Treatment Responses in Patients With Psoriatic Arthritis Axial Disease According to Human Leukocyte Antigen‐B27 Status: An Analysis From the CorEvitas Psoriatic Arthritis/Spondyloarthritis Registry

Abstract

Objective Axial disease is common and burdensome in patients with psoriatic arthritis (PsA). Human leukocyte antigen‐B27 (HLA‐B27) is a risk factor for axial PsA; treatment response by HLA‐B27 status is inadequately characterized. This study evaluated responses to biologic disease‐modifying antirheumatic drugs (bDMARDs) or targeted synthetic DMARDs (tsDMARDs) overall and by HLA‐B27 status in patients with PsA axial disease. Methods This observational study included participants in the CorEvitas (formerly Corrona) PsA/Spondyloarthritis Registry who initiated bDMARD or tsDMARD treatment at baseline, had a 6‐month follow‐up visit, fulfilled Classification Criteria for Psoriatic Arthritis, had a baseline Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score of ≥4, and had known HLA‐B27 status. Disease characteristics at baseline and 6 months were evaluated overall and by HLA‐B27 status. Association between HLA‐B27 status and treatment response was evaluated using an analysis of covariance model. Results The analysis included 173 bDMARD or tsDMARD treatment initiations (54 [31.2%] among patients with HLA‐B27+ status and 119 [68.8%] among patients with HLA‐B27− status). BASDAI total and component scores decreased by ≤0.84 across groups after 6 months of bDMARD or tsDMARD therapy; these changes are not considered clinically meaningful. HLA‐B27 status was not statistically significantly associated with changes in axial‐related outcomes. Conclusion In patients with PsA axial disease, 6 months of bDMARD or tsDMARD therapy provided only mild improvements in axial‐related outcomes, irrespective of HLA‐B27 status. This continued high disease activity reflects a critical unmet need for focus on the axial domain of PsA and for additional safe and effective therapies for psoriatic axial disease.