Is the Early Cyclosporine a Level Predictive to the Outcome of Immunosuppressive Therapy in Severe Aplastic Anemia?

Although there are many recent studies of efficacy of antithymoglobulin (ATG) combined with cyclosporine A (CsA), there has been no study to clarify the correlation between variability of CsA level and the response rate of immunosuppressive therapy (IST). Therefore, we assessed whether the early CsA level would be important or not for IST in acquired severe aplastic anemia (SAA), retrospectively. Thirty one patients were treated with ATG combined with CsA for 6 months. The patient group that achieved higher mean CsA level (≥200 ng/ml, higher CsA group) during first 2 weeks, was shown to more higher response rate than the group, lower mean CsA level (< 200ng/ml, lower CsA group)(response rate of 82.3% in higher CsA group, 21.4% in lower CsA group, p=0.0023). There was also a significant difference in survival rate during median 785 days between higher CsA group and lower CsA group (survival rate of 64.7% in higher CsA group, 28.6% in lower CsA group, p=0.0115). Therefore, we suggest that early higher CsA level during first 2 weeks would be an important factor to achieve the overall response of IST in severe aplastic anemia.