Biologic therapy may be broadly defined as treatment using an agonist or an antagonist to specifically enhance or suppress the level of a naturally occurring protein molecule to manipulate a disease state. Agonists used in biologic therapy include a variety of cytokines and growth factors. Antagonists include monoclonal antibodies and other agents capable of binding soluble and/or cell membrane–bound proteins.
The era of biologic therapy in medicine really began more than 2 decades ago. Using recombinant DNA technology to produce human proteins, the cytokine interferon alfa was made commercially available in the United States in 1981. Interferon alfa is now approved for use in diseases such as chronic hepatitis C and hairy cell leukemia and is also used off label in a myriad of conditions. In ophthalmology, interferon alfa has been shown to be effective in patients with ocular Behçet disease1- 6 and has been included as a second-line agent for the treatment of this disease in European League Against Rheumatism 2008 guidelines.7
Okada AA. The Dream of Biologics in Uveitis. Arch Ophthalmol. 2010;128(5):632-635. doi:10.1001/archophthalmol.2010.47