SAT0258 Baseline MRI/CRP as Predictors of Response to Etanercept in the Management of Patients with Non-Radiographic Axial Spondyloarthritis

BackgroundTreatment with TNFα inhibitors has been shown to be effective in improving disease activity and functional capacity in patients with non-radiographic axial spondyloarthritis (nr-axSpA). Evidence indicates that clinical response to anti-TNFα agents tends to be enhanced in nr-axSpA patients with magnetic resonance imaging (MRI)-documented sacroiliac (SI) joint inflammation and elevated C-reactive protein (CRP).ObjectivesTo determine if MRI sacroiliitis positivity and/or elevated CRP at baseline are predictive or associated with changes in measures of disease activity following etanercept (ETN) treatment in patients with nr-axSpA.MethodsPatients with symptom duration >3 mths–3 mg/L.ResultsA total of 200 subjects (ETN, n=95; PBO, n=105) were included in these analyses. At baseline, breakdown according to MRI sacroiliitis and CRP status was: MRI-/CRP-, n=38; MRI+/CRP-, n=74; MRI-/CRP+, n=21; MRI+/CRP+, n=67. At Week 12, the primary endpoint of ASAS40 was achieved by more patients receiving ETN than those receiving PBO irrespective of MRI/CRP status at baseline (Table). The greatest ASAS40 response was observed in patients with MRI+/CRP+ at baseline and the lowest response was seen in the MRI-/CRP- subgroup. Similar observations were made for all other clinical endpoints with a markedly higher proportion of MRI+/CRP+ patients achieving ASAS20, BASDAI50 and clinically important improvements (Δ≥1.1) in ASDAS-CRP/ESR than those in the other MRI/CRP subgroups.Table 1EndpointMRI−/CRP−MRI+/CRP−MRI−/CRP+MRI+/CRP+ASAS40ETN2/17 (11.8)8/32 (25.0)3/11 (27.3)20/35 (57.1)†PBO2/21 (9.5)6/42 (14.3)1/10 (10.0)7/31 (22.6)ASAS20ETN7/17 (41.2)14/32 (43.8)7/11 (63.6)24/35 (68.6)*PBO5/21 (23.8)16/42 (38.1)3/10 (30.0)13/31 (41.9)ASDAS-CRPETN5/17 (29.4)12/31 (38.7)6/11 (54.5)27/35 (77.1)‡PBO2/21 (9.5)7/42 (16.7)5/10 (50.0)10/32 (31.3)ASDAS-ESRETN6/17 (35.3)12/28 (42.9)4/11 (36.4)25/33 (75.8)‡PBO3/21 (14.3)9/42 (21.4)2/10 (20.0)8/29 (27.6)BASDAI