Background/Purpose: Enthesitis is a common feature of Spondyloarthritis (SpA)¹. Enthesitis at the Achilles tendon is an important manifestation with impact on function which is often refractory to standard NSAID/corticosteroid treatment^1,2. ACHILLES is a double blind, placebo-controlled, multicenter Phase 3 trial designed to investigate the efficacy of secukinumab on enthesitis by clinical as well as imaging assessments in patients (pts) with active psoriatic arthritis (PsA) and axial SpA (axSpA). Here we report the impact of enthesitis on the burden of disease based on the ACHILLES pts characteristics.

Methods: Pts (≥18 years) with active PsA [CASPAR criteria and ≥1 TJC and SJC] or axSpA [ASAS axSpA criteria and total BASDAI ≥ 4], and MRI-positive heel enthesitis (according to the investigator`s judgement) refractory to standard treatment were enrolled in the trial. Enrolment was completed in October 2018. Pts were randomized to receive subcutaneous secukinumab 150 or 300 mg or placebo at baseline (BL), Weeks (Wk) 1, 2, 3, and 4, followed by once every 4 wks. Starting at Wk 24, all pts received secukinumab 150 or 300 mg. The primary endpoint of ACHILLES is the proportion of pts achieving resolution of Achilles tendon enthesitis with secukinumab vs placebo at Wk 24. BL clinical characteristics were analyzed after the last pt was randomized. Summary statistics are presented separately for PsA and axSpA indications, irrespective of treatment arm in order to preserve the blinding of the trial. In addition, the BL characteristics of PsA pts, representing 62.7% of the total ACHILLES population, were compared to PsA pts without enthesitis from the FUTURE studies.

Results: Of the 304 pts screened, 204 (128 PsA and 76 axSpA) pts completed the screening phase and were randomized. BL and disease characteristics of enrolled pts are shown in Table 1. PsA pts presented with a higher weight/BMI compared to axSpA pts at BL. Time since diagnosis was shorter for axSpA pts while duration of enthesitis was comparable for both indications. Physician’s (PhGA) and patient’s global assessment (PtGA) of disease activity scores (0-100 VAS) in the PsA pts were 57.2 and 62.3, respectively, and 66.8 and 71.8, respectively, in the axSpA pts, indicating a high disease burden. Interestingly, while patient’s global assessment of heel enthesiopathy activity and PtGA were comparable in both indications, the physician’s global assessment for enthesitis was rated higher than the PhGA. Comparison with BL data from pooled FUTURE 2 and 3 trials show that pts without enthesitis reported lower PsA pain and PhGA/PtGA scores at BL, although with a higher SJC but comparable clinical characteristics in terms of age and weight (Table 2).

Conclusion: In SpA patients suffering from enthesitis, axSpA pts present with a higher burden of disease compared to PsA pts. PsA pts report higher disease burden when compared to pts without enthesitis, suggesting that enthesitis may be an important factor contributing to the burden of disease in PsA.

References:

1. Schett G, et al. Nat Rev Rheumatol. 2017;13:731─41.
2. Gossec L, et al. Ann Rheum Dis. 2016;75:499─510.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/achilles-tendon-enthesitis-and-disease-burden-in-psoriatic-arthritis-and-axial-spondyloarthritis-baseline-results-from-a-randomized-controlled-trial/