Recombinant human interleukin-3 in patients with hematopoietic failure

Nine patients with bone marrow failure and prolonged severe cytopenias were treated with recombinant human interleukin-3 (rhIL-3) at doses ranging from 30 micrograms/m2 to 500 micrograms/m2. rhIL-3 was administered in a subcutaneous bolus injection daily for 15 days. Platelet counts increased by a mean of 6-fold (range: 1.3- to 14.3-fold) in five out of eight evaluable patients. Reticulocyte counts increased 2.9-fold in three patients, and neutrophil counts increased by a mean of 3.1-fold in all eight patients. Platelet transfusions could be discontinued after treatment with rhIL-3 in two out of three evaluable transfusion-dependent patients. Only mild side effects, mainly fever and headache, were observed. These results indicate that rhIL-3 functions as a multilineage hematopoietic growth factor in vivo in patients with secondary bone marrow failure.