A pilot study of antithymocyte globulin (ATG) in the treatment of patients with 'low-risk' myelodysplasia.

We report 30 'low-risk' patients with myelodysplasia (MDS) (defined as < 10% bone marrow blasts) who were treated with antithymocyte globulin (ATG). In total, 20 patients were evaluable at the study end-point (response to treatment at 6 months). The diagnosis in these 20 patients was refractory anaemia (RA) in 13, RA with excess blasts in four, and RA with ringed sideroblasts in three. Median age was 54.5 years (range, 31-73 years). There were two cases of secondary MDS. The bone marrow was hypocellular in eight cases and cytogenetics were abnormal in four cases. All patients received lymphoglobuline (horse ATG; Sangstat, France) at a dose of 1.5 vials/10 kg/day for 5 d. The treatment was well tolerated. Three patients in the study died (disease progression, invasive aspergillosis and lung carcinoma respectively); 10 out of 20 evaluable patients (50%) responded to treatment and became transfusion independent; eight out of 13 (62%) patients with RA responded. The median duration of response was 15.5 months (2-42+ months) at the time of analysis.