Guselkumab provides durable improvement across psoriatic arthritis disease domains: post hoc analysis of a phase 3, randomised, double-blind, placebo-controlled study.

OBJECTIVE: Evaluate long-term guselkumab effectiveness across Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA)-recognised domains/related conditions of psoriatic arthritis (PsA). METHODS: Post hoc analyses used data from DISCOVER-2 (NCT03158285) biologic/Janus-kinase inhibitor-naïve participants with active PsA (≥5 swollen/≥5 tender joints, C-reactive protein ≥0.6 mg/dL), randomised (1:1:1) to guselkumab every 4 or 8 weeks (Q4W/Q8W) or placebo with crossover to guselkumab. Outcomes aligned with key GRAPPA-recognised domains of overall disease activity, peripheral arthritis, axial disease, enthesitis/dactylitis and skin psoriasis (nail psoriasis was not evaluated). PsA-related conditions (inflammatory bowel disease (IBD)/uveitis) were assessed via adverse events through W112. Least squares mean changes from baseline through W100 in continuous outcomes employed repeated measures mixed-effects models adjusting for baseline scores. Binary measure response rates were determined with non-responder imputation for missing data. RESULTS: 442/493 (90%) of guselkumab-randomised patients completed treatment through W100. Following early reductions in disease activity with guselkumab, durable improvements were observed across key PsA domains (swollen/tender joints, psoriasis, spinal pain, enthesitis/dactylitis) through W100. Response rates of therapeutically relevant targets generally increased through W100 with guselkumab Q4W/Q8W: Disease Activity Index for PsA low disease activity (LDA) 62%/59%, enthesitis resolution 61%/70%, dactylitis resolution 72%/83%, 100% improvement in Psoriasis Area and Severity Index 59%/53%, Psoriatic Arthritis Disease Activity Score LDA 51%/49% and minimal disease activity 38%/40%. Through W112, no cases of IBD developed among guselkumab-randomised patients and one case of uveitis was reported. CONCLUSION: In biologic-naïve patients with active PsA, guselkumab provided early and durable improvements in key GRAPPA-recognised domains through 2 years, with substantial proportions achieving important treatment targets.