Study Findings Support Strict Disease-Activity Targets in Psoriatic Arthritis

Achieving remission in psoriatic arthritis (PsA) is important to prevent further structural damage, especially among patients who have preexisting structural changes, according to new research presented at the 2019 American College of Rheumatology (ACR)/Association of Rheumatology Professionals (ARP) Annual Meeting. The findings support strict disease-activity targets in PsA.

Several disease-activity measures are recommended as treatment targets in PsA. However, consensus lacks on which assessment tool is the most appropriate for these targets.

To study this, Laura Coates, MBChB, MRCP, PhD, from the University of Oxford, and colleagues evaluated data of 409 patients with active PsA enrolled in the RAPID-PsA phase 3 clinical trial. The patients had been previously randomly assigned to receive certolizumab pegol, 200 mg, every 2 weeks, certolizumab pegol, 400 mg, every 4 weeks, or placebo. All patients who had received certolizumab pegol received the same dose to 216 weeks. Patients who had received placebo were randomly reassigned to certolizumab pegol,200 mg, every 2 weeks or certolizumab pegol, 400 mg, every 4 weeks at 16 or 24 weeks.

The researchers assessed disease activity via the Psoriatic Arthritis Disease Activity Score (PASDAS), Disease Activity Index for Psoriatic Arthritis (DAPSA), and minimal disease-activity criteria. A hierarchical linear mixed-effects model was used to estimate the mean change from baseline in modified Total Sharp Score (mTSS), as well as associations with disease-activity states. Among the patients, 407 were assessed for mTSS at least once.

At week 0, the mean DAPSA score was 44.5 (standard deviation [SD], 22.7) and the mean PASDAS score was 6.0 (SD, 1.1). Of the 409 patients, 3 (0.7%) reported minimal disease-activity criteria.

The proportion of patients who achieved remission/very low disease-activity states increased to week 216. The mean mTSS also increased to week 216, although overall progression was low.

Remission/very low disease-activity states were associated with mTSS estimated mean change from baseline of zero or less among all patients across all disease-activity measures. This association was also observed among a subgroup of patients who were at highest risk of structural progression at baseline.

“These data indicate that achievement of remission in PsA is important to prevent further structural damage, particularly when patients have pre-existing structural changes,” the authors conclude. “This supports the rationale for strict disease-activity targets.” —Melinda Stevens