Background/Purpose: The heel is a frequently affected anatomical site for enthesitis in spondyloarthritis (SpA).¹ Recently, the Outcome Measures in Rheumatology (OMERACT) group developed and validated the Heel Enthesitis MRI Scoring system (HEMRIS) that takes both inflammatory and structural features of enthesitis into account.² ACHILLES (NCT02771210) is a prospective randomized controlled trial, investigating both clinical and imaging endpoints in patients (pts) with SpA and heel enthesitis.³ Here, we report a post hoc analysis applying HEMRIS system in blinded and centrally read MRI data of the heel from the ACHILLES trial (N=204).

Methods: ACHILLES included pts (≥18 years) with active psoriatic arthritis or axial SpA, with clinical and MRI-positive heel enthesitis, refractory to standard treatment (either Non-steroidal anti-inflammatory drugs or Tumor necrosis factor-inhibitors). Pts were randomized to receive s.c. secukinumab (SEC) 150 mg, 300 mg or placebo (PBO) at baseline, Weeks (Wks) 1, 2, 3, and 4, followed by once every 4 wks. At Wk 24, pts on PBO were switched to SEC 150 or 300 mg. MRI-positive heel enthesitis was confirmed in all pts by local investigators and was defined as tendinitis and/or bone marrow edema (BME) in the area of the Achilles’ tendon and/or the plantar aponeurosis. MRIs were performed at three time points: screening (SCR), Wks 24, and 52. In the present analysis, all MRIs were re-evaluated by two blinded central readers in a consensus read fashion for a priori defined MRI parameters based on HEMRIS system.

Results: Structural and inflammatory parameters at SCR are shown in Figure. At SCR, 156/204 (76.5%) pts presented with total entheseal inflammation score >0, 131/204 (64.2%) with total structural damage score >0, and 171/204 (83.8 %) with any entheseal inflammation and/or structural damage, considering both Achilles tendon and plantar fascia. The mean total entheseal inflammation score at SCR was 3.58 (N=204) and the mean change (SD) from SCR to Wk 24 and to Wk 52 was -1.05 (2.11) and -1.26 (2.28) in the SEC group vs -0.74 (2.21) and -1.17 (2.73) in the placebo group, respectively. The mean total structural damage score at SCR was 1.85 (N=204) and the mean change (SD) from SCR to Wk 24 and to Wk 52 was -0.01 (0.71) and -0.09 (0.66) in the SEC group vs 0.12 (0.56) and 0.06 (0.83) in the PBO-SEC group, respectively. Mean scores at SCR and mean change over time for individual parameters are given in Table 1 and Table 2, respectively.

Conclusion: Based on the newly developed HEMRIS system, entheseal inflammation and/or structural damage was not confirmed for 16.2% of pts with SpA enrolled in the ACHILLES trial. The mean improvements in total inflammation and total structural damage scores were higher in the SEC-treated pts compared to placebo. The observed magnitude of improvement for the SEC-treated pts was more pronounced for the peri-tendon/aponeurosis hypersignal, bursitis and bone erosion.

References:
1. Schett G, et al. Nat Rev Rheumatol. 2017;13:731–41.
2. Mathew AJ, et al. J Rheumatol. 2019;46:1232–8.
3. Behrens F, et al. Arthritis Rheumatol. 2019;71 (suppl 10). Abstract 2503.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/imaging-characteristics-in-patients-with-spondyloarthritis-using-a-novel-heel-enthesitis-magnetic-resonance-imaging-scoring-hemris-system-post-hoc-analysis-of-a-phase-3-secukinumab-trial/