The Effect of Immunosuppressive Therapy on Aplastic Anemia: Long-Term Treatment Outcome / 대한혈액학회지

ABSTRACT

BACKGROUND: There has been much evidence that immune-mediated stem cell injury may have a significant role in the pathogenesis of aplastic anemia, and as a result immunosuppressive therapy has become known as an effective treatment for patients with aplastic anemia. There have been no reports regarding the long-term follow-up of immunosuppressive therapy of patients with aplastic anemia in Korea. Therefore, we evaluated the response to immunosuppressive therapy for 47 patients with aplastic anemia, investigating the long-term survival, relapse rate and secondary clonal hematologic diseases. METHODS: Antithymocyte globulin (ATG) or antilymphocyte globulin (ALG) was given with cyclosporin A (CsA) to 39 patients (ATG+CsA 27, ALG+CsA 12), and to 8 patients, ATG or ALG alone was given (ATG 6, ALG 2). ATG was administered for 5 (or 8) days, and ALG was administered for 5 days. CsA was orally begun with ATG or ALG for a median total of 4.5 (3~14) months. RESULTS: 1) Response Among 47 patients, 30 (63.8%) responded; 11 showed complete response (CR) and 19 showed partial response (PR). 2) Factors affecting response Responses were equally distributed when patients were stratified for age, neutrophil counts and drug regimens. 3) Survival Median duration of follow-up was 36 (6~84) months. Actuarial survival at 1 year was 100% in responders and 76% in nonresponders, and the 7-year actuarial survival rate was 94% and 76%, respectively (P value = 0.13). 4) Relapse Relapse occurred in 4 of 30 responding patients. Relapse in patients with CR was not observed during follow-up. The risk of relapse was 12% at 2 years and 22% at 6 years. 5) Treatment outcome according to disease duration There was no significant difference in response rate between patients treated within 4 months and beyond 4 months after diagnosis. But the latter group showed a significantly higher relapse rate than the former (4% vs 60%; P value = 0.01). 6) Side effects and complications There were no serious side effects requiring discontinuation of immunosuppressive therapy. Evolution to secondary clonal hematologic diseases was not observed during follow-up. CONCLUSION: Our results of immunosuppressive therapy show the excellent long-term outcome. A prospective study is needed for the establishment of the adequate treatment duration of CsA and the follow-up period for the evaluation of the response of treatment.