Granulocyte-macrophage colony stimulating factor and immunosuppression in the treatment of pediatric acquired severe aplastic anemia

Background. Immunosuppressive therapy (IS) is effective in the treatment of patients with acquired severe aplastic anemia (SAA). An enhanced myeloid response and decreased infection risk may be possible with the addition of a hematopoietic cytokine. Published data on the combination of cytokines and IS in patients with SAA are limited. The addition of C-CSF to IS shortens the time to neutrophil count recovery, but may not improve overall survival. Because CM-CSF acts differently than C-CSF, its use in combination with IS may be different. Procedure. A retrospective chart review was performed on patients diagnosed with SAA and treated with IS and CM-CSF at St. Jude Children's Research Hospital. Hematologic recovery, prognostic factors, and infection data were collected. Results. Eighteen patients were included in this study. The median age at diagnosis was 7.2 years (range 1.8-17.0). Ten patients (56%) had a complete response, four (22%) a partial response, and four (22%) no response. Median time to erythrocyte and platelet transfusion independence were 90 (18,243) and 64 days (18-243), and to discontinuation of treatment 287 days (90-730). Median time to partial (ANC > 500) and full (ANC > 1,500) neutrophil recovery were 41 and 51 days, respectively. Seventeen documented discrete infections occurred in six patients over 36 patient years. Conclusions. CM-CSF, in addition to IS, may shorten time to neutrophil count recovery, may be beneficial in decreasing infection rates, and may improve platelet response in patients with SAA. However, consistent with studies utilizing C-CSF, CM-CSF probably does not affect overall response rate. To fully answer whether or not cytokine therapy is of added value to IS in pediatric patients, a multi-institutional randomized trial is needed.