The new alpha interferons.

Alpha interferons are biological response modifiers that regulate immune function, slow cell proliferation, and inhibit virus replication. Large supplies of purified preparations are now available for clinical trials. Common toxicity includes an influenza-like syndrome to which tolerance occurs after several doses, and chronic fatigue and anorexia that may be dose-limiting. Myelosuppression is mild. Alpha interferons have established clinical activity against several human cancers, including melanoma, Kaposi's sarcoma, multiple myeloma, non-Hodgkin's lymphoma, hairy cell leukemia, and renal cell carcinoma. These data and alpha interferon nomenclature are summarized in table form. Intranasal alpha interferon is effective in prophylaxis of common viral upper respiratory tract infections, although toxicity in long-term use is prohibitive. Short-term administration to high risk populations may be most useful. Optimal doses and schedules need to be determined for all indications.