Analysis of Management of ITP: Single Centre Retrospective Comparison of Dapsone and Azathioprine as second line therapeutic agents

INTRODUCTION: Idiopathic thrombocytopenic purpura (ITP), also known as autoimmune thrombocytopenic purpura, is an entity characterized by isolated thrombocytopenia often occurring in the absence of identifiable and specific precipitants. It is an acquired disease that affects both children and adults and causes a transient or persistent decrease in platelet count. Depending upon the degree of thrombocytopenia it is associated with an increased risk of bleeding. AIMS AND OBJECTIVES OF THE STUDY: To assess efficacy of dapsone and azathioprine children and adults with steroid refractory or steroid dependent ITP and relapsed ITP treated in our institute. METHODOLOGY: We included patients treated with either dapsone or azathioprine for steroid refractory/dependent or relapsed ITP during 5 year period (March 1st 2007 to March 1st 2012). RESULTS: Three hundred patients were included in the study; 104 (34.7%) children & 196 (65.3%) adults. Median ITP duration was 5 months (1-262). Overall response over median treatment duration of 10 months (1-61) was 58.6%, with equivalent response (58.8% and 58.5%) with dapsone and azathioprine respectively. In children with steroid refractory/dependent ITP, dapsone exhibited significantly better response than azathioprine (p=0.023). Median response duration was significantly longer with azathioprine-60 months (2-60) than with dapsone (p=0.015). Relapses on therapy was higher with dapsone than azathioprine (p=0.007). Response less than CR & steroid refractory/dependent ITP were significant predictors of relapse on therapy. Event free survival was significantly better in patients responding to azathioprine compared to dapsone. There were no deaths in present cohort of patients with ITP. CONCLUSION: Present study confirms comparable efficacy of dapsone and azathioprine, although azathioprine produced more durable responses than dapsone. The findings of our study need to be validated in prospective randomized control setting.