, 17 patients received post-remission chemotherapy (PR-CT) and 11 patients received allogeneic hematopoietic stem cell transplantation (allo-HSCT).

RESULTS

For patients with NPM1^mut-negCEBPA^dm-negFLT3-ITD^neg AML, multivariate analysis indicated that allo-HSCT and negative minimal residual disease (MRD^neg) before PRT were favorable prognostic factors of overall survival (OS) (allo-HSCT, P = 0.002; MRD^neg, P = 0.018); whereas relapse was an adverse prognostic factor of OS (P = 0.003). Log-rank analysis showed that allo-HSCT significantly improved their OS and RFS compared with PR-CT (OS, P < 0.001; RFS, P = 001). Otherwise, allo-HSCT improved the OS and RFS of patients with NPM1^mut-negCEBPA^dm-negFLT3-ITD^neg AML, whether they obtained MRD^pos or MRD^neg before PRT (OS: MRD^neg, P = 0.036; MRD^pos, P = 0.012; RFS: MRD^neg, P = 0.047; MRD^pos, P = 0.030).

CONCLUSION

For patients with NPM1^mut-negCEBPA^dm-negFLT3-ITD^neg AML, MRD^neg before PRT and allo-HSCT were favorable prognostic factors of OS. Whether they obtain MRD^neg or not, allo-HSCT is the preferred PRT.

Measurable residual disease status and outcome of transplant in acute myeloid leukemia in second complete remission: a study by the acute leukemia working party of the EBMT

Measurable residual disease (MRD) prior to hematopoietic cell transplant (HCT) for acute myeloid leukemia (AML) in first complete morphological remission (CR1) is an independent predictor of outcome, but few studies address CR2. This analysis by the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation registry assessed HCT outcomes by declared MRD status in a cohort of 1042 adult patients with AML CR2 at HCT. Patients were transplanted 2006–2016 from human leukocyte antigen (HLA) matched siblings (n = 719) or HLA 10/10 matched unrelated donors (n = 293). Conditioning was myeloablative (n = 610) or reduced-intensity (n = 432) and 566 patients (54%) had in-vivo T cell depletion. At HCT, 749 patients (72%) were MRD negative (MRD NEG) and 293 (28%) were MRD positive (MRD POS). Time from diagnosis to HCT was longer in MRD NEG than MRD POS patients (18 vs. 16 months (P < 0.001). Two-year relapse rates were 24% (95% CI, 21–28) and 40% (95% CI, 34–46) in MRD NEG and MRD POS groups (P < 0.001), respectively. Leukemia-free survival (LFS) was 57% (53–61) and 46% (40–52%), respectively (P = 0.001), but there was no difference in terms of overall survival. Prognostic factors for relapse and LFS were MRD NEG status, good risk cytogenetics, and longer time from diagnosis to HCT. In-vivo T cell depletion predicted relapse.

Allogeneic Stem Cell Transplantation for Acute Myeloid Leukemia: Who, When, and How?

Although the majority of patients with acute myeloid leukemia (AML) treated with intensive chemotherapy achieve a complete remission (CR), many are destined to relapse if treated with intensive chemotherapy alone. Allogeneic stem cell transplant (allo-SCT) represents a pivotally important treatment strategy in fit adults with AML because of its augmented anti-leukemic activity consequent upon dose intensification and the genesis of a potent graft-versus-leukemia effect. Increased donor availability coupled with the advent of reduced intensity conditioning (RIC) regimens has dramatically increased transplant access and consequently allo-SCT is now a key component of the treatment algorithm in both patients with AML in first CR (CR1) and advanced disease. Although transplant related mortality has fallen steadily over recent decades there has been no real progress in reducing the risk of disease relapse which remains the major cause of transplant failure and represents a major area of unmet need. A number of therapeutic approaches with the potential to reduce disease relapse, including advances in induction chemotherapy, the development of novel conditioning regimens and the emergence of the concept of post-transplant maintenance, are currently under development. Furthermore, the use of genetics and measurable residual disease technology in disease assessment has improved the identification of patients who are likely to benefit from an allo-SCT which now represents an increasingly personalized therapy. Future progress in optimizing transplant outcome will be dependent on the successful delivery by the international transplant community of randomized prospective clinical trials which permit examination of current and future transplant therapies with the same degree of rigor as is routinely adopted for non-transplant therapies.

Optimizing Transplant Approaches and Post-Transplant Strategies for Patients With Acute Myeloid Leukemia

Acute Myeloid Leukemia (AML) is the commonest indication for allogeneic stem cell transplantation (allo-SCT) worldwide. The increasingly important role of allo-SCT in the management of AML has been underpinned by two important advances. Firstly, improvements in disease risk stratification utilizing genetic and Measurable Residual Disease (MRD) technologies permit ever more accurate identification of allo-mandatory patients who are at high risk of relapse if treated by chemotherapy alone. Secondly, increased donor availability coupled with the advent of reduced intensity conditioning (RIC) regimens has substantially expanded transplant access for patients with high risk AML In patients allografted for AML disease relapse continues to represent the commonest cause of transplant failure and the development of novel strategies with the potential to reduce disease recurrence represents a major unmet need.

Unsupervised Flow Cytometry Analysis Allows for an Accurate Identification of Minimal Residual Disease Assessment in Acute Myeloid Leukemia

The assessment of minimal residual disease (MRD) is increasingly considered to monitor response to therapy in hematological malignancies. In acute myeloblastic leukemia (AML), molecular MRD (mMRD) is possible for about half the patients while multiparameter flow cytometry (MFC) is more broadly available. However, MFC analysis strategies are highly operator-dependent. Recently, new tools have been designed for unsupervised MFC analysis, segregating cell-clusters with the same immunophenotypic characteristics. Here, the Flow-Self-Organizing-Maps (FlowSOM) tool was applied to assess MFC-MRD in 96 bone marrow (BM) follow-up (FU) time-points from 40 AML patients with available mMRD. A reference FlowSOM display was built from 19 healthy/normal BM samples (NBM), then simultaneously compared to the patient's diagnosis and FU samples at each time-point. MRD clusters were characterized individually in terms of cell numbers and immunophenotype. This strategy disclosed subclones with varying immunophenotype within single diagnosis and FU samples including populations absent from NBM. Detectable MRD was as low as 0.09% in MFC and 0.051% for mMRD. The concordance between mMRD and MFC-MRD was 80.2%. MFC yielded 85% specificity and 69% sensitivity compared to mMRD. Unsupervised MFC is shown here to allow for an easy and robust assessment of MRD, applicable also to AML patients without molecular markers.

MRD Tailored Therapy in AML: What We Have Learned So Far

Acute myeloid leukemia (AML) is a heterogeneous clonal disease associated with a dismal survival, partly due to the frequent occurrence of relapse. Many patient- and leukemia-specific characteristics, such as age, cytogenetics, mutations, and measurable residual disease (MRD) after intensive chemotherapy, have shown to be valuable prognostic factors. MRD has become a rich field of research where many advances have been made regarding technical, biological, and clinical aspects, which will be the topic of this review. Since many laboratories involved in AML diagnostics have experience in immunophenotyping, multiparameter flow cytometry (MFC) based MRD is currently the most commonly used method. Although molecular, quantitative PCR based techniques may be more sensitive, their disadvantage is that they can only be applied in a subset of patients harboring the genetic aberration. Next-generation sequencing can assess and quantify mutations in many genes but currently does not offer highly sensitive MRD measurements on a routine basis. In order to provide reliable MRD results, MRD assay optimization and standardization is essential. Different techniques for MRD assessment are being evaluated, and combinations of the methods have shown promising results for improving its prognostic value. In this regard, the load of leukemic stem cells (LSC) has also been shown to add to the prognostic value of MFC-MRD. At this moment, MRD after intensive chemotherapy is most often used as a prognostic factor to help stratify patients, but also to select the most appropriate consolidation therapy. For example, to guide post-remission treatment for intermediate-risk patients where MRD positive patients receive allogeneic stem cell transplantation and MRD negative receive autologous stem cell transplantation. Other upcoming uses of MRD that are being investigated include: selecting the type of allogeneic stem cell transplantation therapy (donor, conditioning), monitoring after stem cell transplantation (to allow intervention), and determining drug efficacy for the use of a surrogate endpoint in clinical trials.

Acute myeloid leukemia: 2021 update on risk-stratification and management

Management of AML involves choosing between purely palliative care, standard therapy and investigational therapy ("clinical trial"). Even most older patients likely benefit from treatment. Based on randomized trials CPX 351, midostaurin, gemtuzumab ozogamicin, and venetoclax, the latter three when combined with other drugs, should now be considered standard therapy. Knowledge of the likely results with these therapies is essential in deciding whether to recommend them or participate in a clinical trial, possibly including these drugs. Hence here, in the context of established prognostic algorithms, we review results with the recently- approved drugs compared with their predecessors and describe other potential options. We discuss benefit/risk ratios underlying the decision to offer allogeneic transplant and emphasize the importance of measurable residual disease. When first seeing a newly-diagnosed patient physicians must decide whether to offer conventional treatment or investigational therapy, the latter preferably in the context of a clinical trial. As noted below, such trials have led to changes in what today is considered "conventional" therapy compared to even 1-2 years ago. In older patients decision making has often included inquiring whether specific anti-AML therapy should be offered at all, rather than focusing on a purely palliative approach emphasizing transfusion and antibiotic support, with involvement of a palliative care specialist.

Randomized trial comparing standard vs sequential high-dose chemotherapy for inducing early CR in adult AML

Here we evaluated whether sequential high-dose chemotherapy (sHD) increased the early complete remission (CR) rate in acute myelogenous leukemia (AML) compared with standard-intensity idarubicin-cytarabine-etoposide (ICE) chemotherapy. This study enrolled 574 patients (age, 16-73 years; median, 52 years) who were randomly assigned to ICE (n = 286 evaluable) or sHD (2 weekly 3-day blocks with cytarabine 2 g/m² twice a day for 2 days plus idarubicin; n = 286 evaluable). Responsive patients were risk-stratified for a second randomization. Standard-risk patients received autograft or repetitive blood stem cell-supported high-dose courses. High-risk patients (and standard-risk patients not mobilizing stem cells) underwent allotransplantation. CR rates after 2 induction courses were comparable between ICE (80.8%) and sHD (83.6%; P = .38). sHD yielded a higher single-induction CR rate (69.2% vs 81.5%; P = .0007) with lower resistance risk (P < .0001), comparable mortality (P = .39), and improved 5-year overall survival (39% vs 49%; P = .045) and relapse-free survival (36% vs 48%; P = .028), despite greater hematotoxicity delaying or reducing consolidation blocks. sHD improved the early CR rate in high-risk AML (odds ratio, 0.48; 95% confidence interval [CI], 0.31-0.74; P = .0008) and in patients aged 60 years and less with de novo AML (odds ratio, 0.46; 95% CI, 0.27-0.78; P = .003), and also improved overall/relapse-free survival in the latter group (hazard ratio, 0.70; 95% CI, 0.52-0.94; P = .01), in standard-risk AML, and postallograft (hazard ratio, 0.61; 95% CI, 0.39-0.96; P = .03). sHD was feasible, effectively achieved rapid CR, and improved outcomes in AML subsets. This study is registered at www.clinicaltrials.gov as #NCT00495287.

Evaluation of event-free survival as a robust end point in untreated acute myeloid leukemia (Alliance A151614)

Event-free survival (EFS) is controversial as an end point for speeding approvals in newly diagnosed acute myeloid leukemia (AML). We aimed to examine the robustness of EFS, specifically timing of complete remission (CR) in defining induction failure and impact of hematopoietic cell transplantation (HCT). The study included 1884 untreated AML patients enrolled across 5 trials conducted through Alliance for Clinical Trials in Oncology using anthracycline and cytarabine induction chemotherapy. EFS was defined as time from randomization/registration to induction failure, relapse, or death. Three definitions of induction failure were evaluated: failure to achieve CR by 60 days after randomization/registration, failure to achieve CR by the end of all protocol-defined induction courses, and failure to achieve CR by the end of all protocol-defined treatment. We considered either censoring or no censoring at time of non-protocol-mandated HCT. Although relapse and death are firm end points, the determination of induction failure was not consistent across studies. There was minimal impact of censoring at HCT on EFS estimates; however, median EFS estimates differed considerably based on the timing of CR in defining induction failure, with the magnitude of difference being large enough in most cases to lead to incorrect conclusions about efficacy in a single-arm trial, if the trial definition was not consistent with the definition used for the historical control. Timing of CR should be carefully examined in the historical control data used to guide the design of single-arm trials using EFS as the primary end point. Trials were registered at www.clinicaltrials.gov as #NCT00085124, #NCT00416598, # NCT00651261, #NCT01238211, and #NCT01253070.

Reassessing the role of high dose cytarabine and mitoxantrone in relapsed/refractory acute myeloid leukemia

A substantial segment of patients with acute myeloid leukemia (AML) will relapse following an initial response to induction therapy or will prove to be primary refractory. High-dose cytarabine and mitoxantrone (HiDAC/MITO) is an established salvage therapy for these patients. We studied all adult patients with relapsed/refractory (R/R) AML who were treated with HiDAC/MITO in our center between the years 2008-2017. To determine whether responding patients harbored a unique molecular signature, we performed targeted next-generation sequencing (NGS) on a subset of patients. The study cohort consisted of 172 patients with a median age of 54 years (range 18–77). The composite complete remission rate was 58%; 11 patients (6%) died during salvage therapy. Median survival was 11.4 months with a 1-year survival rate of 48%. In multivariate analysis favorable risk cytogenetics [Odds ratio (OR)=0.34, confidence interval (CI) 95%, 0.17–0.68; P = 0.002], and de-novo AML (OR = 0.4, CI 95%, 0.16–0.98; P = 0.047) were independently associated with a favorable response. Patients who attained a complete remission had a median survival of 43.7 months compared with 5.2 months for refractory patients (p < 0.0001). Neither the FLT3-ITD and NPM1 mutational status nor the indication for salvage therapy significantly impacted on the response to HiDAC/MITO salvage. NGS analysis identified 20 different mutations across the myeloid gene spectrum with a distinct TP53 signature detected in non-responding patients. HiDAC/MITO is an effective salvage regimen in R/R AML, however patients with adverse cytogenetics or secondary disease may not benefit as much from this approach.