Anti-TNF agents for the treatment of active non-radiographic axial spondyloarthritis.

T he spondyloarthritis (SpA) complex includes ankylosing spondylitis (AS), reactive arthritis, psoriatic arthritis, arthritis related to inflammatory bowel disease and forms that do not meet established criteria for these definite categories which are designated as undifferentiated SpA. In the early 1990s, two sets of classification criteria were suggested with the purpose to cover the whole clinical spectrum of SpA: the Amor criteria and the European Spondylarthropathy Study Group (ESSG) criteria. Since a short time ago, patients with AS were identified by using the modified New York criteria which require the presence of sacroiliitis of grade II bilaterally or grade III to IV unilaterally on radiographs as an indispensable condition for the diagnosis. In the last few years, the management of AS has improved a lot thanks to the anti-tumor necrosis factor (TNF) agents. These drugs reduce signs and symptoms of inflammation and improve quality of life and functional status although there is no evidence on their ability to block the progression of radiographic damage to the spine (1). Recently, the ASAS developed and validated criteria for axial (2) and peripheral SpA (3) that are going to substitute the Amor and the ESSG criteria. The axial criteria also include the non-radiographic (nr) form of SpA in which inflammation can be detected by magnetic resonance imaging (MRI). These classification criteria will extensively be used in clinical and epidemiological studies in the near future and have substituted the modified New York criteria in the updated ASAS recommendations for the beginning of anti-TNF therapy (4) and the new ASAS/EULAR recommendations for the global management of AS (5). The burden of the disease of nr axial SpA patients was similar to that of patients in the radiographic stage meeting the modified New York criteria for AS in a German study published in 2009 (6) but was considered quite different in another 2012 Ger-man research in which the lower proportion of male patient and the lower impact of inflammation were outlined in nr axial SpA (7). These last data could be due to the percentage of nr axial SpA patient without progression to AS. Accordingly, recent data showed that the radiographic progression is strongly dependent on the presence of elevated CPR and/or ESR levels, syndes-mophytes at baseline and smoking (8). The use of anti-TNF in the nr stage could maybe prevent the development of the structural damage (1). However, so far no drug has been approved …