Response to mercaptopurine for refractory autoimmune cytopenias in children

Abstract

Background. Several treatment strategies are available for children with severe immune thrombocytopenic purpura (ITP) and other immune cytopenias refractory to initial therapies. 6-Mercaptopurine (6MP) is one option, however it has not been well studied in children, especially as a single agent, and no pediatric case series have been reported since 1970. Patients and Methods. We reviewed the experience at our institution over 8 years, using 6MP as a steroid sparing treatment for children with ITP, auto-immune hemolytic anemia (AIHA) or Evans syndrome. A total of 29 pediatric patients were treated with 6MP from 2000 to 2007. Results. Response was defined as a rise in hemoglobin by at least 1.5g/dl and to a level of 10 g/dl or greater in patients treated for anemia, or a platelet count ≥50 × 109/L in patients treated for thrombocytopenia. We found an overall response rate of 83% among all patients. Fourteen percent of patients stopped drug because of side effects. Conclusions. These results suggest that 6MP can be an effective single-agent treatment for refractory immune cytopenias in children. Prospective studies are warranted to determine long-term efficacy and toxicity and to more clearly define patient populations most likely to respond. © 2008 Wiley-Liss, Inc.