Low-dose lenalidomide plus cytarabine induce complete remission that can be predicted by genetic profiling in elderly acute myeloid leukemia patients

Dose intensity for induction in acute myeloid leukemia: what, when, and for whom?

Intensive chemotherapy has been the backbone of the treatment of acute myeloid leukemia (AML) for decades. However, an increase in novel targeted agents, which has been brought about in part by a deeper understanding of the genetic makeup of AML, has led to remission-inducing regimens that do not require traditional cytotoxic agents. Combinations of a hypomethylating agent (HMA) and venetoclax have doubled the chance of remission for patients considered unfit for induction chemotherapy who would have traditionally been offered singleagent HMA. In fact, this regimen may rival the complete remission rate achieved with induction chemotherapy for certain populations such as the very elderly and those with secondary AML, but equivalency has yet to be established. Further advances include the addition of gemtuzumab ozogamicin and FLT3 inhibitors to induction chemotherapy, which improves survival for patients with core-binding factor and FLT3-mutated AML, respectively. Still, much work is needed to improve the outcomes of the highest-risk subgroups: frail patients and those with high-risk cytogenetics and/or TP53 mutations. Promisingly, the landscape of AML therapy is shifting dramatically and no longer is intensity, when feasible, always the best answer for AML.

Gene expression profile predicts response to the combination of tosedostat and low-dose cytarabine in elderly AML

Tosedostat is an orally administered metalloenzyme inhibitor with antiproliferative and antiangiogenic activity against hematological and solid human cancers. Clinical activity has been demonstrated in relapsed acute myeloid leukemia (AML). Thirty-three elderly patients with AML (median age, 75 years) received 120 mg tosedostat orally once daily combined with subcutaneous low-dose cytarabine (20 mg twice per day for 10 days, up to 8 cycles), until disease progression. Induction mortality was 12%. According to an intention-to-treat analysis, the complete remission (CR) rate was 48.5%, and thus the primary end point of the study was reached (expected CR, 25%). The partial remission rate was 6.1%, with an overall response rate of 54.5%. Furthermore, 4 of 33 patients had stable disease (median: 286 days). The median progression-free survival and overall survival (OS) were 203 days and 222 days, respectively. Responding patients had a longer median OS than nonresponding patients (P = .001). A microarray analysis performed in 29 of 33 patients identified 188 genes associated with clinical response (CR vs no CR). Three of them (CD93, GORASP1, CXCL16) were validated by quantitative polymerase chain reaction, which correctly classified 83% of the patients. Specifically, CR achievement was efficiently predicted by the gene expression patterns, with an overall accuracy exceeding 90%. Finally, a negative predictive value of 100% was validated in an independent series, thus representing the first molecular predictor for clinical response to a specific combination drug treatment for AML. This trial has been registered at the European Medicines Agency and on the European Clinical Trials Database (https://www.clinicaltrialsregister.eu) as #2012-000334-19.

Immunomodulatory Drugs in Acute Myeloid Leukemia Treatment

Immunomodulatory drugs (IMiDs) are analogs of thalidomide. They have immunomodulatory, antiangiogenic and proapoptotic properties and exert a role in regulating the tumor microenvironment. Recently IMiDs have been investigated for their pleiotropic properties and their therapeutic applications in both solid tumors (melanoma, prostate carcinoma and differentiated thyroid cancer) and hematological malignancies. Nowadays, they are applied in de novo and relapsed/refractory multiple myeloma, in myelodysplastic syndrome, in del5q syndrome with specific use of lenalidomide and B-cell lymphoma. Several studies have been conducted in the last few years to explore IMiDs possible use in acute myeloid leukemia treatment. Here we report the mechanisms of action of IMiDs in acute myeloid leukemia and their potential future therapeutic application in this disease.

Efficacy and safety of lenalidomide for the treatment of acute myeloid leukemia: a systematic review and meta-analysis

Background

Lenalidomide is effective for the treatment of low-risk myelodysplastic syndromes with deletion 5q abnormalities. However, whether lenalidomide leads to a significant improvement in treatment response and overall survival (OS) in cases of acute myeloid leukemia (AML) remains controversial. A systematic review and a meta-analysis were performed to evaluate the efficacy and safety of lenalidomide in the treatment of AML.

Methods

Clinical studies were identified from the Cochrane Central Register of Controlled Trials, PubMed, Embase, and ClinicalTrials.gov. Efficacy outcomes included overall response rate (ORR), complete remission (CR), and OS. Safety was evaluated based on the incidence of grade 3 and 4 treatment-related adverse events (AEs).

Results

Eleven studies were included in our meta-analysis; collectively these studies featured 407 AML patients. Pooled estimates for overall ORR and CR were 31% (95% CI: 26%–36%) and 21% (95% CI: 16%–27%), respectively. Thrombocytopenia, anemia, neutropenia, and infection were the most common grade 3 and 4 AEs.

Conclusion

Lenalidomide may have some clinical activity in AML, but the population that would benefit from lenalidomide and incorporating lenalidomide into combination drug strategies need to be better defined.

Genetic profiling in acute myeloid leukemia: a path to predicting treatment outcome

Despite substantial progresses in acute myeloid leukemia (AML) diagnosis and treatment, at least half of patient will eventually die for the disease. In the last decades, the use of genetic and genomic approaches allowed the identification of patients with higher risk of recurrence after and/or resistance to CHT. However, though many novel drugs have been proposed and tested, only little clinical improvements have been made concerning the treatment of the so called 'high risk' patients. Areas covered: In this article, the authors, based on their own experience and the most updated literature, review the basic knowledge of AML prognostication and treatment prediction developed throughout genetic and genomic profiling, and focus on the use of gene expression profiling as a promising predictive tool. The role of next generation sequencing, run on qPCR/digital PCR platforms or polyvalent ones such as the Nanostring NCounter™ and RNA-sequencing techniques in the near future will also be briefly discussed. Expert commentary: The authors believe that a combination of genetic (including both germline and somatic data), epigenetic and transcriptional data will represent, in the future, the molecular basis for treatment decision with the highest predictive potential.

Low-dose lenalidomide plus cytarabine in very elderly, unfit acute myeloid leukemia patients: Final result of a phase II study

Outcome for elderly patients with acute myeloid leukemia (AML) is extremely poor. Intensive induction chemotherapy is often unsuitable. Sixty-six newly diagnosed AML patients (median age: 76years), ineligible for standard therapy, were consecutively treated with low-dose lenalidomide (10mg/day orally, days 1-21) plus 10mg/m² low-dose cytarabine, subcutaneously, twice a day (days 1-15) every six weeks, up to 6 cycles. Complete remission (CR) rate was 36.3% according to intention-to-treat. Responding patients had a longer median overall survival than non-responders (517 vs. 70days, P<0.001). The achievement of CR was not predicted by bone marrow blast count, cytogenetics, molecular markers, prior MDS, white blood cell count. Conversely, by studying the global gene expression profile, we identified a molecular signature, including 309 genes associated with clinical response (CR versus no CR). Based on the expression of a minimal set of 16 genes, we developed an algorithm to predict treatment response, that was successfully validated by showing an overall accuracy of 88%. We met the primary endpoint of the study, by beating the estimated successful CR rate (P1) fixed at 30%. Moreover, CR induced by this 2-drug combo was efficiently predicted by genetic profiling, identifying a biomarker that warrants validation in independent series.

Persistent Immune Stimulation Exacerbates Genetically Driven Myeloproliferative Disorders via Stromal Remodeling

Systemic immune stimulation has been associated with increased risk of myeloid malignancies, but the pathogenic link is unknown. We demonstrate in animal models that experimental systemic immune activation alters the bone marrow stromal microenvironment, disarranging extracellular matrix (ECM) microarchitecture, with downregulation of secreted protein acidic and rich in cysteine (SPARC) and collagen-I and induction of complement activation. These changes were accompanied by a decrease in Treg frequency and by an increase in activated effector T cells. Under these conditions, hematopoietic precursors harboring nucleophosmin-1 (NPM1) mutation generated myeloid cells unfit for normal hematopoiesis but prone to immunogenic death, leading to neutrophil extracellular trap (NET) formation. NET fostered the progression of the indolent NPM1-driven myeloproliferation toward an exacerbated and proliferative dysplastic phenotype. Enrichment in NET structures was found in the bone marrow of patients with autoimmune disorders and in NPM1-mutated acute myelogenous leukemia (AML) patients. Genes involved in NET formation in the animal model were used to design a NET-related inflammatory gene signature for human myeloid malignancies. This signature identified two AML subsets with different genetic complexity and different enrichment in NPM1 mutation and predicted the response to immunomodulatory drugs. Our results indicate that stromal/ECM changes and priming of bone marrow NETosis by systemic inflammatory conditions can complement genetic and epigenetic events towards the development and progression of myeloid malignancy. Cancer Res; 77(13); 3685-99. ©2017 AACR.

The safety of treatment options for elderly people with acute myeloid leukemia

INTRODUCTION

Life expectancy in elderly patients with acute myeloid leukemia (AML) is a function of age, disability, and co-morbidity, combined with leukemia characteristics. There is currently no consensus regarding the optimal therapeutic strategy for older adults with AML. Although selected older adults with AML can benefit from intensive therapies, recent evidence supports the use of lower-intensity therapies in most patients and emphasizes the importance of tolerability and quality of life.

AREAS COVERED

Results of the current clinical trials and safety data are reviewed.

EXPERT OPINION

Treatment recommendations for elderly patients with AML need to be individualized. In order to avoid toxicities, hematologists should collaborate more with geriatricians to identify clues of vulnerability in elderly patients through the study of functional physical, physiological, cognitive, social, and psychological parameters.

The role of the immunosuppressive microenvironment in acute myeloid leukemia development and treatment

Functional interplay between acute myeloid leukemia (AML) cells and the bone marrow microenvironment is a distinctive characteristic of this hematological cancer. Indeed, a large body of evidence suggests that proliferation, survival and drug resistance of AML are sustained and modulated by the bone marrow immunosuppressive microenvironment, where both innate and adaptive immune responses are profoundly deregulated. Furthermore, the presence of a number of different immunosuppressive mechanisms results in massive immune deregulation, which causes the eventual escape from natural immune control. Modulating the immune system, as documented by 40 years of stem cell transplantation, may improve survival of AML patients, as the immune system is clearly able to recognize and attack leukemic cells. The understanding of the factors responsible for the escape from immune destruction in AML, which becomes more prominent with disease progression, is necessary for the development of innovative immunotherapeutic treatment modalities in AML.