Assessment of anti-TNF-alpha efficacy in rheumatoid arthritis: is 3 months sufficient?

The optimal therapeutic trial duration of anti-TNF-alpha therapy is currently unknown. The British Society for Rheumatology (BSR) guidance states that non-response at 3 months warrants re-evaluation of treatment and recommends not to persist beyond 6 months. The National Institute for Health and Clinical Excellence (NICE) specifies treatment continuation if response is achieved by 6 months, yet the European League against Rheumatism (EULAR) and the American College of Rheumatology (ACR) maintain a 3 month cut-off. No evidence exists to support a 6 month therapeutic trial over 3 months. Thus, we undertook a study to evaluate the proportion of patients who failed to meet NICE response criteria at 3 months but obtained this by 6 months, and to identify predictive factors for this.

Patients who commenced anti-TNF-alpha therapy for RA were studied, counting those who switched to a second or third agent separately for each instigation of therapy (n = 244). Response at 3 and 6 months was defined according to NICE criteria as a >or=1.2 reduction in Disease Activity Score (DAS28).

Of the 189 patients with available 3 month DAS28 responses, 149 fulfilled response criteria. Of the 40 who failed, 27 continued treatment, of whom 21 were available for follow-up at 6 months. Out of the 21 patients, 12 (57%; 95% CI 36, 78) achieved a response at this time. This data set was too small to investigate predictors of response at 6 months.

A substantial proportion of patients who fail NICE response criteria at 3 months and continue on treatment to 6 months achieve a response. These results support a 6 month therapeutic trial over 3 months.