Immunosuppressive therapy for myelodysplastic syndrome: efficacy of methylprednisolone pulse therapy with or without cyclosporin A

Novel Molecular Mechanism of Lenalidomide in Myeloid Malignancies Independent of Deletion of Chromosome 5q

Lenalidomide as well as other immunomodulatory drugs (IMiDs) have achieved clinical efficacies in certain sub-types of hematologic malignancies, such as multiple myeloma, lower-risk myelodysplastic syndromes (MDS) with a single deletion of chromosome 5q (del(5q)) and others. Despite superior clinical response to lenalidomide in hematologic malignancies, relapse and resistance remains a problem in IMiD-based therapy. The last ten years have witnessed the discovery of novel molecular mechanism of IMiD-based anti-tumor therapy. IMiDs bind human cereblon (CRBN), the substrate receptor of the CRL4 E3 ubiquitin ligase complex. Binding of CRBN with IMiDs leads to degradation of the Ikaros family zinc finger proteins 1 and 3 (IKZF1 and IKZF3) and casein kinase 1 alpha. We have found that lenalidomide-mediated degradation of IKZF1 leads to activation of the G protein-coupled receptor 68 (GPR68)/calcium/calpain pro-apoptotic pathway and inhibition of the regulator of calcineurin 1 (RCAN1)/calcineurin pro-survival pathway in MDS and acute myeloid leukemia (AML). Calcineurin inhibitor Cyclosporin-A potentiates the anti-leukemia activity of lenalidomide in MDS/AML with or without del(5q). These findings broaden the therapeutic potential of IMiDs. This review summarizes novel molecular mechanism of lenalidomide in myeloid malignancies, especially without del(5q), in the hope to highlight novel therapeutic targets.

Use of immunosuppressive therapy for management of myelodysplastic syndromes: a systematic review and meta-analysis

Immunosuppressive therapy (IST) is one therapy option for treatment of patients with lower-risk myelodysplastic syndromes (MDS). However, the use of several different immunosuppressive regimens, the lack of high-quality studies, and the absence of validated predictive biomarkers pose important challenges. We conducted a systematic review and meta-analysis according to the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines and searched MEDLINE via PubMed, Ovid EMBASE, COCHRANE registry of clinical trials (CENTRAL), and the Web of Science without language restriction from inception through September 2018, as well as relevant conference proceedings and abstracts, for prospective cohort studies or clinical trials investigating IST in MDS. Fixed and Random-effects models were used to pool response rates. We identified nine prospective cohort studies and 13 clinical trials with a total of 570 patients. Overall response rate was 42.5% [95% confidence interval (CI): 36.1-49.2%] including a complete remission rate of 12.5% (95%CI: 9.3-16.6%) and red blood cell transfusion independence rate of 33.4% (95% CI: 25.1-42.9%). The most commonly used forms of IST were anti-thymocyte globulin alone or in combination with cyclosporin A with a trend towards higher response rates with combination therapy. Progression rate to acute myeloid leukemia was 8.6% per patient year (95%CI: 3.3-13.9%). Overall survival and adverse events were only inconsistently reported. We were unable to validate any biomarkers predictive of a therapeutic response to IST. IST for treatment of lower-risk MDS patients can be successful to alleviate transfusion burden and associated sequelae.

Fibroblast dynamics as an in vitro screening platform for anti-fibrotic drugs in primary myelofibrosis

Although the cause for bone marrow fibrosis in patients with myelofibrosis remains controversial, it has been hypothesized that it is caused by extensive fibroblast proliferation under the influence of cytokines generated by the malignant megakaryocytes. Moreover, there is no known drug therapy which could reverse the process. We studied the fibroblasts in a novel system using the hanging drop method, evaluated whether the fibroblasts obtain from patients are part of the malignant clone of not and, using this system, we screen a large library of FDA-approved drugs to identify potential drugs candidates that might be useful in the treatment of this disease, specifically which would inhibit fibroblast proliferation and the development of bone marrow fibrosis. We have found that the BM fibroblasts are not part of the malignant clone, as previously suspected and two immunosuppressive medications-cyclosporine and mycophenolate mophetil, as most potent suppressors of the fibroblast collagen production thus potentially inhibitors of bone marrow fibrosis production in myelofibrosis.

Predicting survival of patients with hypocellular myelodysplastic syndrome: development of a disease-specific prognostic score system

BACKGROUND

Although most patients with myelodysplastic syndrome (MDS) exhibit bone marrow hypercellularity, a subset of them present with a hypocellular bone marrow. Specific factors associated with poor prognosis have not been investigated in patients with hypocellular MDS.

METHODS

The authors studied a cohort of 253 patients with hypocellular MDS diagnosed at The University of Texas MD Anderson Cancer Center between 1993 and 2007 and a cohort of 1725 patients with hyper-/normocellular MDS diagnosed during the same time period.

RESULTS

Patients with hypocellular MDS presented more frequently with thrombocytopenia (P < .019), neutropenia (P < .001), low serum β-2 microglobulin (P < .001), increased transfusion dependency (P < .001), and intermediate-2/high-risk disease (57% vs 42%, P = .02) compared with patients with hyper-/normocellular MDS. However, no difference in overall survival was observed between the 2 groups (P = .28). Multivariate analysis identified poor performance status (Eastern Cooperative Oncology Group ≥2), low hemoglobin (<10 g/dL), unfavorable cytogenetics (-7/7q or complex), increased bone marrow blasts (≥5%), and high serum lactate dehydrogenase (>600 IU/L) as adverse independent factors for survival.

CONCLUSIONS

A new prognostic model based on these factors was built that segregated patients into 3 distinct risk categories independent of International Prognostic Scoring System (IPSS) score. This model is independent from the IPSS, further refines IPSS-based prognostication, and may be used to develop of risk-adapted therapeutic approaches for patients with hypocellular MDS.

Immunologic aspects of hypoplastic myelodysplastic syndrome

The pathophysiology of myelodysplastic syndromes (MDS) is multiple, complex, and poorly understood. In some cases of MDS, especially those in which the bone marrow is hypocellular, there is increasing experimental and clinical indication that an immune-mediated damage to hematopoietic precursors and changes in the hematopoiesis-supporting microenvironment contribute to disease development. Increased serum levels of type-1 cytokines, tumor necrosis factor-α (TNF-α), and interferon-γ (INF-γ), and oligoclonal expansion of cytotoxic T cells are observed in human MDS. In some cases, the immunologic attack to the marrow appears to be triggered by MDS-specific antigens, damaging the microenvironment and inducing cell apoptosis especially of normal progenitors. In murine models, dysregulation of osteoprogenitors leads to disrupted hematopoiesis of healthy hematopoietic progenitor and stem cells, eventually resulting in MDS and leukemia. In hypocellular MDS, marrow failure appears to be not only the result of ineffective erythropoiesis of abnormal clones, but also due to inhibition of normal progenitors. Immunosuppressive therapy with cyclosporine, anti-thymocyte globulin, or alemtuzumab may alleviate cytopenias and in some instances induce cytogenetic remission. However, not all patients respond to immunosuppression, and the identification of relevant biomarkers for an immune mechanism is necessary to identify those patients who may benefit from this treatment modality.

A Decision analysis to determine the appropriate treatment for low-risk myelodysplastic syndromes

BACKGROUND

The myelodysplastic syndromes (MDS) are divided into low-risk and high-risk diseases. Predictive models for response to growth factors (GF) have been developed based on red blood cell transfusion needs and erythropoietin levels. For low-risk MDS the optimal initial therapy (GF vs nongrowth factor [NGF] therapies, including differentiation and immunomodulatory agents) based on response rates to NGF and GF and survival, has not been defined.

METHODS

A Markov decision analysis was performed on 799 low-risk MDS patients treated with either GF or NGF to determine the appropriate initial therapy. The treatment strategies analyzed included initial GF or NGF therapies, assuming 3 different states: Patients were either in the good GF predictive group (low transfusion needs and low erythropoietin levels), intermediate, or the poor GF predictive group (high transfusion needs and high erythropoietin levels).

RESULTS

In the good GF predictive group, initial therapy with GF improved survival compared with NGF therapies at 3.38 years vs 2.57 years for a typical MDS patient. The advantage of GF to NGF was lost when NGF therapies produced a response in >or=46% of patients. In the intermediate or poor GF predictive groups, NGF maximized survival, provided response rates for NGF were >14% and 4%, respectively, for each predictive group. Quality of life adjustment did not alter the preferred strategy.

CONCLUSIONS

Modeling estimates suggest that patients who fall into a good GF predictive group should almost always receive GF initially, whereas those in intermediate and poor predictive groups should almost always be treated with NGF.