An observational study to investigate how new therapies for rheumatic diseases perform across different conditions has revealed that they may be more successful in certain conditions. The data is presented today at the Annual European Congress of Rheumatology in Amsterdam, the Netherlands. An increasing proportion of patients with rheumatic conditions such as ankylosing spondylitis (AS), psoriatic arthritis (PsA) and rheumatoid arthritis (RA) now receive anti-TNF treatment – a newer group of drugs that are used to reduce inflammation and manage disease activity*. Study lead Dr Marte Heiberg, of the Dept of Rheumatology, Diakonhjemmet Hospital, Oslo, told delegates: “Many studies have focused on the efficacy of these drugs, however less is known about the comparative real-life performance of these drugs across different diagnostic groups”.

The study was conducted across 5 Norwegian Rheumatology Departments and included 796 RA patients, 162 PsA patients and 211 patients with a diagnosis of AS. All patients were on an anti-TNF treatment regimen of infliximab, etanercept or adalimumab +/- methotrexate (MTX). The primary outcome was the number of patients still on therapy at one year – known as the adherence to therapy. RA was used as the reference group and within each diagnostic group, the adherence to anti-TNF monotherapy versus TNF+MTX was compared.

The relative risk for withdrawal from TNF+MTX versus anti-TNF monotherapy was 0.54 for RA patients, 0.49 for PsA patients and 0.83 for AS patients, demonstrating that combination treatment strategy of anti-TNF+MTX worked better than anti-TNF monotherapy in patients with RA and PsA. Although the crude one-year overall drug adherence rates for anti-TNF therapy were superior in patients with PsA and AS compared to RA, after adjusting for age, gender and concomitant MTX, the adherence to anti-TNF treatment were similar in patients with RA and PsA whereas the adherence to anti-TNF treatment was superior in patients with AS compared to RA.

Dr Heiberg stated: “This is a fresh insight into the performance of these very good treatment options and helps to build a greater picture of how they work across the different rheumatology disease areas. Whilst many of the anti-TNFs were originally used in RA, it is most interesting to note that they could actually work for a comparatively larger proportion of patients with an AS diagnosis.”