RECOMBINANT HUMAN INTERLEUKIN-3 HASTENS TRILINEAGE HEMATOPOIETIC RECOVERY FOLLOWING HIGH-DOSE (7 G M(2)) CYCLOPHOSPHAMIDE CANCER-THERAPY/

Background: Interleukin-3, a recombinant cytokine with multilineage st imulatory effect on hematopoietic cells, was administered to 22 previo usly untreated breast cancer patients following high-dose therapy with cyclophosphamide (7 g/m2). Patients and methods: The growth factor, a dministered through continuous intravenous infusion at 1 (3 patients), 2.5 (3 patients), 5 (10 patients) and 10 mug/kg/day (6 patients), was well tolerated up to 5 mug/kg/day. Results: Nausea, vomiting, fever a nd headache prevented administration of the intended dose to all 6 pat ients in the 10 mug/kg/day cohort. At the maximal tolerable dose (5 mu g/kg/day) the growth factor significantly accelerated granulocyte, pla telet and reticulocyte recovery as compared to matched historical cont rols who received high-dose cyclophosphamide without cytokine infusion . Moreover, no platelet transfusions and fewer erythrocyte transfusion s were required in interleukin 3-treated patients. In contrast to GM-C SF and G-CSF, interleukin 3 showed no effect on the mobilization of he matopoietic progenitor cells in the peripheral blood. Conclusions: Int erleukin-3 represents a well-tolerated cytokine, clinically useful for accelerating trilineage hematopoietic recovery following severely mye lotoxic treatments such as high-dose cyclophosphamide.