Pediatric Rheumatology Online Journal → July 2003 → Anti-Phospholipid Antibody Syndrome→ Abstract #115
                                                                August 2003 → Newer Treatments → Anti-CD20 Monoclonal Antibody (Rituximab) → Abstract #115

SUCCESSFUL TREATMENT OF ANTIPHOSPHOLIPID ANTIBODY ASSOCIATED IDIOPATHIC THROMBOCYTOPENIC PURPURA WITH RITUXIMAB

D. A. Wright,¹ M. Henrickson.¹

Rheumatology & Immunology, Children's Hospital Central California, Madera, CA, United States

Background: Chronic idiopathic thrombocytopenic purpura (ITP) can occur as a primary disorder or be associated with antiphospholipid antibody (APA) syndrome, either as a primary disorder or secondary to systemic lupus erythematosus (SLE). Treatment of children with refractory ITP often results in significant morbidity and current therapies induce remission in fewer than half of children with chronic ITP. Rituximab is a humanized mouse monoclonal antibody against the B cell antigen CD20 that results in the prolonged depletion of B cells. CD20 is relatively selectively expressed on pre-B and mature B cells, but not plasma cells or T cells, and may selectively treat antibody-mediated disorders with less immune suppression than other treatment regimens.
Objective: To examine the effectiveness of Rituximab in the treatment of children with chronic ITP associated with either primary or secondary APA syndrome who have previously failed multiple standard treatments.
Methods: Three patients with chronic ITP (mean duration 20 months) associated with APA syndrome (primary x2, secondary with SLE x1; 2M, 1F; age range 10-16 years; mean 14) were treated with 4 to 6 weekly infusions of Rituximab (375 mg/M).
Results: All patients achieved remission with normalization of their platelet counts with follow-up of 1-9 months (mean = 6). Resolution of their ITP occurred rapidly despite the continued presence of antiphospholipid antibodies. There were no significant adverse events. All patients were able to reduce their immune suppressive medication. Additional clinical and serologic data in all three patients and a fourth child with primary APA syndrome who started treatment at the time of abstract submission is being collected and will be reported.
Conclusions: These preliminary findings suggest that Rituximab may represent a safe and effective treatment for children with chronic ITP associated with either primary or secondary APA syndrome and warrant additional investigation.