Treatment of ankylosing spondylitis: focus on etanercept

Ankylosing spondylitis is a chronic inflammatory condition which preferentially affects the axial skeleton, often beginning in the sacroiliac joints. The etiology of the pathologic lesions of this condition including enthesitis, erosive articular changes, osteitis, and fibrous ankylosis, as well as changes which occur in the eye, gastrointestinal tract, cardiovascular system, and lungs is unknown; however, there is a strong association with HLA-B27, which indicates altered immunity. One of the major mediators of the immune response is TNF-alpha, which functions as a pleiotrophic soluble messenger primarily from macrophages. TNF-alpha is principally involved with activation of both normal and transformed cells, including endothelium, synoviocytes, osteoclasts, chondrocytes, and fibroblasts. The cornerstone of medical management of ankylosing spondylitis includes intensive physical therapy and nonsteroidal anti-inflammatories for symptomatic relief. However, it is becoming increasingly recognized that TNF-alpha blockade has an important role in the reduction of spine and joint inflammation. This review discusses the data that supports use of etanercept in the treatment of ankylosing spondylitis.