Sustained complete remission of chronic refractory immune thrombocytopenic purpura (ITP) of 10 years duration after only two infusions of rituximab.

Abstract

The standard treatment regimen using monoclonal anti CD20 antibodies (rituximab) for lymphoproliferative disorders (LPD) is usually between four and six monthly infusions. Recently, rituximab has been used for the treatment of primary autoimmune disorders with some success and the regimen of therapy has been directly adopted from that previously used in LPD. Here we brie y report on a patient with chronic refractory ITP who achieved sustained CR after only two infusions of standard dose rituximab (375 mg/m). This 35-year-old woman was diagnosed as ITP in February 1990 with a platelet (plt) count of 10 ± 20610/l and was initially treated with prednisone, with a transient response (100610/l). Subsequently danazol was added but without signi®cant improvement (plt 520610/l) and in June 1990 she underwent splenectomy. Again, only a short term response was achieved (2610/l) and thereafter, chronic treatment with prednisone (0.5 ± 1 mg/kg/day), monthly IV gammaglobulin (IVIG) injections and various immunosuppressive drugs were used unsuccessfully including oral cylophosphamide in 1992, which was stopped due to erythema multiforme in 1993. Retreatment was introduced with vinblastine (0.1 mg/kg 18-monthly cycles) from February 1993 with danazol 300 mg qd given with the ®rst six cycles. Initially, plt increased to 34.8610/l but after the ®fth cycle once again decreased to 20610/l. High dose dexamethasone started in May 1994 was stopped after the development of severe cellulitis. In addition, cyclosporin A in 1999, azathioprine and colchicine in 2000 were tried but plt remained four to 20610. From January 2001, she received prednisone 60 mg daily with monthly IVIG, but her plt count still remained 6610/l. Then, on 18/2/2001 she received the ®rst infusion of rituximab (375 mg/m). On 28/3/01 she already had 105610/l plt and a second dose of rituximab was given. On 3/5/01 plt increased to 158610/l. Prednisone was now tapered o€ and she had a plt count of 206610/l. She currently receives only 2.5 mg prednisone while IVIG was stopped since the administration of riruximab (Table 1). This case is consistent with others, reporting the successful use of rituximab in autoimmunity in a proportion of patients with autoimmune hemolytic anemia and thrombocytopenia. ± 8 However, this patient, with a 10 year history of refractory ITP responded with sustained complete remission to only two injections of rituximab as monotherapy. In fact, an impressive rise in plt count was already seen after the ®rst injection. Despite the poor response rate of ITP patients to rituximab at a lower than the standard dose (375 mg/m), still a short course (1 ± 3 injections) of standard dose rituximab may suce to eradicate the relatively small and benign population of autoreactive lymphocytes instead of the four cycles regimen adopted from LPD. Yossi Cohen, Aaron Polliack* Department of Hematology, Hadassah University Hospital, Jerusalem, Israel *Correspondence: E-mail rakefet1@012.net.il Table 1