There is no standard therapy for elderly patients with high-riskIn contrast, in several clinical studies with high-dose DAC an myelodysplastic syndrome (MDS). The treatment options of antileukaemic effect was seen with myelosuppression as the low-dose Ara-C and haematopoietic growth factors are disapmain toxic effect. [16][17][18] We conducted a phase II study with pointing in regard to response rate or response duration. We low-dose DAC to study the effectiveness of this drug in MDS Twenty-nine elderly patients with progressive MDS (17 male,Myelotoxicity is its major adverse effect.12 female) who could not be entered in protocols for more Keywords: myelodysplastic syndrome; 5-Aza-2Ј-deoxycytidine;intensive chemotherapy due to their age and/or substantial elderly; continuous infusion; low-dose therapy comorbidity were entered in this study. All patients showed bad prognostic features such as high blast cell count in the bone marrow, anemia, thrombocytopenia or cytogenetic Introduction abnormalities related to a bad prognosis. 7,8 Table 1 shows the characteristics of the patients. The median age was 72 years The myelodysplastic syndromes (MDS) consist of a hetero-(range 58-82 years). The following myelodysplastic subtypes geneous group of clonal haemopathies characterized by matuwere included: RA four, RARS two, RAEB 11, RAEB-T nine, ration defects resulting in ineffective haematopoiesis and so CMML one, secondary (sAML) two patients. The last two in various combinations of anemia, leucopenia and thrompatients were known to have progressive MDS but at entry to bocytopenia.1,2 MDS frequently occur in elderly patients and the study their bone marrow revealed 30-40% of blasts, thus some of the cases are secondary or related to long-term bone they were scored as sAML. All patients but one (No. 25) were marrow damage after radiation or chemotherapy.3,4 Several blood and/or platelet transfusion-dependent. In 20 patients a studies delineating the course and the prognosis of MDS more or less severe comorbidity was present not affecting showed a poor median survival especially in patients with renal and/or hepatic function. CMML, RAEB and RAEB-T. 5,6 A high blast cell count, the grade of (pan)cytopenia and some of the karyotypic abnormalities associated with MDS predict such a poor outcome. 7,8 Therapy The treatment of MDS remains a challenge for the clinician, especially in elderly patients, because no currently available 5-Aza-2′-deoxycytidine (DAC) was a gift from Pharmachemie, therapy has been shown to be generally effective.Haarlem, The Netherlands. In the first 21 patients DAC was 5-Aza-2′-deoxycytidine (DAC) is a pyrimidine analogue that given by continuous infusion for 72 h starting with a dose of inhibits DNA methylation.9 It has been proposed that the inhi-50 mg/m 2 /24 h. Courses were repeated every 6 weeks when bition of DNA methylation by deoxycytidine analogues is no serious clinical problems other than (pan)cytopenia were responsible for gene activation and so to the induction of cell present. No dose redu...

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