Research in Brief.

Abstract

A comparison of composite indices could help to inform future trial design in psoriatic arthritis. In an analysis of secondary outcomes of an international phase 2 trial, the Psoriatic Arthritis Disease Activity Score (PASDAS) and Grappa Composite score (GRACE) were more sensitive than the modified Composite Psoriatic Disease Activity Index (mCPDAI) and Disease Activity index for PSoriatic Arthritis (DAPSA) tools in distinguishing the treatment effect of the IL-23p19 inhibitor guselkumab over placebo. In the original trial, patients with psoriatic arthritis were randomised (2:1) to receive guselkumab 100 mg (n=100) or placebo (n=49) once every eight weeks for 44 weeks. All of the indices distinguished the treatment effect of guselkumab from placebo at week 24, but significantly more patients who received guselkumab achieved low disease states or remission according to PASDAS (35·0% vs 4·1% for placebo) and GRACE (29·6% vs 2·1%) than according to mCPDAI (45·9% vs 10·4%) or DAPSA (40·0% vs 12·2%; all p<0·001). Residual non-articular disease activity was more common in patients achieving DAPSA low disease activity than those achieving low disease according to the other indices.