Treatment of Diamond-Blackfan anemia with recombinant human interleukin-3

This report describes the response of eighteen Diamond-Blackfan anemia (DBA) patients to recombinant human interleukin-3 (rhlL-3). rhlL-3 was administered subcutaneously once daily on an escalating dose schedule (0.5 to 10 Mg/kg/d). The rhlL-3 dose was escalated every 21 days until erythroid response was attained, grade III or IV nonhematologic toxicity was observed, or the maximum rhlL-3 dose was reached. Four patients experienced clinically significant erythroid responses. Two of the responders were steroid-dependent and transfusion-independent, while two were steroid-independent and transfusion-dependent. Baseline clinical or laboratory parameters, in particular in vitro bone marrow erythroid progenitor assays, were not useful in predicting rhlL-3 response. rhlL-3 administered at 5 to 10 μg/kg/d was associated with an increase in total white blood cell count, secondary to increases in neutrophils, eosinophils, and lymphocytes. Patients experienced a dose-dependent elevation in absolute eosinophils across the entire dose range. Two of the responding patients remain on maintenance rhlL-3, without diminution of effect at 244 and 370+ days. rhlL-3 was discontinued in the other two responders, because of the development of deep venous thrombi.