Fatigue occurred in one patient entered at 300 ng/kg and in one patient dose-escalated to 300 ng/kg necessitating dose decrease in both cases.

Elevated liver enzymes occurred in the context of alcohol ingestion at a dose of 300 ng/kg and rapidly returned to baseline values with the holding of a single dose of rhIL-12.

Depression occurred at a dose of 100 ng/kg necessitating discontinuation of rhIL-12. This patient had experienced severe depression during the previous administration of recombinant IFN-α.