Outcomes of immunosuppressant therapy with lower dose of antithymocyte globulin and cyclosporine in aplastic anemia

Objective: Immunosuppressant therapy (IST) with antithymocyte globulin (ATG) and cyclosporine is an established treatment option for patients with aplastic anemia (AA), who are not eligible for allogeneic stem cell transplantation. However, data on the dose of ATG and its efficacy from the developing countries is minimal. Methods: We performed a retrospective analysis of all AA patients (age > 12 years), treated with equine ATG and cyclosporine from a single center in India. Patients who received or were eligible for stem cell transplantation were excluded. The overall response rate (ORR) to IST was calculated at 3 and 6 months. We also determined the influence of using a lower dose of Atgam ATG (25 mg/kg/day x 4 days) and compared its efficacy against the standard dose of locally manufactured Thymogam ATG (40 mg/kg/day x 4 days). Factors influencing the ORR were analyzed using Fisher's exact test with a significant P < 0.05. Results: Thirty-nine patients with AA treated with ATG and cyclosporine were studied. Median age was 31 years with a male: female ratio of 0.85: 1. The ORR was 58% at 3 months, 77% at 6 months and was similar with lower dose Atgam and standard dose Thymogam. On multivariate analysis of ORR at 6 months, the interval between the onset of symptoms to the initiation of therapy was close to attaining statistical significance (odds ratio 23.53, P value 0.053) while the other variables did not attain significance. Conclusions: IST with equine ATG in a lower dose (25 mg/kg/day x 4 days) and cyclosporine is a feasible and effective treatment option for AA in resource-constrained settings.