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We read the recent article by van Vollenhoven et al1 on the efficacy of one tumour necrosis factor α antagonist (infliximab or etanercept) when the other has failed with great interest. The authors concluded that infliximab is efficacious in a significant proportion of patients who have not responded to etanercept. No conclusive results were reported when they analysed the opposite situation, probably because 11 of the 13 patients who switched from infliximab to etanercept did so owing to adverse events rather than inefficacy.
We recently studied 12 patients with rheumatoid arthritis (11 women) who were switched from infliximab to etanercept because of inefficacy.2 Infliximab was used for a mean (SD) of 15.6 (8.6) months (range 2–29). Most patients had a satisfactory clinical response to infliximab at the start of treatment with a later reduction in efficacy despite increased doses of infliximab and/or frequency of infusions. They were switched to etanercept and after 6 months of treatment, 10/12 (83%) patients had a good (2 patients) or moderate (8 patients) therapeutic response according to the EULAR criteria, in comparison with the response at the end of infliximab treatment. The Disease Activity Score, DAS28, improved from a mean (SD) of 5.63 (1.1) to 4.30 (0.8) (p = 0.019) and the percentage of patients with DAS28>5.1 was reduced from 75% at the end of infliximab treatment to 8% (p = 0.009). Figure 1 shows the DAS28 scores during treatment. Interestingly, the four patients who never achieved a response to infliximab, showed an impressive response to etanercept; similar results were recently reported by Buch et al.3 There were no serious adverse events with the etanercept treatment.
Few reports are available on this subject.3–6 Based on available data and our results, we suggest that etanercept is effective in a significant proportion of patients with a poor or non-sustained response to infliximab.