Integrated analysis of patient samples identifies biomarkers for venetoclax efficacy and combination strategies in acute myeloid leukemia

Impact of splicing mutations in acute myeloid leukemia treated with hypomethylating agents combined with venetoclax

Spliceosome mutations (SRSF2, SF3B1, U2AF1, ZRSR2), are encountered in ∼50% of secondary acute myeloid leukemia cases (sAML) and define a molecular subgroup with outcomes similar to sAML in de novo AML patients treated with intensive chemotherapy. Outcomes in patients with spliceosome mutations treated with hypomethylating agents in combination with venetoclax (HMA+VEN) remains unknown. The primary objective was to compare outcomes in patients with spliceosome mutations vs wild-type patients treated with HMA+VEN. Secondary objectives included analysis of the mutational landscape of the spliceosome cohort and assessing the impact of co-occurring mutations. We performed a retrospective cohort analysis of patients treated with HMA+VEN-based regimens at The University of Texas MD Anderson Cancer Center. A total of 119 patients (spliceosome mutated n = 39 [SRSF2, n = 24; SF3B1, n = 8; U2AF1, n = 7]; wild-type, n = 80) were included. Similar responses were observed between spliceosome and wild-type cohorts for composite complete response (CRc; 79% vs 75%, P = .65), and measurable residual disease-negative CRc (48% vs 60%, P = .34). Median overall survival for spliceosome vs wild-type patients was 35 vs 14 months (P = .58), and was not reached; 35 months and 8 months for patients with SRSF2, SF3B1, and U2AF1 mutations, respectively. IDH2 mutations were enriched in patients with SRSF2 mutations and associated with favorable outcomes (1- and 2-year overall survival [OS] of 100% and 88%). RAS mutations were enriched in patients with U2AF1 mutations and associated with inferior outcomes (median OS, 8 months). Comparable outcomes were observed between patients with vs without spliceosome mutations treated with HMA+VEN regimens, with specific co-mutation pairs demonstrating favorable outcomes.

Targeting LSCs: Peeling Back the Curtain on the Metabolic Complexities of AML

Most patients with AML succumb to chemoresistant leukemia stem cells (LSCs), which persist and reinitiate disease years after clinical remission. In this issue of Cell Stem Cell, Jones et al. (2020) identify a therapeutically targetable mechanism of resistance to venetoclax in relapsed and refractory AML LSCs mediated by nicotinamide metabolism.

Laboratory Evaluation and Pathological Workup of Neoplastic Monocytosis - Chronic Myelomonocytic Leukemia and Beyond

PURPOSE OF REVIEW

Monocytosis is a distinct but non-specific manifestation of various physiologic and pathologic conditions. Among hematopoietic stem cell neoplasms, depending on the criteria used for disease classification, monocytosis may be a consistent and integral component of diseases such as chronic myelomonocytic leukemia or acute myeloid leukemia with monocytic differentiation, or it may represent an inconsistent finding that often provides a clue to the underlying genetic changes driving the neoplasm. The purpose of this review is to provide the readers with a laboratory-based approach to neoplastic monocytosis.

RECENT FINDINGS

In-depth elucidation of the genomic landscape of myeloid neoplasms within the past few years has broadened our understanding of monocytosis and its implications for diagnosis and prognosis. Genetic findings also shed light on potential disease response - or lack thereof - to various therapeutic agents used in the setting of myeloid neoplasms. In this review, we provide our approach to diagnose neoplastic monocytosis in the context of case-based studies while incorporating the most recent literature on this topic.

Mutational landscape of chronic myeloid leukemia: more than a single oncogene leukemia

The BCR-ABL1 fusion gene, which causes aberrant kinase activity and uncontrolled cell proliferation, is the hallmark of chronic myeloid leukemia (CML). The development of tyrosine kinase inhibitors (TKI) that target the BCR-ABL oncoprotein has led to dramatic improvement in CML management. However, some challenges remain to be addressed in the TKI era, including patient stratification and the selection of frontline TKIs and CML progression. Additionally, with the emerging goal of treatment-free remission (TFR) in CML management, biomarkers that predict the outcomes of stopping TKI remain to be identified. Notably, recent reports have revealed the power of genome screening in understanding the role of genome aberrations other than BCR-ABL1 in CML pathogenesis. These studies have discovered the presence of disease-phase specific mutations and linked certain mutations to inferior responses to TKI treatment and CML progression. A personalized approach that incorporates genetic data in tailoring treatment strategies has been successfully implemented in acute leukemia, and it represents a promising approach for the management of high-risk CML patients. In this article, we will review current knowledge about the mutational profile in different phases of CML as well as patterns of mutational dynamics in patients having different outcomes. We highlight the effects of somatic mutations involving certain genes (e.g. epigenetic modifiers) on the outcomes of TKI treatment. We also discuss the potential value of incorporating genetic data in treatment decisions and the routine care of CML patients as a future direction for optimizing CML management.

Clinical and molecular predictors of response and survival following venetoclax therapy in relapsed/refractory AML

Azacitidine + venetoclax, decitabine + venetoclax, and low-dose cytarabine + venetoclax are now standard treatments for newly diagnosed older or unfit patients with acute myeloid leukemia (AML). Although these combinations are also commonly used in relapsed or refractory AML (RR-AML), clinical and molecular predictors of response and survival in RR-AML are incompletely understood. We retrospectively analyzed clinical and molecular characteristics and outcomes for 86 patients with RR-AML who were treated with venetoclax combinations. The complete remission (CR) or CR with incomplete hematologic recovery (CRi) rate was 24%, and the overall response rate was 31% with the inclusion of a morphologic leukemia-free state. Azacitidine + venetoclax resulted in higher response rates compared with low-dose cytarabine + venetoclax (49% vs 15%; P = .008). Median overall survival (OS) was 6.1 months, but it was significantly longer with azacitidine + venetoclax compared with low-dose cytarabine + venetoclax (25 vs 3.9 months; P = .003). This survival advantage of azacitidine + venetoclax over low-dose cytarabine + venetoclax persisted when patients were censored for subsequent allogeneic stem cell transplantation (8.1 vs 3.9 months; P = .035). Mutations in NPM1 were associated with higher response rates, whereas adverse cytogenetics and mutations in TP53, KRAS/NRAS, and SF3B1 were associated with worse OS. Relapse was driven by diverse mechanisms, including acquisition of novel mutations and an increase in cytogenetic complexity. Venetoclax combination therapy is effective in many patients with RR-AML, and pretreatment molecular characteristics may predict outcomes. Trials that evaluate novel agents in combination with venetoclax therapy in patients with RR-AML that have adverse risk genomic features are warranted.

Mechanisms for resistance in AML insights into molecular pathways mediating resistance to venetoclax

Resistance to therapy continues to pose hurdles in the therapeutic management of acute myeloid leukemia (AML). Although the approval and development of therapies such as venetoclax, was expected to overcome this issue, resistance remains a common occurrence in AML treatment. This review has summarized evidence that will provide insights into acquired mutations that influence response to venetoclax therapy and the utility of novel combination approaches in improving outcomes.

A comprehensive assessment of the prognostic role of cell adhesion molecules in acute myeloid leukemia

Background

The outcomes for patients with acute myeloid leukemia (AML) have been shown to vastly differ, predominantly due to genetic heterogeneity. Cell adhesion molecules (CAMs) concluding numerous genes play an important role in AML. We aimed to systematically assess the expression characteristics of adhesion molecules and their correlation to the outcomes of AML.

Method

A total of 173 patients with AML were enrolled in this study. The genetic expressional information and clinical data sourced in previous studies were collected from the Cancer Genome Atlas (TCGA) database. The expression profiles of 141 CAMs were assessed, and the AML subgroups with specific patterns of expression were identified. The outcomes and clinical features of each AML subgroup were compared to detect the factors associated with prognosis. The differentially expressed genes (DEGs) between each subgroup were identified and the prognostic roles of those molecules were evaluated.

Results

According to subgroup clustering, both the primary cluster_1 and subcluster_1 showed a favorable prognosis compared to that of the other patients (26.3 vs. 17.0 months of overall survival (OS) and 46.5 vs. 15.8 months of OS, respectively). Both of the two subgroups were characterized by depressed human leukocyte antigen (HLA) genes. Assessment of the expression of prognosis-associated CAMs revealed that the expressions of SELE, NRCAM, ITGA4, and SDC1 were positively correlated with AML prognosis, while the expression of L1CAM, PDCD1, CD276, SELPLG, and CLDN14 were negatively correlated with AML. Among the abovementioned genes, we detected that the individual gene expressions of NRCAM and VCAM1 were capable of independently predicting OS, and the OS was correlated with CAMs closely enough to enable the construction of models for prognosis prediction [area under the curve (AUC) =0.78 and AUC=0.77, respectively].

Conclusions

This study showed a landscape of the expression of CAMs in AML and identified a distinct subgroup with a significantly favorable prognosis. We detected that CAMs can assist in distinguishing the cohort with long term survival and constructed two models to predict the prognosis. Those CAMs have the potential to be developed as therapy targets in the treatment of AML.