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

Targeting protein tyrosine phosphatase non-receptor type 6 (PTPN6) as a therapeutic strategy in acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogeneous hematologic malignancy characterized by the clonal expansion of myeloid progenitor cells. Despite advancements in treatment, the prognosis for AML patients remains poor, highlighting the need for novel therapeutic targets. Protein Tyrosine Phosphatase Non-Receptor Type 6 (PTPN6), also known as SHP-1, is a critical regulator of hematopoietic cell signaling and has been implicated in various leukemias. This study investigates the therapeutic potential of targeting PTPN6 in AML. We employed both in vitro and in vivo models to evaluate the effects of PTPN6 inhibition on AML cell proliferation, apoptosis, and differentiation. Our results demonstrate that PTPN6 inhibition leads to a significant reduction in AML cell viability, induces apoptosis, and promotes differentiation of leukemic cells into mature myeloid cells. Mechanistic studies revealed that PTPN6 inhibition disrupts key signaling pathways involved in AML pathogenesis, including the JAK/STAT and PI3K/AKT pathways. Furthermore, the combination of PTPN6 inhibitors with standard chemotherapeutic agents exhibited a synergistic effect, enhancing the overall therapeutic efficacy. These findings suggest that PTPN6 is a promising therapeutic target in AML and warrants further investigation into the development of PTPN6 inhibitors for clinical application in AML treatment.

Single-cell transcriptome profiling of m6A regulator-mediated methylation modification patterns in elderly acute myeloid leukemia patients

Millions of people worldwide die of acute myeloid leukaemia (AML) each year. Although N6-methyladenosine (m6A) modification has been reported to regulate the pathogenicity of AML, the mechanisms by which m6A induces dysfunctional hematopoietic differentiation in elderly AML patients remain elusive. This study elucidates the mechanisms of the m6A landscape and the specific roles of m6A regulators in hematopoietic cells of elderly AML patients. Notably, fat mass and obesity-associated protein (FTO) was found to be upregulated in hematopoietic stem cells (HSCs), myeloid cells, and T-cells, where it inhibits their differentiation via the WNT signaling pathway. Additionally, elevated YT521-B homology domain family proteins 2 (YTHDF2) expression in erythrocytes was observed to negatively regulate differentiation through oxidative phosphorylation, resulting in leukocyte activation. Moreover, IGF2BP2 was significantly upregulated in myeloid cells, contributing to an aberrant chromosomal region and disrupted oxidative phosphorylation. m6A regulators were shown to induce abnormal cell-cell communication within hematopoietic cells, mediating ligand-receptor interactions across various cell types through the HMGB1-mediated pathway, thereby promoting AML progression. External validation was conducted using an independent single-cell RNA sequencing (scRNA-Seq) dataset. The THP-1 and MV411 cell lines were utilized to corroborate the m6A regulator profile; in vitro experiments involving short hairpin RNA (shRNA) targeting FTO demonstrated inhibition of cell proliferation, migration, and oxidative phosphorylation, alongside induction of cell cycle arrest and apoptosis. In summary, these findings suggest that the upregulation of m6A regulators in HSCs, erythrocytes, myeloid cells, and T-cells may contribute to the malignant differentiation observed in AML patients. This research provides novel insights into the pathogenesis of AML in elderly patients and identifies potential therapeutic targets.

N-Phenyl ureidobenzenesulfonates, a novel class of human dihydroorotate dehydrogenase inhibitors inducing differentiation and apoptosis in acute myeloid leukemia cells

N-Phenyl ureidobenzensulfonates (PUB-SOs) are a novel family of dihydroorotate dehydrogenase (DHODH) inhibitors. Herein, we investigate the potential of PUB-SOs to induce acute myeloid leukemia (AML) cell differentiation and apoptosis. To that end, we screened our chemolibrary to select the most potent PUB-SOs based on their antiproliferative activity and their ability to arrest the cell progression of AML cells in the S phase. The most promising PUB-SOs show antiproliferative activity in the range of 0.13-23 µM against THP-1, MOLM-13 and HL-60 AML cells. Moreover, those PUB-SOs arrested the cell cycle progression in the S phase. In addition, molecular docking studies evidenced their potential to bind in the brequinar-binding site located on DHODH which was confirmed using the DHODH inhibition assay showing that PUB-SOs are potent DHODH inhibitors (half maximal inhibitory concentration (IC50) = 7.7-1000 nM). Our results also show that selected PUB-SOs induced the differentiation of THP-1 and HL-60 cells into cluster of differentiation (CD) 11b+/CD14+ phenotypes, up to 74 % and 50 %, respectively. They also promoted CD11b+ differentiation in MOLM-13 cells (up to 44 %). Additionally, the prototypical PUB-SOs SFOM-0046 induced lactate dehydrogenase (LDH) release, mitochondrial stress and mitochondrial membrane potential loss in MOLM-13 cell line. Furthermore, SFOM-0046 induced apoptosis in MOLM-13 cells, which was confirmed by the increase of annexin V/propidium iodide (PI) and caspase 3/7 positive cells. In summary, our results highlight PUB-SOs as a novel family of DHODH inhibitors inducing both cell differentiation and apoptosis in AML cells, underscoring their potential as therapeutic agents for AML treatment.

Modern Risk Stratification of Acute Myeloid Leukemia in 2023: Integrating Established and Emerging Prognostic Factors

An accurate estimation of AML prognosis is complex since it depends on patient-related factors, AML manifestations at diagnosis, and disease genetics. Furthermore, the depth of response, evaluated using the level of MRD, has been established as a strong prognostic factor in several AML subgroups. In recent years, this rapidly evolving field has made the prognostic evaluation of AML more challenging. Traditional prognostic factors, established in cohorts of patients treated with standard intensive chemotherapy, are becoming less accurate as new effective therapies are emerging. The widespread availability of next-generation sequencing platforms has improved our knowledge of AML biology and, consequently, the recent ELN 2022 recommendations significantly expanded the role of new gene mutations. However, the impact of rare co-mutational patterns remains to be fully disclosed, and large international consortia such as the HARMONY project will hopefully be instrumental to this aim. Moreover, accumulating evidence suggests that clonal architecture plays a significant prognostic role. The integration of clinical, cytogenetic, and molecular factors is essential, but hierarchical methods are reaching their limit. Thus, innovative approaches are being extensively explored, including those based on "knowledge banks". Indeed, more robust prognostic estimations can be obtained by matching each patient's genomic and clinical data with the ones derived from very large cohorts, but further improvements are needed.

Assessing eligibility for treatment in acute myeloid leukemia in 2023

INTRODUCTION

Age has historically been considered the main criterion to determine eligibility for intensive chemotherapy in patients with acute myeloid leukemia (AML), but age alone can no longer be considered an absolute indicator in determining which patients should be defined as unfit. Assessment of fitness for a given treatment today serves an important role in tailoring therapeutic options.

AREAS COVERED

This review examines the main options used in real life to define eligibility for intensive and nonintensive chemotherapy in patients with AML, with a main focus on the Italian SIE/SIES/GITMO Consensus Criteria. Other published real-life experiences are also reviewed, analyzing the correlation between these criteria and short-term mortality, and thus expected outcomes.

EXPERT OPINION

Assessment of fitness is mandatory at diagnosis to tailor treatment to the greatest degree possible, evaluating the patient's individual profile. This is especially relevant when considering the availability of newer, less toxic therapeutic regimens, which have shown promising results in patients with AML who are older or considered unfit for intensive treatment. Fitness assessment is now a fundamental part of AML management and a critical step that can potentially influence outcomes and not just predict them.

Combining the HCT-CI, G8, and AML-Score for Fitness Evaluation of Elderly Patients with Acute Myeloid Leukemia: A Single Center Analysis

BACKGROUND

Accurate assessment of elderly acute myeloid leukemia (AML) patients is essential before intensive induction chemotherapy and subsequent allogeneic hematopoietic stem cell transplantation. In this context, we investigated the capacity of three scores for frailty prediction.

METHODS

At diagnosis, 197 patients were clinically evaluated for appropriate treatment intensity. In parallel and independently, the G8-score, the Hematopoietic Stem Cell Index (HCT-CI) and the AML-score for CR were determined for each patient and analyzed with respect to overall survival (OS).

RESULTS

The G8-score and the HCT-CI were able to significantly separate "fit" from "unfit" patients, <0.001 and p = 0.008. In univariate Cox models, the predictive role for OS was confirmed: for the G8-score (HR: 2.35, 95% CI 1.53-3.60, p < 0.001), the HCT-CI (HR: 1.91, 95% CI 1.17-3.11, p = 0.009) and the AML-score (HR: 5.59, 95% CI 2.04-15.31, p = 0.001), the latter was subsequently used to verify the cohort. In the multivariate Cox model, the results were confirmed for the G8- (HR: 2.03, p < 0.001) and AML-score (HR: 3.27, p = 0.001). Of interest, when combining the scores, their prediction capacity was significantly enhanced, p < 0.001.

CONCLUSIONS

The G8-, the HCTCI and the AML-score represent valid tools in the frailty assessment of elderly AML patients at diagnosis.

Comparison of Hospital Length of Stay and Supportive Care Utilization Between Patients Treated with CPX-351 and 7+3 for Therapy-Related Acute Myeloid Leukemia or Acute Myeloid Leukemia with Myelodysplasia-Related Changes

Purpose

CPX-351 is dual-drug liposomal encapsulation of daunorubicin and cytarabine at a fixed synergistic 1:5 molar ratio. This study determined current real-world use of CPX-351 versus conventional 7+3 (cytarabine+daunorubicin) therapy and evaluated hospital length of stay (LOS) and supportive care utilization in t-AML and AML-MRC.

Patients and Methods

This retrospective, observational study utilized the Premier Healthcare Database and included patients who were aged ≥18 years with t-AML or AML-MRC and treated with CPX-351 or 7+3 between August 1, 2017 and February 28, 2019. All patients treated with 7+3 were required to be eligible for CPX-351 based on its FDA-approved indication. Outcome variables were annualized and adjusted for patient, hospital, and clinical confounding factors. The primary outcome was inpatient LOS. Secondary outcomes included use of blood products and use of anti-infectives.

Results

The study included 195 qualifying patients treated with CPX-351 and 160 patients treated with 7+3 who were eligible for CPX-351. Approximately one-third of the patients treated with CPX-351 were administered therapy in a hospital-based outpatient setting, and all patients treated with 7+3 received it in the inpatient setting. The regression-adjusted annualized inpatient LOS was shorter with CPX-351 than 7+3 (mean of 183.7 vs 197.1 days, p<0.001). The difference in mean-adjusted LOS was most pronounced for t-AML, with a mean-adjusted LOS of 168.9 versus 192.5 days for CPX-351 versus 7+3, respectively (nominal p<0.001). Supportive care utilization, including the number of administrations of red blood cells, the number of administrations of platelets, and the number of days on anti-infectives, was similar between treatment groups.

Conclusion

CPX-351 was associated with a shorter inpatient LOS than 7+3. Supportive care use, including blood products and anti-infectives, was similar for CPX-351 and 7+3. These findings suggest CPX-351 conveys resource advantages over 7+3 in patients with newly diagnosed t-AML and AML-MRC.