Background/Purpose:

Minimal disease activity (MDA)¹ is a clinically meaningful and comprehensive treatment target for psoriatic arthritis (PsA). The purpose was to determine if baseline (BL) disease activity and/or patient (pt) demographics predict the ability to achieve MDA at weeks (wks) 12 through 144 in pts with PsA, and to evaluate patient-reported outcomes (PROs) at wk 24 and 144 associated with achieving MDA.

Methods: Data was from the ADEPT trial, where PsA pts were randomized to adalimumab or placebo for 24 wks, followed by an open-label (OL) period out to 144 wks. In this post-hoc analysis, BL characteristics which predicted achievement of MDA at wk 12, 24, 48, 96 and 144 were identified by univariate (UV) and multivariate (MV) analyses (LASSO). A more stringent assessment was made for correlation with sustained MDA (defined as MDA achievement at 2 time points, 12 wks apart). Continuous variables were age, weight, modified total Sharp score (mTSS), tender/swollen joint count (T/SJC), Pt Global Assessment of disease activity (PtGA) or pain (PtGA-pain), Physician’s Global assessment of disease activity (PhGA), HAQ, enthesitis (2 sites), Psoriasis Area Severity Index (PASI) and Physician’s Global Assessment of Psoriasis (PhGA-Psoriasis). Categorical variables were gender, smoking, alcohol use, methotrexate use, investigator-reported spondylitis, CRP (<2.87 vs ≥2.87), duration of psoriasis/ PsA (< 5 or ≥5 years). Pts achieving MDA were termed achievers and those who did not, non-achievers (NA). Quality of life (QoL) – related PROs assessed at wks 24 (and for completers at wk144), were Dermatology Life Quality Index (DLQI), SF-36, and Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) score.

Results:

The numbers of MDA achievers vs NA were as follows: 18.9% vs 81.1% (wk 12, N=127); 21.6% vs 78.4 (wk 24, N=125); 40.5% vs 59.5% (wk 48, N=116); 38.5% vs 61.5% (wk 96, N=104); 43.2% vs 56.8% (wk 144, N=88).  In the UV analysis, lower PtGA-pain, TJC, SJC, enthesitis and HAQ at BL were associated with MDA at later time points. Sustained MDA at all/most time points was associated with lower TJC, SJC, HAQ and enthesitis at BL. MV analysis confirmed BL HAQ as a significant limiting factor for achieving MDA at later time points. A one unit increase in BL HAQ reduced the odds of achieving MDA at later time points by 64-77%. Lower age, TJC and HAQ at BL were associated with sustained MDA at wk 48; lower BL enthesitis with sustained MDA at wk 144. At week 24, MDA achievers demonstrated significantly better scores for QoL-related PROs compared to NA²; for pts completing 144 weeks, no significant differences in PRO scores were observed.

Conclusion: Lower scores at BL for HAQ increased the likelihood of MDA at later time points. Lower age and impairment at BL, as measured by TJC, HAQ and enthesitis increased the likelihood of reaching sustained MDA, suggesting the importance of early intervention. MDA achievers had significantly improved QoL compared to NA at wk 24; however, among pts completing 144 weeks, these differences were not evident.

Ref:

1. Coates LC, et al. ARD 2010;69:48
2. Mease P et al. ACR 2014 Ann meeting, Boston MA, USA. S697

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-prediction-of-long-term-minimal-disease-activity-and-its-benefits-in-patients-with-psoriatic-arthritis/