The evaluation of low-dose cytarabine in the treatment of myelodysplastic syndromes: a phase-III intergroup study

Silylation of Deoxynucleotide Analog Yields an Orally Available Drug with Antileukemia Effects

DNA methyltransferase inhibitors have improved the prognosis of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). However, because these agents are easily degraded by cytidine deaminase (CDA), they must be administered intravenously or subcutaneously. Recently, two orally bioavailable DNA methyltransferase inhibitors, CC-486 and ASTX727, were approved. In previous work, we developed 5-O-trialkylsilylated decitabines that resist degradation by CDA. However, the effects of silylation of a deoxynucleotide analog and enzymatic cleavage of silylation have not been fully elucidated. Enteric administration of OR21 in a cynomolgus monkey model led to high plasma concentrations and hypomethylation, and in a mouse model, oral administration of enteric-coated OR21 led to high plasma concentrations. The drug became biologically active after release of decitabine (DAC) from OR21 following removal of the 5'-O-trisilylate substituent. Toxicities were tolerable and lower than those of DAC. Transcriptome and methylome analysis of MDS and AML cell lines revealed that OR21 increased expression of genes associated with tumor suppression, cell differentiation, and immune system processes by altering regional promoter methylation, indicating that these pathways play pivotal roles in the action of hypomethylating agents. OR21 induced cell differentiation via upregulation of the late cell differentiation drivers CEBPE and GATA-1 Thus, silylation of a deoxynucleotide analog can confer oral bioavailability without new toxicities. Both in vivo and in vitro, OR21 exerted antileukemia effects, and had a better safety profile than DAC. Together, our findings indicate that OR21 is a promising candidate drug for phase I study as an alternative to azacitidine or decitabine.

The high NRF2 expression confers chemotherapy resistance partly through up-regulated DUSP1 in myelodysplastic syndromes

Although cytarabine has been widely considered as one of the chemotherapy drugs for high-risk myelodysplastic syndromes (MDS), the overall response rate is only approximately 20-30%. Nuclear factor erythroid 2-related factor 2 (NRF2, also called NFE2L2) has been shown to play a pivotal role in preventing cancer cells from being affected by chemotherapy. However, it is not yet known whether NRF2 can be used as a prognostic biomarker in MDS, or whether elevated NRF2 levels are associated with cytarabine resistance. Here, we found that NRF2 expression levels in bone marrow from high-risk patients exceeded that of low-risk MDS patients. Importantly, high NRF2 levels are correlated with inferior outcomes in MDS patients (n=137). Downregulation of NRF2 by the inhibitor Luteolin, or lentiviral shRNA knockdown, enhanced the chemotherapeutic efficacy of cytarabine, while MDS cells treated by NRF2 agonist Sulforaphane showed increased resistance to cytarabine. More importantly, pharmacological inhibition of NRF2 could sensitize primary high-risk MDS cells to cytarabine treatment. Mechanistically, downregulation of dual specificity protein phosphatase 1, an NRF2 direct target gene, could abrogate cytarabine resistance in NRF2 elevated MDS cells. Silencing NRF2 or dual specificity protein phosphatase 1 also significantly sensitized cytarabine treatment and inhibited tumors in MDS cells transplanted mouse models in vivo. Our study suggests that targeting NRF2 in combination with conventional chemotherapy could pave the way for future therapy for high-risk MDS.

Laboratory and clinical risk assessment to treat myelodysplatic syndromes

Myelodisplastic syndromes (MDS) are heterogeneous myeloid disorders characterized by peripheral cytopenias and increased risk of transformation into acute myelogenous leukemia (AML). MDS are generally suspected in the presence of cytopenia on routine analysis and the evaluation of bone marrow cells morphology and cellularity leads to correct diagnosis of MDS. The incidence of MDS is approximately five cases per 100,000 people per year in the general population, but it increases up to 50 cases per 100,000 people per year after 60 years of age. Typically MDS affect the elderly, with a median age at diagnosis of 65–70 years. Here the current therapeutic approaches for MDS are evaluated by searching the PubMed database. Establishing the prognosis in MDS patients is a key element of therapy. In fact an accurate estimate of prognosis drives decisions about the choice and timing of the therapeutic options. Therapy is selected based on prognostic risk assessment, cytogenetic pattern, transfusion needs and biological characteristics of the disease, comorbidities and clinical condition of the patients. In lower-risk patients the goals of therapy are different from those in higher-risk patients. In lower-risk patients, the aim of therapy is to reduce transfusion needs and transformation to higher risk disease or AML, improving the quality of life and survival. In higher-risk patients, the main goal of therapy is to prolong survival and to reduce the risk of AML transformation. Current therapies include growth factor support, lenalidomide, immunomodulatory and hypomethylating agents, intensive chemotherapy, and allogenic stem cell transplantation. The challenge when dealing with MDS patients is to select the optimal treatment by balancing efficacy and toxicity.

Targeting epigenetic pathways in acute myeloid leukemia and myelodysplastic syndrome: a systematic review of hypomethylating agents trials

Background

Aberrant DNA methylation has been identified as a key molecular event regulating the pathogenesis of myelodysplastic syndromes (MDS); myeloid neoplasms with an inherent risk of transformation to acute myeloid leukemia (AML). Based on the above findings, DNA hypomethylating agents (HMA) have been widely used to treat AML and MDS, especially in elderly patients and in those who are not eligible for allogeneic stem cell transplantation (SCT). Our goal was to determine if there is any therapeutic advantage of HMA vs. conventional care regimens (CCR) and indirectly compare the efficacy of azacitidine and decitabine in this patient population.

Methods

Eligible studies were limited to randomized controlled trials comparing HMA to CCR in adult patients with AML or MDS.

Results

Overall survival (OS) rate was 33.2 vs. 21.4 % (RR 0.83, 95 % CI 0.71–0.98) and overall response rate (ORR) 23.7 vs. 13.4 % (RR 0.87, 95 % CI 0.81–0.93) for HMA and CCR, respectively. In subgroup analyses, only azacitidine treatment showed OS improvement (RR 0.75, 95 % CI 0.64–0.98) and not decitabine. Cytogenetic risk or bone marrow blast count did not have independent prognostic impact.

Conclusion

Collectively, these results demonstrate that HMA have superior outcomes compared to CCR and suggest that azacitidine in comparison to decitabine, may be more effective.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-016-0233-2) contains supplementary material, which is available to authorized users.

Ezatiostat hydrochloride for the treatment of myelodysplastic syndromes

INTRODUCTION

Myelodysplastic syndromes (MDSs) are associated with significant morbidity due to ineffective hematopoiesis. Given the limited number of drugs approved by the FDA, there is a need for new therapeutic options. Ezatiostat is a novel agent targeting oxidative stress via inhibition of glutathione S-transferase 1.

AREAS COVERED

Herein, the authors summarize the standard of care in order to build the framework for therapeutic advancements. The purpose of this paper is to review the body of preclinical and clinical research literature on the investigational agent ezatiostat hydrochloride (TLK199) for the treatment of MDSs. The article includes details of the pathophysiology, pharmacology, toxicity and efficacy of ezatiostat hydrochloride from controlled studies in patients with myelodysplasia.

EXPERT OPINION

MDS clonal heterogeneity and clonal architecture complexity has presented a significant technical challenge in developing effective therapies. Ezatiostat offers a unique and specific mechanism to improve the transfusion burden associated with myelodysplasia. Since it is tolerable as a monotherapy, combining ezatiostat with agents such as lenalidomide may have the most potential benefit.

Minimizing risk of hypomethylating agent failure in patients with higher-risk MDS and practical management recommendations

In Europe, azacitidine is the only hypomethylating agent approved for the treatment of patients with int-2-/high-risk myelodysplastic syndromes, offering significantly improved survival compared with conventional care. However, not all patients treated with azacitidine respond to treatment, and the vast majority of responders subsequently relapse. Currently, no standard care regimens have been established for patients after failure of azacitidine. Here, we discuss treatment options after loss of response or progression on azacitidine. In addition, we briefly consider optimization of first-line treatment along with potential biomarkers for identifying and monitoring response during treatment with azacitidine.

Stopping higher-risk myelodysplastic syndrome in its tracks

Higher-risk myelodysplastic syndromes (MDS) are a collection of diseases associated with poor outcomes from complications related to bone marrow failure and evolution to acute myeloid leukemia. While most patients receive epigenetic therapies, intensive chemotherapy or allogeneic stem cell transplantation, more tolerable and effective treatments are necessary to realize the goal of stopping this disease in its tracks. Recent efforts, building on decades of research exploring the pathogenesis of this disease, have revealed exciting clues that elucidate critical biological features that drive or contribute to MDS, and may serve as targets for selective and well-tolerated future therapies. Here, we review the current diagnostic, prognostic, and therapeutic approaches to higher-risk MDS.

Cost-effectiveness analysis of azacitidine in the treatment of high-risk myelodysplastic syndromes in Spain

BACKGROUND

The objective of the study was to analyse whether azacitidine is a cost-effective option for the treatment of myelodysplastic syndrome in the Spanish setting compared with conventional care regimens, including best supportive care, low dose chemotherapy and standard dose chemotherapy.

METHODS

A life-time Markov model was constructed to evaluate the cost-effectiveness of azacitidine compared with conventional care regimens. The health states modelled were: myelodysplastic syndrome, acute myeloid leukemia and death. Variables measured included survival rates, progression probabilities and quality of life indicators. Resource use and cost data reflect the Spanish context. The analysis was performed from the Spanish National Health System perspective, discounting both costs (in 2012 euros) and future effects at 3%. The time horizon considered was end-of-life. Results were expressed in cost per quality-adjusted life-year gained and cost per life-year gained and compared with cost-effectiveness thresholds.

RESULTS

According to the current use of each conventional care regimens options in Spain, azacitidine resulted in €34,673 per quality-adjusted life-year gained (€28,891 per life-year gained) with an increase of 1.89 in quality-adjusted life-years (2.26 in life-years). Azacitidine was superior to best supportive care and low dose chemotherapy in terms of quality-adjusted life-years gained, 1.82 and 2.03, respectively (life-years 2.16 vs. best supportive care, 2.39 vs. low dose chemotherapy). Treatment with azacitidine resulted in longer survival time and thus longer treatment time and lifetime costs. The incremental cost-effectiveness ratio was €39,610 per quality-adjusted life-year gained vs. best supportive care and €30,531 per quality-adjusted life-year gained vs. low dose chemotherapy (€33,111 per life-year gained vs. best supportive care and €25,953 per life-year gained vs. low dose chemotherapy).

CONCLUSIONS

The analysis showed that the use of azacitidine in the treatment of high-risk myelodysplastic syndrome is a cost-effective option compared with conventional care regimen options used in the Spanish setting and had an incremental cost-effectiveness ratio within the range of the thresholds accepted by health authorities.

Diagnosis and treatment of primary myelodysplastic syndromes in adults: recommendations from the European LeukemiaNet

Within the myelodysplastic syndrome (MDS) work package of the European LeukemiaNet, an Expert Panel was selected according to the framework elements of the National Institutes of Health Consensus Development Program. A systematic review of the literature was performed that included indexed original papers, indexed reviews and educational papers, and abstracts of conference proceedings. Guidelines were developed on the basis of a list of patient- and therapy-oriented questions, and recommendations were formulated and ranked according to the supporting level of evidence. MDSs should be classified according to the 2008 World Health Organization criteria. An accurate risk assessment requires the evaluation of not only disease-related factors but also of those related to extrahematologic comorbidity. The assessment of individual risk enables the identification of fit patients with a poor prognosis who are candidates for up-front intensive treatments, primarily allogeneic stem cell transplantation. A high proportion of MDS patients are not eligible for potentially curative treatment because of advanced age and/or clinically relevant comorbidities and poor performance status. In these patients, the therapeutic intervention is aimed at preventing cytopenia-related morbidity and preserving quality of life. A number of new agents are being developed for which the available evidence is not sufficient to recommend routine use. The inclusion of patients into prospective clinical trials is strongly recommended.

Bortezomib combined with low-dose cytarabine in Intermediate-2 and high risk myelodysplastic syndromes. A phase I/II Study by the GFM

Marrow cells from patients with higher-risk myelodysplastic syndrome (MDS) exhibit constitutive nuclear factor (NF)-κB activation. The proteasome inhibitor, bortezomib, has limited efficacy as a single agent in acute myeloid leukaemia. Its activity on leukaemic cell lines is potentiated by chemotherapy. We treated 43 higher-risk MDS patients with bortezomib (1·5 mg/m(2) , days 1, 4, 8 and 11) and low dose cytarabine arabinoside (LDAC; 10 mg/m(2) , then 20 mg/m(2) from days 1-14), every 28 d for four cycles. Median follow-up was 29·7 months. Responses were seen in 12 of the 43 patients (28%), including complete response (CR, n = 1), marrow-CR (n = 3), partial response (PR, n = 5) and haematological improvement (HI, n = 3). Responses were seen in 12 (36%) of the 33 previously untreated patients (11% CR, 13% PR, 2·5% HI), compared to none in the 12 previously treated patients (P < 0·01). Responders had better overall survival (median 18·2 vs. 10 months). One CR and 3 marrow-CRs were seen in patients with complex karyotypes. Main toxicity was haematological, responsible for infection in six patients and bleeding in 3. Three patients with Grade 1-2 pre-treatment haematotoxicity developed Grade 3-4 toxicity. Neuropathy was seen in 12% of patients. The addition of bortezomib to LDAC in higher-risk MDS may improve results obtained with LDAC alone, especially in patients with unfavourable karyotypes.

A cost-effectiveness analysis of using azacitidine vs. decitabine in treating patients with myelodysplastic syndromes

OBJECTIVE

Azacitidine and decitabine are used to treat patients with myelodysplastic syndromes (MDS) in the United States (US). This study sought to assess their relative cost-effectiveness.

DESIGN AND METHODS

The authors developed a cost-effectiveness Markov model (1-month cycles) tracking hypothetical cohorts of MDS patients treated with azacitidine or decitabine over 2 years. The model used a US payer perspective and 2009 costs. Health states modeled included MDS with Transfusion Dependence, MDS with Transfusion Independence, Progression to Acute Myelogenous Leukemia (AML), and Death. Incremental cost-effectiveness outcomes included cost per quality-adjusted life year (QALY), cost per life year (LY), cost per patient-month of transfusion independence, and cost per case of AML progression avoided. One-way sensitivity analyses were performed on key model parameters.

RESULTS

Compared to decitabine, azacitidine was associated with better survival (1.512 LYs vs 1.292), more QALYs gained (1.041 vs 0.870), more patient-months with transfusion independence (8.328 vs 6.224), and a greater proportion of patients avoiding progression to AML (50.9% vs 28.5%). Total per-patient costs over 2 years for azacitidine were lower than for decitabine ($150,322 vs $166, 212).

LIMITATIONS

To inform and update the model over time, it will be important that randomized or observational clinical studies be conducted to directly compare azacitidine and decitabine, provide new information on how these medicines are used, and on their relative clinical effectiveness.

CONCLUSION

Results demonstrate that azacitidine provides greater clinical benefit and costs less than decitabine across all key outcomes. These results accentuate the positive role of azacitidine in providing cost-effective care for MDS.

Low-dose decitabine versus best supportive care in elderly patients with intermediate- or high-risk myelodysplastic syndrome (MDS) ineligible for intensive chemotherapy: final results of the randomized phase III study of the European Organisation for Research and Treatment of Cancer Leukemia Group and the German MDS Study Group

PURPOSE

To compare low-dose decitabine to best supportive care (BSC) in higher-risk patients with myelodysplastic syndrome (MDS) age 60 years or older and ineligible for intensive chemotherapy.

PATIENTS AND METHODS

Two-hundred thirty-three patients (median age, 70 years; range, 60 to 90 years) were enrolled; 53% had poor-risk cytogenetics, and the median MDS duration at random assignment was 3 months. Primary end point was overall survival (OS). Decitabine (15 mg/m(2)) was given intravenously over 4 hours three times a day for 3 days in 6-week cycles.

RESULTS

OS prolongation with decitabine versus BSC was not statistically significant (median OS, 10.1 v 8.5 months, respectively; hazard ratio [HR], 0.88; 95% CI, 0.66 to 1.17; two-sided, log-rank P = .38). Progression-free survival (PFS), but not acute myeloid leukemia (AML) -free survival (AMLFS), was significantly prolonged with decitabine versus BSC (median PFS, 6.6 v 3.0 months, respectively; HR, 0.68; 95% CI, 0.52 to 0.88; P = .004; median AMLFS, 8.8 v 6.1 months, respectively; HR, 0.85; 95% CI, 0.64 to 1.12; P = .24). AML transformation was significantly (P = .036) reduced at 1 year (from 33% with BSC to 22% with decitabine). Multivariate analyses indicated that patients with short MDS duration had worse outcomes. Best responses with decitabine versus BSC, respectively, were as follows: complete response (13% v 0%), partial response (6% v 0%), hematologic improvement (15% v 2%), stable disease (14% v 22%), progressive disease (29% v 68%), hypoplasia (14% v 0%), and inevaluable (8% v 8%). Grade 3 to 4 febrile neutropenia occurred in 25% of patients on decitabine versus 7% of patients on BSC; grade 3 to 4 infections occurred in 57% and 52% of patients on decitabine and BSC, respectively. Decitabine treatment was associated with improvements in patient-reported quality-of-life (QOL) parameters.

CONCLUSION

Decitabine administered in 6-week cycles is active in older patients with higher-risk MDS, resulting in improvements of OS and AMLFS (nonsignificant), of PFS and AML transformation (significant), and of QOL. Short MDS duration was an independent adverse prognosticator.

Treatment of myelodysplastic syndromes in elderly patients

Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal neoplasms with the median age at diagnosis being in the seventh decade. If left untreated, the disease progresses to acute myeloblastic leukemia (AML). There are many options for the management of MDS, but the only potentially curative treatment is allogenic hematopoietic stem cell transplantation (allo-HSCT), which is often not an option because of advanced age or comorbidities at diagnosis or lack of a human leukocyte antigen-identical donor. MDS in the elderly should be managed similar to that in young patients, but the fact that many advanced age patients cannot undergo allo-HSCT precludes any chance of cure. Despite the main objective of prolonging overall survival and the time to progression to AML, the key is to improve quality of life for the longest possible time. To achieve these objectives, supportive care is essential. Likewise, immunomodulatory drugs, such as lenalidomide, can reduce transfusion requirements and reverse cytologic and cytogenetic abnormalities in patients with MDS with chromosome 5q deletion. Elderly patients with high-risk MDS can benefit from 5-azacitidine (5-AZA), with efficacy and safety profiles comparable with those found in patients under 75 years of age. In any patient, predictive drug response scores are required in order to ensure more rational use of these medications.

Effects of azacitidine compared with conventional care regimens in elderly (≥ 75 years) patients with higher-risk myelodysplastic syndromes

This analysis compared azacitidine (AZA) to conventional care regimens (CCR) and their associated overall survival (OS) and tolerability in the subset of 87 elderly (≥ 75 years) patients with higher-risk MDS (FAB: RAEB, RAEB-t, CMML and IPSS: Int-2 or High) from the AZA-001 trial. Patients were randomized to AZA (75 mg/m(2)/daysubcutaneously × 7 days every 28 days) (n=38) or CCR (n=49) and had median ages of 78 and 77 years, respectively. AZA significantly improved OS vs CCR (HR: 0.48 [95%CI: 0.26, 0.89]; p=0.0193) and 2-year OS rates were 55% vs 15% (p<0.001), respectively. AZA was generally well tolerated compared with CCR, which was primarily best supportive care (67%). Grade 3-4 anemia, neutropenia, and thrombocytopenia with AZA vs CCR were 13% vs 4%, 61% vs 17%, and 50% vs 30%, respectively. Given this efficacy and tolerability, AZA should be considered the treatment of choice in patients aged ≥ 75 years with good performance status and higher-risk MDS.

Prolonged survival with improved tolerability in higher-risk myelodysplastic syndromes: azacitidine compared with low dose ara-C

In the phase III AZA-001 trial, low-dose cytarabine (LDara-C), the most widely used low-dose chemotherapy in patients with higher-risk myelodysplastic syndrome (MDS) who are ineligible for intensive treatment, was found to be associated with poorer survival compared with azacitidine. This analysis further compared the efficacy and the toxicity of these two drug regimens. Before randomization, investigators preselected patients to receive a conventional care regimen, one of which was LDara-C. Of 94 patients preselected to LDara-C, 45 were randomized to azacitidine and 49 to LDara-C. Azacitidine patients had significantly more and longer haematological responses and increased red blood cell transfusion independence. Azacitidine prolonged overall survival versus LDara-C in patients with poor cytogenetic risk, presence of -7/del(7q), and French-American-British subtypes refractory anaemia with excess blasts (RAEB) and RAEB in transformation. When analyzed per patient year of drug exposure, azacitidine treatment was associated with fewer grade 3-4 cytopenias and shorter hospitalisation time than LDara-C in these higher-risk MDS patients.

Comparative analysis of remission induction therapy for high-risk MDS and AML progressed from MDS in the MDS200 study of Japan Adult Leukemia Study Group

A total of 120 patients with high-risk myelodysplastic syndrome (MDS) and AML progressed from MDS (MDS-AML) were registered in a randomized controlled study of the Japan Adult Leukemia Study Group (JALSG). Untreated adult patients with high-risk MDS and MDS-AML were randomly assigned to receive either idarubicin and cytosine arabinoside (IDR/Ara-C) (Group A) or low-dose cytosine arabinoside and aclarubicin (CA) (Group B). The remission rates were 64.7% for Group A (33 of 51 evaluable cases) and 43.9% for Group B (29 out of 66 evaluable cases). The 2-year overall survival rates and disease-free survival rates were 28.1 and 26.0% for Group A, and 32.1 and 24.8% for Group B, respectively. The duration of CR was 320.6 days for Group A and 378.7 days for Group B. There were 15 patients who lived longer than 1,000 days after diagnosis: 6 and 9 patients in Groups A and B, respectively. However, among patients enrolled in this trial, intensive chemotherapy did not produce better survival than low-dose chemotherapy. In conclusion, it is necessary to introduce the first line therapy excluding the chemotherapy that can prolong survival in patients with high-risk MDS and MDS-AML.

Managing myelodysplastic symptoms in elderly patients

Most patients with myelodysplastic syndromes (MDS) are elderly (median age range 65 to 70 years); as a consequence, the incidence and prevalence of these diseases are rising as the population ages. Physicians are often uncertain about how to identify patients who may benefit from specific treatment strategies. The International Prognostic Scoring System is a widely used tool to assess the risk of transformation to leukemia and to guide treatment decisions, but it fails to take into account many aspects of treating elderly patients, including comorbid illnesses, secondary causes of MDS, prior therapy for MDS, and other age-related health, functional, cognitive, and social problems that affect the outcome and managing of myelodysplastic symptoms. Patients with low-risk disease traditionally have been given only best supportive care, but evidence is increasing that treatment with novel non-conventional drugs such as lenalidomide or methyltransferase inhibitors may influence the natural history of the disease and should be used in conjunction with supportive-care measures. Supportive care of these patients could also be improved in order to enhance their quality of life and functional performance. Elderly patients commonly have multiple medical problems and use medications to deal with these. In addition, they are more likely to have more than one health care provider. These factors all increase the risk of drug interactions and the consequent treatment of toxicities. Manifestations of common toxicities or illnesses may be more subtle in the elderly, owing to age-associated functional deficits in multiple organ systems. Particularly important to the elderly MDS patient is the age-related decline in normal bone marrow function, including the diminished capacity of response to stressors such as infection or myelosuppressive treatments. Through the integration of geriatric and oncological strategies, a personalized approach toward this unique population may be applied. As with many diseases in the elderly, reliance on family members or friends to maintain the prescribed treatments, including travel to and from appointments, may place additional stressors on the patient and his/her support network. Careful evaluation and knowledge of functional status, ability to tolerate treatments, effect of disease progression, and general overall health conditions can provide the best opportunity to support these patients. Immediate assessment of daily living activities may detect deficiencies or deficits that often require early interventions.

Treatment of myelodysplastic syndrome with 2 schedules and doses of oral topotecan: a randomized phase 2 trial by the Cancer and Leukemia Group B (CALGB 19803)

BACKGROUND

The Cancer and Leukemia Group B evaluated oral topotecan administered at 2 schedules and doses for myelodysplastic syndrome (MDS).

METHODS

Patients with previously untreated primary or therapy-related MDS were eligible. Patients with refractory anemia (RA), RA with ringed sideroblasts, or refractory cytopenia with multilineage dysplasia (RCMD) were eligible only if they were dependent on erythrocyte transfusion, had a platelet count<50,000/microL, or had an absolute neutrophil count<1000/microL with a recent infection that required antibiotics. Patients were randomized to receive oral topotecan either at a dose of 1.2 mg/m2 twice daily for 5 days (Arm A) or once daily for 10 days (Arm B) repeated every 21 days for at least 2 cycles. Responding patients continued until they developed disease progression or unacceptable toxicity or until they had received 2 cycles beyond a complete response.

RESULTS

Ninety patients received treatment, including 46 patients on Arm A and 44 patients on Arm B. Partial responses with improvement in all 3 cell lines occurred in 6 patients (7%), and hematologic improvement (in 1 or 2 cell lines) was observed in 21 patients (23%), for an overall response rate of 30%. Response duration was longer on Arm A (23 months vs 14 months; P=.02). Seven of 14 patients with chronic myelomonocytic leukemia responded. There were 8 treatment-related deaths from infection (6 deaths) and bleeding (2 deaths). Diarrhea was the most frequent nonhematologic toxicity (grade 3, 11%; grade 4, 2%; grading determined according to the National Cancer Institute Comman Toxicity Criteria v.2.0).

CONCLUSIONS

Oral topotecan in the dose and schedules evaluated in this trial demonstrated only a modest response rate with a troublesome toxicity profile in the treatment of MDS.

Myelodysplastic syndromes: biology and treatment

Optimal management of patients with myelodysplastic syndromes (MDS) requires an insight into the biology of the disease and the mechanisms of action of the available therapies. This review focuses on low-risk MDS, for which chronic anaemia and eventual progression to acute myeloid leukaemia are the main concerns. We cover the updated World Health Organization classification, the latest prognostic scoring system, and describe novel findings in the pathogenesis of 5q- syndrome. We perform in depth analyses of two of the most widely used treatments, erythropoietin and lenalidomide, discussing mechanisms of action, reasons for treatment failure and influence on survival.

Efficacy of azacitidine compared with that of conventional care regimens in the treatment of higher-risk myelodysplastic syndromes: a randomised, open-label, phase III study

BACKGROUND

Drug treatments for patients with high-risk myelodysplastic syndromes provide no survival advantage. In this trial, we aimed to assess the effect of azacitidine on overall survival compared with the three commonest conventional care regimens.

METHODS

In a phase III, international, multicentre, controlled, parallel-group, open-label trial, patients with higher-risk myelodysplastic syndromes were randomly assigned one-to-one to receive azacitidine (75 mg/m(2) per day for 7 days every 28 days) or conventional care (best supportive care, low-dose cytarabine, or intensive chemotherapy as selected by investigators before randomisation). Patients were stratified by French-American-British and international prognostic scoring system classifications; randomisation was done with a block size of four. The primary endpoint was overall survival. Efficacy analyses were by intention to treat for all patients assigned to receive treatment. This study is registered with ClinicalTrials.gov, number NCT00071799.

FINDINGS

Between Feb 13, 2004, and Aug 7, 2006, 358 patients were randomly assigned to receive azacitidine (n=179) or conventional care regimens (n=179). Four patients in the azacitidine and 14 in the conventional care groups received no study drugs but were included in the intention-to-treat efficacy analysis. After a median follow-up of 21.1 months (IQR 15.1-26.9), median overall survival was 24.5 months (9.9-not reached) for the azacitidine group versus 15.0 months (5.6-24.1) for the conventional care group (hazard ratio 0.58; 95% CI 0.43-0.77; stratified log-rank p=0.0001). At last follow-up, 82 patients in the azacitidine group had died compared with 113 in the conventional care group. At 2 years, on the basis of Kaplan-Meier estimates, 50.8% (95% CI 42.1-58.8) of patients in the azacitidine group were alive compared with 26.2% (18.7-34.3) in the conventional care group (p<0.0001). Peripheral cytopenias were the most common grade 3-4 adverse events for all treatments.

INTERPRETATION

Treatment with azacitidine increases overall survival in patients with higher-risk myelodysplastic syndromes relative to conventional care.

An epigenetic approach to the treatment of advanced MDS; the experience with the DNA demethylating agent 5-aza-2'-deoxycytidine (decitabine) in 177 patients

During the last 10 years, three European phase II studies were performed to investigate the treatment of elderly patients with myelodysplastic syndrome (MDS) with low-dose 5-aza-2'-deoxycytidine (decitabine, DAC). All these European trial data were reviewed on the basis of the International Prognostic Scoring System (IPSS) risk criteria and the response criteria as recently published by an international working group. To investigate the results in a larger cohort of patients and to determine risk factors, all data were pooled with some observations from the PCH 95-06 US phase II study. The response rate in the 177 patients evaluated (median age 70 years) was 49%. The median response duration was 36 weeks, and the median survival was 15 months. Analysis of the data according to sex, age, French-American-British classification, percentage of blasts in the bone marrow, IPSS risk group, lactate dehydrogenase and cytogenetics did not reveal any factor predictive of response. Overall, 69% of patients benefited, including those with stable disease during therapy. Response duration was significantly shorter with increasing risk (according to the IPSS classification). Haemoglobin level and neutrophil count showed an inverse correlation to the IPSS classification. Univariate analysis showed a significantly inferior survival for elderly patients (>75 years of age) and for those with high levels of serum lactate dehydrogenase (LDH) (more than two times the normal values). Patients with high-risk cytogenetic abnormalities according to the IPSS risk criteria showed better overall survival than those with intermediate-risk abnormalities. When analysed according to the IPSS risk classification, high-risk patients had worse survival prospects following decitabine therapy than those with intermediate risk; however, compared to the originally reported IPPS outcomes for high-risk patients, they probably showed better survival. During the treatment period, 18% of the patients progressed towards acute leukaemia. Decitabine showed a rather low toxicity profile in this elderly patient group. In conclusion, low-dose decitabine is an active drug for the treatment of MDS patients, even for those older than 75 years with bad prognostic characteristics.

All-trans Retinoic Acid in Association with Low Dose Cytosine Arabinoside in the Treatment of Acute Myeoid Leukemia in Elderly Patients

All-trans retinoic acid (ATRA) has shown a synergistic activity in combination with cytosine arabinoside in vitro in the treatment of acute myeloid leukaemia (AML). In this paper we report the results of treatment with low dose cytosine arabinoside (LDAC) with or without ATRA in 28 patients with acute myeloid leukaemia aged over 60 years: 14 patients received only LDAC and the other 14 LDAC + ATRA. The patients of the 2 groups showed similar clinical features: in 10 patients AML developed after a myelodysplastic form and 4 patients presented a previous malignancy. All the patients received subcutaneous (sc) LDAC (15 mg twice a day for 14 days) and in 14 patients oral ATRA (45 mg/sqm in the same days) was added to LDAC; the courses were repeated every 4 weeks from diagnosis to relapse. The treatment was well tolerated and the patients could self-administer sc LDAC and oral ATRA at home. No statistically significant differences were observed in complete remission rate (21% vs. 50%, respectively) and resistant rate (57% vs. 29%), but the patients treated with the combination of the 2 drugs had a better time to treatment failure (15 weeks vs. 30 weeks, respectively) (P = 0.045) and a longer survival (37 weeks vs. 66 weeks) (P = 0.019). Our experience, although with a low number of patients, confirms the efficacy of ATRA in combination with sc LDAC in the treatment of AML in elderly patients.

Efficacy of growth factors compared to other therapies for low-risk myelodysplastic syndromes

The myelodysplastic syndromes (MDS) represent a heterogeneous group of disorders. Low-risk MDS represent a subgroup with a relatively good prognosis, but with few trials evaluating outcomes. A pooled analysis based upon a MEDLINE search identified 162 original articles describing patient characteristics and effect of therapy on 2592 individuals with pathologically confirmed refractory anaemia or refractory anaemia with ringed sideroblasts with <5% bone marrow blasts. Treatments were categorised as growth factors (GF) or non-growth factors (NGF). International Prognostic Scoring System (IPSS) score was documented or calculated when possible. Responses and outcomes were standardised according to the International Working Group MDS criteria. Growth factors produced higher overall response rates (39.5% vs. 31.4% for NGF, P = 0.019), while NGF yielded better CR/PR rates (25.6% vs. 9.1% for GF, P = 0.03). Over 2 years of follow-up, those receiving GF demonstrated greater overall and progression-free survival than NGF, after controlling for baseline patient characteristics. Decision tools need to be developed to determine which therapy to choose for patients with low-risk MDS.

Clinical significance of high-Km 5'-nucleotidase (cN-II) mRNA expression in high-risk myelodysplastic syndrome

We analyzed cytosolic high-Km 5'-nucleotidase (cN-II) and deoxycytidine kinase (dCK) mRNA expression in bone marrow mononuclear cells (BMMNC) of patients with high-risk myelodysplastic syndrome (MDS) using quantitative real-time polymerase chain reaction (rt-PCR). At diagnosis, the cN-II mRNA expression of patients was higher than that of healthy volunteers, but the dCK mRNA expression showed no significant difference. Patients with ara-C-containing chemotherapies whose BMMNC showed a high level of cN-II expression (greater than the median value) had shorter median overall survival (15 months versus 22 months, p<0.01) and shorter median post-chemotherapy survival (10 months versus 16 months, p=0.012). These data suggest that the expression level of cN-II mRNA might be a prognostic factor of high-risk MDS.

Superiority of prolonged low-dose azanucleoside administration? Results of 5-aza-2'-deoxycytidine retreatment in high-risk myelodysplasia patients

BACKGROUND

The optimal treatment duration with decitabine (DAC) in patients with myelodysplastic syndromes (MDS) remains a matter of debate. Although at least 2 consolidating courses after best response usually are performed, the response to treatment after disease recurrence has not been systematically studied to date.

METHODS

In the current study, the authors report on 22 of 108 patients with MDS (20%) treated with low-dose DAC in 3 Phase II trials who received DAC as retreatment at the time of disease recurrence.

RESULTS

According to the International Prognostic Scoring System (IPSS) at the time of initial treatment, 5 of 22 patients (23%) had a score of intermediate-1 (Int-1), 4 patients (18%) had a score of Int-2, and 13 patients (59%) were scored as high-risk. Patients initially received a median of 6 courses of DAC (range, 2 courses-6 courses), which resulted in a complete remission (complete response [CR]) in 12 of the 22 patients (55%). Retreatment with DAC at the time of disease recurrence was initiated at a median of 11 months (range, 3 mos-27 mos) after the last course of initial treatment. With regard to DAC retreatment, patients received a median of 3 courses (range, 1 courses-6 courses), with 10 of 22 patients (45%) responding (1 with a CR and 2 with partial remissions [partial response (PR)]; all 3 patients achieved a CR at the time of initial treatment) and 7 patients demonstrating a hematologic improvement (HI) (at the time of initial treatment there were 2 CRs, 4 PRs, and 1 HI). Twelve of the 22 patients (55%) did not demonstrate any objective responses to retreatment, including 4 patients with primary resistance to the first course of retreatment. The median survival of all patients from the initiation of the first DAC course was 27.5 months (range, 15 mos-50+ mos). The median survival of 43 patients who also had achieved a response to the initial treatment with DAC but who received best supportive care (n = 33 patients) or induction chemotherapy (n = 10 patients) was 18 months (range, 5 mos-72 mos). Second responders to DAC retreatment were found less frequently in the IPSS high-risk group compared with nonresponders (40% vs. 83%). Age, French-American-British classification subtype, serum lactate dehydrogenase level at retreatment, and previous response to DAC were not found to strongly differ between the groups; however, the subgroups were too small to perform a statistical analysis.

CONCLUSIONS

Retreatment with DAC was found to result in objective responses in 45% of previously DAC-responsive patients. However, the quality and duration of the second disease remissions were found to be inferior. Therefore, DAC-responsive patients might derive more clinical benefit from continuation of the initial treatment.

Are myelodysplastic syndromes "cancer"? Unexpected adverse consequences of linguistic ambiguity

Myelodysplastic syndromes (MDS) are clonal, neoplastic disorders of hematopoietic tissue that convey a guarded prognosis, but physicians vary in whether they refer to MDS as a "cancer" when discussing the diagnosis with patients. Because of past ambiguity about whether MDS is truly a malignancy, confusion about MDS terminology is widespread. Additionally, patients who carry one of the dubious cancer-specific health insurance policies are usually not eligible for financial benefits when they receive a diagnosis of MDS. Likewise, patients with MDS who have been led to believe they do not have a form of cancer by their primary physician may become upset when seeing another health care provider who does refer to MDS in this way. Here, I discuss evidence supporting broader consideration of MDS as a form of malignant neoplasia - i.e., cancer - as well as some of the relevant practical issues.

The myelodysplastic syndromes: diagnosis and treatment

The myelodysplastic syndromes (MDSs) are common, acquired, clinically challenging hematologic conditions that are characterized by bone marrow failure and a risk of progression to acute leukemia. These disorders can arise de novo, especially in elderly patients or, less often, as a consequence of prior chemotherapy or radiotherapy for an unrelated disease. The MDS classification systems were revised recently and updated. These refined classification and prognostic schemes help stratify patients by their risk of leukemia progression and death; this knowledge can help clinicians select appropriate therapy. Although many treatments for MDS have been proposed and evaluated, at present, only hematopoietic stem cell transplantation offers any real hope for cure, and no available therapy beyond general supportive care offers benefit to more than a minority of patients. However, recent clinical trials enrolling patients with MDS have reported encouraging results with use of newer drugs, including lenalidomide, decitabine, and darbepoetin alfa. Other exciting treatment regimens are being tested. Here, we present a contemporary, practical clinical approach to the diagnosis and risk-stratified treatment of MDS. We review when to suspect MDS, detail how to evaluate patients who may have a form of the condition, explain key features of treatments that are currently available in the United States, and summarize a general, common-sense therapeutic approach to patients with MDS.

Low-dose cytosine arabinoside (LD-AraC) vs LD-AraC plus granulocyte/macrophage colony stimulating factor vs LD-AraC plus Interleukin-3 for myelodysplastic syndrome patients with a high risk of developing acute leukemia: final results of a randomized phase III study (06903) of the EORTC Leukemia Cooperative Group

In this randomized phase III study of the EORTC Leukemia Cooperative Group, patients with myelodysplastic syndromes (MDS) with 10-30% bone marrow blasts and hematopoietic failure were treated with low-dose cytosine arabinoside (LD-AraC) (2 x 10 mg/m2/day subcutaneously (s.c.) days 1-14) either alone or in combination with rhGM-CSF or interleukin-3 (IL-3) both given s.c. at a dose of 150 microg/day from day 8 to 21. A total of 180 evaluable patients with a median age of 65 years and refractory anemia with an excess of blasts (RAEB, n = 107) or RAEB in transformation (RAEBt, n = 73) were randomized. There were no differences among the three treatment regimens with respect to numbers of courses applied or treatment delays. Hemorrhage occurred in approximately 40% in all arms, whereas infection rates were higher in the granulocyte/macrophage colony stimulating factor (GM-CSF)- or IL3-containing arm. The overall response rate was 38.6% with no statistically significant difference among the three arms. In summary, a substantial proportion of patients had achieved relatively durable responses in all the three arms. No influence of either growth factor was detected on the grade of cytopenia. Thus, the combination of LD-AraC with GM-CSF or IL-3 cannot be recommended for routine use in a high-risk MDS population.

Management of patients with higher risk myelodysplastic syndromes

Higher risk myelodysplastic syndromes (MDS) include patients in the Intermediate-2 and high-risk categories of the International Prognostic Scoring System, as well as patients with MDS secondary to radiation or chemical exposure. Ideally, the goal of therapy is to alter the natural history of disease in these patients to achieve cure or durable remission. High-intensity chemotherapy can achieve moderate rates of complete remission, however, durability of remission and overall survival tend to be short. Hematopoietic stem cell transplantation (HSCT) offers the possibility of cure, with long-term disease-free survival inversely related to age. Patients who are elderly or have poor functional status are candidates for reduced intensity HSCT, although this is still an experimental modality. Azacitidine is a hypomethylating agent that is a reasonable option for many patients ineligible for high-intensity therapies. Other therapies, such as immunomodulatory agents, arsenic trioxide, and farnesyl transferase inhibitors have thus far shown limited usefulness in higher risk MDS. This paper reviews the various therapeutic options for higher risk MDS, providing rationale for specific management approaches for these patients.

Decitabine in Myelodysplastic Syndromes

Myelodysplastic syndromes (MDS) are a heterogenous group of hematopoietic stem cell disorders that are multifactorial in their etiology. Aberrant DNA hypermethylation is now thought to be involved in MDS, as numerous tumor-suppressor genes have been identified that are silenced in these patients. Thus, the use of DNA methyltransferase inhibitors, such as 5-aza-2'-deoxycytidine (decitabine, Dacogen, MGI Pharma Inc, Bloomington, MN), for reversal of this process appears to be a rational intervention that may influence the course of the disease. Several phase I/II studies have been conducted using a low-dose schedule of decitabine in MDS patients. Based on these studies, decitabine appears to be effective and generally well tolerated, especially in those patients with worse prognostic indicators. Recent results of a phase III study also confirmed that patients treated with decitabine compared to standard supportive care had higher overall response rates and longer time to AML transformation. Decitabine appears to be a promising new therapy for the treatment of MDS; however, defining the optimal dosing schedule and exploring the possible use in combination with other agents such as the histone deacetylase inhibitors need further evaluation.

Arsenic trioxide for the treatment of myelodysplastic syndromes

The impressive activity of arsenic trioxide in acute promyelocytic leukaemia (APL) has renewed the interest in this old compound. Arsenic trioxide targets the sulfhydryl groups present in many proteins involved in oncogenesis and has a broad spectrum of biological activities. This article will review the mechanisms of action of the drug and their relevance to the treatment of myelodysplastic syndrome (MDS), a disease for which no standard treatment currently exists. The early clinical experience has confirmed the activity of arsenic trioxide in MDS. The preliminary results of ongoing Phase II studies conducted in patients with MDS suggest that arsenic trioxide produces haematological improvement including durable transfusion independence in approximately 30% of patients. The current data are presented and discussed in this review.

Chronic myelomonocytic leukemia: lost in classification?

Chronic myelomonocytic leukemia (CMML) comprises a spectrum of disease variably considered as a myelodysplastic (MDS) and/or myeloproliferative (MPD) disorder. Now classified by the WHO within a separate nosological group from MDS or MPD, the reality is that there is a dynamic of evolution through increasing monocyte counts in one-third of patients. The principal clinical difference between CMML and other MPD is the presence of ineffective hematopoiesis, manifesting as more frequent anemia and thrombocytopenia in CMML. A fundamental biological characteristic shared with MPD is progenitor hypersensitivity to growth factors, but the pathways mediating this likely differ, as does the lineage specificity. Activation of the STAT pathway in MPD contrasts with frequent RAS pathway activation in CMML. Therapy of CMML is unsatisfactory, with the median age dictating that supportive care and control of myeloproliferation remains the mainstay for the majority. Intensive chemotherapy alone is of little benefit, and stem cell transplantation is the only curative modality in the small number of eligible patients, although outcome remains suboptimal. A deeper understanding of the biological basis of CMML may lead to targeted therapy analogous to the evolving management of MPD best exemplified for chronic myeloid leukemia.

Low dose Ara-C for myelodysplastic syndromes: is it still a current therapy?

The myelodysplastic syndromes (MDS) are characterized by hemopoietic insufficiency associated with severe cytopenias, leading to serious morbidity, and acute leukemia development. MDS typically occur in elderly people, with a median age at diagnosis ranging between 60 and 75 years. The patients' prognosis, estimated according to the International Prognostic Scoring System, age and performance status should be considered before choosing among the various treatment options. A therapeutic dilemma exists in MDS, due to the multifactorial pathogenetic features of the disease, the heterogeneous stage and the elderly age of patients at diagnosis. This is underlined by the absence of a Food and Drug Administration-approved agent with an indication for this disease. The therapeutic end-points vary from symptom management (using low-intensity treatment with biological targeted agents, or only supportive therapy), to attempts to change the natural history of the disease (generally using high intensity treatment, including intensive chemotherapy and hemopoietic stem cell transplantation). The main goal of low-intensity therapies is generally to induce hematological improvements and is mainly used for low-risk disease. On the other hand, high-intensity therapies generally aims to alter the disease's natural history (improving survival, and decrease progression to acute myeloid leukemia), and are mainly used for high-risk disease. This review will focus on the current role of low-dose Ara-C therapy in the management of MDS. In fact, there is evidence that low-dose chemotherapy with Ara-C can induce responses in patients with MDS. In particular, the use in combinations with growth factors, such as G-CSF or M-CSF, looks promising, suggesting further investigations about this old new therapeutic tool.

DNA methylation as a therapeutic target in hematologic disorders: recent results in older patients with myelodysplasia and acute myeloid leukemia

DNA methylation provides a major epigenetic code (besides histone modification) of the lineage- and development-specific genes (such as regulators of differentiation in the hematopoietic lineages) that control expression of normal cells. However, DNA methylation is also involved in malignancies because aberrant methylating gene activity occurs during leukemic transformation. Thus, genes such as tumor suppressor genes, growth-regulatory genes, and adhesion molecules are often silenced in various hematopoietic malignancies by epigenetic inactivation via DNA hypermethylation. This inactivation is frequently seen not only in transformed cell lines but also in primary leukemia cells. Because this defect is amenable to reversion by pharmacologic means, agents that inhibit DNA methylation have been developed to specifically target this hypermethylation defect in leukemia and preleukemia cases. The most clinically advanced agents, the azanucleosides 5-azacytidine and 5-aza-2'-deoxycytidine (decitabine), were discovered more than 25 years ago, when their methylation-inhibitory activities, even at low concentrations, became apparent. Although both of these agents, like cytarabine, had been clinically used until then at high doses, the redevelopment of these agents for low-dose schedules has revealed very interesting clinical activities for treating myelodysplasia (MDS) and acute myeloid leukemia (AML). Because these diseases occur mostly in patients over 60 years of age, low-dose schedules with these compounds provide a very promising approach in such patient groups by virtue of their low nonhematologic toxicity profiles. In the present review, we describe the development of treatments that target DNA hypermethylation in MDS and AML, and clinical results are presented. In addition, pharmacologic DNA demethylation may be viewed as a platform for biological modification of malignant cells to become sensitized (or resensitized) to secondary signals, such as differentiating signals (retinoids, vitamin D3) and hormonal signals (eg, estrogen receptor in breast cancer cells, androgen receptor in prostate cancer cells). Finally, an in vitro synergism between the reactivating potency of demethylating agents and inhibitors of histone deacetylation has been tested in several pilot studies of AML and MDS treatment. Finally, gene reactivation by either group of compounds results in therapeutically meaningful reactivation of fetal hemoglobin in patients with severe hemoglobinopathies, extending the therapeutic range of derepressive epigenetic agents to nonmalignant hematopoietic disorders.

The myelodysplastic/myeloproliferative disorders: the interface

Most patients with myelodysplastic syndromes can be identified easily and separated from patients who have myeloproliferative disorders. A few have overlapping features, however, with evidence of morphologic dysplasia and a proliferative advantage of one or more of the myeloid differentiating cell lines. For practical purposes and therapeutic considerations, chronic myelomonocytic leukemia is viewed now as a composite disorder along with atypical chronic myeloid leukemia and juvenile myelomonocytic leukemia.

Opportunities for Trisenox (arsenic trioxide) in the treatment of myelodysplastic syndromes

Arsenic trioxide (ATO) has a long history of efficacy as an antileukemic agent. However, with the advent of modern therapy, it had been relegated to a historical footnote. In the 1990s, investigators in China reported that ATO was safe and had dramatic efficacy in patients with acute promyelocytic leukemia (APL). Preclinical investigations indicate that the biological targets of this novel drug extend to a variety of malignancies other than APL and include induction of apoptosis, nonterminal differentiation, and suppression of proliferation and angiogenesis. The myelodysplastic syndromes (MDSs) present a particular therapeutic challenge. Ineffective hematopoiesis predominates in patients with low-grade prognostic scores. The survival of those patients with high-grade disease is compromised by a high risk of leukemia transformation. Although a number of therapeutic options have been investigated, none has emerged as being broadly efficacious and having an acceptable toxicity profile. No drug has yet received approval by the Food and Drug Administration for this indication. Biologic features of MDS, which include accelerated apoptotic potential, limited maturation capacity, and medullary neovascularity, create a strong scientific rationale for the investigation of ATO in MDS. This report describes the history and scientific basis for ATO treatment of hematologic malignancies, enumerates the potential benefits of ATO in MDS, and discusses the direction of ongoing trials of this novel antineoplastic agent.

Phase II trial of CPT-11 in myelodysplastic syndromes with excess of marrow blasts

CPT-11 is an antineoplastic agent which acts as a specific inhibitor of DNA topisomerase 1 and has a broad spectrum of activity in solid tumors. Very few studies have evaluated the activity of CPT-11 in hematological malignancies. We conducted a phase II trial of CPT-11 in 26 patients with high-risk MDS (RAEB 1: n = 4; RAEB 2: n = 9; MDS having progressed to AML: n = 10; CMML: n = 3) who could not receive anthracycline/cytarabine intensive chemotherapy. Induction therapy consisted of four courses of CPT-11 given intravenously at 200 mg/m(2) every 2 weeks. Patient characteristics were: median age, 71 (range 51-77); sex, (M/F), 21/5, median % marrow blasts cells, 13.5 (range 7-52). Cytogenetics according to IPSS were: low-risk n = 13, intermediate-risk n = 6, high-risk n = 3, failure or not done n = 4. Six patients stopped treatment after only one or two courses of CPT-11 due to severe infection (n = 2), progressive disease (n = 3), acute lysis syndrome with renal failure (n = 1). In the 20 patients who received at least three cycles of CPT-11, complete remission was achieved in one case, partial remission in four cases, and hematological improvement in three cases with an overall response rate of 33% in the 26 patients. Duration of response was short (median 4 months, range 1-6 months) and median survival was 8 months (range 1-23 months). Digestive toxicity (diarrhea) occurred in 26/89 (29%) courses, but was mild (grade 1, 20% courses; grade 2 or 3, 9% courses). Hematological toxicity was difficult to assess in non-responders because of initial pancytopenia, but all the patients who responded had grade 3/4 hematological toxicity associated with grade >/=2 infection requiring hospitalization in 18% of the courses. No other major toxicity was observed. Thus CPT-11 has an interesting activity in MDS with excess of blasts; toxicity is easily managed and most patients can be treated in the out-clinic setting. These results suggest that further evaluation of CPT-11 in MDS is warranted.

The myelodysplastic syndrome(s): a perspective and review highlighting current controversies

The myelodysplastic syndrome (MDS) includes a diverse group of clonal and potentially malignant bone marrow disorders characterized by ineffective and inadequate hematopoiesis. The presumed source of MDS is a genetically injured early marrow progenitor cell or pluripotential hematopoietic stem cell. The blood dyscrasias that fall under the broad diagnostic rubric of MDS appear to be quite heterogeneous, which has made it very difficult to construct a coherent, universally applicable MDS classification scheme. A recent re-classification proposal sponsored by the World Health Organization (WHO) has engendered considerable controversy. Although the precise incidence of MDS is uncertain, it has become clear that MDS is at least as common as acute myelogenous leukemia (AML). There is considerable overlap between these two conditions, and the former often segues into the latter; indeed, the distinction between AML and MDS can be murky, and some have argued that the current definitions are arbitrary. Despite the discovery of several tantalizing pathophysiological clues, the basic biology of MDS is incompletely understood. Treatment at present is generally frustrating and ineffective, and except for the small subset of patients who exhibit mild marrow dysfunction and low-risk cytogenetic lesions, the overall prognosis remains rather grim. In this narrative review, we highlight recent developments and controversies within the context of current knowledge about this mysterious and fascinating cluster of bone marrow failure states.