In Europe, it is widely accepted that people with non-radiographic axial spondyloarthritis (nr-axSpA) share the same pain symptoms, and laboratory and imaging features as those with radiographically visible disease. This view is shared in new classification criteria that have been developed for axial spondyloarthritis (SpA) covering both patients who already show radiographic evidence of structural damage in the sacroiliac joints (or spine), and patients in the earlier phase without radiographic evidence of structural damage. There is general agreement that these two stages represent a continuum of the same disease. “In many, if not most cases of nr-axSpA people will progress to active SpA”, said Joachim Sieper, rheumatologist at the Charité Universitätsmedizin Berlin (Germany). In these patients, inflammation is visible on MRI, or C–reactive protein (CRP) is elevated, but changes are not seen on radiography. The increased use of MRI as an imaging method in the mid-1990s was what first alerted rheumatologist to the importance of non-radiographic disease. In Europe, a couple of biological medications are available to treat patients with nr-axSpA. “We now know that if you are CRP positive, you are much more likely to show good response to TNF blockage, so we´ve learned to value CRP in managing the nr-axSpA”, said Sieper.
In contrast, in the United States (US) no biologics are approved for nr-axSpA as the FDA had concerns regarding a possible risk of overtreatment. However, the trend both in Europe and the US is to view nr-axSpA as part of the broader spectrum of radiographic axSpA (AS) and to treat it with biological agents after first-line non-steroidal anti-inflammatory drugs have failed. “In RA you also treat, even if you don´t have erosions yet”, Sieper noted.
The ESTHER trial, presented during a poster session of EULAR, supported the European view and a more proactive treatment approach: it demonstrated a substantial reduction of radiographic sacroiliitis progression between year 2 and year 6 of anti-TNF treatment. Higher baseline CRP and higher MRI fatty lesions score demonstrated a positive association with progression from nr-axSpA to AS.
Rodriguez VR et al. Long-term anti-TNF treatment is associated with reduction of progression of radiographic changes in the sacroiliac joints in patients with non-radiographic axial SPA: six-year results of the ESTHER trial. Abstract SAT0422 and Sieper J. Different approaches to drug approval by EMA and FDA – the example of non-radiographic axial spondyloarthritis. Abstract SP0108, both presented on the 11th of June 2016.