Ixekizumab Treatment Persistence in Psoriatic Arthritis: Response to Joaquin et al

Abstract We appreciate the interest of Joaquin et al in our recent study on the treatment persistence of ixekizumab in psoriatic arthritis. In response, we clarify that our study utilized prospectively collected real-world clinical data from a multicenter observational cohort, rather than administrative databases. We emphasize the importance of persistence, as assessed through the Drug Retention Rate (DRR), a validated measure in observational studies of biologic therapies. The DRR reflects a complex interplay of factors, including efficacy, safety, and patient choice, making it a valuable indicator of therapeutic performance. We agree that adherence is an interesting topic, but argue that its absence does not invalidate persistence data. Our study was designed to evaluate treatment persistence, not behavioural pharmacology. We believe that our methodological rigor, real-world design, and consistency with international literature make our data a reliable reference for understanding ixekizumab persistence in routine clinical pratice.