ASSESSING THE EFFICACY OF ANTI-TNF-ALPHA TREATMENT AS DISEASE MODIFYING OR DISEASE CONTROLLING THERAPY FOR PATIENTS WITH ANKYLOSING SPONDYLITIS

D. Van der Heijde Rheumatology, University Hospital Maastricht, Maastricht, NetherlandsThere is a profound effect of anti-TNF-alpha treatment on the clinical signs and symptoms of ankylosing spondylitis. Also if assessed by the ASAS improvement criteria, the majority of patients show a response. In addition there is a major effect on acute phase reactants. This is an indication that anti-TNF-alpha treatment might be able to have a more substantial effect on the disease than just relief of clinical signs and symptoms. The definition of ASAS improvement criteria is derived from clinical trials on NSAIDs in AS. The domains included in the ASAS improvement criteria are: patient global, pain, morning stiffness and function. Improvement is defined as a 20% improvement and 10 units in 3 of the 4 domains with no worsenign in the remaining domain. The ASAS working group has proposed to use two newly defined improvement criteria which are derived from trials on TNF-blocking agents, based on the work from the group in Berlin. One is the ASAS40 improvement criteria: a higher (40%) improvement in the same domains and the other is the so-called '5 out of 6' domains response. This is the same magnitude of response (20%) but now in two additional domains: acute phase reactants and spinal mobility. And exactly a response in these two new domains proved to be very hard to achieve in patients treated with placebo. Depending on further validation, one of the two new improvement criteria could be preferred.If we apply the same definition for a disease modifying or disease controlling effect in AS as in RA, there should also be an effect on prevention of disability and an effect on structural damage. At the moment there is a lot of debate on which instrument to use to assess disability. As a surrogate an assessment of physical function is used. For RA this is the HAQ and for AS this can be the BASFI. Until now, little was known about the progression of structural damage in paients with AS. However, recent data show that there is substantial progression in a large percentage of patients after two years of follow-up. And also that there is a good relation between structural damage on radiographs and spinal mobility and physical function. A follow-up of two years seems to be the minimum to see progression in a large enough number of patients. Assuming that TNF-blockers really have an effect on structural damage, this could be shown ideally in a randomized, placebo-controlled, double-blind trial of two year follow-up. However, it is ethically unjustifiable to perform such a trial given the profound effect on signs and symptoms. As a second best option seems to be the use of historical control data on progression of structural damage in an unselected cohort of patients. The usefulness with the possbile caveats of such an approach will be presented. Based on the available data, the modified SASSS scoring method, assessing the anterior site of the cervical and lumbar spine, is the preferred method to score structural damage.Citation: , volume , supplement , year 2003, page Session: New insights of anti-TNF therapies in spondylarthropathies