Clinical study of recombinant DNA-produced leukocyte interferon (clone A) in a intermittent schedule in cancer patients.

The effects of recombinant DNA-produced leukocyte interferon (IFLrA) were studied in 37 patients with metastatic cancer who received sequentially escalating doses of 9-86 million units (MU) of IFLrA by im injection twice weekly. The IFLrA was absorbed rapidly and reached a peak serum concentration 6-8 hours after injection. Serum concentration of IFLrA increased proportionately with the dose. The most common side effects included fever, chills, asthenia, anorexia, and weight loss, and leukopenia, granulocytopenia, and lymphopenia occurred frequently. Elevation of serum glutamic-oxaloacetic transaminase was frequent above doses of 50 MU. All side effects were reversible by discontinuation of the drug. Antibodies to IFLrA were detected in 3 patients while on treatment. The presence of antibodies coincided with drastic reduction in serum IFLrA concentration and, in 1 patient, with relapse of disease. Objective tumor responses were documented in patients with lymphomas but not in other groups of patients.