In idiopathic thrombocytopenic purpura (ITP), corticosteroids have been widely recognized as the most appropriate first-line treatment, even if the best therapeutic approach is still a matter of debate. Recently, a single high-dose dexamethasone (HD-DXM) course was administered as first-line therapy in adult patients with ITP. In this paper we show the results of 2 prospective pilot studies (monocentric and multicentric, respectively) concerning the use of repeated pulses of HD-DXM in untreated ITP patients. In the monocenter study, 37 patients with severe ITP, age at least 20 years and no more than 65 years, were enrolled. HD-DXM was given in 4-day pulses every 28 days, for 6 cycles. Response rate was 89.2%; relapse-free survival (RFS) was 90% at 15 months; long-term responses, lasting for a median time of 26 months (range 6-77 months) were 25 of 37 (67.6%). In the multicenter study, 95 patients with severe ITP, age at least 2 years and no more than 70 years, were enrolled. HD-DXM was given in 4-day pulses every 14 days, for 4 cycles; 90 patients completed 4 cycles. Response rate (85.6%) was similar in patients classified by age (<18 years, 36 of 42=85.7%; >or=18 years, 41 of 48=85.4%, P=not significant), with a statistically significant difference between the second and third cycle (75.8% vs 89%, P=.018). RFS at 15 months 81%; long-term responses, lasting for a median time of 8 months (range 4-24 months) were 67 of 90 (74.4%). In both studies, therapy was well tolerated. A schedule of 3 cycles of HD-DXM pulses will be compared with standard prednisone therapy (eg, 1 mg/kg per day) in the next randomized Gruppo Italiano Malattie EMatologiche dell'Adulto (GIMEMA) trial.