Article
Is anti-TNF Treatment response in peripheral Psoriatic Arthritis influenced by concomitant use of Methotrexate?
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Published: | September 12, 2014 |
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Background: In active psoriatic arthritis (PsA) the efficacy of TNF-inhibitors (TNFi) has been proven in randomized clinical trials (RCT). Methotrexate (MTX) co-medication can improve the therapeutic benefit of TNFi in rheumatoid arthritis (RA), but its role in PsA remains unclear. Thus, distinct patterns of disease manifestations such as peripheral joint and axial involvement might influence the choice of co-medication, treatment response and drug adherence differently in PsA. Accordingly, an appropriate study on the impact of MTX on TNFi treatment in PsA has to consider the confounding effects of the distinct disease manifestations on outcome measures.
Methods: Data of a large (n=1455) German multicentre, non-interventional study (NIS) with active PsA patients treated with Adalimumab (ADA) in routine care was analysed. Patients with exclusive peripheral arthritis (pPsA) i.e. no evidence for axial involvement, enthesitis and dactylitis were analysed and compared to those with additional musculoskeletal manifestations (aPsA). Safety and efficacy of ADA-monotherapy were analysed and compared to the results obtained by add-on treatment to MTX pre-medication. Besides documentation of demographic data, disease activity assessments (number of swollen (SJC), tender joints (TJC), disease activity score 28 (DAS28)) were calculated at baseline, month 3, 6, 12, 24. Step-wise regression analysis for influence of MTX on patient-outcome was calculated.
Results: Outcome in patients with peripheral PsA is independent from concomitant MTX use as indicated in DAS28 results (pPsA: ADA+MTX 2.58, ADA-Monotherapy 2.70; aPsA: ADA+MTX 2.82, ADA-Monotherapy 2.79 respectively). Moreover, treatment responses remained robust to changes of MTX co-medication either by discontinuation in combined TNFi therapy or by addition to TNFi-monotherapy. In step-wise regression analysis no parameters for MTX were found to influence patient-outcome.
Conclusion: In active peripheral PsA co-medication of MTX added to TNFi treatment with ADA has no relevant impact on efficacy and safety. Not even the addition of MTX to ongoing TNFi treatment or refusal of MTX in combinational therapy with TNFi exhibits any influence on outcome parameters. RCTs are needed to confirm the data.