[Show abstract][Hide abstract] ABSTRACT: We previously showed in a prospective study that rituximab appears to be effective in some children and adolescents with severe chronic immune thrombocytopenia. Eleven of 36 patients achieved and maintained platelet counts over 50,000/mm(3) within the first 12 weeks. These patients were followed for the next year.
Platelet counts were monitored monthly and all subsequent bleeding manifestations and need for further treatment was noted.
Eight of the 11 initial responders maintained a platelet count over 150,000/mm(3) without further treatment intervention. Three patients had a late relapse. One initial non-responder achieved a remission after 16 weeks, and two additional patients maintained platelet counts around 50,000/mm(3) without the need for further intervention.
Rituximab resulted in sustained efficacy with platelet counts of 50,000/mm(3) or higher in 11 of 36 patients (31%).
[Show abstract][Hide abstract] ABSTRACT: We assessed safety and efficacy of rituximab in a prospective study of 36 patients, age 2.6 to 18.3 years, with severe chronic immune thrombocytopenic purpura (ITP). The primary outcome of sustained platelets above 50 x 10(9)/L (50,000/mm3) during 4 consecutive weeks, starting in weeks 9 to 12, was achieved by 11 of 36 patients (31%, confidence interval [CI], 16% to 48%). Median response time was 1 week (range, 1 to 7 weeks). Attainment of the primary outcome was not associated with age, prior pharmacologic responses, prior splenectomy, ITP duration, screening platelet count, refractoriness, or IgM reduction. First-dose, infusion-related toxicity was common (47%) despite premedication. Significant drug-related toxicities included third-dose hypotension (n = 1) and serum sickness (n = 2). Peripheral B cells were depleted in all subjects. IgM decreased 3.4% per week, but IgG did not significantly decrease. Rituximab was well tolerated, with manageable infusion-related side effects, but 6% of subjects developed serum sickness. Rituximab is beneficial for some pediatric patients with severe, chronic ITP.