Adjuvant therapy with recombinant interleukin-3 and granulocyte-macrophage colony-stimulating factor

Granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3) are important members of the system of hematopoietic growth factors which control blood formation. Recombinant human (rh) GM-CSF stimulates proliferation and differentiation of myeloid cells and enhances effectively the regeneration of granulocytes and monocytes after chemotherapy or bone marrow transplantation. RhIL-3 acts on multipotent progenitor cells and induces an increase of leukocytes, platelets and reticulocytes after in vivo application. Combination of rhIL-3 and rhGM-CSF exerts a highly synergistic action on several hematopoietic cell lineages in monkeys and patients. Sequential application of rhIL-3 (5 days) followed by rhGM-CSF (10 days) has equivalent effects on myelopoiesis and thrombopoiesis compared with the effects of 15 days' monotherapy with rhGM-CSF on myelopoiesis and of a 15 days' treatment with IL-3 on platelet production. This combination seems to be very potent to reduce risk of neutropenia-associated infection and thrombocytopenic bleeding in patients with hematopoietic failure.