A DOSE INCREASE OF TNF BLOCKING AGENTS WAS LIMITED EFFECTIVE AND CAUSED A CONSIDERABLE INCREASE OF COSTS IN DAILY CLINICAL PRACTICE

Background: anti-TNF dose increases are applied in daily clinical practice but evidence on the effectiveness and costs of dose increases is lacking. Objectives: To describe the effectiveness and costs of dose increase in adalimumab, etanercept and infliximab in the treatment of rheumatoid arthritis (RA) in daily clinical practice. Methods: RA patients with an anti-TNF dose increase prior to January 2008 were selected from registry data. The primary outcome was the change in DAS28 at 3 months from dose increase, tested for statistical significance using a one sample t-test. The observed costs of the first year after dose increase were compared (Wilcoxon signed ranks test) with the expected costs if the initial dose would have been continued. Furthermore, effectiveness of dose increase was determined by reason for dose increase: non-response, loss of response and partial response. Results: Included were 44 adalimumab, 32 etanercept and 115 infliximab patients with a dose increase. The mean change in DAS28 at 3 months after dose increase was limited: -0.51 (P = 0.035) in etanercept, -0.25 (P = 0.276) in adalimumab, and -0.22 (P = 0.147) in infliximab patients. The observed costs were €4093-5032 (depending on the type of anti-TNF) higher per patient per year after dose increase compared to the expected costs during the first 12 months which was significant in all three agents (P ≤ 0.002). This equalled an increase of 50% of medication costs per patient per year. As the figure shows, disease activity decreased significantly at 3 months from dose increase non-responders and in patients with loss of response (-0.66 and -0.99, both P = 0.001), but not in the partial responders. Conclusion: These results suggest that the effectiveness of dose increase is limited in adalimumab, etanercept and infliximab, and that dose increase is associated with a considerable increase in the costs of therapy. Therefore, the effectiveness of other therapeutic strategies should be investigated in patients with inadequate response to the first TNF blocking agent. Disclosure of Interest: None declaredCitation: Annals of the Rheumatic Diseases, volume 68, supplement 3, year 2009, page 434Session: Rheumatoid arthritis Anti-TNF therapy (Poster Presentations )