A COMPARISON OF 2 GM-CSF SCHEDULES TO COUNTERACT THE GRANULO-MONOCYTOPENIA OF CARBOPLATIN ETOPOSIDE CHEMOTHERAPY

In order to obtain the beneficial effects from granulocyte-macrophage colony-stimulating factor (GM-CSF) on granulo-monocyte recovery with t he minimum dose and toxicity, we compared the effect of two different GMCSF schedules (5 mu g/kg/day subcutaneously, days 5 to > 18 versus d ays 12 to > 18 on the cytopenias which follow cytostatic treatment wit h carboplatin (400 mg/m(2) intravenous (i.v.) day 1) and etoposide (10 0 mg/m(2) i.v. days 1 to > 3). 13 patients entered the study for a tot al of 36 evaluable cycles. The cytostatic treatment produced a neutrop enia that persisted for up to day 22 (absolute neutrophil count (ANC) < 1000/mu l in 25% and ANC < 2000 in 50% of control cycles). Early GM- CSF administration markedly increased the leucocyte nadir and produced two waves of leucocytosis: an early one, linked to marrow reserve rel ease and presumably of no value to the patients; and a delayed one, du e to marrow precursor and progenitor cell proliferation, in which the granulo-monocytosis was associated with a marked eosinophilia. The del ayed GM-CSF administration markedly increased the leucocyte nadir and accelerated granulo-monocyte recovery (with an only modest eosinophili a), so that chemotherapy could be repeated every 21 days in all the pa tients.