Characteristics and outcome of patients with acute myeloid leukemia refractory to 1 cycle of high-dose cytarabine-based induction chemotherapy

Exploration of ETV6::ABL1-positive AML with concurrent NPM1 and FLT3-ITD mutations

ETV6::ABL1 is a rare fusion gene that found in MPN, ALL, and AML. It has a complex and diverse formation mechanism due to the reciprocal orientations of the ETV6 and ABL1 genes relative to the centromeres. NPM1 is frequently mutated in adult AML, often accompanied by FLT3-ITD, which suggests molecular synergisms in AML pathogenesis. Previous reports on ETV6::ABL1 mostly focus on FLT3-ITD. In this study, we present a case of AML with ETV6::ABL1, along with NPM1 and FLT3-ITD. The patient showed a rapid increase in primitive cells at the initial stage, along with the presence of immature granulocytes and erythrocytes. Through cytogenetic analysis, fluorescence in situ hybridization (FISH), and RNA-seq, we elucidated the mechanism behind the formation of the ETV6::ABL1 fusion gene. Despite conventional chemotherapy failure and rapid tumor proliferation, we attempted to add FLT3 inhibitor sorafenib to the treatment, along with chemotherapy bridging to haploidentical transplantation. After haplo-HSCT, a combination of sorafenib and dasatinib was administered as maintenance therapy. The patient achieved complete remission (CR) and maintained it for 11 months. The intricate genetic landscape observed in this case presents diagnostic dilemmas and therapeutic challenges, emphasizing the importance of a comprehensive understanding of its implications for disease classification, risk stratification, and treatment selection.

Allogeneic hematopoietic cell transplantation for older patients with AML with active disease. A study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation (EBMT)

Older adults with acute myeloid leukemia (AML) refractory to initial or reinduction chemotherapy have a dismal prognosis if they do not undergo hematopoietic stem-cell transplantation (HCT). However, data assessing HCT outcomes from different donors are scarce. We evaluated results from a retrospective analysis on patients aged ≥70 years, with AML not in remission who received an allogeneic HCT from HLA-matched sibling donor (MSD), HLA-10/10 matched unrelated donor (MUD), or T-cell replete haploidentical (Haplo) donor, from 2010 to 2021, reported to the ALWP-EBMT database. A total of 360 patients (median age 72 years, range 70-79) were included in the analysis. Median follow-up for the entire population was 35.5 months. Donors were MSD (n = 58), 10/10 HLA-MUD (n = 228), and Haplo (n = 74). A total of 213 (59.2%) patients were primary induction failures, while 147 (40.8%) were in first or subsequent relapse. Graft source was peripheral blood in 92% of the patients. Patients transplanted from Haplo donors more frequently received marrow grafts (p < 0.01) and presented the combination female donor to male recipient (p < 0.01). The overall 2-year rates of overall survival (OS) and leukemia-free survival (LFS) were: 62.4% (95% CI 47.2-74.3) and 47.6% (95% CI 33.1-60.8) for MSD, 43% (95% CI 35.8-49.9), and 37.5% (95% CI 30.7-44.4) for MUD, and 25.9% (95% CI 15.8-37.2), and 26.5% (95% CI 16.3-37.8) for recipients of Haplo transplants. The 2-year cumulative incidence of relapse (RI) was slightly lower for Haplo recipients at 29.6% (95% CI 19-40.9), for MUD it was 30.2% (95% CI 23.9-36.7), and for MSD 34.9% (95% CI 22-48.2); counterbalanced by a higher incidence of non-relapse mortality (NRM) of 43.9% (95% CI 31.6-55.6) for Haplo recipients, 32.2% (95% CI 26-33.1) for MUD and 17.5% (95% CI 8.4-29.3) for MSD. Graft-versus-host disease (GVHD-free, relapse-free survival (GRFS) was 35.3% (95% CI 22.3-48.5) for MSD, 29.6% (95% CI 23.2-36.2) for MUD, and 19.2% (95% CI 10.7-29.6) for Haplo patients. In the multivariate model, compared to the referent group of MSD recipients, the risk of NRM was higher among patients transplanted from Haplo donors ([hazard ratio] HR 5.1, 95% CI 2.23-11.61, p < 0.001) and MUD (HR 3.21, 95% CI 1.48-0.6.94, p = 0.003). Furthermore, both Haplo and MUD were associated with inferior OS, (HR 3.6, 95% CI 1.98-0.6.56, p < 0.001, and HR 2.3, 95% CI 1.37-0.3.88, p = 0.002, respectively), and LFS (HR 2.24, 95% CI 1.31-0.3.84, p = 0.003, and HR 1.64, 95% CI 1.04-0.2.60, p = 0.034, respectively). Patients transplanted from Haplo donors were also associated with worse GFRS (HR 1.72, 95% CI 1.07-2.77, p:0.025) compared with MSD patients. Older adult AML patients with active disease transplanted from MSD experienced prolonged OS and LFS compared to 10/10 MUD and Haplo due to lower NRM. Prospective clinical trials are warranted.

White blood cell count nadir to zero following intensive chemotherapy as a predictive factor for patients with acute myeloid leukemia

Predictors for response to intensive therapy in AML have focused on baseline factors: percent leukemic blasts in marrow, cytogenetic/molecular genetic abnormalities, and presence of secondary AML. Non-baseline dynamic factors, occurring after induction but before response, may be useful for decisions related to salvage chemotherapy. We hypothesized white blood cell (WBC) count nadir after induction may be a real time indicator of treatment efficacy. We also examined whether time to stem cell transplant (SCT) or baseline molecular genetic abnormalities are associated with a low nadir. Data showed WBC nadir = 0 was a negative predictor for response to intensive induction and was correlated with reduced overall survival and progression free survival. Patients with WBC nadir = 0 did not have a significantly longer time to SCT, and none of the mutations increased the likelihood of reaching WBC nadir = 0. WBC nadir may be a useful real-time monitor in AML patients receiving intensive induction chemotherapy.

Real-world results of venetoclax combined with hypomethylating agents in young adults with relapsed/refractory acute myeloid leukemia

OBJECTIVES

Young adults with acute myeloid leukemia (AML) often fail to achieve permanent complete remission (CR) and frequently relapse, indicating an urgent need to explore effective salvage therapies. Recent advances in AML treatment have been attributed to the combination of the B-cell lymphoma 2 (Bcl-2) inhibitor venetoclax (VEN) with hypomethylating agents (HMAs); however, the use of this combination in young adults with relapsed or refractory (R/R) AML has not been reported.

METHODS

We retrospectively examined 31 young patients with R/R AML treated with VEN plus an HMA. We evaluated the demographic data, cytogenetic characteristics, AML types, response rates, and transplantation-related data for the patients in our cohort.

RESULTS

The combination of VEN + HMA yielded a CR rate of 48.4%. The most prominent hematologic adverse event was neutropenia, which occurred in all patients, with 90.3% of cases being grade ≥3. Non-hematologic toxicities were relatively mild and infrequent, with an incidence of 45.2%. More than half of the patients with sustained CR had received an allogeneic hematopoietic stem cell transplantation (allo-HSCT), of whom two died of transplant-related complications.

CONCLUSION

Our results showed that the combination of VEN + HMA appeared to be a highly effective and well-tolerated salvage therapy option for young patients with R/R AML, enabling more young patients to proceed to potentially curative allo-HSCT. However, additional, well-designed studies with larger numbers of patients are required to confirm the advantages of VEN + HMA in this population.

Venetoclax-based therapy for relapsed or refractory acute myeloid leukaemia following intensive induction chemotherapy

BACKGROUND

The treatment of relapsed or refractory (R/R) acute myeloid leukaemia (AML) remains challenging and outcomes extremely poor. The introduction of venetoclax has transformed the treatment of AML and emerging data suggest that venetoclax-based therapy may enforce salvage treatment.

MATERIALS AND METHODS

In this nationwide Danish retrospective study, we analysed treatment outcomes of venetoclax-based salvage treatment for R/R AML between 2019 and 2022. Only venetoclax-naive patients who had previously received treatment with intensive chemotherapy therapy were included.

RESULTS

The cohort consisted of 43 R/R patients with a median age of 57 years. Nine (20.9%) were primary refractory and 34 (79.1%) patients had relapsed, including 21 after previous allogeneic stem cell transplantation. The overall response rate was 76.2% including 61.9% with composite complete remission (CRc: CR + CRi). Among CRc-responders with information on measurable residual disease (MRD), 8/13 (61.5%) obtained an MRD-negativity response. The overall survival was 9.3 months for all patients with an estimated 1-year overall survival of 34%. For CRc-responders the median overall survival was 13.3 months, and the median relapse-free survival was 12.8 months.

CONCLUSION

Venetoclax-based salvage treatment for R/R AML produced high response rates; however, for most patients the response was of limited duration. This study is limited by an observational design and prone to selection bias.

Allogeneic Hematopoietic Stem Cell Transplantation for Relapsed/Refractory Acute Myeloid Leukemia: A Single-Centre Experience

INTRODUCTION

Patients with relapsed/refractory acute myeloid leukemia (r/r AML) are characterized as having a poor prognosis. The only viable option of treatment for these patients is allogenic stem cell transplantation (allo-HSCT). Therefore, we have attempted to analyse factors related to both the disease itself and the transplantation procedure that could have an influence on the improvement of outcomes in this group of patients.

PATIENTS AND METHODS

Sixty-four patients with r/r AML underwent allo-HSCT at our center in 2012 to 2021. Fifty-two had active disease at the beginning of theallo-HSCT procedure, with amedian number of blasts in bone marrow (BM) of 18, and 12 had therapeutic aplasia after the last reinduction (blasts < 5% in BM).

RESULTS

The probability of overall survival (OS) at 2 years was 25%. The median follow-up for survivors was 21.5 months. Progression-free survival (PFS) estimates were above 46%. The main cause of death was disease progression (49%). A statistically significant effect on premature death was reported for the diagnosis of secondary AML (sAML) and cytomelovirus (CMV) reactivation post allo-HSCT. On the other hand, chronic graft versus host disease (cGVHD) decreased the risk of disease progression. sAML and CMV reactivation were found to have opposite effects.

Management of Acute Myeloid Leukemia: A Review for General Practitioners in Oncology

Acute myeloid leukemia (AML) is a hematologic malignancy that most frequently develops in older adults. Overall, AML is associated with a high mortality although advancements in genetic risk stratification and new treatments are leading to improvements in outcomes for some subgroups. In this review, we discuss an individualized approach to intensive therapy with a focus on the role of recently approved novel therapies as well as the selection of post-remission therapies for patients in first remission. We discuss the management of patients with relapsed and refractory AML, including the role of targeted treatment and allogeneic stem cell transplant. Next, we review non-intensive treatment for older and unfit AML patients including the use of azacitidine and venetoclax. Finally, we discuss the integration of palliative care in the management of patients with AML.

Augmented FLAMSA-Bu versus FluBu2 reduced-intensity conditioning in patients with active relapsed/refractory acute myeloid leukemia: an EBMT analysis

Comparative data of fludarabine, cytarabine and amsacrine (FLAMSA) chemotherapy followed by busulfan (Bu)-based reduced-intensity conditioning (RIC) (FLAMSA-Bu) versus RIC regimens are lacking in patients with active relapsed/refractory (R/R) acute myeloid leukemia (AML) at the time of allogeneic hematopoietic stem cell transplantation (alloSCT). Here, we retrospectively analyzed outcomes after FLAMSA-Bu versus fludarabine/busulfan (FluBu2) conditioning in this patient population. A total of 476 patients fulfilled the inclusion criteria, of whom 257 received FluBu2 and 219 FLAMSA-Bu. Median follow-up was 41 months. Two-year non-relapse mortality (21%), graft-versus-host disease-free, relapse-free survival (24%) and chronic graft-versus-host disease (GVHD) (29%) were not statistically different between cohorts. FLAMSA-Bu was associated with lower 2-year relapse incidence (RI) (38 vs 49% after FluBu2, p = 0.004), and increased leukemia-free survival (LFS) (42 vs 29%, p = 0.001), overall survival (47 vs 39%, p = 0.008) and grades II-IV acute GVHD (36 vs 20%, p = 0.001). In the multivariate analysis, FLAMSA-Bu remained associated with lower RI (HR 0.69, p = 0.042), increased LFS (HR 0.74, p = 0.048) and a higher risk of acute GVHD (HR 2.06, p = 0.005). Notwithstanding the limitations inherent in this analysis, our data indicate that FLAMSA-Bu constitutes a tolerable conditioning strategy, resulting in a long-term benefit in a subset of patients reaching alloSCT with active disease.

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.

Acute Myeloid Leukemia Patients Requiring Two Cycles of Intensive Induction for Attainment of Remission Experience Inferior Survival Compared with Patients Requiring a Single Course of Induction Chemotherapy

BACKGROUND

Achievement of initial remission remains the most important clinical factor predicting long term survival in acute myeloid leukemia (AML) patients treated with intensive chemotherapy. Yet, whether the patient subset in need of a second cycle of intensive induction chemotherapy to reach remission experiences inferior outcomes compared to patients reaching remission after a single cycle of therapy, remains uncertain.

PATIENTS AND METHODS

Retrospective analysis of 302 consecutive AML patients treated with intensive induction chemotherapy in our institution in 2007-2020.

RESULTS

Median patient age was 55 years with a median follow-up duration of 23 months. In terms of European LeukemiaNet (ELN) 2017 classification, 122 patients (40%) were designated as favorable risk disease, 108 patients (36%) were intermediate risk, and 71 patients (24%) were adverse risk. A hundred and seventy-seven patients (60%) attained remission following initial chemotherapy while 58 patients (20%) required an additional cycle of intensive chemotherapy for remission. Patients requiring 2 cycles to reach remission were less likely to be NPM1 mutated (33% versus 51%; P=.025) or be in the ELN 2017 favorable risk category (25% versus 57%; P<.001). In multivariate analysis achievement of remission following 2 cycles of intensive compared with a single cycle resulted in significantly inferior survival [hazard ratio (HR)=1.67, 95% CI, 1.07-2.59; P=.025] whereas leukemia-free survival was not significantly impacted (HR=1.26, 95% CI, 0.85-1.85) (P=.23). Relapse rates also did not differ to a significant degree between groups (45% versus 47%, P=.8).

CONCLUSION

Attainment of an early remission significantly impacts long term survival in AML patients.

Clinical experience with venetoclax in patients with newly diagnosed, relapsed, or refractory acute myeloid leukemia

Background

Diagnosis of acute myeloid leukemia (AML) is associated with poor outcome in elderly and unfit patients. Recently, approval of the BCL-2 inhibitor venetoclax (VEN) in combination with hypo-methylating agents (HMA) led to a significant improvement of response rates and survival. Further, application in the relapsed or refractory (r/r) AML setting or in context of allogeneic stem cell transplantation (alloHSCT) seems feasible.

Methods and patients

Fifty-six consecutive adult AML patients on VEN from January 2019 to June 2021 were analyzed retrospectively. Patients received VEN either as first-line treatment, as subsequent therapy (r/r AML excluding prior alloHSCT), or at relapse after alloHSCT. VEN was administered orally in 28-day cycles either combined with HMA or low-dose cytarabine (LDAC).

Results

After a median follow-up of 11.5 (range 6.1–22.3) months, median overall survival (OS) from start of VEN treatment was 13.3 (2.2–20.5) months, 5.0 (0.8–24.3) months and 4.0 (1.5–22.1) months for first-line, subsequent line treatment and at relapse post-alloHSCT, respectively. Median OS was 11.5 (10–22.3) months from start of VEN when subsequent alloHSCT was carried out. Relapse-free survival (RFS) for the total cohort was 10.2 (2.2 – 24.3) months. Overall response rate (composite complete remission + partial remission) was 51.8% for the total cohort (61.1% for VEN first-line treatment, 52.2% for subsequent line and 42.8% at relapse post-alloHSCT). Subgroup analysis revealed a significantly reduced median OS in FLT3-ITD mutated AML with 3.4 (1.9–4.9) months versus 10.4 (0.8–24.3) months for non-mutated cases, (HR 4.45, 95% CI 0.89–22.13, p = 0.0002). Patients harboring NPM1 or IDH1/2 mutations lacking co-occurrence of FLT3-ITD showed a survival advantage over patients without those mutations (11.2 (5–24.3) months versus 5.0 (0.8–22.1) months, respectively, (HR 0.53, 95% CI 0.23 – 1.21, p = 0.131). Multivariate analysis revealed mutated NPM1 as a significant prognostic variable for achieving complete remission (CR) (HR 19.14, 95% CI 2.30 – 436.2, p < 0.05). The most common adverse events were hematological, with grade 3 and 4 neutropenia and thrombocytopenia reported in 44.6% and 14.5% of patients, respectively.

Conclusion

Detailed analyses on efficacy for common clinical scenarios, such as first-line treatment, subsequent therapy (r/r AML), and application prior to and post-alloHSCT, are presented. The findings suggest VEN treatment combinations efficacious not only in first-line setting but also in r/r AML. Furthermore, VEN might play a role in a subgroup of patients with failure to conventional chemotherapy as a salvage regimen aiming for potential curative alloHSCT.

European LeukemiaNet-defined primary refractory acute myeloid leukemia: the value of allogeneic hematopoietic stem cell transplant and overall response

We sought to appraise the value of overall response and salvage chemotherapy, inclusive of allogeneic hematopoietic stem cell transplant (AHSCT), in primary refractory acute myeloid leukemia (prAML). For establishing consistency in clinical practice, the 2017 European LeukemiaNet (ELN) defines prAML as failure to attain CR after at least 2 courses of intensive induction chemotherapy. Among 60 consecutive patients (median age 63 years) correspondent with ELN-criteria for prAML, salvage was documented in 48 cases, 30/48 (63%) being administered intensive chemotherapy regimens and 2/48 consolidated with AHSCT as first line salvage. 13/48 (27%) attained response: CR, 7/13 (54%), CRi, 2/13 (15%), MLFS, 4/13 (31%). The CR/CRi rate was 9/48 (19%), with CR rate of 7/48 (15%). On univariate analysis, intermediate-risk karyotype was the only predictor of response (44% vs 17% in unfavorable karyotype; P = 0.04). Administration of any higher-dose (>1 g/m²) cytarabine intensive induction (P = 0.50), intensive salvage chemotherapy (P = 0.72), targeted salvage (FLT3 or IDH inhibitors) (P = 0.42), greater than 1 salvage regimen (P = 0.89), age < 60 years (P = 0.30), and de novo AML (P = 0.10) did not enhance response achievement, nor a survival advantage. AHSCT was performed in 12 patients with (n = 8) or without (n = 4) CR/CRi/MLFS. 1/2/5-year overall survival (OS) rates were 63%/38%/33% in patients who received AHSCT (n = 12) vs 27%/0%/0% in those who achieved CR/CRi/MLFS but were not transplanted (n = 5), vs 14%/0%/0% who were neither transplanted nor achieved CR/CRi/MLFS (n = 43; P < 0.001); the median OS was 18.6, 12.6 and 5.6 months, respectively. Although CR/CRi/MLFS bridged to AHSCT (n = 8), appeared to manifest a longer median OS (20 months), vs (13.4 months) for those with no response consolidated with AHSCT (n = 4), the difference was not significant P = 0.47. We conclude AHSCT as indispensable for securing long-term survival in prAML (p = 0.03 on multivariate analysis), irrespective of response achievement.

Phase II Trial of Pembrolizumab after High-Dose Cytarabine in Relapsed/Refractory Acute Myeloid Leukemia

Immune suppression, exhaustion, and senescence are frequently seen throughout disease progression in acute myeloid leukemia (AML). We conducted a phase II study of high-dose cytarabine followed by pembrolizumab 200 mg i.v. on day 14 to examine whether PD-1 inhibition improves clinical responses in relapsed/refractory (R/R) AML. Overall responders could receive pembrolizumab maintenance up to 2 years. Among 37 patients enrolled, the overall response rate, composite complete remission (CRc) rate (primary endpoint), and median overall survival (OS) were 46%, 38%, and 11.1 months, respectively. Patients with refractory/early relapse and those receiving treatment as first salvage had encouraging outcomes (median OS, 13.2 and 11.3 months, respectively). Grade ≥3 immune-related adverse events were rare (14%) and self-limiting. Patients who achieved CRc had a higher frequency of progenitor exhausted CD8⁺ T cells expressing TCF-1 in the bone marrow prior to treatment. A multifaceted correlative approach of genomic, transcriptomic, and immunophenotypic profiling offers insights on molecular correlates of response and resistance to pembrolizumab.

Significance

Immune-checkpoint blockade with pembrolizumab was tolerable and feasible after high-dose cytarabine in R/R AML, with encouraging clinical activity, particularly in refractory AML and those receiving treatment as first salvage regimen. Further study of pembrolizumab and other immune-checkpoint blockade strategies after cytotoxic chemotherapy is warranted in AML.See related commentary by Wei et al., p. 551. This article is highlighted in the In This Issue feature, p. 549.

TP53 abnormalities correlate with immune infiltration and associate with response to flotetuzumab immunotherapy in AML

Somatic TP53 mutations and 17p deletions with genomic loss of TP53 occur in 37% to 46% of acute myeloid leukemia (AML) with adverse-risk cytogenetics and correlate with primary induction failure, high risk of relapse, and dismal prognosis. Herein, we aimed to characterize the immune landscape of TP53-mutated AML and determine whether TP53 abnormalities identify a patient subgroup that may benefit from immunotherapy with flotetuzumab, an investigational CD123 × CD3 bispecific dual-affinity retargeting antibody (DART) molecule. The NanoString PanCancer IO360 assay was used to profile 64 diagnostic bone marrow (BM) samples from patients with TP53-mutated (n = 42) and TP53-wild-type (TP53-WT) AML (n = 22) and 45 BM samples from patients who received flotetuzumab for relapsed/refractory (R/R) AML (15 cases with TP53 mutations and/or 17p deletion). The comparison between TP53-mutated and TP53-WT primary BM samples showed higher expression of IFNG, FOXP3, immune checkpoints, markers of immune senescence, and phosphatidylinositol 3-kinase-Akt and NF-κB signaling intermediates in the former cohort and allowed the discovery of a 34-gene immune classifier prognostic for survival in independent validation series. Finally, 7 out of 15 patients (47%) with R/R AML and TP53 abnormalities showed complete responses to flotetuzumab (<5% BM blasts) on the CP-MGD006-01 clinical trial (NCT #02152956) and had significantly higher tumor inflammation signature, FOXP3, CD8, inflammatory chemokine, and PD1 gene expression scores at baseline compared with nonresponders. Patients with TP53 abnormalities who achieved a complete response experienced prolonged survival (median, 10.3 months; range, 3.3-21.3 months). These results encourage further study of flotetuzumab immunotherapy in patients with TP53-mutated AML.

Reinduction chemotherapy regimen involved decitabine and cladribine improves the prognosis of patients with relapsed or refractory acute myeloid leukemia: A preliminary study

Relapsed/refractory acute myeloid leukemia (R/R-AML) is characterized by a high incidence, short survival and poor prognosis. Presently, no unified effective reinduction chemotherapy regimen has been developed. Therefore, the use of reinduction chemotherapy regimens before allogeneic hematopoietic stem cell transplantation (allo-HSCT) is controversial. Our study aims to analyze the prognostic factors of R/R-AML and to evaluate the efficacy of the regimen involved decitabine, cladribine, idarubicin or homoharringtonine, and cytarabine (DCIA/DCHA). Clinical and survival data of 112 R/R-AML patients were obtained. Among the 102 R/R-AML patients that were treated with conventional regimens, we found that poor prognosis was related to a greater proportion of bone marrow blasts (>70%) and not achieving complete remission (non-CR) after the first reinduction chemotherapy. Hematopoietic stem cell transplantation (of which 89.47% was allo-HSCT) following CR after the first reinduction chemotherapy often improves the prognosis. Of the 10 R/R-AML patients that were treated with the DCIA/DCHA regimen, nine patients achieved CR or complete response with incomplete hematopoietic recovery (CRi) after one course of chemotherapy. The median overall survival of the 10 patients was 10.14 (1.23-29.13) months. In conclusion, non-CR was associated with poor prognosis in R/R-AML. Therefore, intensive reinduction chemotherapy should be selected to achieve CR. This creates conditions for allo-HSCT and improves prognosis of R/R-AML patients. The DCIA/DCHA regimen showed good efficacy and tolerable adverse reactions in R/R-AML treatment. This combination may be used as a bridging regimen for allo-HSCT in R/R-AML.

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.

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.

Isavuconazole as Primary Antifungal Prophylaxis in Patients With Acute Myeloid Leukemia or Myelodysplastic Syndrome: An Open-label, Prospective, Phase 2 Study

BACKGROUND

Mold-active primary antifungal prophylaxis (PAP) is routinely recommended in neutropenic patients with newly diagnosed acute myeloid leukemia (AML) or high-risk myelodysplastic syndrome (MDS) undergoing remission-induction chemotherapy (RIC). Isavuconazole (ISAV) is an extended spectrum mold-active triazole and has superior tolerability and fewer significant drug-drug interactions compared with other triazoles.

METHODS

In our investigator-initiated, phase 2 trial, treatment-naive adult patients with AML or MDS starting RIC received ISAV per the dosing recommendations in the US label until neutrophil recovery (absolute neutrophil count [ANC] ≥ 0.5 × 109/L) and attainment of complete remission, occurrence of invasive fungal infection (IFI), or for a maximum of 12 weeks. The primary endpoint was the incidence of proven/probable IFI during ISAV PAP and up to 30 days after the last dose.

RESULTS

Sixty-five of 75 enrolled patients received ISAV PAP (median age, 67 years, median ANC at enrollment, 0.72 × 109/L). Thirty-two patients (49%) received oral targeted leukemia treatments (venetoclax, FTL3 inhibitors). Including the 30-day follow-up period, probable/proven and possible IFIs were encountered in 4 (6%) and 8 patients (12%), respectively. ISAV trough serum concentrations were consistently > 1 µg/mL, showed low intraindividual variation, and were not significantly influenced by chemotherapy regimen. Tolerability of ISAV was excellent, with only 3 cases (5%) of mild to moderate elevations of liver function tests and no QTc prolongations.

CONCLUSIONS

ISAV is a safe and effective alternative for PAP in patients with newly diagnosed AML/MDS undergoing RIC in the era of recently approved or emerging small-molecule antileukemia therapies.

CLINICAL TRIALS REGISTRATION

NCT03019939.

Day 14 Bone Marrow Evaluation During Acute Myeloid Leukemia Induction in a Real-world Canadian Cohort

INTRODUCTION

The 2017 National Comprehensive Cancer Network guidelines for acute myeloid leukemia have recommended performing bone marrow (BM) aspiration and BM trephine biopsy (BMTB) 14 to 21 days after starting induction therapy (commonly referred to as "day 14 [D14] marrow"). Those who do not achieve a hypoplastic marrow, with cellularity < 20% and blasts < 5%, are recommended to undergo 2-cycle induction (2CI). We performed a retrospective analysis to determine the impact of D14 BM characteristics in predicting for remission, association with overall survival (OS), and the effect of 2CI according to the D14 BM results.

PATIENTS AND METHODS

Patients aged 18 to 70 years undergoing induction therapy with standard "7 + 3" regimens were included. D14 cellularity was determined from BMTB samples and the blast percentage was assessed by morphology on BM aspiration and BMTB samples. The outcomes evaluated included the rates of complete remission (CR) and OS.

RESULTS

A total of 486 patients with results from D14 BM evaluation were included in the present study. On multivariate analysis, cytogenetic risk and D14 blasts < 5% were predictive of CR/CR with incomplete count recovery (P < .001). Cytogenetic risk (P < .001), age < 60 years (P = .001), and D14 blasts < 5% (P = .045) predicted for OS. 2CI was performed in 131 patients (27%). Patients with hypocellular D14 BM but residual blasts (n = 106) underwent 2CI in 46% of cases, with improved remission rates (43.9% vs. 72.0%; P = .004) but no difference in OS.

CONCLUSIONS

The results from D14 BM evaluations are predictive of subsequent remission and OS. Our findings did not show a survival benefit with D14 BM-driven 2CI.

Heterogeneity in refractory acute myeloid leukemia

Successful clinical remission to therapy for acute myeloid leukemia (AML) is required for long-term survival to be achieved. Despite trends in improved survival due to better supportive care, up to 40% of patients will have refractory disease, which has a poorly understood biology and carries a dismal prognosis. The development of effective treatment strategies has been hindered by a general lack of knowledge about mechanisms of chemotherapy resistance. Here, through transcriptomic analysis of 154 cases of treatment-naive AML, three chemorefractory patient groups with distinct expression profiles are identified. A classifier, four key refractory gene signatures (RG4), trained based on the expression profile of the highest risk refractory patients, validated in an independent cohort (n = 131), was prognostic for overall survival (OS) and refined an established 17-gene stemness score. Refractory subpopulations have differential expression in pathways involved in cell cycle, transcription, translation, metabolism, and/or stem cell properties. Ex vivo drug sensitivity to 122 small-molecule inhibitors revealed effective group-specific targeting of pathways among these three refractory groups. Gene expression profiling by RNA sequencing had a suboptimal ability to correctly predict those individuals resistant to conventional cytotoxic induction therapy, but could risk-stratify for OS and identify subjects most likely to have superior responses to a specific alternative therapy. Such personalized therapy may be studied prospectively in clinical trials.

Checkpoint inhibitors and acute myelogenous leukemia: promises and challenges

INTRODUCTION

Immunity, for treatment of acute myelogenous leukemia (AML), has been leveraged historically in the form of allogeneic stem cell transplantation. Checkpoint inhibitors (CPI) as positive modulators of immune response have been recent major breakthroughs in solid tumors. Areas covered: Emerging concepts and clinical data with CPIs in acute Myeloid Leukemia - the focus of this review- will be discussed. CPIs can potentially be effective in absence of 'actionable' mutations and are expected to be effective against poor-risk AML. Immune inhibitory checkpoint molecules are upregulated in both de novo and relapsed AML. Similar data also suggest role of checkpoint molecules in mediating resistance particularly to hypomethylating agent (HMA) therapy, which can potentially be reversed by using checkpoint inhibitors. Expert commentary: Ongoing clinical trials in combination with HMAs are showing early promise, with doubling of response than that seen in historic controls. The optimal combinations of CPIs and the optimal space that they will fit in the continuum of AML therapies need lot of in depth work.

Molecular remission and response patterns in patients with mutant-IDH2 acute myeloid leukemia treated with enasidenib

Approximately 8% to 19% of patients with acute myeloid leukemia (AML) have isocitrate dehydrogenase-2 (IDH2) mutations, which occur at active site arginine residues R140 and R172. IDH2 mutations produce an oncometabolite, 2-hydroxyglutarate (2-HG), which leads to DNA and histone hypermethylation and impaired hematopoietic differentiation. Enasidenib is an oral inhibitor of mutant-IDH2 proteins. This first-in-human phase 1/2 study evaluated enasidenib doses of 50 to 650 mg/d, administered in continuous 28-day cycles, in patients with mutant-IDH2 hematologic malignancies. Overall, 214 of 345 patients (62%) with relapsed or refractory (R/R) AML received enasidenib, 100 mg/d. Median age was 68 years. Forty-two patients (19.6%) attained complete remission (CR), 19 patients (10.3%) proceeded to an allogeneic bone marrow transplant, and the overall response rate was 38.8% (95% confidence interval [CI], 32.2-45.7). Median overall survival was 8.8 months (95% CI, 7.7-9.6). Response and survival were comparable among patients with IDH2-R140 or IDH2-R172 mutations. Response rates were similar among patients who, at study entry, were in relapse (37.7%) or were refractory to intensive (37.5%) or nonintensive (43.2%) therapies. Sixty-six (43.1%) red blood cell transfusion-dependent and 53 (40.2%) platelet transfusion-dependent patients achieved transfusion independence. The magnitude of 2-HG reduction on study was associated with CR in IDH2-R172 patients. Clearance of mutant-IDH2 clones was also associated with achievement of CR. Among all 345 patients, the most common grade 3 or 4 treatment-related adverse events were hyperbilirubinemia (10%), thrombocytopenia (7%), and IDH differentiation syndrome (6%). Enasidenib was well tolerated and induced molecular remissions and hematologic responses in patients with AML for whom prior treatments had failed. The study is registered at www.clinicaltrials.gov as #NCT01915498.

Sequential HLA-haploidentical transplantation utilizing post-transplantation cyclophosphamide for GvHD prophylaxis in high-risk and relapsed/refractory AML/MDS

This study evaluates the role of sequential therapy in HLA-haploidentical transplantation (haplo-HSCT) of high-risk, relapsed/refractory AML/MDS. We analyzed the course of 33 adults with active disease at time of transplantation (AML n = 30; MDS n = 3; median age 58 years, range: 32-71). Sequential therapy consisted of cytoreductive chemotherapy (FLAMSA n = 21; clofarabine n = 12) applied shortly prior to reduced intensity conditioning for T-cell-replete haplo-HSCT using post-transplantation cyclophosphamide as GvHD prophylaxis. No graft rejection was observed. Complete remission at day +30 was achieved in 97% of patients. CI of acute GvHD grade II-IV and chronic GvHD was 24% (no grade IV) and 23%, respectively. NRM at 1 and 3 years was 15%, each. Severe regimen-related toxicities (grade III-IV) were observed in 58%, predominantly involving the gastrointestinal tract (diarrhea 48%, mucositis 15%, transient elevation of transaminases 18%). Probability of relapse at 1 and 3 years was 28% and 35%. At a median follow-up of 36 months, the estimated 1- and 3-year overall survival was 56% and 48%. Disease-free survival was 49% and 40%, respectively. At 3 years, GvHD and relapse-free survival (GRFS) was 24% while chronic GvHD and relapse-free survival (CRFS) was 29%. Thus, our results indicate that sequential haplo-HSCT is an effective salvage treatment providing high anti-leukemic activity, favorable tolerance, and acceptable toxicity in patients suffering from advanced AML/MDS.

Aberrant GSK3β nuclear localization promotes AML growth and drug resistance

Acute myeloid leukemia (AML) is a devastating disease with poor patient survival. As targetable mutations in AML are rare, novel oncogenic mechanisms are needed to define new therapeutic targets. We identified AML cells that exhibit an aberrant pool of nuclear glycogen synthase kinase 3β (GSK3β). This nuclear fraction drives AML growth and drug resistance. Nuclear, but not cytoplasmic, GSK3β enhances AML colony formation and AML growth in mouse models. Nuclear GSK3β drives AML partially by promoting nuclear localization of the NF-κB subunit, p65. Finally, nuclear GSK3β localization has clinical significance as it strongly correlates to worse patient survival (n = 86; hazard ratio = 2.2; P < .01) and mediates drug resistance in cell and animal models. Nuclear localization of GSK3β may define a novel oncogenic mechanism in AML and represent a new therapeutic target.

Adoptive Immunotherapy with Cord Blood for the Treatment of Refractory Acute Myelogenous Leukemia: Feasibility, Safety, and Preliminary Outcomes

Adoptive immunotherapy has shown efficacy in patients with relapsed/refractory acute myelogenous leukemia (AML). We conducted a prospective evaluation of cord blood (CB)-based adoptive cell therapy following salvage chemotherapy in patients with AML or myelodysplastic syndrome (MDS) and describe the safety and early outcomes of this approach. To enhance the antileukemic effect, we selected CB units (CBUs) with a shared inherited paternal antigen (IPA) and/or noninherited maternal antigen (NIMA) match with the recipients. Furthermore, the CBUs had total nucleated cell (TNC) dose <2.5 × 10⁷/kg and were at least 4/6 HLA-matched with the patients; a higher allele-level match was preferred. Heavily pretreated adult patients with AML/MDS were enrolled. CBU searches were performed for 50 patients. CBUs with shared IPA targets were identified for all, and CBUs with NIMA matches were found for 80%. Twenty-one patients underwent treatment (AML, primary induction failure, n = 8; refractory relapse, n = 10, including 7 recipients of previous allogeneic HSCT; blast crisis chronic myelogenous leukemia, n = 1; MDS, n = 2). Most received combination chemotherapy; those not fit for intensive treatment received a hypomethylating agent. Response was defined as <10% residual blasts in hypocellular bone marrow at approximately 2 weeks after treatment. Ten of the 19 evaluable patients responded, including 5 of the 7 recipients of previous transplant. Response was seen in 4 of 4 patients with full CBU-derived chimerism, 2 of 2 of those with partial, low-level chimerism and 4 of 12 of the recipients with no detectable CBU chimerism. The most common adverse events were infections (bacterial, n = 5; viral, n = 2; fungal, n = 5). Grade IV acute graft-versus-host disease (GVHD) developed in 2 patients with full CBU chimerism; 2 other patients had grade 1 skin GVHD. A total of 11 patients died, 7 from disease recurrence and 4 from infections (1 early death; the other 3 in remission at the time of death). Overall, 12 patients proceeded to allogeneic HSCT; of those, 7 had responded to treatment, 3 had not (and had received additional therapy), and 2 had persistent minimal residual disease. In conclusion, the use of CB as adoptive immunotherapy in combination with salvage chemotherapy for patients with refractory AML/MDS is feasible, can induce disease control, can serve as a bridge to allogeneic HSCT, and has an acceptable incidence of adverse events. Alloreactivity was enhanced through the selection of CBUs targeting a shared IPA and/or NIMA match with the patients. CBUs with lower cell doses, already available in the CB bank and unlikely to be adequate grafts for adult transplants, can be used for cell therapy within a short time frame.

Acute myeloid leukemia: 2019 update on risk-stratification and management

Outcome in patients with acute myeloid leukemia (AML) ranges from death within a few days of beginning treatment (treatment related mortality, TRM) to likely cure. The major reason patients are not cured is resistance to treatment, often manifested as relapse from remission, rather than, even in older patients, TRM, whose incidence is decreasing. Knowledge of the pre-treatment mutation status of various genes has improved our ability to assign initial treatment and, of particular importance, knowledge of whether patients ostensibly in remission have measurable residual disease should influence subsequent management. Several new drugs have been approved by the FDA and we discuss their role in treatment.

Management of primary refractory acute myeloid leukemia in the era of targeted therapies

Primary refractory acute myeloid leukemia (AML), or primary induction failure, represents a continued challenge in clinical management. This review presents an overview of primary refractory disease and a discussion of risk factors for induction failure, including current evidence regarding the impact of karyotype and molecular mutation status on responsiveness to chemotherapy. We review the evidence for various treatment options for refractory AML including salvage chemotherapy regimens, allogeneic hematopoietic stem cell transplantation, targeted agents, and non-intensive therapies such as hypomethylating agents. A therapeutic approach to this patient population is presented, and several new and emerging therapies are reviewed.

Efficacy of haploidentical hematopoietic stem cell transplantation compared to HLA-matched transplantation for primary refractory acute myeloid leukemia

Newly diagnosed acute myeloid leukemia (AML) failed to achieve complete remission after two courses of intensive chemotherapy. This was considered as primary refractory AML (PRR-AML), and still has a dismal prognosis. Allogeneic hematopoietic stem cell transplantation could be the only cure for these patients. However, the role of haploidentical hematopoietic stem cell transplantation (HID-HCT) for PRR-AML is still undetermined. We retrospectively analyzed the outcomes of 45 adult patients with PRR-AML who underwent HID-HCT, and compared it with the result of 53 patients who received HLA-matched related or unrelated donor transplantation (MD-HCT) during the same treatment period. The 3-year overall survival (OS), leukemia-free survival (LFS), cumulative incidence of relapse (CIR), and non-relapse mortality (NRM) rates in the HID-HCT group were 19.0, 16.5, 70.0, and 35.2%, respectively, but showed no significant differences from the results of MD-HCT. Multivariate analysis showed that complex karyotype with del(7) and time > 6 months from diagnosis to transplantation were associated with lower OS and LFS, and chronic GVHD demonstrated better OS and LFS in the entire cohort. Complex karyotype with del(7) was related with higher CIR and chronic GVHD with lower CIR. In conclusion, HID-HCT could be an alternative treatment strategy to improve the long-term survival in PRR-AML adult patients who have no HLA-matched donors.

Results of second salvage therapy in 673 adults with acute myelogenous leukemia treated at a single institution since 2000

BACKGROUND

The prognosis is poor for patients who have relapsed-refractory acute myelogenous leukemia (AML). Most published reports analyzed results from therapies in first-salvage AML or in studies that were conducted before 2000. Several novel agents and strategies are being tested for potential approval as treatment for patients with relapsed-refractory AML in second salvage. Therefore, it is important to establish the historic results of anti-AML therapies in this setting in the modern era. The objective of the current study was to analyze the results from second salvage therapies in patients with AML since 2000 with regard to response and survival.

METHODS

In total, 673 patients who received second salvage therapies for AML since 2000 were analyzed. Their median age was 60 years (range, 18-89 years). Salvage therapy consisted of cytarabine-based regimens in 267 patients, noncytarabine combinations in 37, hypomethylating agent-based regimens in 136, and phase 1 and 2 single agents in 233.

RESULTS

Eighty-six of the 673 patients (13%) achieved a complete response (CR) or a CR with low platelet count (CRp). The median duration of CR-CRp was 7.2 months. The median survival was 4.4 months (95% confidence interval, 4.0-4.8 months), and the 1-year survival rate was 16% (95% confidence interval, 14%-19%). Multivariate analysis identified the following as independent adverse factors for achievement of CR-CRp: platelets < 50 × 10⁹ /L (P < .001), complex karyotype with ≥3 chromosomal abnormalities (P = .02), regimens that did not include cytarabine or hypomethylating agents (P = .014), and no prior CR lasting ≥12 months with frontline or salvage 1 therapies (P < .001). The independent adverse factors associated with worse survival were age ≥60 years (P = .01), platelets < 50 × 10⁹ /L (P = .02), peripheral blasts ≥ 20% (P = .03), albumin ≤ 3 g/dL (P = .04), and complex karyotype (P = .003). The authors also applied and validated, in the current population, the 2 multivariate-derived prognostic models for CR and survival developed in their previous study of 594 patients who received treatment for second salvage AML from the previous 2 decades.

CONCLUSIONS

This large-scale analysis establishes the modern historic results of second salvage therapy in AML and validates the prognostic models associated with outcome. These data could be used to analyze the differential benefits of current or future investigational strategies under evaluation in this setting and for the purpose of potential approval of new agents in the United States and the world. Cancer 2018;124:2534-40. © 2018 American Cancer Society.

AML refractory to primary induction with Ida-FLAG has a poor clinical outcome

We evaluated outcomes of 100 patients with high risk AML treated with Ida-FLAG induction as first-line therapy. 72 achieved remission with one cycle; 19 did not. High risk cytogenetics and TP53 mutations were associated with failure to achieve remission. In those reaching remission, allogeneic bone marrow transplantation was associated with better relapse-free and overall survival. Those not achieving remission with induction therapy were extremely unlikely to reach remission with further therapy and had a dismal prognosis. Exploratory molecular analysis confirmed persistence of the dominant genetic mutations identified at diagnosis. Ex vivo chemosensitivity did not demonstrate significant differences between responders and non-responders. Thus, Ida-FLAG induction has a high chance of inducing remission in patients with high risk AML. Those achieving remission require allogeneic transplantation to achieve cure; those not achieving remission rarely respond to salvage chemotherapy and have a dismal outcome. Alternatives to conventional chemotherapy must be considered in this group.

Treatment of relapsed/refractory acute myeloid leukaemia in adults

The prognosis of relapsed acute myeloid leukaemia (AML) is poor and treatment is challenging. While the most potent treatment modality for patients who achieve a complete remission after relapse is still allogeneic haematopoietic cell transplantation (allo-HCT), both transplant-related mortality and relapse rates are high and many patients are not candidates for this approach. After a few decades of relative stasis in this field, a large number of novel approaches have become available to tackle this highly fatal disease. This is mostly due to our improved understanding of disease pathogenesis (including targetable mutations) and the anti-leukaemia potential of the immune system. Several small-molecule inhibitors and immunotherapeutic options are being explored in clinical trials and many more are in pre-clinical phase. Future studies will focus on novel and mechanistically driven combinations, sequential treatments, and low-toxicity maintenance strategies. While cure of relapsed/refractory AML without allo-HCT is currently unlikely, treatments are becoming less toxic and remissions are lasting longer.

Found in Translation: How Preclinical Research Is Guiding the Clinical Development of the BCL2-Selective Inhibitor Venetoclax

Since the discovery of apoptosis as a form of programmed cell death, targeting the apoptosis pathway to induce cancer cell death has been a high-priority goal for cancer therapy. After decades of effort, drug-discovery scientists have succeeded in generating small-molecule inhibitors of antiapoptotic BCL2 family proteins. Innovative medicinal chemistry and structure-based drug design, coupled with a strong fundamental understanding of BCL2 biology, were essential to the development of BH3 mimetics such as the BCL2-selective inhibitor venetoclax. We review a number of preclinical studies that have deepened our understanding of BCL2 biology and facilitated the clinical development of venetoclax.Significance: Basic research into the pathways governing programmed cell death have paved the way for the discovery of apoptosis-inducing agents such as venetoclax, a BCL2-selective inhibitor that was recently approved by the FDA and the European Medicines Agency. Preclinical studies aimed at identifying BCL2-dependent tumor types have translated well into the clinic thus far and will likely continue to inform the clinical development of venetoclax and other BCL2 family inhibitors. Cancer Discov; 7(12); 1376-93. ©2017 AACR.

Allogeneic transplantation for advanced acute myeloid leukemia: The value of complete remission

BACKGROUND

Patients with acute myeloid leukemia (AML) without complete remission (CR) or in first relapse (Rel1) can have extended leukemia control and survival after allogeneic hematopoietic cell transplantation (HCT). For patients in Rel1 or primary induction failure (PIF), transplantation versus treatment to achieve a second CR (CR2) and subsequent HCT might yield similar outcomes, but available comparative data are scarce.

METHODS

Survival was analyzed in 4682 HCT recipients according to disease status: PIF (N = 1440), Rel1 (failing ≥1 reinduction; N = 1256), and CR2 (N = 1986).

RESULTS

Patient, disease, and transplantation characteristics were similar, except that patients in CR2 more often had performance scores of 90% to 100%, de novo AML, and longer CR1 duration. Adverse cytogenetics were more common in patients who experienced PIF. The 5-year survival rate adjusted for performance score, cytogenetic risk, and donor type for CR2 was 39% (95% confidence interval [CI], 37%-41%) compared with 18% (95% CI, 16%-20%) for HCT in Rel1 and 21% (95% CI, 19%-23%) in PIF (P < .0001).

CONCLUSIONS

Although survival is superior for patients who undergo HCT in CR2, transplantation for selected patients in Rel1 or PIF may still be valuable. These data can guide decision making about additional salvage therapy versus prompt HCT for patients not in CR, but they also highlight that AML is intrinsically more treatable in patients who have favorable-risk cytogenetics, those with longer CR1 duration, and younger patients with better performance status. Cancer 2017;123:2025-2034. © 2017 American Cancer Society.

Impact of salvage regimens on response and overall survival in acute myeloid leukemia with induction failure

We evaluated the impact of salvage regimens and allogeneic hematopoietic cell transplantation (allo-HCT) in acute myeloid leukemia (AML) with induction failure. Between 1993 and 2009, 3324 patients with newly diagnosed AML were enrolled in 5 prospective treatment trials of the German-Austrian AML Study Group. After first induction therapy with idarubicin, cytarabine and etoposide (ICE), 845 patients had refractory disease. In addition, 180 patients, although responding to first induction, relapsed after second induction therapy. Of the 1025 patients with induction failure, 875 (median age 55 years) received intensive salvage therapy: 7+3-based (n=59), high-dose cytarabine combined with mitoxantrone (HAM; n=150), with all-trans retinoic acid (A; A-HAM) (n=247), with gemtuzumab ozogamicin and A (GO; GO-A-HAM) (n=140), other intensive regimens (n=165), experimental treatment (n=27) and direct allo-HCT (n=87). In patients receiving intensive salvage chemotherapy (n=761), response (complete remission/complete remission with incomplete hematological recovery (CR/CRi)) was associated with GO-A-HAM treatment (odds ratio (OR), 1.93; P=0.002), high-risk cytogenetics (OR, 0.62; P=0.006) and age (OR for a 10-year difference, 0.75; P<0.0001). Better survival probabilities were seen in an extended Cox regression model with time-dependent covariables in patients responding to salvage therapy (P<0.0001) and having the possibility to perform an allo-HCT (P<0.0001). FLT3 internal tandem duplication, mutated IDH1 and adverse cytogenetics were unfavorable factors for survival.

Targeting the PI3K/AKT pathway via GLI1 inhibition enhanced the drug sensitivity of acute myeloid leukemia cells

Combination targeted therapy is commonly used to treat acute myeloid leukemia (AML) patients, particularly in refractory/relapse (RR) population. However, concerns have been raised regarding the safety and patient tolerance of combination chemotherapy. It is critical to choose the appropriate treatment for precision therapy. We performed genome-wide RNA profiling using RNA-Seq to compare the RR group and the complete remission (CR) group (a total of 42 adult AML patients). The Hedgehog (Hh) and PI3K/AKT pathways were upregulated in the RR population, which was further confirmed by western blot and/or qPCR. Overexpression of GLI1 in AML cells led to increased AKT phosphorylation and decreased drug sensitivity, which was attenuated by GLI1 inhibition. By contrast, neither the expression of GLI1 nor apoptosis in response to Ara-C treatment of AML cells was significantly affected by PI3K inhibition. Furthermore, co-inhibition of GLI1 and PI3K induced apoptosis of hematopoietic stem/progenitor cells (HSPCs), which raised serious concerns about the side effects of this treatment. These results indicated that GLI1 inhibition alone, but not combined inhibition, is sufficient to enhance AML drug sensitivity, which provides a novel therapeutic strategy for AML treatment.

Harnessing the Immune System Against Leukemia: Monoclonal Antibodies and Checkpoint Strategies for AML

Acute myeloid leukemia (AML) is the most common leukemia among adults and is associated with a poor prognosis, especially in patients with adverse prognostic factors, older age, or relapsed disease. The last decade has seen a surge in successful immune-based therapies in various solid tumors; however, the role of immune therapies in AML remains poorly defined. This chapter describes the rationale, clinical data, and toxicity profiles of immune-based therapeutic modalities in AML including naked and conjugated monoclonal antibodies, bispecific T-cell engager antibodies, chimeric antigen receptor (CAR)-T cells, and checkpoint blockade via blockade of PD1/PDL1 or CTLA4. Monoclonal antibodies commonly used in AML therapy target highly expressed "leukemia" surface antigens and include (1) naked antibodies against common myeloid markers such as anti-CD33 (e.g., lintuzumab), (2) antibody-drug conjugates linked to either, (a) a highly potent toxin such as calicheamicin, pyrrolobenzodiazepine, maytansine, or others in various anti-CD33 (gemtuzumab ozogamicin, SGN 33A), anti-123 (SL-401), and anti-CD56 (lorvotuzumab mertansine) formulations, or (b) radioactive particles, such as 131I, 213Bi, or 225Ac-labeled anti-CD33 or CD45 antibodies. Novel monoclonal antibodies that recruit and promote proximity-induced cytotoxicity of tumor cells by T cells (bispecific T-cell engager [BiTE] such as anti CD33/CD3, e.g., AMG 330) or block immune checkpoint pathways such as CTLA4 (e.g., ipilimumab) or PD1/PD-L1 (e.g., nivolumab) unleashing the patients T cells to fight leukemic cells are being evaluated in clinical trials in patients with AML. The numerous ongoing clinical trials with immunotherapies in AML will improve our understanding of the biology of AML and allow us to determine the best approaches to immunotherapy in AML.

Diagnosis and management of AML in adults: 2017 ELN recommendations from an international expert panel

The first edition of the European LeukemiaNet (ELN) recommendations for diagnosis and management of acute myeloid leukemia (AML) in adults, published in 2010, has found broad acceptance by physicians and investigators caring for patients with AML. Recent advances, for example, in the discovery of the genomic landscape of the disease, in the development of assays for genetic testing and for detecting minimal residual disease (MRD), as well as in the development of novel antileukemic agents, prompted an international panel to provide updated evidence- and expert opinion-based recommendations. The recommendations include a revised version of the ELN genetic categories, a proposal for a response category based on MRD status, and criteria for progressive disease.

Persistence of minimal residual disease assessed by multiparameter flow cytometry is highly prognostic in younger patients with acute myeloid leukemia

BACKGROUND

Predicting outcomes for patients with acute myeloid leukemia (AML) on the basis of pretreatment predictors has been the cornerstone of management. Posttreatment prognostic factors are increasingly being evaluated.

METHODS

Among 280 younger patients who were treated with intermediate-dose cytarabine (total ≥ 5 g/m² ) and idarubicin-based induction chemotherapy and achieved remission, 186 were assessed for minimal residual disease (MRD) with an 8-color multiparameter flow cytometry panel performed on bone marrow specimens with a sensitivity of 0.1% or higher.

RESULTS

One hundred sixty-six patients had samples available 1 to 2 months after induction at the time of complete remission (CR), and 79% became negative for MRD, with an MRD-negative status associated with an improvement in relapse-free survival (RFS; P = .0002) and overall survival (OS; P = .0002). One hundred sixteen were evaluated for their MRD status during consolidation, and 86% were negative, with an MRD-negative status associated with a significant improvement in RFS (P < .0001) and OS (P < .0001). Sixty-nine patients were evaluated for their MRD status after completion of all therapy, and 84% were negative, with an MRD-negative status associated with an improvement in RFS (P < .0001) and OS (P < .0001). In a multivariate analysis including age, cytogenetics, response (CR vs CR with incomplete platelet recovery/incomplete blood count recovery), and MRD, achieving an MRD-negative status was the most important independent predictor of RFS and OS at response (P = .008 and P = .0008, respectively), during consolidation (P < .0001 for both), and at the completion of therapy (P < .0001 and P = .002, respectively).

CONCLUSIONS

Achieving an MRD-negative status according to multiparameter flow cytometry is associated with a highly significant improvement in the outcomes of younger patients with AML receiving cytosine arabinoside plus idarubicin-based induction and consolidation regimens. Cancer 2017;123:426-435. © 2016 American Cancer Society.

An operational definition of primary refractory acute myeloid leukemia allowing early identification of patients who may benefit from allogeneic stem cell transplantation

Up to 30% of adults with acute myeloid leukemia fail to achieve a complete remission after induction chemotherapy - termed primary refractory acute myeloid leukemia. There is no universally agreed definition of primary refractory disease, nor have the optimal treatment modalities been defined. We studied 8907 patients with newly diagnosed acute myeloid leukemia, and examined outcomes in patients with refractory disease defined using differing criteria which have previously been proposed. These included failure to achieve complete remission after one cycle of induction chemotherapy (RES), less than a 50% reduction in blast numbers with >15% residual blasts after one cycle of induction chemotherapy (REF1) and failure to achieve complete remission after two courses of induction chemotherapy (REF2). 5-year overall survival was decreased in patients fulfilling any criteria for refractory disease, compared with patients achieving a complete remission after one cycle of induction chemotherapy: 9% and 8% in patients with REF1 and REF2 versus 40% (P<0.0001). Allogeneic stem cell transplantation improved survival in the REF1 (HR 0.58 (0.46-0.74), P=0.00001) and REF2 (HR 0.55 (0.41-0.74), P=0.0001) cohorts. The utilization of REF1 criteria permits the early identification of patients whose outcome after one course of induction chemotherapy is very poor, and informs a novel definition of primary refractory acute myeloid leukemia. Furthermore, these data demonstrate that allogeneic stem cell transplantation represents an effective therapeutic modality in selected patients with primary refractory acute myeloid leukemia.

Acute myeloid leukemia: 2016 Update on risk-stratification and management

Evidence suggest that even patients aged 70 or above benefit from specific AML therapy. The fundamental decision in AML then becomes whether to recommend standard or investigational treatment. This decision must rest on the likely outcome of standard treatment. Hence we review factors that predict treatment related mortality and resistance to therapy, the latter the principal cause of failure even in patients aged 70 or above. We emphasize the limitations of prediction of resistance based only on pre- treatment factors and stress the need to incorporate post-treatment factors, for example indicators of minimal residual disease. We review various newer therapeutic options and considerations that underlie the decision to recommend allogeneic hematopoietic cell transplant. Am. J. Hematol. 91:825-846, 2016. © 2016 Wiley Periodicals, Inc.

Relapsed Acute Myeloid Leukemia: Need for Innovative Treatment Strategies to Improve Outcome

Relapse continues to be a major hurdle in achieving cure in patients with acute myeloid leukemia (AML). The outcome after relapse is not uniform in all patients with AML and is dependent on several prognostic variables, including age, cytogenetics at initial diagnosis, duration of first complete remission, whether an allogeneic stem cell transplant was performed during first complete remission, and the presence of a number of molecular aberrations. Despite extensive research over the past several decades, there is no standard of care for treating patients with relapsed AML. This is possibly due to the accrual of patients with widely different disease profiles in most trials for relapsed AML. With increasing insights into the disease biology based on identification of pathogenic and aberrant molecular and cellular pathways, novel therapeutic strategies are emerging. Hopefully in the near future, we can improve the outcome of patients with relapsed AML with treatment strategies based on identification of specific targets and methods to overcome these aberrant processes.

MYC-dependent recruitment of RUNX1 and GATA2 on the SET oncogene promoter enhances PP2A inactivation in acute myeloid leukemia

The SET (I2PP2A) oncoprotein is a potent inhibitor of protein phosphatase 2A (PP2A) that regulates many cell processes and important signaling pathways. Despite the importance of SET overexpression and its prognostic impact in both hematologic and solid tumors, little is known about the mechanisms involved in its transcriptional regulation. In this report, we define the minimal promoter region of the SET gene, and identify a novel multi-protein transcription complex, composed of MYC, SP1, RUNX1 and GATA2, which activates SET expression in AML. The role of MYC is crucial, since it increases the expression of the other three transcription factors of the complex, and supports their recruitment to the promoter of SET. These data shed light on a new regulatory mechanism in cancer, in addition to the already known PP2A-MYC and SET-PP2A. Besides, we show that there is a significant positive correlation between the expression of SET and MYC, RUNX1, and GATA2 in AML patients, which further endorses our results. Altogether, this study opens new directions for understanding the mechanisms that lead to SET overexpression, and demonstrates that MYC, SP1, RUNX1 and GATA2 are key transcriptional regulators of SET expression in AML.