Effects of granulocyte/monocyte colony stimulating factor (GM-CSF) have generally been disappointing: it is expensive, poorly tolerated, and without beneficial effect except perhaps in a rare patient who develops severe neutropenia due to interferon, in whom GM-CSF may permit continuation of higher doses of interferon.
GM-CSF is available on a case-by-case, limited "compassionate use" basis from Schering-Plough (201-298- 4000, Professional Services Department). Patients who qualify must have low WBC counts due to underlying disease or drug therapy. Schering-Plough representatives will speak about individual cases with the patient's physician.
An open label trial of GM-CSF plus high-dose interferon (IFN) alpha 2b was performed in 16 patients with chronic hepatitis C, who either failed to clear the virus with 6 months of daily high-dose IFN (5 MU daily) therapy (n = 22) or were considered untreatable because of advanced disease and leukopenia (n = 2). The dose of GM-CSF used was 500 mu g subcutaneously twice weekly. The dose of IFN used was 5 MU daily. Both agents were administered for 4 months. Five of the 16 hepatitis C virus patients responded to combined therapy having previously failed IFN therapy alone.
Data from another study suggests that the combination of GM-CSF and IFN may be more effective at achieving viral clearance than IFN alone. - “A Preliminary Experience with GM-CSF Plus Interferon in Patients with HBV and HCV Resistant to Interferon Therapy,” (Journal of Viral Hepatitis 1997 ;4:101-106).
“Daily s.c. GM-CSF administration is safe and shows effects against HCV; the GM-CSF/IFNalpha2b combination has an additional-but transient-antiviral activity in chronic hepatitis C.” (Cytokine 2000 Feb;12(2):165-170).
Studies are being done in Taiwan on mice inoculated with HCV core and GM-CSF to create an immune response (J Med Virol. 2002 Mar;66(3):320-8).