Infliximab in the treatment of ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic, progressive disease characterized by inflammation in the spine and sacroiliac joints which causes pain, stiffness and the potential for spinal ankylosis. It is associated with significant functional impairment. It is common and since onset is often in young people, the burden of disease is considerable. Conventional treatment including non-steroidal antiinflammatory drugs (NSAIDs) and physiotherapy have proven but limited efficacy in controlling symptoms and preventing progression of spinal manifestations. Infliximab, a chimeric monoclonal antibody which binds to and inhibits tumor necrosis factor alpha (TNFalpha), is highly effective in controlling disease activity in AS. In AS, infliximab 5 mg/kg body weight is usually given as an infusion at weeks 0, 2 and 6, and then every 6-8 weeks. When infliximab is used in combination with NSAIDs a rapid improvement in disease activity by at least 50% is seen in as many as 50% of AS patients. Infliximab has been shown to have ongoing efficacy for as long as regular infusions continue and is safe in the medium term. Magnetic resonance studies show major reductions in spinal inflammation during treatment with infliximab, however ongoing studies will assess if infliximab has disease modifying effect in AS.