[Comparison between two different dose of r-ATG combined with CsA for treating children with severe aplastic anemia]

This study was purposed to compare the efficacy and safety of two different doses of rabbit anti-thymocyte globulin (r-ATG) combined with cyclosporine (CsA) for treating children with severe aplastic anemia (SAA). From January 2005 to July 2010, a total of 95 children with SAA accepted intensive immunosuppressive therapy (IIST) in our department, out of them 55 cases were treated with r-ATG 2.5 mg/(kg·d) for 5 days in combination with CsA (group I) and other 40 cases were treated with r-ATG 3.5 mg/(kg·d) for 5 days in combination with CsA (group II). The responsive rate, adverse reactions, early mortality, relapse and clonal disease were analyzed retrospectively and results between the two groups were compared. Out of 95 patients 43 were boys and 52 were girls, their ages were from 1 to 16 years. The sex, age, severity and course of the disease were comparable between the two groups. The results showed that after treating for 3 and 6 months, the response of patients in group II was higher than that of patients in group I (50% vs 32.1%, P = 0.08 and 65% vs 45.3%, P = 0.059), at 9 and 12 months the response rate of patients in group II and group I did not show significant difference (70.0% vs 71.1%,P = 0.904 and 82.5% vs 80.8%,P = 0.832); at 12 months of treatment, the complete response rate of patients in group II was significantly higher than that of patients in group I (40.0% vs 23.1%,P = 0.08); at 3, 6, 9 months of treatment, the complete response rate of 2 groups showed no obvious difference. The incidence of serum disease, early infection and early mortality did not show statistical difference between two groups. There was no statistical difference in 2 year overall survival rate of two groups. In group I 39 patients were followed-up for more than 2 years, among them 3 patients relapsed, 1 patient died and 1 patient was diagnosed as acute monocytic leukemia (M5). In group II 15 patients were followed up for more than 2 years, there were no relapse, death and clonal disease. It is concluded that the r-ATG combined with CsA is an effective and safe therapeutic regimen for the SAA children. The effect of r-ATG 3.5 mg/(kg·d) is better than the 2.5 mg/(kg·d). The early safety is comparable between the two groups. However, the long-term effect, complications and survival rate need longer follow-up study to evaluate.