BASELINE MRI/CRP AS PREDICTORS OF RESPONSE TO ETANERCEPT IN THE MANAGEMENT OF PATIENTS WITH NON-RADIOGRAPHIC AXIAL SPONDYLOARTHRITIS

Background: Treatment 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). Objectives: To 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. Methods: Patients with symptom duration >3 mths–<5 yrs, meeting ASAS axSpA classification criteria but not radiographic criteria for ankylosing spondylitis, having BASDAI ≥4, and failure with ≥2 NSAIDs were randomized to 12 wks of double-blind treatment with ETN 50mg QW or PBO. Both groups continued stable NSAID therapy. Standard clinical outcomes were assessed in 4 patient subgroups based on MRI sacroiliitis (positive/negative [+/-]) and CRP (elevated/normal [+/-]) status at baseline. MRI sacroiliitis positivity was defined as SPARCC SI joint score ≥2; elevated CRP was defined as >3 mg/L. Results: A 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. EndpointMRI−/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) BASDAI50ETN4/17 (23.5)10/32 (31.3)4/11 (36.4)25/35 (71.4) PBO4/21 (19.0)11/42 (26.2)2/10 (20.0)9/32 (28.1) *p<0.05, p<0.01, p<0.001 vs PBO. Values are patients achieving endpoint n/N (%). Values for ASDAS-CRP/ESR are patients achieving clinically important improvement Δ≥1.1. Conclusions: Our findings, in patients with early, active nr-axSpA and an inadequate response to ≥2 NSAIDs, are consistent with the hypothesis that a combination of MRI positivity and elevated hsCRP at baseline has a positive predictive value on the SI joint inflammation score and a better clinical response to ETN. A larger sample size is required to test this definitively. Disclosure of Interest: M. Brown Grant/research support from: Abbvie, Pfizer, UCB, Wyeth, Leo Pharma, NIAMS, NHMRC, Arthritis Australia, Qld Government, Consultant for: Pfizer, Abbvie, UCB, Speakers bureau: Pfizer, Abbvie, UCB, P. Bird Speakers bureau: Pfizer, Abbvie, Roche, Janssen, BMS, P. Robinson Grant/research support from: NHMRC, ARA, RACP, Consultant for: Pfizer, UCB, Abbvie, Janssen, Menarini, Speakers bureau: Menarini, Janssen, Abbvie, UCB, P. Mease Grant/research support from: AbbVie, Amgen, Biogen Idec, BMS, Celgene, Crescendo, Genentech, Janssen, Lilly, Merck, Novartis, Pfizer, UCB, Consultant for: AbbVie, Amgen, Biogen Idec, BMS, Celgene, Covagen, Crescendo, Genentech, Janssen, Lilly, Merck, Novartis, Pfizer, UCB, Speakers bureau: AbbVie, Amgen, Biogen Idec, BMS, Celgene, Crescendo, Genentech, Janssen, Lilly, Pfizer, UCB, F. van den Bosch Consultant for: Abbvie, Celgene, Novartis, Pfizer, UCB, Speakers bureau: Abbvie, Celgene, Janssen, Novartis, Pfizer, UCB, C. Surian Employee of: Pfizer, Z. Wiid Employee of: Pfizer, H. Jones Employee of: Pfizer, A. Szumski Consultant for: Employee of inVentiv Health and was contracted by Pfizer Inc. to provide statistical support, L. Marshall Employee of: Pfizer DOI: 10.1136/annrheumdis-2015-eular.2254Citation: Annals of the Rheumatic Diseases, volume 74, supplement 2, year 2015, page 752Session: Spondyloarthritis - clinical aspects (other than treatment) (Poster Presentations )