The role of myeloid growth factors in acute leukemia

Myeloid growth factors granulocyte-colony stimulating and granulocyte macrophage colony-stimulating factors have been extensively studied in acute leukemias. Whether administered before, during, or after chemotherapy for acute myeloid leukemia and acute lymphoblastic leukemia, these agents reduce the duration of neutropenia and seem to be safe and well tolerated. Despite consistently showing a shorter duration of neutropenia, multiple, prospective, randomized trials have documented only modest benefits in terms of reduction in the incidence and severity of infections, without substantial gains or impact in complete remission, overall survival, and disease-free survival rates. Growth factors have also been used to recruit quiescent leukemia cells into the S-phase of the cell cycle to increase their susceptibility to chemotherapy with the goal to reduce relapse and resistance. Randomized trials evaluating this priming strategy have consistently shown improvement in disease- or event-free survival in the intermediate-risk group of patients with acute myeloid leukemia, but no overall survival benefit. This article focuses on the clinical experience with these agents as adjuncts to the treatment of acute leukemias.