MYELOPROCTECTIVE EFFECT OF GM-CSF ADMINISTERED PRIORTO CHEMOTHERAPY (CT)

In an effort to overcome myelosuppression and reduce treatment delays, a short course of GM-CSF prior to CT was studied in patients (PTS) receiving conventional regimens. Nine patients with various tumors were given GM-CSF 400 microg s.c. on the 17, 18 and 19th day of each 21 day cycle. Patients were followed through at last 4 cycles of CT with weekly blood and neutrophil counts. Treatment delays and dose reductions were carefully recorded. There was no epidose of severe neutropenia or infection. The neutrophil and platelet counts on days 1 and 14 remained fairly constant with no evidence of cumulative myelotoxicity. No dose reduction, and only two one-week treatment delays were necessary. GM-CSF given just prior to CT may enable CT to be administered on time. Increased myeloid mass and quiescent progenitors at the initiation of CT may be responsible for the myeloprotection. This pilot study has provided evidence that short-term GM-CSF just prior to CT may result in myeloprotection, reduced rate of infection and better dose-intensity in conventional CT regimens.