Phase I/II study of recombinant human granulocyte colony-stimulating factor in patients receiving intensive...

Twelve patients with advanced small cell carcinoma of the bronchus were treated by continuous infusion of recombinant human granulocyte colony-stimulating factor (rh G-CSF) at the following dose levels: 1 microgram, 5 micrograms, 10 micrograms, 20 micrograms and 40 micrograms/kg/day 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 in one patient at 10 micrograms/kg/day. The neutrophils were shown to be functionally normal in tests of their mobility and bactericidal activity. During the Phase II part of the patients were treated using a combination of i.v. Adriamycin, Ifosfamide and Etoposide. The chemotherapy was repeated every 3 weeks. rh G-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. Ten severe infective episodes were observed during the 20 cycles of chemotherapy which did not include rh G-CSF, while only one infective episode occurred in 20 courses when treated with rh G-CSF. These results demonstrate the utility of rh G-CSF in restoring functional neutrophils to patients undergoing intensive chemotherapy.