ACTIVE MRI LESIONS PREDICT CLINICAL RESPONSE BUT NOT TIME UNTIL RELAPSE FOR PATIENTS WITH ACTIVE AXIAL NON-RADIOGRAPHIC SPONDYLOARTHRITIS —52-WEEK RESULTS OF A PLACEBO-CONTROLLED, DOUBLE-BLIND CLINICAL TRIAL

Background: Adalimumab improves the signs and symptoms of active, axial non-radiographic spondyloarthritis (SpA). Young age and elevated C-reactive protein have been reported to be the best predictors of good clinical response. Objectives: To investigate the influence of inflammatory lesions, as detected by MRI, at baseline and Week 52 on clinical response in a placebo-controlled trial of adalimumab in non-radiographic SpA patients, which also included an open-label extension. Methods: Adult patients with active SpA (BASDAI ≥4) were included in the study. MRI investigations of the SI joints were conducted at baseline and Week 52. After 52 weeks, patients stopped therapy and were retreated in case of relapse. Active inflammation in the SI joints was scored, with each SI joint divided into quadrants and with modifications for additional points of intensity for each SI joint (range: 0–34). MRIs were scored independently by 2 readers blinded to time points of the MRIs. Results: At Week 52, a Bath Activity Disease Index (BASDAI) 50 response was achieved by 51% of patients, and the Asessments in SpondyloArthritis Society (ASAS) criteria for partial remission (ASAS PR) were attained by 28% of patients. MRIs of the SI joints were available for 37 patients at baseline. For the group of patients with an MRI score ≥1 (n=29) at baseline, mean BASDAI decreased from 6.2 at baseline to 2.6 at Week 52. For the group of patients with an MRI score <1 (n=8), mean BASDAI decreased from 6.2 at baseline to 5.0 at Week 52 (p=0.039). Moreover, 58% of patients with an MRI score ≥1 achieved a BASDAI 50, and 32% attained ASAS PR at Week 52. However, BASDAI 50 was reached by just 33% and ASAS PR by just 16% of patients with an MRI score <1. Mean duration until relapse did not differ significantly between these 2 groups (MRI score ≥1: 14 weeks; MRI score <1: 11.5 weeks). At Week 52, MRIs of the SI joints were available for 35 patients. More patients reached ASAS PR (53.8%) in the group of patients with an MRI score <1 vs. patients with an MRI score ≥1 (ASAS PR: 27.3%, p=not significant). However, there was no difference in time until relapse between the group of patients with an MRI <1 (n=13, mean duration 12.4 weeks) and the group of patients with MRI ≥1 (n=22, mean duration 14.9 weeks). Conclusion: In patients with active axial spondyloarthritis without radiologic sacroiliits treated with adalimumab, degree of active inflammation, as observed by MRI at baseline, predicted clinical response. However, degree of active inflammation (as observed by MRI at either baseline or Week 52) did not influence time until relapse, after adalimumab was stopped at Week 52. References: 1. Haibel H, et al. Arthritis Rheum. 2008;58:1981-91. 2. Hermann KG, et al. Radiologe. 2004;44:217-28. Disclosure of Interest: H. Haibel, Abbott, Scherring Plough, Speakers fees X. Baraliakos, Abbott, Consultant D. Poddubnyy, Abbott, Consultant M. Rudwaleit, Abbott, MSD, Schering-Plough, Pfizer, and Wyeth, Consultancies, speaking fees, honoraria J. Listing, Abbott, Consultant R. Wong, Abbott, Employee, stocks H. Kupper, Abbott, Employee, stocks J. Braun, Abbott, Schering-Plough, Wyeth, Centocor, Amgen, Reiumbursements, fees, grants J. Sieper, Abbott, Schering-Plough, Wyeth, Research grants, Abbott, BMS, Roche, Schering-Plough, Wyeth, Consulting fees, Abbott, Roche, Pfizer, Scheering-Plough, Wyeth, Speakers' bureauCitation: Annals of the Rheumatic Diseases, volume 68, supplement 3, year 2009, page 629Session: Spondylarthropathies Treatment (Poster Presentations )