Comparison of anthracyclines used for induction chemotherapy in patients with FLT3 -ITD-mutated acute myeloid leukemia

Current status and research directions in acute myeloid leukemia

The understanding of the molecular pathobiology of acute myeloid leukemia (AML) has spurred the identification of therapeutic targets and the development of corresponding novel targeted therapies. Since 2017, twelve agents have been approved for the treatment of AML subsets: the BCL2 inhibitor venetoclax; the CD33 antibody drug conjugate gemtuzumab ozogamicin; three FLT3 inhibitors (midostaurin, gilteritinib, quizartinib); three IDH inhibitors (ivosidenib and olutasidenib targeting IDH1 mutations; enasidenib targeting IDH2 mutations); two oral hypomethylating agents (oral poorly absorbable azacitidine; fully absorbable decitabine-cedazuridine [latter approved as an alternative to parenteral hypomethylating agents in myelodysplastic syndrome and chronic myelomonocytic leukemia but commonly used in AML]); and CPX-351 (encapsulated liposomal 5:1 molar ratio of cytarabine and daunorubicin), and glasdegib (hedgehog inhibitor). Other targeted therapies (menin inhibitors, CD123 antibody-drug conjugates) are showing promising results. To achieve optimal results in such a rare and heterogeneous entity as AML requires expertise, familiarity with this rare cancer, and the access to, and delivery of disparate therapies under rigorous supportive care conditions. In this review, we update the standard-of-care and investigational therapies and outline promising current and future research directions.

Real-world treatment outcomes from a retrospective cohort of patients with acute myeloid leukemia from an urban safety net hospital

INTRODUCTION

While continual advancements in acute myeloid leukemia have augmented response rates and survival, outcomes in clinical trials may not correlate with real-world practice as trials may underrepresent individuals with comorbidities, decreased performance status, and older age. Additionally, clinical trials may underrepresent certain ethnicities, and disparities based on ethnicity, socioeconomic status, and insurance have been demonstrated in acute myeloid leukemia.

METHODS

We performed a retrospective chart review of adult patients with acute myeloid leukemia who were treated at Harbor-UCLA from 2014 to 2022 to examine patient characteristics, management patterns, and outcomes in a safety net hospital setting.

RESULTS

The median age was 56 years old (range 18-84). In regards to risk stratification, 22%, 33%, and 41% had favorable, intermediate, and adverse risk acute myeloid leukemia, respectively. The most common induction regimens included 7 + 3 (55%), azacitidine (10%), azacitidine + venetoclax (7%), and 7 + 3 + midostaurin (7%). The complete remission rate was 51%. Among patients who received intensive induction chemotherapy, 15% underwent re-induction with a second cycle, 51% received consolidation therapy, and 5% received maintenance therapy with a targeted agent. Overall, 12% of patients received allogeneic stem cell transplant. Median overall survival was 12.2 months, and 5-year overall survival was 18%.

CONCLUSIONS

Suboptimal response rates and survival in this population may be related to low rates of re-induction and allogeneic transplant in addition to high rates of adverse cytogenetics, secondary acute myeloid leukemia, and supportive care only. Efforts to increase access to clinical trials, novel therapies, and transplants for diverse and underinsured populations are essential.

Autophagy in Hematological Malignancies

Simple Summary

Autophagy is a dynamic and tightly regulated process that seems to have dual effects in cancer. In some contexts, it can induce carcinogenesis and promote cancer cell survival, whereas in others, it acts preventing tumor cell growth and tumor progression. Thus, autophagy functions seem to strictly depend on cancer ontogenesis, progression, and type. Here, we will dive into the current knowledge of autophagy in hematological malignancies and will highlight the main genetic components involved in each cancer type.

Abstract

Autophagy is a highly conserved metabolic pathway via which unwanted intracellular materials, such as unfolded proteins or damaged organelles, are digested. It is activated in response to conditions of oxidative stress or starvation, and is essential for the maintenance of cellular homeostasis and other vital functions, such as differentiation, cell death, and the cell cycle. Therefore, autophagy plays an important role in the initiation and progression of tumors, including hematological malignancies, where damaged autophagy during hematopoiesis can cause malignant transformation and increase cell proliferation. Over the last decade, the importance of autophagy in response to standard pharmacological treatment of hematological tumors has been observed, revealing completely opposite roles depending on the tumor type and stage. Thus, autophagy can promote tumor survival by attenuating the cellular damage caused by drugs and/or stabilizing oncogenic proteins, but can also have an antitumoral effect due to autophagic cell death. Therefore, autophagy-based strategies must depend on the context to create specific and safe combination therapies that could contribute to improved clinical outcomes. In this review, we describe the process of autophagy and its role on hematopoiesis, and we highlight recent research investigating its role as a potential therapeutic target in hematological malignancies. The findings suggest that genetic variants within autophagy-related genes modulate the risk of developing hemopathies, as well as patient survival.

Harnessing the benefits of available targeted therapies in acute myeloid leukaemia

Research has resulted in regulatory approval of nine agents for acute myeloid leukaemia indications by the US Food and Drug Administration since 2017: the Bcl-2 inhibitor, venetoclax; two FLT3 inhibitors, midostaurin and gilteritinib; two IDH inhibitors, ivosidenib (IDH1 inhibitor) and enasidenib (IDH2 inhibitor); the anti-CD33 antibody-drug conjugate, gemtuzumab ozogamicin; the oral, poorly absorbable hypomethylating agent, azacitidine; the liposomal formulation of cytarabine and daunorubicin (5:1 ratio), CPX-351; and the hedgehog signalling pathway inhibitor, glasdegib. A 100% absorbable oral formulation of the hypomethylating agent decitabine was approved for the treatment of myelodysplastic syndrome and chronic myelomonocytic leukaemia, and might be used as an alternative to parenteral hypomethylating agents. Several of the approvals are as single-agent therapies or in specific combinations for narrow indications, thus offering poor treatment value. In this Review, we discuss ongoing research into combinations containing these commercially available targeted therapies for acute myeloid leukaemia.

Acute Myeloid Leukemia: Historical Perspective and Progress in Research and Therapy Over 5 Decades

With the Food and Drug Administration approval of 9 agents for different acute myeloid leukemia (AML) indications, the prognosis and management of AML is evolving rapidly. Herein, we review the important milestones in the history of AML research and therapy, discuss insights regarding prognostic assessment and prediction of treatment outcome, detail practical supportive care measures, and summarize the current treatment landscape and areas of evolving research.

Acute myeloid leukemia: Treatment and research outlook for 2021 and the MD Anderson approach

The unraveling of the pathophysiology of acute myeloid leukemia (AML) has resulted in rapid translation of the information into clinical practice. After more than 40 years of slow progress in AML research, the US Food and Drug Administration has approved nine agents for different AML treatment indications since 2017. In this review, we detail the progress that has been made in the research and treatment of AML, citing key publications related to AML research and therapy in the English literature since 2000. The notable subsets of AML include acute promyelocytic leukemia (APL), core-binding factor AML (CBF-AML), AML in younger patients fit for intensive chemotherapy, and AML in older/unfit patients (usually at the age cutoff of 60-70 years). We also consider within each subset whether the AML is primary or secondary (therapy-related, evolving from untreated or treated myelodysplastic syndrome or myeloproliferative neoplasm). In APL, therapy with all-trans retinoic acid and arsenic trioxide results in estimated 10-year survival rates of ≥80%. Treatment of CBF-AML with fludarabine, high-dose cytarabine, and gemtuzumab ozogamicin (GO) results in estimated 10-year survival rates of ≥75%. In younger/fit patients, the "3+7" regimen (3 days of daunorubicin + 7 days of cytarabine) produces less favorable results (estimated 5-year survival rates of 35%; worse in real-world experience); regimens that incorporate high-dose cytarabine, adenosine nucleoside analogs, and GO are producing better results. Adding venetoclax, FLT3, and IDH inhibitors into these regimens has resulted in encouraging preliminary data. In older/unfit patients, low-intensity therapy with hypomethylating agents (HMAs) and venetoclax is now the new standard of care. Better low-intensity regimens incorporating cladribine, low-dose cytarabine, and other targeted therapies (FLT3 and IDH inhibitors) are emerging. Maintenance therapy now has a definite role in the treatment of AML, and oral HMAs with potential treatment benefits are also available. In conclusion, AML therapy is evolving rapidly and treatment results are improving in all AML subsets as novel agents and strategies are incorporated into traditional AML chemotherapy. LAY SUMMARY: Ongoing research in acute myeloid leukemia (AML) is progressing rapidly. Since 2017, the US Food and Drug Administration has approved 10 drugs for different AML indications. This review updates the research and treatment pathways for AML.

Acute myeloid leukemia: current progress and future directions

Progress in the understanding of the biology and therapy of acute myeloid leukemia (AML) is occurring rapidly. Since 2017, nine agents have been approved for various indications in AML. These included several targeted therapies like venetoclax, FLT3 inhibitors, IDH inhibitors, and others. The management of AML is complicated, highlighting the need for expertise in order to deliver optimal therapy and achieve optimal outcomes. The multiple subentities in AML require very different therapies. In this review, we summarize the important pathophysiologies driving AML, review current therapies in standard practice, and address present and future research directions.

FLT3-ITD and CD135 Over-Expression are Frequent Findings of Poor Survival in Adult Patients with Acute Leukemias

BACKGROUND

Fms-like tyrosine kinase 3 (FLT3) expression and mutation have been considered a poor prognostic factor in acute myeloid leukemia (AML). FLT3-ITD mutation is present in 30% of adult patients with AML and 2-5% in childhood acute lymphoblastic leukemia (ALL). The impact of these mutations on the prognosis of ALL patients, has not yet been established. Moreover, a limited number of publications regarding the level of expression of the FLT3 receptor (CD135) in both leukemias exist. This study aimed to analyze the clinical outcomes associated to the presence of FLT3-ITD mutation and the expression of CD135.

METHODS

82 adult patients with newly diagnosed acute leukemia (39 with AML and 43 with ALL) were included. Flow cytometry and RT-PCR were done to analyze the expression of CD135 and the presence of FLT3 ITD mutation, respectively.

RESULTS

FLT3-ITD was present in 14 (36%) of AML and 15 (35%) of ALL patients. Disease free survival (DFS) and overall survival (OS) were lower in ALL patients having a CD135 expression >3000 cells/μL. There was a trend for poor OS in AML patients expressing FLT3 ITD. OS was worse in AML patients with high expression of CD135.

CONCLUSION

A higher (35%) frequency of FLT3-ITD was found in adult ALL patients. The presence of FLT3-ITD was associated with a trend of poor OS in AML cases, and overexpression of CD135 was correlated with poor DFS in ALL cases and poor OS in both acute leukemias.

Genome mining of biosynthetic and chemotherapeutic gene clusters in Streptomyces bacteria

Streptomyces bacteria are known for their prolific production of secondary metabolites, many of which have been widely used in human medicine, agriculture and animal health. To guide the effective prioritization of specific biosynthetic gene clusters (BGCs) for drug development and targeting the most prolific producer strains, knowledge about phylogenetic relationships of Streptomyces species, genome-wide diversity and distribution patterns of BGCs is critical. We used genomic and phylogenetic methods to elucidate the diversity of major classes of BGCs in 1,110 publicly available Streptomyces genomes. Genome mining of Streptomyces reveals high diversity of BGCs and variable distribution patterns in the Streptomyces phylogeny, even among very closely related strains. The most common BGCs are non-ribosomal peptide synthetases, type 1 polyketide synthases, terpenes, and lantipeptides. We also found that numerous Streptomyces species harbor BGCs known to encode antitumor compounds. We observed that strains that are considered the same species can vary tremendously in the BGCs they carry, suggesting that strain-level genome sequencing can uncover high levels of BGC diversity and potentially useful derivatives of any one compound. These findings suggest that a strain-level strategy for exploring secondary metabolites for clinical use provides an alternative or complementary approach to discovering novel pharmaceutical compounds from microbes.

Prognosis and outcome of patients with acute myeloid leukemia based on FLT3-ITD mutation with or without additional abnormal cytogenetics

The FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) gene mutation is present in ~20% of patients with de novo acute myeloid leukemia (AML). Patients with an FLT3-ITD mutation have a poor prognosis. However, the prognostic function of FLT3-ITD combined with other cytogenetic abnormalities are not clear. In the present study, a retrospective analysis of 103 newly diagnosed patients with AML was performed. The results revealed that the overall survival (OS) and recurrence-free survival (RFS) times were significantly longer in patients with an FLT3-ITD mutation combined with other favorable risk genes, compared with in those patients with a single FLT3-ITD mutation (P=0.0361 and P=0.0426). Sorafenib combined with chemotherapy significantly improved the overall response rate (ORR) when compared with mono-chemotherapy (P=0.039), but no significant differences were observed in the OS and RFS. In conclusion, favorable-risk cytogenetics may improve the clinical outcomes of patients with FLT3-ITD-mutated AML, but adverse-risk cytogenetics may not further worsen the prognosis. Sorafenib combined with chemotherapy may increase the ORR but would not result in a longer OS and RFS.

Differences in ex-vivo Chemosensitivity to Anthracyclines in First Line Acute Myeloid Leukemia

Background

Induction schedules in acute myeloid leukemia (AML) are based on combinations of cytarabine and anthracyclines. The choice of the anthracycline employed has been widely studied in multiple clinical trials showing similar complete remission rates.

Materials and Methods

Using an ex vivo test we have analyzed if a subset of AML patients may respond differently to cytarabine combined with idarubicin, daunorubicin or mitoxantrone. Bone marrow (BM) samples of 198 AML patients were incubated for 48 hours in 96 well plates, each well containing different drugs or drug combinations at different concentrations. Ex vivo drug sensitivity analysis was made using the PharmaFlow platform maintaining the BM microenvironment. Drug response was evaluated as depletion of AML blast cells in each well after incubation. Annexin V-FITC was used to quantify the ability of the drugs to induce apoptosis, and pharmacological responses were calculated using pharmacokinetic population models.

Results

Similar dose-respond graphs were generated for the three anthracyclines, with a slight decrease in EC₅₀ with idarubicin (p=1.462E-06), whereas the interpatient variability of either drug was large. To identify those cases of selective sensitivity to anthracyclines, potency was compared, in terms of area under the curve. Differences in anthracycline monotherapy potency greater than 30% from 3 pairwise comparisons were identified in 28.3% of samples. Furthermore, different sensitivity was detected in 8.2% of patients comparing combinations of cytarabine and anthracyclines.

Discussion

A third of the patients could benefit from the use of this test in the first line induction therapy selection, although it should be confirmed in a clinical trial specifically designed.

[Clinical characteristics and prognosis of 34 cases of acute myeloid leukemia with FLT3 internal tandem duplication and MLL gene rearrangement]

Objective: To analyze the clinical characteristics and prognosis of 34 cases of acute myeloid leukemia (AML) with FLT3 internal tandem duplication (FLT3-ITD) and MLL gene rearrangement. Methods: The clinical data of 34 AML patients with FLT3-ITD and MLL gene rearrangement was compared and analyzed for the therapeutic efficacy, prognostic factors when treated with chemotherapy, chemotherapy combined with targeted therapy or allogenic hematopoietic stem cell transplantation (allo-HSCT). Results: Of the thirty-four cases with median age 41 (4-71) years old, 63.6% presented with white blood cells (WBC) greater than 30×10(9)/L, 39.4% greater than 50 × 10(9)/L respectively on admission. M(5) (35.3%) made up the highest proportion. The cytogenetic abnormality reached 61.8%, of which the complex cytogenetic abnormality accounted for 11.8%. Eleven patients (32.35%) had both FLT3-ITD and MLL gene abnormalities. In addition to FLT3 and MLL abnormalities, 23 patients (67.6%) had one or more other gene abnormalities (multiple gene abnormalities). Of the 34 cases, 29.4% patients went into complete remission (CR) after two courses of chemotherapy. 20.6% (7 patients) went into CR after 3 or more courses of chemotherapy. The rate of early relapse in the CR group was 52.9%. Patients with WBC>50×10(9)/L or multiple gene abnormalities had a lower remission rate (7.7%, 5.4%) after two courses of chemotherapy. CR rate for the patients with more than three gene abnormalities was 0. The total 2-year overall survival (OS) in the 34 patients was 28.8% (95% CI 13.5%-46.0%) and the disease-free survival (DFS) was 27.1% (95% CI 12.5%-44.0%). Of the 18 patients treated with chemotherapy alone or chemotherapy combined with targeted therapy, 17 cases died within 2 years and 1 lost follow-up after giving up treatment. For the 16 patients received allo-HSCT, the 3-year OS was 43.4% (95% CI 13.7%-70.4%) and DFS 42.7% (95% CI 13.4%-69.7%). Conclusion: AML patients with FLT3-ITD and MLL gene rearrangement often presented with M(5), accompanied by hyperleukocytosis, cytogenetic or multiple gene abnormalities. Those patients were observed to have low response rate and high early relapse when treated with chemotherapy without allo-HSCT. Patients had multiple gene abnormalities may be an important poor prognostic factor. Allo-HSCT is an effective treatment which could significantly improve the prognosis and survival of AML patients with FLT3-ITD and MLL gene abnormalities.

Efficacy and Toxicity of Idarubicin Versus High-dose Daunorubicin for Induction Chemotherapy in Adult Acute Myeloid Leukemia: A Systematic Review and Meta-analysis

BACKGROUND

The 2 main formulations of anthracycline used for acute myeloid leukemia (AML) induction therapy are idarubicin (IDA) and daunorubicin.

PATIENTS AND METHODS

The present systematic review and meta-analysis compared the efficacy and toxicity between IDA and high-dose daunorubicin (HDD) for induction therapy for adult AML. Relevant studies reported before June 2018 were searched from the Medline and Embase databases.

RESULTS

A total of 5 studies with 1809 participants (3 randomized controlled studies and 2 retrospective cohort studies) met the eligibility criteria and were included in the meta-analysis. The patients in the IDA arm for induction therapy had a significantly greater complete response rate after the first course of induction therapy compared with those in the HDD arm (66.7% vs. 61.1%, respectively; odds ratio, 1.23; P = .04; I² = 0%). A significantly lower rate of refractory AML was also observed in the IDA group than in the HDD group (16.8% vs. 20.7%, respectively; odds ratio, 0.77; P = .04; I² = 0%). However, no difference was found in the long-term overall survival between the 2 groups. Also, the induction mortality rate, febrile neutropenia rate, and cardiotoxicity rate were not significantly different between the 2 groups. The major limitation was the relatively small number of included studies, which could have limited the power of the meta-analysis to demonstrate significant long-term benefits.

CONCLUSION

The complete response rate after the first course of induction therapy was significantly greater among adult patients with AML who had received IDA as part of induction therapy compared with those who had received HDD.