ABSTRACT: To estimate the incremental cost-effectiveness of infliximab versus conventional combination treatment over 21?months in patients with methotrexate-refractory early rheumatoid arthritis.In this multicentre, two-arm, parallel, randomised, active-controlled, open-label trial, rheumatoid arthritis patients with <1?year symptom duration were recruited from 15 rheumatology clinics in Sweden between October 2002 and December 2005. After 3-4?months of methotrexate monotherapy, patients not achieving low disease activity were randomised to addition of infliximab or sulfasalazine+hydroxychloroquine (conventional treatment group). Costs of drugs, healthcare use, and productivity losses were retrieved from nationwide registers, while EuroQol 5-Dimensions utility was collected quarterly.Of 487 patients initially enrolled, 128 and 130 were randomised to infliximab and conventional treatment, respectively. The infliximab group accumulated higher drug and healthcare costs (€27,487 vs €10,364; adjusted mean difference €16,956 (95% CI 14,647 to 19,162)), while productivity losses did not differ (€33,804 vs €29,220; €3961 (95% CI -3986 to 11,850)), resulting in higher societal cost compared to the conventional group (€61,291 vs €39,584; €20,916 (95% CI 12,800 to 28,660)). Mean accumulated quality-adjusted life-years (QALYs) did not differ (1.10 vs 1.12; adjusted mean difference favouring infliximab treatment 0.01 (95% CI -0.07 to 0.08)). The incremental cost-effectiveness ratios for the infliximab versus conventional treatment strategy were €2,404,197/QALY from the societal perspective and €1,948,919/QALY from the healthcare perspective.In early, methotrexate-refractory rheumatoid arthritis, a treatment strategy commencing with addition of infliximab, as compared to sulfasalazine+hydroxychloroquine, was not cost-effective over 21?months at willingness to pay levels generally considered acceptable.NCT00764725.