[Effect of low-dose Ara-C regimen on myelodysplastic syndrome (MDS)]

A low-dose Ara C (LDAC) regimen (0.2 mg/kg/d) was tried in two groups of eleven patients with MDS and in ten with hypoplastic leukemia (HL) proven by biopsy. In HL, seven patients achieved complete remission (CR), but CR duration was rather short (4-9 months). Some cases showing relapse could be induced back into CR by the LDAC regimen. All patients showed marked bone marrow aplasia before reaching CR. Therefore, the main effect of LDAC was considered to be cytotoxic activity. In one HL patient, the karyotype of 47, XX, +8 at diagnosis was converted to normal, 46, XX after CR. In MDS, there were no CR cases but five patients partially responded to the LDAC regimen. One patient died of cerebral hemorrhage soon after LDAC treatment. Three patients developed overt leukemia and in one of them the disease was well controlled by LDAC over thirty months. One patient with typical refractory anemia with excess blasts (RAEB) suffered severe bone marrow aplasia after 12 mg/d for 10 days of LDAC, but one month later his hematopoiesis gradually recovered and reached a normal hemoglobin level (12 g/dl). However, all of his karotypes showed 45, XY, -7 at that time. LDAC regimen is effective, especially for HL, but may have a limited effect on MDS.