Single-dose granulocyte colony-stimulating factor concomitant with multifractionated dose chemotherapy: a strategy for maintaining dose intensity.

Multifractionated dosing (MFD) schedules for chemotherapy administration such as weekly or twice weekly administration are intended to maximize dose intensity while minimizing toxicity, but the cumulative drug effect may result in neutropenia necessitating interruption of dose fractions and thereby compromising dose intensity. Intermittent granulocyte colony-stimulating factor (G-CSF, Neupogen, Amgen) was administered to patients receiving MFD on three paclitaxel-based chemotherapy regimens. Single-dose G-CSF was administered concomitant with the chemotherapy dose fraction when the white blood count was between 2000 and 3500 cells/microliter. A retrospective analysis of the concomitant administration of single-dose G-CSF with chemotherapy in these trials demonstrated that in most patients, G-CSF administration guided by the level or grade of leukopenia permitted maintenance of the chemotherapy dose intensity and completion of the treatment cycle. The common pattern in a six-dose, twice weekly, multifractionated cycle was for G-CSF to be administered with every other chemotherapy dose beginning with the third, fourth, or fifth dose, but some courses required G-CSF administration with each chemotherapy dose fraction. Guidelines for the concomitant use of G-CSF and paclitaxel-based MFD chemotherapy can be used to maintain chemotherapy dose intensity. A prospective study of guidelines for cytokine usage developed on the basis of this retrospective study will be necessary to determine the optimal cytokine dose and schedule for use simultaneously with chemotherapy.