Effectiveness of interleukin (IL)-23 and IL-12/23 inhibitors and factors associated with response in psoriatic arthritis with axial involvement: the APxis-IL12-23 study.

OBJECTIVES

To assess the real-world effectiveness of two interleukin (IL)-23 inhibitors [guselkumab (GUS), risankizumab (RIS)] and an IL-12/23 inhibitor [ustekinumab (UST)] in patients with purely axial psoriatic arthritis (PsA) or mixed PsA (both axial and peripheral involvement), and identify response predictors.

METHOD: In this retrospective multicentre study of patients treated with GUS, RIS, or UST, composite treatment response was defined as achieving a clinically important improvement (≥1.1) in Axial Spondyloarthritis Disease Activity Score-C-reactive protein (ASDAS-CRP) or ≥50% improvement from the initial Bath Ankylosing Spondylitis Disease Activity Index value (BASDAI50). Disease activity was evaluated using mixed models, and predictors were evaluated by modified Poisson regression.

RESULTS

In total, 167 patients were included: 87.4% had mixed PsA and 12.6% purely axial PsA. Baseline therapies were GUS (47.9%), RIS (13.2%), and UST (38.9%). Significant decreases in ASDAS-CRP and BASDAI (p < 0.001) occurred over 12 months. The total cohort's composite response rate at 12 months was 26.4%. Notably, 12 month response rates were numerically higher for IL-23 inhibitors (GUS 30.4%, RIS 40.0%) than for UST (15.7%), although these differences lacked statistical significance. Fulfilling Assessment of Spondyloarthritis International Society (ASAS) criteria [relative risk (RR) = 7.25, p = 0.023] and baseline ASDAS-CRP > 2.1 (RR = 2.30, p < 0.001) independently predicted clinical response.

CONCLUSION

IL-23 and IL-12/23 inhibitors improved disease activity in a predominantly mixed PsA cohort. Although IL-23 inhibitors exhibited higher numerical response rates, statistical superiority over UST was not confirmed. Effectiveness strongly correlated with baseline disease burden and ASAS criteria.