Clinical applications of colony-stimulating factors: a historical perspective

The development of the therapeutic roles of filgrastim and sargramostim over the past decade is reviewed. Filgrastim, a recombinant granulocyte colony-stimulating factor (G-CSF), and sargramostim, a recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF), have been available in the United States for over a decade to treat various types of neutropenia. In addition, data are available to support their use in a variety of clinical settings. Because of the high cost of these agents, clinical guidelines for their appropriate use have been developed. With respect to the comparability of filgrastim and sargramostim, the American Society of Clinical Oncology recommends that additional data be generated since current data are insufficient to adequately address this question in each clinical setting. A limited number of randomized, comparative trials have directly compared filgrastim with sargramostim. Outcomes data from these trials are reviewed. Further, there is evidence to suggest that, at least for GM-CSF, tolerability is dependent on the degree of protein glycosylation. A nonglycosylated protein, molgramostim, available in Europe appears to be associated with greater toxicity in clinical trials, although randomized comparative trials are lacking. The therapeutic equivalence of CSFs requires further study. While data show that the efficacy and tolerability of CSFs are similar in certain settings, there has been no definitive, randomized, large-scale clinical trial conducted to address this issue. Pharmacists should continue to evaluate clinical data to determine not only which CSF to use but also when a CSF should be used.