Current Knowledge of Biologics in Treatment of Noninfectious Uveitis

The arena of uveitis deals with a number of entities, which can be infectious or immune mediated. Noninfectious uveitis (NIU) has been managed with corticosteroids and immunosuppressives. However, their prolonged use has side effects limiting clinical utility in the long run. Improved knowledge regarding pathogenesis of uveitis and associated systemic disease has led to a new epoch in the development of treatment strategies, of which biologics are the recent ones. Biologics revolutionized the management of NIU especially uveitis associated with spondyloarthropathy and refractory uveitis. They target inflammation at a molecular level with less side effects. The most widely used are tumor necrosis factor-alpha inhibitors (infliximab and adalimumab). Other drugs include anti-CD20 inhibitors (rituximab), interleukin-6R-inhibitor (tocilizumab), Interleukin-1R-inhibitor (anakinra), Iinterleukin-2-inhibitor (daclizumab), and the list is further increasing. New advances in biologics are the biosimilar molecules, which are biological products that are highly similar to the reference product, and they include Infimab (biosimilar of infliximab), Exemptia or Adfrar (biosimilar of adalimumab), and Intacept or Etacept (biosimilar of etanercept). Other group of biologics are Janus Associated Kinase inhibitors (JAK-inhibitors), which are long-term oral treatment options of rheumatoid arthritis. They inhibit JAKs, which cause activation of signal transducer and activator of transcription (STAT) proteins, and initiate transcription of inflammatory genes. Many inflammatory cytokines that are implicated in pathogenesis of ocular inflammation are known to utilize the JAK/STAT-signaling pathway, including interleukin-2 (IL-2) and IL-6. Thus, biologics are the future of uveitis treatment with promising results. This article aims to summarize the current knowledge on biologics and their clinical utility in the management of NIU.