High feasibility and antileukemic efficacy of fludarabine, cytarabine, and idarubicin (FLAI) induction followed by risk-oriented consolidation: A critical review of a 10-year, single-center experience in younger, non M3 AML patients

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

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

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

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

Evolving Therapeutic Approaches for Older Patients with Acute Myeloid Leukemia in 2021

Simple Summary

The better understanding of disease biology, the availability of new effective drugs and the increased awareness of patients’ heterogeneity in terms of fitness and personal expectations has made the current treatment paradigm of AML in the elderly very challenging. Here, we discuss the evolving criteria used to define eligibility for induction chemotherapy and transplantation, the introduction of new agents in the treatment of patients with very different clinical conditions, the implications of precision medicine and the importance of quality of life and supportive care, proposing a simplified algorithm that we follow in 2021.

Abstract

Acute myeloid leukemia (AML) in older patients is characterized by unfavorable prognosis due to adverse disease features and a high rate of treatment-related complications. Classical therapeutic options range from intensive chemotherapy in fit patients, potentially followed by allogeneic hematopoietic cell transplantation (allo-HCT), to hypomethylating agents or palliative care alone for unfit/frail ones. In the era of precision medicine, the treatment paradigm of AML is rapidly changing. On the one hand, a plethora of new targeted drugs with good tolerability profiles are becoming available, offering the possibility to achieve a prolonged remission to many patients not otherwise eligible for more intensive therapies. On the other hand, better tools to assess patients’ fitness and improvements in the selection and management of those undergoing allo-HCT will hopefully reduce treatment-related mortality and complications. Importantly, a detailed genetic characterization of AML has become of paramount importance to choose the best therapeutic option in both intensively treated and unfit patients. Finally, improving supportive care and quality of life is of major importance in this age group, especially for the minority of patients that are still candidates for palliative care because of very poor clinical conditions or unwillingness to receive active treatments. In the present review, we discuss the evolving approaches in the treatment of older AML patients, which is becoming increasingly challenging following the advent of new effective drugs for a very heterogeneous and complex population.

Pre-transplant minimal residual disease assessment and transplant-related factors predict the outcome of acute myeloid leukemia patients undergoing allogeneic stem cell transplantation

We studied pretransplant minimal residual disease (MRD) in 224 patients (median age 44 years; range 17-65) with acute myeloid leukemia (AML) undergoing allogeneic stem cell transplant (HSCT) in complete remission. MRD was evaluated on marrow samples using multicolor flow cytometry and assessment of WT1 gene expression. Both methods showed a strong prognostic value and their combination allowed the identification of three groups of patients with different risk of relapse. In multivariate analysis, combined MRD was the only predictor of cumulative incidence of relapse, regardless of donor type, conditioning regimen, first or second CR at HSCT, HSCT year, and ELN risk group. Multivariate regression model showed that only negative combined MRD status (P < .001) and myeloablative conditioning (P = .004) were independently associated with better OS. Among MRD-positive patients, a reduced incidence of relapse was observed in patients receiving haplo transplant (P < .05) and in patients who showed grade II-IV aGVHD (P < .03). In patients with negative combined MRD, the intensity of conditioning regimen did not affect the overall favorable outcome. We suggest that pretransplant MRD evaluation combined with transplant-related factors can identify AML patients at higher risk for relapse and might help in defining the overall transplant strategy.

Fludarabine, High-Dose Cytarabine and Idarubicin-Based Induction May Overcome the Negative Prognostic Impact of FLT3-ITD in NPM1 Mutated AML, Irrespectively of FLT3-ITD Allelic Burden

Simple Summary

The prognostic relevance of molecular aberrations in acute myeloid leukemia (AML) has been prevalently tested in patients receiving conventional 3+7 induction. Recently, there has been a renewed interest in intensified inductions, but very few data are available on the impact of the most frequent genetic alterations with these alternative treatments. We analyzed a large multicentric cohort of younger AML patients harboring NPM1 and FLT3-ITD mutations receiving an intensified fludarabine-containing regimen (FLAI). Our data suggest that in NPM1 mut patients, FLAI may overcome the prognostic influence of co-mutated FLT3-ITD. The increased efficacy of this treatment seems to reduce the need for early consolidation with allogeneic transplant in double-mutated patients. Our data strongly support FLAI as an ideal backbone for combination with innovative targeted drugs, in order to further improve patients’ outcome.

Abstract

The mutations of NPM1 and FLT3-ITD represent the most frequent genetic aberration in acute myeloid leukemia. Indeed, the presence of an NPM1 mutation reduces the negative prognostic impact of FLT3-ITD in patients treated with conventional “3+7” induction. However, little information is available on their prognostic role with intensified regimens. Here, we investigated the efficacy of a fludarabine, high-dose cytarabine and idarubicin induction (FLAI) in 149 consecutive fit AML patients (median age 52) carrying the NPM1 and/or FLT3-ITD mutation, treated from 2008 to 2018. One-hundred-and-twenty-nine patients achieved CR (86.6%). After a median follow up of 68 months, 3-year overall survival was 58.6%. Multivariate analysis disclosed that both NPM1mut (p < 0.05) and ELN 2017 risk score (p < 0.05) were significant predictors of survival. NPM1-mutated patients had a favorable outcome, with no significant differences between patients with or without concomitant FLT3-ITD (p = 0.372), irrespective of FLT3-ITD allelic burden. Moreover, in landmark analysis, performing allogeneic transplantation (HSCT) in first CR proved to be beneficial only in ELN 2017 high-risk patients. Our data indicate that FLAI exerts a strong anti-leukemic effect in younger AML patients with NPM1mut and question the role of HSCT in 1st CR in NPM1mut patients with concomitant FLT3-ITD.

Prognostic relevance of a blastic plasmacytoid dendritic cell neoplasm-like immunophenotype in cytogenetically normal acute myeloid leukemia patients

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a poor prognosis myeloid malignancy characterized by an atypical phenotype (CD123+, CD56+, and CD4+). We reported that BPDCN-like phenotype (CD123+ and either CD56+ or CD4+ or both) confers poor prognosis to acute myeloblastic leukemia (AML) patients with mutated NPM1. Here, we evaluated the incidence and the prognostic relevance of BPDCN-like phenotype in cytogenetically normal AML (CN-AML) patients. From 2006 to 2016, 83 young (age <60 yrs), consecutive, CN-AML patients underwent intensive treatment. Fifteen patients (18%) showed a BPDCN-like phenotype with no difference between NPM1-mutated (mut) and NPM1-wt patients. It did not significantly affect survival neither in the whole cohort, nor in NPM1-wt patients. However, as reported, it conferred a dismal prognosis in NPM1-mut AML (p < 0.001), irrespectively of the mutational status for FLT3-ITD. In conclusion we show that BPDCN-like phenotype displays a negative prognostic relevance only in NPM1-mutated AML.

Flai (fludarabine, cytarabine, idarubicin) plus low-dose Gemtuzumab Ozogamicin as induction therapy in CD33-positive AML: Final results and long term outcome of a phase II multicenter clinical trial

The aim of this prospective clinical trial was to evaluate the efficacy and safety of a combination of Gemtuzumab-Ozogamicin (GO) and FLAI scheme (fludarabine, cytarabine, idarubicin) as a first-line therapy in CD33 positive AML. We treated 130 patients, aged <65, with a median age of 52 years. FLAI-GO induction regimen included fludarabine (30 mg/sqm) and cytarabine (2 g/sqm) on days 1-5; idarubicin (10 mg/sqm) on days 1, 3, and 5; and GO (3 mg/sqm) on day 6. SCT was planned for all high-risk AML patients, after consolidation with intermediate doses of cytarabine and idarubicin and a high dose of cytarabine. CD33 expression exceeded 20% in all cases. Primary endpoints of the study included feasibility, overall response rate (ORR) and toxicity. Secondary endpoints included the evaluation of MRD by WT1 expression, feasibility and outcome of consolidation with SCT, overall survival (OS) and disease-free survival (DFS). After induction with FLAI-GO, complete remission (CR) rate was 82%. Four patients achieved partial remission (PR) and 12% were resistant (ORR 85%); death during induction (DDI) was 3%. The hematological and extra hematological toxicity of FLAI-GO was manageable; 45% of patients experienced transient and reversible GO infusion related adverse events. In the setting of patients who achieved a cytological CR after FLAI-GO, the mean of WT1 copies dropped from 8337±9936 copies/10⁴ ABL (diagnosis) to 182 ± 436 copies after induction therapy (p = 0.0001) showing a very good disease debulking. After a median follow-up of 54 months, 67/130 (52%) patients were alive. The probability of 1, 2, and 5-year OS was 80%, 63%, and 52%, respectively. The probability of 1, 2, and 5-year DFS was 77%, 58%, and 52%, respectively. Allogeneic and autologous SCT was performed in 60 (46%) and 23 (18%) patients, respectively. In summary, the final results of this trial confirm that FLAI-GO is an active and safe treatment strategy for CD33-positive AML patients aged ≤ 65 years, allowing a high ORR, a good disease debulking, favorable safety profile, low DDI, and subsequent high SCT rate. The encouraging results of this trial, consolidated by a long follow-up, support the reintroduction of GO in clinical practice.

Tumorablative conditioning regimen for haploidentical stem cell transplantation in 102 children with hematologic malignancies: a single-center experience

Haploidentical hematopoietic stem cell transplantation (Haplo-HSCT) is widely carried out in China, and transplantation related complications decreased gradually with the transplant technology improving, and the overall survival(OS) increased year by year. However, relapse after transplantation is still one of the main causes of death in patients with hematological malignancy. In order to reduce the recurrence after HSCT, we set a tumorablative conditioning regimen (TAC ) regimen; the aim is as much as possible to eliminate the malignant clone to reduce the recurrence without increasing the conditioning toxicity. We retrospectively analyzed 102 cases of haplo-HSCT in our hospital from 2012 to 2017. Ninety-eight out of the 99 (99.0%) patients achieved primary engraftment. The 2-year OS and disease free survival (DFS) are 81.4% (83/102) and 77.45% (79/102). The cumulative incidence of leukemia relapse is 16.2% (16/99), Twenty-nine patients developed II-IV acute graft-versus-host disease (aGVHD) (29%) within 100 days and only nine patients have grade III-IV aGVHD (9%) in measurable 99 patients. The conditioning regimen was relatively well tolerated with limited regimen-related toxicity. The preliminary results show that TAC is safe and effective in haplo-HSCT of children with hematologic malignancies. This study will provide a clinical basis for the individualized conditioning regimen.

Depletion of SIRT6 enzymatic activity increases acute myeloid leukemia cells' vulnerability to DNA-damaging agents

Genomic instability plays a pathological role in various malignancies, including acute myeloid leukemia (AML), and thus represents a potential therapeutic target. Recent studies demonstrate that SIRT6, a NAD⁺-dependent nuclear deacetylase, functions as genome-guardian by preserving DNA integrity in different tumor cells. Here, we demonstrate that also CD34⁺ blasts from AML patients show ongoing DNA damage and SIRT6 overexpression. Indeed, we identified a poor-prognostic subset of patients, with widespread instability, which relies on SIRT6 to compensate for DNA-replication stress. As a result, SIRT6 depletion compromises the ability of leukemia cells to repair DNA double-strand breaks that, in turn, increases their sensitivity to daunorubicin and Ara-C, both in vitro and in vivo In contrast, low SIRT6 levels observed in normal CD34⁺ hematopoietic progenitors explain their weaker sensitivity to genotoxic stress. Intriguingly, we have identified DNA-PKcs and CtIP deacetylation as crucial for SIRT6-mediated DNA repair. Together, our data suggest that inactivation of SIRT6 in leukemia cells leads to disruption of DNA-repair mechanisms, genomic instability and aggressive AML. This synthetic lethal approach, enhancing DNA damage while concomitantly blocking repair responses, provides the rationale for the clinical evaluation of SIRT6 modulators in the treatment of leukemia.

Phase I clinical trial of the base excision repair inhibitor methoxyamine in combination with fludarabine for patients with advanced hematologic malignancies

PURPOSE

We determined the safety, pharmacokinetics, pharmacodynamics and recommended phase II dose of the base excision repair blocker methoxyamine combined with fludarabine.

MATERIALS AND METHODS

This was a phase I study with intravenous fludarabine (25 mg/m2, days 1-5), and methoxyamine (15 mg/m2-120 mg/m2, once). A maximum of six cycles were given. Adult patients with relapsed/refractory hematologic malignancies, excluding acute myeloid leukemia, were eligible.

RESULTS

Twenty patients were treated; diagnoses included CLL/SLL (n = 10), follicular lymphoma (n = 3), DLBCL (n = 3), mantle cell lymphoma (n = 1), anaplastic large cell lymphoma (n = 1) and plasma cell myeloma (n = 2). No DLTs were observed and dose escalation reached the maximum planned dose. Hematologic toxicity was frequent; most common grade 3-4 toxicities were lymphopenia (70%), neutropenia (60%), leukopenia (50%) and anemia (40%). Four patients achieved a partial remission and 8 achieved stable disease. The drug combination resulted in increased DNA damage measured with the Comet assay.

CONCLUSIONS

Methoxyamine combined with fludarabine was safe and well tolerated. Hematologic toxicity was comparable to single agent fludarabine. Activity appears to correlate with increased levels of DNA damage. Further studies will examine use of this combination of as part conditioning regimens of stem cell transplant and use of methoxyamine as fludarabine dose-sparing agent.

A phase I/II randomized trial of clofarabine or fludarabine added to idarubicin and cytarabine for adults with relapsed or refractory acute myeloid leukemia

The purine nucleoside analogues clofarabine and fludarabine are active in acute myeloid leukemia (AML). We conducted a phase I/II randomized study of idarubicin and cytarabine with either clofarabine (CIA) or fludarabine (FIA) for relapsed or refractory AML. Clofarabine 15 mg/m² was identified as the recommended phase II dose. Eighty-one patients were assigned using adaptive randomization to CIA (n = 48) or FIA (n = 33). The complete response (CR)/CR without platelet recovery rate did not differ between CIA and FIA (38% versus 30%, respectively; p = .50). In both arms, more than half of patients who had received only one prior line of therapy achieved remission. The median event-free survival for CIA and FIA was 2.0 and 1.9 months (p = .48), and the median overall survival was 6.3 and 4.7 months, respectively (p = .28). No significant differences in adverse events or early mortality rates were observed. Overall, CIA and FIA resulted in similar response rates and survival in patients with relapsed/refractory AML.

Angiomodulators in cancer therapy: New perspectives

The formation of new blood vessels plays a crucial for the development and progression of pathophysiological changes associated with a variety of disorders, including carcinogenesis. Angiogenesis inhibitors (anti-angiogenics) are an important part of treatment for some types of cancer. Some natural products isolated from marine invertebrates have revealed antiangiogenic activities, which are diverse in structure and mechanisms of action. Many preclinical studies have generated new models for further modification and optimization of anti-angiogenic substances, and new information for mechanistic studies and new anti-cancer drug candidates for clinical practice. Moreover, in the last decade it has become apparent that galectins are important regulators of tumor angiogenesis, as well as microRNA. MicroRNAs have been validated to modulate endothelial cell migration or endothelial tube organization. In the present review we summarize the current knowledge regarding the role of marine-derived natural products, galectins and microRNAs in tumor angiogenesis.

Intesive fludarabine-high dose cytarabine-idarubicin combination as induction therapy with risk-adapted consolidation may improve treatment efficacy in younger Acute Myeloid Leukemia (AML) patients: Rationales, evidences and future perspectives

Acute Myeloid Leukemia (AML) is the commonest form of leukemia in the adults, with an incidence of 3-4 cases per 100,000 people/year. After the first description of the effective cytarabine + antracycline (3+7) induction regimen, in the last 3 decades, no effective targeted drug has been included in the standard treatment of AML. Many efforts of modifying 3+7 adding a third drug or increasing the dose of anthracycline, cytarabine or both did not lead to substantial improvements, mainly due to increased toxicity. Many in vitro and in vivo evidences suggested that fludarabine may increase efficacy of cytarabine through a synergistic effect. Considering the continuous improvements in supportive care and management of infectious complications the feasibility of more intensive induction strategies have increased and a renewed interest in fludarabine-containing induction strategies arose. The recent MRC AML 15 trial has shown that a fludarabine-containing induction, FLAG-Ida, resulted superior to conventional 3+7 in terms of complete remission rates, relapse incidence and survival, although only a minority of patients could complete the whole planned consolidation program due to an excessive hematological toxicity. Our group recently published a 10-year experience with a fludarabine-containing induction that slightly differed from the MRC one and resulted in good efficacy and higher feasibility. In this commentary we review the major evidences supporting the employ of a fludarabine-containing induction in AML, and discuss the future perspectives.