Background The current treatment for rheumatic disease (RD) includes biological drugs such as infliximab (IFX), etanercept (ETT), adalimumab (ADM), golimumab (GLM) rituximab (RTX), abatacept (ABT) and tocilizumab (TCZ). The treatment algorithm (clinical guidelines) includes IFX, ADM, ETT and GLM as first line, RTX as second line and ABT and TCZ as third line of choice.

Purpose The aim of this study was to assess the incidence of, and evaluate the reasons for, switching biological drugs in a RD population, as well as to analyse the reasons for each biological drug separately.

Materials and methods Cross-sectional study (June 2011), which took a sample of 166 patients (30% of the complete population) with 257 drug-patient records, with RDs such as psoriatic arthritis (PA), rheumatoid arthritis (RA), ankylosing spondylitis (AS), psoriatic spondyloarthropathy (PS), Behçe syndrome (BS) and others, treated with biological drugs and who were being followed up in our centre. The indication (confirmed RD), clinical records of treatment with biological drugs and reasons for switching, were collected and analysed.

Results 35% (97/257) of biological drug treatments evaluated were switched for all reasons combined. 68.1% of switching of the biological drug was due to lack of efficacy, 29.7% was due to adverse effects, while a 1.1% was due to remission and 1.1% was due to unknown reasons. The table shows the reasons for switch in %, analysing biological drugs separately:

Conclusions The main reason for switching biological drugs was the lack of efficacy (68.1%) while the appearance of adverse effects represents 29.7%. The pattern for each biological drug shows than more than 50% of changes were due to lack of efficacy in treatments with IFX, ADM, ETT and RTX.