Background Modification of structural lesions by anti-TNF therapy has not been demonstrated in a randomized placebo (PBO)-controlled trial. The Spondyloarthritis Research Consortium of Canada (SPARCC) sacroiliac joint (SIJ) score (SSS) assesses the degree of fat metaplasia (new tissue growth after resolution of inflammation), erosion, backfill (new tissue growth at erosion site), and ankylosis observed on MRI in the SIJ.
Objectives To evaluate the impact on these lesions at 12 wks in patients with non-radiographic axial SpA receiving PBO or etanercept (ETN) in the EMBARK study (ClinicalTrials.gov: NCT01258738).
Methods Patients had axial SpA per ASAS criteria without meeting modified NY radiographic criteria; BASDAI score ≥4; symptoms for >3 months and <5 yrs; and had failed ≥2 NSAIDs. Patients were randomized to double-blind ETN 50 mg/wk or PBO for 12 wks, then received open-label ETN. Structural lesions were scored using the SPARCC SSS method on T1-weighted spin echo (T1WSE) MRI. Two readers independently scored baseline (BL) and 12-wk T1WSE MRI scans, blinded to patients, time point, and inflammation scores assessed by short tau inversion recovery MRI scans. Readers' mean scores were used.
Results Mean (SD) age was 32 (7.8) yrs, 60.5% were male, duration of disease symptoms was 2.4 (1.8) yrs, 71.6% were human leukocyte antigen B27+, and 80.9% had sacroiliitis on MRI (modified intent-to-treat [mITT] population, N=215). MRI scans from 185 patients (ETN, n=88; PBO, n=97) with BL and 12-wk scans were reviewed. At BL, there were no significant differences in mean SPARCC SSS scores between ETN and PBO (table). From BL to 12 wks, change in mean SPARCC SSS score was significantly greater for ETN than PBO for erosion (-0.57 vs -0.08, respectively, p=0.009) and backfill (0.36 vs 0.06, p=0.021), table. A treatment difference was also present for the subgroup of patients with MRI inflammation (figure).
Conclusions Treatment with ETN was associated with significantly greater reduction in erosion and increase in backfill at 12 wks vs. PBO, consistent with a very early reparative response to anti-TNF therapy. The impact of this new data on disease progression in SpA should be studied further.
Disclosure of Interest W. Maksymowych Grant/research support from: AbbVie, Consultant for: AbbVie, Amgen, Boehringer Ingelheim, Eli Lilly, Janssen Pharmaceutica, L.P, Pfizer, UCB, S. Wichuk: None declared, M. Dougados Grant/research support from: Pfizer, AbbVie, UCB, Merck, Eli Lilly, Sanofi, Consultant for: Pfizer, AbbVie, UCB, Merck, Eli Lilly, Sanofi, H. Jones Shareholder of: Pfizer, Employee of: Pfizer, A. Szumski Employee of: InVentiv Health, L. Marshall Shareholder of: Pfizer, Employee of: Pfizer, J. Bukowski Shareholder of: Pfizer, Employee of: Pfizer, R. Lambert Consultant for: Bioclinica