Viragen's natural alpha interferon had previously been approved in Sweden and certain other countries for the treatment of patients with hairy cell leukemia (HCL) and chronic myelogenous leukemia (CML) who did not respond to recombinant interferon regimens. Global interferon sales are estimated to exceed $2 billion per year.

Viragen's newly appointed chief medical officer, Professor Orjan Strannegard, MD, stated, "Recombinant interferon products are the dominant treatment for a broad range of chronic viral and malignant diseases. However, a significant percentage of patients cannot tolerate the adverse side-effects typically associated with recombinant regimens or fail the therapy, probably due to the formation of neutralizing antibodies. For those patients that do fail, there are few safe and effective alternatives. Our expanded Swedish approval provides further evidence that it may be advantageous for a patient to be treated with Viragen's naturally-derived interferon. This drug has been demonstrated to have excellent effects in various viral diseases and cancers. It is well tolerated by the treated patients and it is able to elicit a renewed response in patients that have been resistant to recombinant interferons."

Natural interferon, produced by white blood cells, is part of the human immune system. It is one of the body's natural defensive responses to foreign substances such as viruses, and is so named because it "interferes" with viral growth. Recombinant interferons, which currently dominate the interferon market, are genetically engineered and are sometimes recognized as "foreign" by the body's immune system. Recombinant interferons usually contain only one subtype of interferon as compared to multiple subtypes produced by human white blood cells.