Rituximab Treatment In Pediatric Patients with Immunohematologic Diseases Refractory to Convertional Therapy

Abstract

AbstractAbstract 2764 Objective:To evaluate the effectiveness and safety of rituximab in the treatment of antibody mediated hematologic disorders refractory to conventional therapy. Study Design:Retrospective chart review of 16 patients treated at Rainbow Babies and Children's Hospital with rituximab for antibody mediated hematologic disorders. Treatment effects and adverse reactions potentially attributed to rituximab therapy were recorded. Results:Patients (age range 4 months- 17 years) with the following disorders were included: autoimmune hemolytic anemia (4); chronic immune thrombocytopenia (5); autoimmune pancytopenia (4); hemophilia with inhibitor (2); acquired Factor VIII inhibitor (1). All patients received rituximab at 375mg/m2/dose, after failure to obtain a durable response to conventional therapies. The majority of patients were treated with 4 weekly dose “cycles”. One patient only received 2 doses, and two patients were maintained on prolonged weekly therapy. Two patients showed no clinical or laboratory improvement with rituximab therapy. Two patients initially responded to rituximab therapy, but relapsed 2 months after therapy. Of the remaining patients, 7 had no recurrence of disease by the end of the study period, median follow-up 14months (4mo-72mo). The remaining patients relapsed requiring repeat cycles of rituximab. Median time to relapse was 15 months (13-18mo). The most common adverse reactions were serum sickness (n=3) and hypogammaglobulinemia (n=2). Of the patients who developed hypogammaglobulinemia, one improved after a single infusion of IVIG, the other patient required chronic IVIG infusions. One patient developed chronic sinusitis and one developed acute demylinating encephalomyelitis after receiving rituximab. It is unclear if these illnesses were due to the rituximab or secondary to underlying immune dysfunction. Conclusions:Rituximab appears to be effective in a variety of antibody mediated hematologic disorders refractory to more conventional therapies in children and adolescents. The observed adverse reactions were generally mild and self-limited. Disclosures:Off Label Use: Rituximab. B cell immununosuppresion.