Real-world adherence to biologic therapies targeting interleukin 17, interleukin 23 and ustekinumab in moderate-to-severe psoriasis: A multicenter cohort study.

Abstract

Objectives: Biologic therapies targeting interleukin IL-17, IL-23 and IL-12/23 have substantially improved outcomes in patients with moderate-to-severe psoriasis. In real-world settings, treatment effectiveness depends not only on drug efficacy but also on patient adherence, which is essential for the appropriate interpretation of treatment persistence. The objectives of the present study were to evaluate adherence to biologic therapy with IL-17 inhibitors, IL-23 inhibitors and IL-12/23 inhibitors in patients with moderate-to-severe psoriasis in real-world clinical practice and to identify factors associated with high adherence.

Methods: A retrospective, multicenter observational study was conducted in one tertiary hospital and two regional hospitals within the same regional public healthcare system. Adult patients with moderate-to-severe psoriasis treated with IL-17 inhibitors, IL-23 inhibitors or IL-12/23 inhibitors for at least 4 months were included. Adherence was assessed using the medication possession ratio (MPR), calculated as the mean adherence across all dispensations recorded between December 2009 and October 2025. Multivariable logistic regression (with patient-level clustering to account for repeated courses) identified factors associated with excellent adherence (MPR ≥90%).

Results: A total of 423 patients and 626 treatment courses were included. Mean overall adherence was 94.5%. Adherence ≥80% was observed in 97.4% of treatment courses, and 78.8% achieved adherence ≥90%. Older age, female sex and treatment with IL-23 inhibitors were independently associated with excellent adherence.

Conclusions: Adherence to biologic therapies targeting interleukin IL-17, IL-23 and IL-12/23 in patients with moderate-to-severe psoriasis managed in hospital settings for at least 4 months is very high. Systematic assessment of adherence is essential for interpreting clinical outcomes and is essential for persistence analyses.