Background/Purpose:

Patients (pts) with psoriatic arthritis (PsA) may experience structural damage if not appropriately treated. The purpose was to determine 1) the frequency of radiographic structural damage in PsA pts at baseline (BL), and BL patient and disease characteristics associated with having BL structural damage 2) the risk of further radiographic progression in PsA pts with/without BL structural damage 3) the inhibition of radiographic progression by adalimumab (ADA) in PsA pts with/without BL structural damage.

Methods:

The analysis used data from the ADEPT trial¹, which was a 24-week (wk) randomized placebo (PBO)- controlled trial that evaluated efficacy and safety of ADA in pts with moderate to severe PsA (mean duration of approx. 9.5 years). Pts with available radiographs of hands and feet at BL and wk 24 were included in the present analyses. Radiographic damage at BL was defined as modified Total Sharp Score (mTSS) >0.5; radiographic progression was defined as a change in mTSS by >0.5 over 24 wks. In each treatment group (ADA or PBO), the proportion of pts with radiographic progression (progressors) from BL to wk 24 was determined among pts with/without BL structural damage. The association of the following BL characteristics with radiographic damage at BL was determined by univariate and multivariate logistic regression: age, weight, swollen joint count at 28 joints (SJC28), tender joint count at 28 joints (TJC28), duration of psoriasis or PsA, C-reactive protein (CRP), and Psoriasis Area Severity Index (PASI).

Results:

Out of 313 pts randomized in the ADEPT trial (151 to ADA, 162 to PBO), 296 pts (95%) had radiographic data available at BL and wk 24. Eighty-one percent (81%; 239/296 pts) had radiographic damage at BL; 83% of pts with PsA duration ≥2 years and 72% of pts with PsA duration <2 years. Among 239 pts with BL damage, significantly fewer pts in the ADA-treated group (13/118, 11.0%) vs the PBO-treated group (43/121, 35.5%) experienced radiographic progression by wk 24 (p<.001). The treatment effect of ADA in pts with BL damage was larger than the treatment effect of ADA in the overall population (24.5% vs 19.2% of non-progressors). Among pts without BL damage, 1/26 (3.8%) and 1/31 (3.2%) pts in the ADA and PBO group, respectively, had further damage by wk 24. Multivariate analysis indicated that higher CRP and age at BL were associated with an increased risk of having existing BL structural damage (p<.01).

Conclusion:

The majority of PsA pts had radiographic damage at BL, even with < 2 years of disease duration. Pts with BL structural damage had a greater risk for further progression overall, while the inhibitory effect of ADA on radiographic progression was more pronounced in pts with BL damage. Higher CRP and age at BL were associated with BL damage. The data suggests that effective treatment to prevent further radiographic damage would be particularly beneficial in pts with existing damage, who in the ADEPT trial constituted the majority.

 Reference: 1) Mease P et al, Arthritis Rheum 2005;52:3279-89

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-majority-of-patients-with-moderate-to-severe-psoriatic-arthritis-had-existing-structural-damage-predisposing-them-to-further-progression-which-was-markedly-inhibited-by-adalimumab/