Somatic mutations predict poor outcome in patients with myelodysplastic syndrome after hematopoietic stem-cell transplantation

Genome sequencing in myelodysplastic syndromes: can molecular mutations predict benefit from hypomethylating agent therapy?

Evaluation of: Bejar R, Lord A, Stevenson K, et al. TET2 mutations predict response to hypomethylating agents in myelodysplastic syndrome patients. Blood 2014 Oct 23;124(17):2705-12. Patients with myelodysplastic syndromes (MDS) have clinically variable courses even within the same prognostic subgroups. Although hypomethylating agents (HMAs) have been shown to improve outcomes in patients with high-risk MDS, many patients do not derive benefit. There is an urgent clinical need to identify patients with low probability of benefiting from HMAs but no reliable clinical predictors or biomarkers have been discovered to date. Although some recurrent molecular mutations in MDS carry independent prognostic value, their ability to predict benefit from HMAs is not clear. Here, we discuss an important article in which sequencing from samples of 213 patients identified recurrent mutations associated with response to HMAs. Although an important step in the right direction, the clinical implications of these findings are far from optimal and identification of biomarkers that can reliably predict benefit from HMAs and other therapies in patients with MDS remains a top clinical and a research priority.

Potential relationship between inadequate response to DNA damage and development of myelodysplastic syndrome

Hematopoietic stem cells (HSCs) are responsible for the continuous regeneration of all types of blood cells, including themselves. To ensure the functional and genomic integrity of blood tissue, a network of regulatory pathways tightly controls the proliferative status of HSCs. Nevertheless, normal HSC aging is associated with a noticeable decline in regenerative potential and possible changes in other functions. Myelodysplastic syndrome (MDS) is an age-associated hematopoietic malignancy, characterized by abnormal blood cell maturation and a high propensity for leukemic transformation. It is furthermore thought to originate in a HSC and to be associated with the accrual of multiple genetic and epigenetic aberrations. This raises the question whether MDS is, in part, related to an inability to adequately cope with DNA damage. Here we discuss the various components of the cellular response to DNA damage. For each component, we evaluate related studies that may shed light on a potential relationship between MDS development and aberrant DNA damage response/repair.

Myelodysplastic syndromes and myelodysplastic/myeloproliferative neoplasms: an update on risk stratification, molecular genetics, and therapeutic approaches including allogeneic hematopoietic stem cell transplantation

Myelodysplastic syndromes are a heterogeneous group of clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis, peripheral cytopenias, and a variable propensity for leukemic transformation. In recent years there has been an explosion of information on the molecular genetic changes underlying these disorders. This information has substantial prognostic implications, and the influence on therapeutic approaches and the treatment of patients is evolving. Allogeneic hematopoietic stem cell transplantation (alloSCT) is the only known cure for these diseases, but appropriate patient selection is of utmost importance from a risk-benefit perspective. This review focuses on the factors influencing risk stratification in MDS and optimal choice of front-line therapy in the current era, including the interplay of clinical factors and molecular genetic factors, and factors that determine eligibility for alloSCT. The myelodysplastic/myeloproliferative diseases also will be discussed, including the increasing effort to understand the molecular genetics and natural history of these disorders and treatment approaches.

Nine years without a new FDA-approved therapy for MDS: how can we break through the impasse?

The myelodysplastic syndromes (MDSs) are a heterogeneous collection of clonal hematopoietic malignancies that compromise a large subgroup of the myeloid neoplasms and collectively are the most common acquired adult bone marrow failure syndromes. Currently, only 3 agents are approved for the treatment of MDS by the US Food and Drug Administration (FDA): azacitidine, decitabine, and lenalidomide. The latter drug, approved in 2006, is the most recent agent approved by the FDA for MDS and there has been mediocre success with novel agents for the past 9 years. The heterogeneity of MDS as a disease group is likely to be a strong contributor to this slow progress but recent developments in molecular characterization of MDS are improving diagnostic accuracy, providing insights into pathogenesis and refining our prognostic ability in the field. With the advent of these developments, appropriately chosen therapeutics or even targeted agents may be able to improve patient outcomes in the future.

Impact of the revised International Prognostic Scoring System, cytogenetics and monosomal karyotype on outcome after allogeneic stem cell transplantation for myelodysplastic syndromes and secondary acute myeloid leukemia evolving from myelodysplastic syndromes: a retrospective multicenter study of the European Society of Blood and Marrow Transplantation

The aim of this study was to determine the impact of the revised 5-group International Prognostic Scoring System cytogenetic classification on outcome after allogeneic stem cell transplantation in patients with myelodysplastic syndromes or secondary acute myeloid leukemia who were reported to the European Society for Blood and Marrow Transplantation database. A total of 903 patients had sufficient cytogenetic information available at stem cell transplantation to be classified according to the 5-group classification. Poor and very poor risk according to this classification was an independent predictor of shorter relapse-free survival (hazard ratio 1.40 and 2.14), overall survival (hazard ratio 1.38 and 2.14), and significantly higher cumulative incidence of relapse (hazard ratio 1.64 and 2.76), compared to patients with very good, good or intermediate risk. When comparing the predictive performance of a series of Cox models both for relapse-free survival and for overall survival, a model with simplified 5-group cytogenetics (merging very good, good and intermediate cytogenetics) performed best. Furthermore, monosomal karyotype is an additional negative predictor for outcome within patients of the poor, but not the very poor risk group of the 5-group classification. The revised International Prognostic Scoring System cytogenetic classification allows patients with myelodysplastic syndromes to be separated into three groups with clearly different outcomes after stem cell transplantation. Poor and very poor risk cytogenetics were strong predictors of poor patient outcome. The new cytogenetic classification added value to prediction of patient outcome compared to prediction models using only traditional risk factors or the 3-group International Prognostic Scoring System cytogenetic classification.

Transplant for MDS: challenges and emerging strategies

Allogeneic hematopoietic stem cell transplantation is the only curative treatment for myelodysplastic syndrome. Major improvements in the field of allogeneic stem cell transplantation have made it a better tolerated treatment that can be offered to older patients and patients with co-morbidities. However, treatment related toxicities, graft versus host disease, infectious complications and relapse remain major problems post transplant. With better understanding of disease biology and prognosis and with different types of conditioning regimens as well as different graft sources, a transplant strategy should be tailored to the individual host to maximize the benefits of this procedure.