A phase I study of human lymphoblastoid interferon administered by continuous intravenous infusion.

A phase I study of human lymphoblastoid interferon (IFN-alpha) was undertaken in patients with acute leukaemia and other malignancies. The pharmacokinetics of intravenous IFN-alpha were also investigated. IFN-alpha was administered to two patients by intravenous (IV) bolus injection at a dose of 5 X 10(6) U/m2; and to a further 37 patients (40 cycles) by continuous intravenous infusion (IVI) for 5, 7, or 10 days at doses ranging from 5 to 200 X 10(6) U/m2/day. Pyrexia, general malaise, anorexia, and rigors were observed at all dose levels; three patients became hypotensive. Myelosuppression occurred in all patients, including seven without bone marrow infiltration. Transient rises in alkaline phosphatase and transaminases (SGOT) were observed in patients receiving daily doses greater than 30 X 10(6) U/m2. Dose-limiting central nervous system toxicity, hyperkalaemia, and hypocalcaemia were encountered at 200 X 10(6) U/m2. In six patients with acute leukaemia there was a fall in the number of circulating leukaemic blasts and in one patient with acute myelogenous leukaemia (AML) the degree of bone marrow infiltration decreased from 99% to less than 5% with cellularity returning to normal. Serum levels of IFN above 1,000 U/ml were achieved with daily doses above 30 X 10(6) U/m2 given by IVI. The maximum safely tolerated daily dose, 100 X 10(6) U/m2 administered for 7 days, is appreciably higher than that used in most previous studies, although even at this level considerable toxicity may be encountered.