Abstract:
BACKGROUND: Treatment of refractory severe chronic idiopathic thrombocytopenic purpura (ITP) is a difficult challenge especially in young patients who become steroid-dependant and when splenectomy is unfavourable or refused by some patients. Current strategy in ITP is to withdraw steroids and try any of the drugs that have been found effective in clinical trials. Dapsone, an inexpensive drug, was reported to be effective in the disease.
RESULTS: Thirty consecutively patients (3 males&27 females) with resistant ITP with a mean age ± SE of 22.7 ± 4.2 years used 50 -100 mg of dapsone per day for 20 weeks with a mean of 12.2 ± 1.2 weeks. The mean platelet count (PC) increased significantly in all group from 26.8 ± 5.3 x 109/l. at start of the study to 60.9 ± 10.6 x 109/l after 4 weeks (P < 0.01) and to 92.2 ± 15.9 x 109/l in the last visit (P< 0.01). Patients with severe and moderate to severe thrombocytopenia had significant increase in PC after 2 and 4 weeks of dapsone therapy and in last visit PC ( P < 0.001, P < 0.01 and P < 0.01 respectively for severe & P < 0.05, P < 0.05 and P < 0.05 respectively for moderate to severe cases). Out of thirty patients 9(30 %) had a good response, 9 (30 %) a moderate response, and 12 (40%) a poor or no response. Good responders group had significantly lower age compared to bad responders group. Significant positive correlations were observed between platelet response to dapsone after 2 weeks and final platelet response in all patients (R = 0.461, P < 0.05), in patients with poor response to treatment (R = 0.821, P <0.05) and patients with moderate to severe thrombocytopenia (R= 0.71, P <0.01). Significant inverse correlations were observed between duration of ITP and PC after 4 weeks treatment in all patients and in groups with moderate and moderate to severe thrombocytopenia.
CONCLUSION: Dapsone is an effective and safe second line treatment in chronic ITP. Predictors of response are young age, PC more than 15 x 109 /L, short duration of disease and initial good response in the first 2 weeks.