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

ITACA: A new validated international erythropoietic stimulating agent-response score that further refines the predictive power of previous scoring systems

BACKGROUND

In 'real-life', the Nordic score guides Erythropoietic stimulating agent (ESA) use in lower-risk myelodysplastic syndrome (MDS) with predicted response rates of 25% or 74%. As new treatments emerge, a more discriminating score is needed.

OBJECTIVES

To validate existing ESA predictive scores and develop a new score that identifies non-responders.

METHODS

ESA-treated patients were identified in 3 MDS registries in Italy and Canada (FISM 555, GROM 233, and MDS-CAN 208). Clinical and disease-related variables were captured. Nordic, MDS-CAN, and IPSS-R-based ESA scores were calculated and documented ESA responses compared.

RESULTS

996 ESA-treated patients were identified. Overall response rate (ORR) was 59%. The database was randomly divided into balanced derivation (n = 463) and validation (n = 462) cohorts. By multivariate analysis, transfusion independence, erythropoietin (EPO) level <100 IU/L, and IPSS low-risk were independently predictive of response. Assigning a score of 1 to each resulted in a scoring system of 0-3 with response rates of 23%, 43%, 67%, and 85%. ORR was concordant in the validation cohort. The 'ITACA' score had the highest discriminating power of response.

CONCLUSION

ITACA is an internally-validated predictive SS of ESA response in real-life 'good risk' MDS patients derived from a large international dataset that surpasses others. The incorporation of biologic markers to better identify non-responders is still needed.

Established and novel agents for myelodysplastic syndromes

The myelodysplastic syndromes (MDS) are the most commonly diagnosed myeloid malignancy, with >15 000 new cases identified in the United States yearly. Prognostic scoring systems supplant a formal staging approach and, in general, divide patients into those with lower-risk and those with higher-risk MDS. Although treatment goals for patients with lower-risk disease focus on minimizing transfusions and optimizing quality of life, in higher-risk MDS, the goal is to delay transformation to acute leukemia and to prolong survival. In lower-risk patients, isolated cytopenias are treated with erythropoiesis-stimulating agents or growth factors such as thrombopoietin mimetics. For patients with the del(5q) cytogenetic abnormality or those who fail these initial approaches, lenalidomide may be tried, as can experimental agents. Lower-risk patients with multiple cytopenias may be treated with immunosuppressive drugs or low-dose hypomethylating agents. For patients with higher-risk disease, hypomethylating agents are the preferred initial treatment approach, with evaluation for hematopoietic cell transplantation at diagnosis. Several novel agents are being developed for MDS patients who have failed hypomethylating drugs.

Resuscitating a dying marrow: the role of hematopoietic growth factors

The treatment landscape for myelodysplastic syndromes (MDS) has evolved over the last two decades, with a better understanding of the disease pathophysiology and the use of newer or combination therapies. For lower-risk MDS patients, hematopoietic growth factors have continued to be the mainstay of therapy. However, better patient selection criteria and decision tools to predict responses have made these therapies more beneficial to patients. As the range of newer drugs continues to expand in our treatment armamentarium for lower-risk MDS, questions still remain regarding the safety of these drugs with long-term use. This review will discuss the role of growth factors in MDS, focusing on dosing and combination strategies to improve responses, selecting the appropriate patient population, and recognizing the safety profile based on evidence from published literature.

Revisiting use of growth factors in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) represent a heterogeneous group of clonal hematologic neoplasms characterized by morphologic dysplasia, aberrant hematopoiesis and peripheral blood refractory cytopenias. MDS is recognized to be associated with an increased risk of symptomatic anemia, infectious complications and bleeding diathesis, as well as a risk of progression to acute myeloid leukemia, particularly in patients with a high IPSS score. The advent of use of hematopoietic growth factors such as granulocyte colony-stimulating factor (G-CSF) and recombinant erythropoietin (EPO) has improved symptoms in MDS patients in addition to some data that suggest there might be an improvement in survival. G-CSF is an effective therapeutic option in MDS patients, and it should be considered for the management of refractory symptomatic cytopenias. G-CSF and EPO in combination can improve outcomes in appropriate MDS patients such as those with lower-risk MDS and refractory anemia with ring sideroblasts (RARS) . This article reviews use of growth factors for lower-risk MDS patients, and examines the data for G-CSF, EPO and thrombopietic growth factors (TPO) that are available or being developed as therapeutic modalities for this challenging disease.

Management of lower-risk myelodysplastic syndromes: the art and evidence

Myelodysplastic syndromes (MDS) represent a spectrum of bone marrow failure with variable outcome. Patients with "lower-risk" disease have an expected median survival measured in years, and a low risk of leukemia progression. Patients with "higher-risk" MDS, on the other hand, have expected survival measured in months without treatment and rapid leukemia progression. The outcome of those distinct groups can be explained by different underlying disease biology. In clinical practice, patients are stratified into risk groups based on prognostic models, most commonly the International Prognostic Scoring System (IPSS). In higher-risk disease, the standard of care is hypomethylating agents to extend survival and suppress leukemia potential, and consideration of allogeneic stem cell transplantation, which remains the only curative option. Patients classified as having lower-risk disease begin treatment with management focused on ameliorating hematologic deficits, related symptoms, or both. This review of lower-risk MDS highlights the biology of the disease and models for risk stratification. We use a case-based format to discuss current options for treatment, including erythropoiesis-stimulating agents, hypomethylating agents, lenalidomide, immunosuppressive therapy, supportive care, and investigational agents.

Darbepoetin alfa for anemia in patients with low or intermediate-1 risk myelodysplastic syndromes and positive predictive factors of response

BACKGROUND

Current guidelines support the use of erythropoiesis-stimulating agents for the treatment of anemia associated with low-risk myelodysplastic syndromes (MDS).

DESIGN AND METHODS

Single-arm, open-label, multi-center, phase 2 trial that evaluated the efficacy and safety of darbepoetin alfa (DA) in patients with low or intermediate-risk MDS, hemoglobin <100 g/L, erythropoietin (EPO) levels <500 IU/L and transfusion requirements <2 units/month over the preceding 2 months. Erythroid response (major [MaR] or minor [MiR]) and fatigue (Functional Assessment of Cancer Therapy-Fatigue [FACT-F]) were evaluated at 8, 16 and 24 weeks. DA was initiated at 300 μg weekly. For patients who did not achieve MaR by 8 weeks, filgrastim 300 μg weekly was added.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov identifier: NCT01039350.

RESULTS

Forty-four patients (72.7% transfusion independent) were included. Median age was 76.0 years (range 41.3-92.4), 54.5% were male, and 90.9% presented ECOG Status (0-1). Eighteen patients received filgrastim. An erythroid response was achieved by 31 of 44 patients (70.5%) at week 8 (47.7% MaR, 22.7% MiR), 31 of 44 patients (70.5%) at week 16 (61.4% MaR, 9.1% MiR), and 32 of 44 patients (72.7%) at week 24 (61.3% MaR, 11.4% MiR). Mean (95% CI) change in FACT-F at week 24 was 3.61 (0.72 to 6.51). Baseline EPO levels <100 IU/L were a predictive factor of response. DA was well tolerated. Four mild (two iron deficiencies, flu syndrome and headache) and one fatal (thromboembolic event) adverse events were considered related to darbepoetin alfa.

CONCLUSIONS

A fixed dose of 300 μg of darbepoetin alfa weekly (with or without filgrastim) seems to be an effective and safe treatment for anemic patients with low or intermediate-risk MDS, low transfusion burden and EPO levels <500 IU/L. Results may not be extrapolable to unselected MDS patients.

The revolution of myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are clonal disorders of the hematopoietic system with resultant cytopenias and shortened survival. Better recognition of MDS and an aging population, some of whom have been treated with chemotherapy and radiation therapy for other cancers, is largely responsible for the growing incidence of this malignancy, which is divided into lower- and higher-risk subtypes. Erythropoiesis-stimulating agents are the first-line treatment options for patients with lower-risk MDS and symptomatic anemia or for those requiring transfusion support. Lenalidomide has been successfully used for patients with the del(5q) chromosomal abnormality who are also transfusion dependent. Hypomethylating agents, such as azacitidine and decitabine, are indicated for patients with higher-risk disease, with azacitidine demonstrating a survival advantage. Hematopoietic stem cell transplantation (HSCT) is a curative therapeutic approach available to less than 5% of patients with MDS. Combination therapies and newer single agents targeting the important cellular pathways are being explored for treatment of MDS with promising results.

Phase I combination trial of lenalidomide and azacitidine in patients with higher-risk myelodysplastic syndromes

PURPOSE

Lenalidomide and azacitidine are active in patients with lower- and higher-risk myelodysplastic syndromes (MDS). These agents may complement each other by targeting both the bone marrow microenvironment and hypomethylating action on the malignant clone.

PATIENTS AND METHODS

This phase I trial explored the safety of combination therapy in patients with higher-risk MDS. Response and characterization of molecular and methylation status of responders were secondary objectives. Patients were enrolled using a 3 + 3 dose escalation. Cycles lasted 28 days, and patients received a maximum of seven cycles.

RESULTS

Of 18 patients enrolled, median age was 68 years (range, 52 to 78 years), interval from diagnosis was 5 weeks (range, 2 to 106 weeks), and follow-up was 7 months (range, 1 to 26 months). International Prognostic Scoring System categories were intermediate 1 (n = 2), intermediate 2 (n = 10), and high (n = 6). No dose-limiting toxicities occurred, and a maximum-tolerated dose was not reached. Grades 3 to 4 nonhematologic toxicities (> 1) included febrile neutropenia (n = 5), cardiac (n = 2), and CNS hemorrhage (n = 2). Median absolute neutrophil count decrease was 26%, and platelet decrease was 1% (mean, 24%). The overall response rate was 67%: eight patients (44%) had a complete response (CR); three patients (17%) had hematologic improvement; one patient (6%) had marrow CR. Patients achieving CR were more likely to have normal cytogenetics and lower methylation levels.

CONCLUSION

The combination of lenalidomide and azacitidine is well tolerated with encouraging clinical activity. The go-forward dose is azacitidine 75 mg/m(2) on days 1 through 5 and lenalidomide 10 mg on days 1 through 21.

Update on the therapy for myelodysplastic syndrome

The myelodysplastic syndromes (MDS) are a diverse group of clonal hematopoietic stem cell disorders characterized by cytopenias. Patients have a risk of developing acute leukemia though most succumb to complications of low blood counts. Over the past decade many novel treatments have been developed and investigation of new agents is ongoing. In this article, we discuss the classification and prognostic systems that are used in MDS, the agents available for treatment of MDS as well as review supportive and palliative care options for patients who are not candidates for, or opt against, newer treatment strategies.

Supportive care and chelation therapy in MDS: are we saving lives or just lowering iron?

The myelodysplastic syndromes (MDS) are characterized by cytopenias and risk of transformation to acute myeloid leukemia (AML). Although new treatments are available, a mainstay in MDS remains supportive care, which aims to minimize the impact of cytopenias and transfusion of blood products. Red blood cell (RBC) transfusions place patients at risk of iron overload (IOL). In beta-thalassemia major (BTM), IOL from chronic RBC transfusions inevitably leads to organ dysfunction and death. With iron chelation therapy (ICT), survival in BTM improved from the second decade to near normal and correlated with ICT compliance. Effects of ICT in BTM include reversal of cardiac arrhythmias, improvement in left ventricular ejection fraction, arrest of hepatic fibrosis, and reduction of glucose intolerance. It is not clear whether these specific outcomes are applicable to MDS. Although retrospective, recent studies in MDS suggest an adverse effect of transfusion dependence and IOL on survival and AML transformation, and that lowering iron minimizes this impact. These data raise important points that warrant further study. ICT is potentially toxic and cumbersome, is costly, and in MDS patients should be initiated only after weighing potential risks against benefits until further data are available to better justify its use. Since most MDS patients eventually require RBC transfusions, the public health implications both of transfusion dependence and ICT in MDS are considerable. This paper summarizes the impact of cytopenias in MDS and treatment approaches to minimize their impact, with a focus on RBC transfusions and their complications, particularly with respect to iron overload.

Treatment of MDS: something old, something new, something borrowed

As opposed to the treatment landscape for myelodysplastic syndromes (MDS) two decades ago, potential therapies now abound for the treatment of lower-risk and higher-risk populations. In lower-risk patients, decision tools can be used to determine the likelihood of response to erythropoiesis stimulating agents (ESAs), which have demonstrated survival advantages in retrospective studies in patients with MDS, and whether these patients should be treated initially with ESAs or non-growth factor ("active") therapies. Lenalidomide has shown good activity in transfusion-dependent patients with the del(5q) cytogenetic abnormality and modest activity in other lower-risk patients. In higher-risk patients, the DNA methyltransferase inhibitors produce complete and partial responses in 20% to 30% of patients, and for the first time, the MDS drug azacitidine has demonstrated a survival advantage when compared with conventional therapies. Newer therapies stimulate platelet production and target novel pathways, while a panoply of combination studies are underway or recently completed and that likely represent the next frontier in MDS therapy.

Characteristics of US patients with myelodysplastic syndromes: results of six cross-sectional physician surveys

BACKGROUND

Myelodysplastic syndromes (MDS) comprise a group of pathologically and cytogenetically distinct bone marrow disorders. Little is known about the characteristics of MDS patients, including their pathological and prognostic classifications, cytopenias, transfusion and supportive care needs, and treatment regimens. We describe these characteristics in a large group of recently diagnosed and existing (ie, established) MDS patients.

METHODS

We conducted six consecutive cross-sectional surveys among US hematology and medical oncology specialists (identified from an American Medical Association [AMA] database of physicians who administer chemotherapy) between June 2005 and January 2007. A questionnaire collected data on the characteristics and treatment patterns of the 4-10 most recently seen MDS patients for each physician, including demographic data, transfusion needs, treatment approaches, and consideration for clinical trials or bone marrow transplantation.

RESULTS

A panel of 101 physicians who were geographically representative of physicians registered with the AMA characterized 614-827 patients per survey, for a total of 4514 responses. Among recently diagnosed patients, 55% were male (95% confidence interval [CI] = 52% to 59%), the median age at diagnosis was 71 years (range = 65-80 years), and 10% (95% CI = 8% to 12%) had MDS secondary to chemotherapy, radiation therapy, or environmental exposure. The median duration of MDS in established patients ranged from 13 to 16 months over the six surveys. Among recently diagnosed MDS patients, fewer patients with lower-risk disease than with higher-risk disease were dependent on either red blood cell transfusions (22% vs 68%) or platelet transfusions (6% vs 33%). More than 50% of all newly diagnosed and established patients used erythropoiesis-stimulating agents. A small percentage of all patients either had had or were being considered for bone marrow transplantation (recently diagnosed: 4%; established: 4% or less) or were being treated on clinical trials (recently diagnosed: 1%; established: 4% or less).

CONCLUSIONS

MDS patients in the United States have substantial transfusion needs, and use of erythropoiesis-stimulating agents and are seldom considered for bone marrow transplantation or clinical trials. These data may be useful in characterizing the health care resource use and pharmacoeconomic impact of MDS in the United States.

Phase 2, single-arm trial to evaluate the effectiveness of darbepoetin alfa for correcting anaemia in patients with myelodysplastic syndromes

Patients with myelodysplastic syndromes (MDS) often develop anaemia resulting in frequent transfusions and fatigue. Darbepoetin alfa is an erythropoiesis-stimulating agent (ESA) approved for treating chemotherapy-induced anaemia. This single-arm, phase 2 study examined the efficacy of darbepoetin alfa 500 μg every 3 weeks (Q3W) for treating anaemia in low-risk MDS patients (after 6 weeks, poor responders received darbepoetin alfa 500 μg every 2 weeks). The primary end-point was the incidence of erythroid responses (International Working Group criteria) after 13 weeks of therapy. Secondary end-points included the incidence of erythroid responses at weeks 28 and 55, [or weeks 27 and 53 for dose escalations to every two weeks (Q2W)], and safety parameters. Analyses were stratified by the patient's previous ESA therapy status [ESA-naïve (n = 144) vs. prior ESA-treated (n = 62)]. After 13 weeks of therapy, 49% of ESA-naïve patients and 26% of prior ESA-treated patients achieved a major erythroid response. After 53/55 weeks, 59% of ESA-naïve patients and 34% of prior ESA-treated patients achieved a major erythroid response; 82% of ESA-naïve patients and 55% of prior ESA-treated patients achieved target haemoglobin of 110 g/l. Thromboembolic or related adverse events occurred in 2% of patients; no pulmonary embolisms were reported. In conclusion, darbepoetin alfa, 500 μg Q3W appeared well tolerated and increased haemoglobin levels in low-risk MDS patients.

New data with arsenic trioxide in leukemias and myelodysplastic syndromes

Arsenic and its derivatives have been used for medicinal purposes for thousands of years. Arsenic trioxide has demonstrated remarkable activity in the treatment of acute promyelocytic leukemia (APL), for which it can bring about complete remissions (CR) in > 80% of patients with relapsed disease, and molecular remission in 90% of those who enter a CR. Clinical trials have explored its use in the first-line setting and as part of consolidation therapy for de novo APL, for which it appears to provide an event-free and overall survival advantage. Two multicenter trials have examined its use in the treatment of the myelodysplastic syndromes; as a single agent, it yields responses in 20% of patients, and smaller trials have provided evidence for its use in non-APL acute myeloid leukemia populations in combination with other drugs such as gemtuzumab ozogamicin, ascorbic acid, and cytarabine.

Hematopoietic Growth Factors in the Treatment of Acquired Bone Marrow Failure States

In severe aplastic anemia (SAA), the use of hematopoietic growth factors (HGFs) to support blood counts is of limited value, as predicted by in vitro studies and measurement of endogenous serum levels of hematopoietic growth factors (HGF), which are markedly elevated. Benefit is usually only seen in those with less severe disease who are unlikely to require HGFs in practice. HGFs administered alone play no role in the treatment of SAA. The main indication for using HGFs, most often granulocyte colony-stimulating factor (G-CSF), in SAA has been to determine whether they increase the response rate to immunosuppressive therapy (IST) and improve survival. While earlier neutrophil recovery occurs when G-CSF is administered with IST, studies to date show no significant advantage in hematologic response or overall survival. Conflicting results have been reported concerning whether G-CSF increases the known risk of myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML) after IST; follow-up of at least 10 years is required, lacking in many clinical studies reported to date. In MDS, HGFs have been used to counteract the intramedullary apoptosis, which leads to ineffective hematopoiesis. In several uncontrolled and controlled studies, especially in low-risk MDS, high-dose erythropoietin (EPO) or its glycosylated derivative darbepoetin (DPO), alone or in combination with G-CSF, increased hemoglobin levels and diminished the need for red blood cell transfusions, in selected patients with prior transfusion frequency of less than 2 units per month and EPO levels below 500 IU/L. Quality-of-life measures were claimed to have improved, but the cost-effectiveness of this approach is debated, as is safety with regard to the risk of progression. G-CSF is used in supportive care of MDS to improve neutropenia during infectious complications, but to date there is no compelling evidence for a survival benefit or alteration of the course of the disease through the use of HGFs in MDS.