Background Anti-TNF therapy has been a great advance in the treatment of rheumatic diseases. However, these drugs have a high cost and potentially severe adverse effects, therefore it would be useful to analyze their use at lower doses with a longer dosing interval.

Objectives The aim of this study is to analyze whether lengthening the recommended dosing interval with anti-TNF therapies in rheumatoid arthritis and psoriatic peripheral arthritis in remission provides good control of the disease.

Methods We collected the clinical data of patients diagnosed with rheumatoid arthritis (RA) and peripheral psoriatic arthritis (PSA) in subcutaneous anti-TNF therapy (adalimumab, etanercept and golimumab), which were in remission/low activity at two successive consultations and in which the anti-TNF dosing interval has been lengthened according to the following pattern: etanercept 50 mg/15 days, adalimumab 40 mg/21 days, and golimumab 50mg/5 weeks. In order to evaluate disease activity, we used the DAS28, serum C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) before changing the dosing interval at 6, 12, 18, 24 and 30 months of follow-up. Biostatistical analysis was performed using linear regression models.

Results We included a total of 67 patients from February 2011 (42 AR and 25 PSA) who were treated with anti-TNF therapy (39 with adalimumab, 23 with etanercept and 5 with golimumab). The mean DAS28 score at different intervals is shown in the table below. During follow-up, there were 9 interruptions in lengthening (4 RA and 5 PSA), 5 exacerbations and 3 transfers to another hospital.

According to the data obtained, DAS28 in RA cases slightly increased with lengthening of the dosing interval but does not reach values exceeding low disease activity. Linear regression revealed a tendency that the adalimumab and biological therapy combined with methotrexate maintained low disease activity more efficiently.

Conclusions Although no statistically significant results were obtained due to the small number of patients, in all cases the disease control was achieved. Furthermore, better control was achieved with the combined use of biological therapy and methotrexate, as well as with adalimumab. However, a larger number of cases and longer follow-up period is needed in order to confirm that prolonging the anti-TNF dosing interval is useful for disease control.

Disclosure of Interest None declared

DOI 10.1136/annrheumdis-2014-eular.4944