Phase I/II study of recombinant human granulocyte colony-stimulating factor in patients receiving intensive chemotherapy for small cell lung cancer.

Twelve patients with advanced small cell carcinoma of the bronchus were treated by continuous infusion of recombinant human granulocyte colony-stimulating factor (rhG-CSF) at the following dose levels: 1 microgram, 5 micrograms, 10 micrograms, 20 micrograms and 40 micrograms kg-1 day-1 for 5 days. No toxicities resulted from the treatment and in all 12 patients the number of peripheral neutrophils increased rapidly to a maximum of 100 x 10(9) l-1 at 10 micrograms kg-1 day-1. The neutrophils were shown to be functionally normal in tests of their mobility and bactericidal activity. During the phase II part of the study the patients were treated by a combination of intravenous adriamycin 50 mg m-2, ifosfamide 5 g m-2 by i.v. infusion with mesna 8 g m-2 on day 1, and etoposide 120 mg m-2 on days 1, 2 and 3 also intravenously. The chemotherapy regime was repeated every 3 weeks. RhG-CSF was given to each patient for 14 days on alternate cycles of chemotherapy and reduced the period of absolute neutropenia considerably (median of 80%), with a return to normal, or above normal, neutrophil counts within 2 weeks after day 1 of chemotherapy. Six severe infective episodes were observed during the cycles of chemotherapy which did not include rhG-CSF, while no infective episodes occurred when patients were treated with rhG-CSF. These results demonstrate the utility of rhG-CSF in restoring functional neutrophils to patients undergoing intensive chemotherapy.