[Phase I-II study of recombinant interferon gamma]

A phase I-II study of human recombinant interferon gamma (rIFN-gamma) was conducted in patients with various advanced cancer refractory to standard chemotherapies. In the phase I study, seven patients received 14 courses of escalating doses ranging from 2 X 10(6)U/m2 to 64 X 10(6)U/m2 by 1-hour intravenous infusion for 5 consecutive days. The toxicities were high fever with chills, anorexia, occasional nausea and vomiting, elevation of serum GOT, and dose-related leukopenia and neurotoxic symptoms such as heavy fatigue with somnolence or lethargy, both of which were reversible. The pharmacokinetics showed that the peak levels of serum rIFN-gamma activity were dose-related but decreased rapidly to below measurable levels within 6 hours after infusion in patients receiving less than 12 X 10(6)U/m2. Considering these data, the dosage of rIFN-gamma 6 X 10(6) U/m2 by daily intramuscular injection for more than 4 weeks was selected for the early phase II study. There was no partial response out of 11 evaluable patients but a stable condition was observed in 2 cases of renal cell carcinoma and one case each of breast cancer and ovarian cancer. All toxicities seen were similar to those observed in the phase I study, but no tachyphylaxis developed with continued dosage. The antitumor effect of rIFN-gamma remains to be evaluated in a further study employing higher doses.