Effect of cA2 Anti–Tumor Necrosis Factor-α Antibody Therapy on Hematopoiesis of Patients with Myelodysplastic Syndromes

Inflammation and myeloid malignancy: Quenching the flame

Chronic inflammation with aging ("inflammaging") plays a prominent role in the pathogenesis of myeloid malignancies. Aberrant inflammatory activity impacts many different cells in the marrow, including normal blood and stromal marrow elements and leukemic cells, in unique and distinct ways. Inflammation can promote selective clonal expansion through differential immune-mediated suppression of normal hematopoietic cells and malignant clones. We review these complex roles, how they can be understood by separating cell-intrinsic from extrinsic effects, and how this informs future clinical trials.

Immunosuppressive therapy in myelodysplastic syndromes: a borrowed therapy in search of the right place

INTRODUCTION

Myelodysplastic syndromes (MDS) encompass a heterogenous collection of clonal hematopoietic stem cell disorders defined by dysregulated hematopoiesis, peripheral cytopenias, and a risk of leukemic progression. Increasing data support the role of innate and adaptive immune pathways in the pathogenesis and disease course of MDS. The role of immunosuppressive therapy has an established role in the treatment of other hematologic diseases, such as aplastic anemia whose pathogenesis is postulated to reflect that of MDS with regards to many aspects of immune activation. Areas covered: This paper discusses the current understanding of immune dysregulation as it pertains to MDS, the clinical experience with immunosuppressive therapy in the management of MDS, as well as future prospects which will likely improve therapeutic options and outcomes for patients with MDS. Expert commentary: Though limited by paucity of high quality data, immunomodulatory and immunosuppressive therapies for the treatment of MDS have shown meaningful clinical activity in selected patients. Continued clarification of the immune pathways that are dysregulated in MDS and establishing predictors for clinical benefit of immunosuppressive therapy are vital to improve the use and outcomes with these therapies.

The relationship between idiopathic cytopenias/dysplasias of uncertain significance (ICUS/IDUS) and autoimmunity

INTRODUCTION

This review examines the several lines of evidence that support the relationship between myelodysplasia and autoimmunity, i.e. their epidemiologic association, the existence of common immune-mediated physiopathologic mechanisms, and the response to similar immunosuppressive therapies. The same relationship is reviewed here considering idiopathic cytopenia of uncertain significance (ICUS) and idiopathic dysplasia of uncertain significance (IDUS), two recently recognized provisional conditions characterized by isolated/unexplained cytopenia and/or dysplasia in <10% bone marrow cells. Areas covered: The review focuses on alterations of cytokine profiles, telomere/telomerase and toll-like receptors, and on increased myelosuppressive mediators and apoptotic markers in both myelodysplasia and autoimmunity. In addition, the presence of an autoimmune reaction directed against marrow precursors is described in refractory/relapsing autoimmune cytopenias (autoimmune hemolytic anemia, immune thrombocytopenia, chronic idiopathic neutropenia), possibly contributing to their evolution to ICUS/IDUS/bone marrow failure syndromes. Expert commentary: The increasing availability of omics methods has fuelled the discussion on the role of somatic mutations in the pathogenesis of IDUS/ICUS, clonal hematopoiesis of indeterminate potential, and clonal cytopenias of undetermined significance, and in their possible evolution. Even more attracting is the involvement of the genetic background/accumulating somatic mutations in cytopenias with autoimmune alterations.

The immune landscape of myelodysplastic syndromes

Even though the pathogenesis of myelodysplastic syndromes (MDS) is dominated by specific molecular defects involving hematopoietic precursors, also immune mechanisms seem to play a fundamental functional role. In this review we will first describe the clinical and laboratory autoimmune manifestations often detectable in MDS patients. We will then focus on studies addressing the possible influence of different immune cell subpopulations on the disease onset and evolution. We will finally consider therapeutic approaches based on immunomodulation, ranging from immunosuppressants to vaccination and transplantation strategies.

TNF alpha antagonist therapy and safety monitoring

OBJECTIVES

To develop and/or update fact sheets about TNFα antagonists treatments, in order to assist physicians in the management of patients with inflammatory joint disease.

METHODS

1. selection by a committee of rheumatology experts of the main topics of interest for which fact sheets were desirable; 2. identification and review of publications relevant to each topic; 3. development and/or update of fact sheets based on three levels of evidence: evidence-based medicine, official recommendations, and expert opinion. The experts were rheumatologists and invited specialists in other fields, and they had extensive experience with the management of chronic inflammatory diseases, such as rheumatoid. They were members of the CRI (Club Rhumatismes et Inflammation), a section of the Société Francaise de Rhumatologie. Each fact sheet was revised by several experts and the overall process was coordinated by three experts.

RESULTS

Several topics of major interest were selected: contraindications of TNFα antagonists treatments, the management of adverse effects and concomitant diseases that may develop during these therapies, and the management of everyday situations such as pregnancy, surgery, and immunizations. After a review of the literature and discussions among experts, a consensus was developed about the content of the fact sheets presented here. These fact sheets focus on several points: 1. in RA and SpA, initiation and monitoring of TNFα antagonists treatments, management of patients with specific past histories, and specific clinical situations such as pregnancy; 2. diseases other than RA, such as juvenile idiopathic arthritis; 3. models of letters for informing the rheumatologist and general practitioner; 4. and patient information.

CONCLUSION

These TNFα antagonists treatments fact sheets built on evidence-based medicine and expert opinion will serve as a practical tool for assisting physicians who manage patients on these therapies. They will be available continuously at www.cri-net.com and updated at appropriate intervals.

TNF-alpha regulates the effects of irradiation in the mouse bone marrow microenvironment

Background

Secondary bone marrow (BM) myelodysplastic syndromes (MDS) are increasingly common, as a result of radio or chemotherapy administered to a majority of cancer patients. Patients with secondary MDS have increased BM cell apoptosis, which results in BM dysfunction (cytopenias), and an increased risk of developing fatal acute leukemias. In the present study we asked whether TNF-α, known to regulate cell apoptosis, could modulate the onset of secondary MDS.

Principal Findings

We show that TNF-α is induced by irradiation and regulates BM cells apoptosis in vitro and in vivo. In contrast to irradiated wild type (WT) mice, TNF-α deficient (TNF-α KO) mice or WT mice treated with a TNF-α-neutralizing antibody were partially protected from the apoptotic effects of irradiation. Next we established a 3-cycle irradiation protocol, in which mice were sub-lethally irradiated once monthly over a 3 month period. In this model, irradiated WT mice presented loss of microsatellite markers on BM cells, low white blood cell (WBC) counts, reduced megakaryocyte (MK) and platelet levels (thrombocytopenia) and macrocytic anemia, phenoypes that suggest the irradiation protocol resulted in BM dysfunction with clinical features of MDS. In contrast, TNF-α KO mice were protected from the irradiation effects: BM cell apoptosis following irradiation was significantly reduced, concomitant with sustained BM MK numbers and absence of other cytopenias. Moreover, irradiated WT mice with long term (≥5 months) BM dysfunction had increased BM angiogenesis, MMPs and VEGF and NFkB p65, suggestive of disease progression.

Conclusion

Taken together, our data shows that TNF-α induction following irradiation modulates BM cell apoptosis and is a crucial event in BM dysfunction, secondary MDS onset and progression.

Loss of SIMPL compromises TNF-alpha-dependent survival of hematopoietic progenitors

OBJECTIVE

Emerging work has revealed an integral role of the tumor necrosis factor-alpha (TNF-alpha) nuclear factor (NF)-kappaB pathway in the regulation of hematopoiesis. TNF-alpha inhibition of hematopoietic stem/progenitor cell growth involves type I TNF-alpha receptor (TNF-RI) and type II TNF-alpha receptor (TNF-RII). However, the role of TNF-RI vs TNF-RII in mediating this response is less clear. Full induction of NF-kappaB-dependent gene expression through TNF-RI requires the transcriptional coactivator SIMPL (substrate that interacts with mouse pelle-like kinase). To address the role of SIMPL in TNF-alpha-dependent signaling in hematopoiesis, endothelial cells and hematopoietic progenitors expressing SIMPL short hairpin RNA were characterized.

MATERIAL AND METHODS

In vitro gene expression and progenitor assays employing SIMPL short hairpin RNA were used to examine the requirement for SIMPL in TNF-alpha-dependent effects upon cytokine gene expression and hematopoietic progenitor cell growth. Competitive repopulation studies were used to extend these studies in vivo.

RESULTS

SIMPL is required for full TNF-RI-dependent expression of NF-kappaB-controlled cytokines in endothelial cells. Hematopoietic progenitor cell expansion is not affected if progenitors lacked SIMPL or if progenitors are treated with human TNF-alpha, which signals through TNF-RI. In the absence of SIMPL, human TNF-alpha leads to a dramatic decrease in progenitor cell expansion that is not due to apoptosis. Loss of SIMPL does not affect the activity of transforming growth factor-beta1 and interferon-gamma, other known suppressors of hematopoiesis.

CONCLUSIONS

Suppression of myeloid progenitor cell expansion requires signaling through TNF-RI and TNF-RII. Signals transduced through the TNF-alpha-TNF-RI-SIMPL pathway support hematopoietic progenitor cell survival, growth and differentiation.

Effect of lenalidomide therapy on hematopoiesis of patients with myelodysplastic syndrome associated with chromosome 5q deletion

BACKGROUND

Lenalidomide improves erythropoiesis in patients with low/intermediate-1 risk myelodysplastic syndrome and interstitial deletion of the long arm of chromosome 5 [del(5q)]. The aim of this study was to explore the effect of lenalidomide treatment on the reserves and functional characteristics of bone marrow hematopoietic progenitor/precursor cells, bone marrow stromal cells and peripheral blood lymphocytes in patients with low/intermediate-1 risk myelodysplastic syndrome with del(5q).

DESIGN AND METHODS

We evaluated the number and clonogenic potential of bone marrow erythroid/myeloid/megakaryocytic progenitor cells using clonogenic assays, the apoptotic characteristics and adhesion molecule expression of CD34(+) cells by flow cytometry, the hematopoiesis-supporting capacity of bone marrow stromal cells using long-term bone marrow cultures and the number and activation status of peripheral blood lymphocytes in ten patients with low/intermediate-1 risk myelodysplastic syndrome with del(5q) receiving lenalidomide.

RESULTS

Compared to baseline, lenalidomide treatment significantly decreased the proportion of bone marrow CD34+ cells, increased the proportion of CD36(+)/GlycoA(+) and CD36(-)/GlycoA(+) erythroid cells and the percentage of apoptotic cells within these cell compartments. Treatment significantly improved the clonogenic potential of bone marrow erythroid, myeloid, megakaryocytic colony-forming cells and increased the proportion of CD34(+) cells expressing the adhesion molecules CD11a, CD49d, CD54, CXCR4 and the SLAM antigen CD48. The hematopoiesis-supporting capacity of bone marrow stroma improved significantly following treatment, as demonstrated by the number of colony-forming cells and the level of stromal-derived factor-1 alpha and intercellular adhesion molecule-1 in long-term bone marrow culture supernatants. Lenalidomide treatment also increased the proportion of activated peripheral blood T lymphocytes.

CONCLUSIONS

The beneficial effect of lenalidomide in patients with lower risk myelodysplastic syndrome with del(5q) is associated with significant increases in the proportion of bone marrow erythroid precursor cells and in the frequency of clonogenic progenitor cells, a substantial improvement in the hematopoiesis-supporting potential of bone marrow stroma and significant alterations in the adhesion profile of bone marrow CD34(+) cells.

Incorporating novel agents in the treatment of myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a group of heterogeneous clonal stem cell (SC) disorders that mainly affect the elderly population. They are characterized by ineffective hematopoiesis which results in quantitative and qualitative cellular defects and high incidence of leukemic transformation. Recent advances in MDS research have led to the development of novel agents which appears to improve remission rates and survival when compared to best supportive care. Currently azacitidine, decitabine, and lenalidomide are approved by the US FDA for the treatment of MDS, while the activity of other novel agents such as histone deacetylase inhibitors, farnesyl-transferase inhibitors, novel thrombopoietic agents, and anti-angiogenesis molecules is under evaluation. Erythropoietin-stimulating agents, iron chelating therapy and thrombopoietin receptor ligands may also improve quality of life and possibly prolong survival in MDS patients. The only treatment modality that can achieve long-term survival is the allogeneic SC transplantation which is given only in selected patients. Moreover the heterogeneity of MDS and the patient's advanced age and co-morbidity are significant factors besides cytogenetics, IPSS and WPSS that should be taken into account during the decision-making process. Therefore clinicians should treat patients with MDS on an individual basis aiming the increase of the response rates and the decrease of treatment-associated toxicities. This can only be achieved through the better understanding of the MDS subgroups. If we can better define MDS subgroups we will be able to identify patients who will benefit from the incorporation of the novel agents, as monotherapy or in combinations regimens along with supportive care.

A placebo-controlled double blind trial of etanercept for the cancer anorexia/weight loss syndrome: results from N00C1 from the North Central Cancer Treatment Group

BACKGROUND

Tumor necrosis factor-alpha (TNF-alpha) is a putative mediator of the cancer anorexia/weight loss syndrome. The current study was designed to determine whether etanercept (a dimeric fusion protein consisting of the extracellular ligand-binding portion of the human 75-kilodalton TNF receptor linked to the Fc portion of human immunoglobulin [Ig] G1) could palliate this syndrome.

METHODS

A total of 63 evaluable patients were randomly assigned to receive either etanercept at a dose of 25 mg subcutaneously twice weekly versus a comparably administered placebo. All patients had an incurable malignancy, acknowledged loss of weight and/or appetite as a concern, and reported a weight loss of >2.27 kg over 2 months and/or a daily intake of <20 calories/kg body weight.

RESULTS

Over time, weight gain was found to be minimal in both treatment arms; no patient gained >or=10% of their baseline weight. Previously validated appetite questionnaires revealed negligible improvements in both treatment arms. The median survival was also comparable (175 days vs 148 days in etanercept-treated and placebo-exposed patients, respectively; P = .82). Finally, preliminary data regarding adverse events demonstrated that patients treated with etanercept had higher rates of neurotoxicity (29% vs 0%) but lower rates of anemia (0% vs 19%) and thrombocytopenia (0% vs 14%). Infection rates were negligible in both groups. Genotyping for TNF-alpha-238 and TNF-alpha-308 polymorphisms revealed no clinical significance for these genotypes, except for a preliminary association between presence of the -238 G/A genotype and relatively less favorable survival.

CONCLUSIONS

Etanercept, as prescribed in the current trial, does not appear to palliate the cancer anorexia/weight loss syndrome in patients with advanced disease.