Phase I pharmacotoxicology study of human fibroblast interferon in human cancers.

Twelve patients with advanced cancer were treated with human fibroblast interferon. Interferon administered im in doses up to 10 x 10(6) U three times weekly for 2 weeks was associated with highly variable, but detectable, plasma levels. Bolus interferon given iv was associated with a reproducible, immediate peak of activity followed by a rapid loss of detectable activity. Continuous infusion of interferon over 2 hours resulted in a slowly increasing dose-related level to a maximum near the end of the infusion followed by a loss of detectable activity for about 1 hour following infusion. Interferon administered both im and iv caused a mild, easily tolerated pyrexia as the only regularly occurring side effect. In 1 patient interferon treatment suppressed a malignant clone of circulating blasts trisomic for chromosomes No. 8 and 21 from 59 to 0%.