Comparing IL-23 Inhibitors — Dosing Intervals, Radiographic Data, and Long-Term Drug Survival

Within the IL-23 inhibitor class — which includes risankizumab, guselkumab, and tildrakizumab — headline efficacy for skin disease is broadly comparable across agents, and large differences in PASI 90 or PASI 100 response rates at the class level are not observed in clinical practice. The more clinically meaningful distinctions lie in maintenance dosing intervals, emerging data in psoriatic arthritis, and the depth of accumulated long-term experience. Risankizumab is administered every 12 weeks at maintenance, while guselkumab requires every-8-week dosing — a difference that carries practical significance for patients who highly value infrequent injections. For some patients, the difference between 4 and 6 maintenance injections per year is a material factor in long-term adherence and treatment satisfaction, and clinicians should address it explicitly rather than treating it as incidental to the prescribing decision. Tildrakizumab occupies a similar maintenance interval to guselkumab and represents an additional option within the class, though its use in psoriatic arthritis is more limited.

Psoriatic arthritis data are increasingly reviewed to understand nuance within the IL‑23 class; however, clear clinical differentiation between agents remains limited. In routine practice, treatment selection is guided by overall disease control, durability, safety profile, comorbidities, and patient‑reported outcomes rather than any single joint‑specific endpoint. Differences in available PsA data across IL‑23 therapies largely reflect variations in clinical development programs rather than established superiority.

For patients with concomitant skin and joint involvement, IL‑23 inhibitors are commonly selected based on their consistent skin efficacy and favorable long‑term profiles, with improvement in joint symptoms viewed as part of broader inflammatory control. Structural or imaging outcomes may provide supportive context but are generally interpreted alongside functional measures and symptomatic response. For axial disease, IL‑17 inhibitors continue to have the strongest supporting evidence, while IL‑23 therapies are primarily positioned for patients whose treatment priorities are centered on sustained skin clearance with acceptable joint outcomes.

In this Special Report segment, Bruce Strober, MD, PhD, Clinical Professor of Dermatology at Yale University School of Medicine, identifies long-term drug survival as perhaps the most underappreciated factor in biologic selection. Registry and real-world data consistently demonstrate that IL-23 inhibitors exhibit superior drug survival compared with other biologic classes — patients are more likely to remain on an IL-23 inhibitor without loss of response, switching, or discontinuation over a 3- to 5-year horizon. This durability has direct practical consequences: each therapy switch in psoriasis carries administrative burden through prior authorization requirements, potential coverage gaps, and patient disruption — all of which add friction and can compromise disease control during transitions. A therapy that a patient can remain on effectively for 5 or more years avoids that friction entirely. Strober's real-world experience with risankizumab across approximately 800 treated patients reflects this durability in practice — he characterizes it as a mature agent whose performance is predictable, producing responses that deepen over the first 24 to 36 weeks and are sustained reliably over years in the majority of patients who respond initially. Patients on risankizumab frequently describe their outcomes in strongly positive terms, a pattern he attributes to the combination of deep skin clearance, infrequent dosing burden, and a tolerability profile that imposes no meaningful limitations on daily life.