Pepgen had been a privately held biopharmaceutical company holding an exclusive license form the University of Florida, to developi novel products for the prevention and treatment of autoimmune and viral disorders. Interferons are naturally occurring proteins produced by human and other animals that inhibit viral replication, inhibit cell proliferation and regulate inflammatory responses. In pre-clinical studies, Tau showed the potential to overcome the then two major drawbacks of interferons. First, a patient can take Interferon Tau orally -- a key benefit for a medication that must be taken throughout a patient's life, as is the case with a chronic disease such as multiple sclerosis. Patients can only take all other interferons currently available by injection, either intermuscularly or subcutaneously (injected just below the skin). Secondly, Interferon Tau appears to have remarkably few side effects. In October 1995, Calypte Biomedical Corporation purchased a major equity interest in Pepgen. In April 2001, Calypte sold its minority position (by then only 29%).