Tumour necrosis factor (TNF) inhibitors, particularly in combination with methotrexate, have demonstrated excellent symptomatic and radiographic control in rheumatoid arthritis.1, 2 A rapid clinical response to such therapy, often within 2 weeks, is commonly observed.1, 3, 4 It is widely held that most patients who respond to TNF inhibitor therapy will show an adequate response after 12 weeks of treatment. Here, TNF is linked to rheumatoid arthritis.