G-CSF Preferable in Some Cases

Physicians have reported a reaction to bone marrow stimulators that led them toconclude that G-CSF is a better choice than GM-CSF in some cases for treatingcomplications of chemotherapy.

Doctors at Medical College of Pennsylvania in Philadelphia were treating a woman whohad undergone extensive chemotherapy for lymphoma. The patient developed fever and loss ofwhite blood cells. Treatment with GM-CSF appeared to cause destruction of her red bloodcells. After therapy to save the red cells was started, she was switched to G-CSF, andchemotherapy could proceed.

GM-CSF stimulates macrophages as well as granulocytes, and the macrophages wereprobably ingesting the red cells. G-CSF only stimulates the production of granulocytes. Ina letter in last week’s New England Journal of Medicine, the doctors concludedthat “when choosing which growth factors to use to support aggressive chemotherapy,one should consider the important differences between the two available growthfactors.“ In their patient, macrophage stimulation was undesirable because she hadbeen diagnosed with hemolytic anemia linked to macrophage activity.

Immunex of Seattle (NASDAQ:IMNX) is approved to sell GM-CSF for use in cancer patientswho have had autologous bone marrow transplants. Amgen Inc. (NASDAQ:AMGN) of ThousandOaks, Calif., sells G-CSF for use against low white blood cell counts associated withcancer therapy.

--Roberta Friedman, Ph.D.