Use of Dapsone in Chronic/refractory Immune Thrombocytopenic Patients: A Single Center Experience

Background: Dapsone is a second-line therapy for immune thrombocytopenia (ITP). It is cost-effective, with a response rate comparable to other drugs used as second-line therapy, such as azathioprine, danazol, cyclophosphamide, cyclosporine, vincristine, rituximab, and eltrombopag. Material and Methods: This retrospective study analyzed ten adult patients who presented to our hematology division outpatient clinic between March 2013 and July 2021, was diagnosed with chronic/refractory ITP, did not respond to first-line therapy, and used dapsone. Results: Eight (80%) patients were female, and 2 (20%) were male. The median age was 50 (range, 24-64) years. The mean pre-treatment platelet value was 12.8x109/L (range: 4-22.1x109/L). The median duration of symptoms before dapsone treatment was 60 (6-360) months. The median number of treatments received before dapsone was 4 (range: 3-6). All patients were routinely treated with oral dapsone 50 mg for two weeks, followed by 100 mg. The median time to treatment response was 39 (range: 14-90) days. The response rate was 60% (complete response 40%, partial response 20%). Asymptomatic anemia was observed as a side effect in only one patient. Conclusions: Based on these results, it can be speculated that dapsone is an effective, inexpensive, and well tolerated treatment option. Considering the economic status of developing countries, it seems very attractive to use dapsone as the second-line therapy for chronic/refractory ITP. To the best of our knowledge, this is the first study in Turkey on the use of dapsone for chronic/refractory ITP.