Purpose: We compared hematologic and clinical effects of granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) after treatment with high-dose cyclophosphamide (HD-CTX, 7 g/m2), given as the first phase of a high-dose sequential chemotherapy program that includes a myeloablative therapy with mobilized progenitor cell autografting.
Patients and methods: Forty-nine consecutive patients with non-Hodgkin's lymphoma, Hodgkin's disease, or poor-prognosis breast cancer received GM-CSF (n = 27) or G-CSF (n = 22) after HD-CTX in two consecutive, nonrandomized studies. Cytokines were administered in continuous intravenous (i.v.) infusion for 14 to 15 days at a median dose of 5.5 and 10 micrograms/kg/d, respectively, starting 24 hours after HD-CTX.
Results: Neutrophil recovery was faster with G-CSF administration (11.5 v 13.2 days; P = .01), whereas platelet counts recovered more rapidly with GM-CSF (13.7 v 16.6 days; P = .01). Prophylactic platelet transfusions were administered more frequently to patients treated with G-CSF than with GM-CSF (66% v 22% of the patients; P = .02). No clinically significant difference was observed between the two groups concerning days of absolute neutropenia or neutropenic fever. Both cytokines reduced the time to eligibility for subsequent chemotherapy administration compared with historical controls not given cytokine (14 to 16 v 20 days). Both cytokines increased circulation of hematopoietic progenitors. Most side effects were World Health Organization (WHO) median grade 1 to 2, were more frequent during GM-CSF than during G-CSF treatment, and were reversible by simple supportive measures and/or by dose reduction or suspension of the cytokine. Permanent suspension of cytokine administration was never required in either group.
Conclusion: GM-CSF or G-CSF administration after HD-CTX reduces hematologic toxicity of high-dose chemotherapy and induces circulation of large amounts of hematopoietic progenitors suitable for autografting in cancer patients.