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

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.