1 out of 3 Patients with PsA/PsO Switch, Swap Biologics Within 3 Years

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At 1 year, patients with treated with IL-23 switched or swapped biological treatment less frequently compared with IL-12/23, IL-17, and TNF-α inhibitors.

Results of a study analyzing switches and swaps between originators and biosimilars among patients with psoriatic arthritis (PsA) and psoriasis (PsO) showed more than a third of patients changed therapies within a 3-year follow-up period, according to research published in Expert Opinion on Biological Therapy.1

Compared with anti-interleukin (IL) agents, patients receiving tumor necrosis factor (TNF)-α inhibitors were more likely to switch or swap. Anti-IL therapy was also linked to a reduced risk of multiple switches during a follow-up period.

Switching between therapies is common among patients with PsA and PsO, with estimates ranging from 5% to 30% during the first year of treatment. Reasons for switching include adverse events, loss of efficacy, and switching from a reference product to a lower cost biosimilar.2

“To date, little is known about the pattern of switch (replacement of a biological drug with another one of the same pharmacological class) and swap (replacement of a biological drug with another one of a different pharmacological class) among biological drugs, especially in real-world patients with PsO and PsA,” wrote a team of investigators led by Andrea Spini, PharmD, PhD, Department of Diagnostics and Public Health, University of Verona, Verona, Italy.

To understand the switching patterns of biological drugs and to help determine which patients were more likely to undergo multiple switches and switch-back, investigators used data from the large-scale, multiregional, Italian VALORE database. Eligible patients were bio-naïve, had clinically diagnosed PsA or PsO, and were treated between 2010 and 2022. The time to switch or swap, as well as predictors of switches and switch-back, were assessed.

Although 112,651 patients were initially identified, 30,700 bio-naïve patients were ultimately included in the study. Among this cohort, 22,796 (74.3%) were treated with TNF-α inhibitors and 7583 (24.7%) received anti-IL drugs. In the anti-IL cohort, most received IL-17 inhibitors (n = 4322), followed by IL-12/23 (n = 2800), and IL-23 (n = 461). The mean age of patients was 50.7 years, approximately half (47.5%) were female, and most (58.3%) had a psoriasis indication on the index drug. One out of 4 patients were treated with a biosimilars. At years 3 and 5 of follow-up, 37.1% and 47.8% of patients, respectively, reported ≥ 1 switch or swap.

The median time to the first switch or swap was significantly shorter among those who were treated with TNF-α inhibitors compared with anti-IL (2068 days vs 2780 days, respectively; P <.001).

At 1 year, patients treated with IL-23 switched or swapped biological treatment less frequently compared with those receiving IL-12/23 or IL-17 agents (4.9% vs 8.7% and 9.4%, respectively).

Additionally, patients initiating treatment with IL-12/23 had a significantly lower risk of both multiple switches and switch-back compared with those treated with TNF-α inhibitors (.74, 95% confidence interval [CI], .67–.83; .58, 95% CI, .44–.77, respectively). The frequency of a single switch or a single swap was higher in those receiving TNF-α at all measured timepoints. At year 5, the percentage of multiple switchers who switched back was 15.4%.

The predictors of multiple switches included initiating treatment with a biosimilar drug (1.52, 95% CI: 1.40–1.65) as well as a history of conventional disease-modifying antirheumatic drug (cDMARD) therapy (1.16, 95% CI: 1.10–1.23). However, older age was linked to a reduction of risk (65–79 years old vs <65: .69, 95%CI: .62–.75; 80+ years old vs <65: .63, 95% CI: .50–.76).

Investigators noted limitations including a potential misclassification between PsO and PsA due to possible administrative data errors. Additionally, the data provided do not include information on the reasons for switching or the severity of disease.

“This Italian large-scale, population-based study found that at 3 years of follow-up more than 1 out of 3 incident users of biological drugs with PsO/PsA have at least 1 switch/swap (multiple switches in >10% of incident users), which further increases over time,” investigators concluded.


  1. Spini A, Pellegrini G, Ingrasciotta Y, et al. Switching patterns of biological drugs in patients with psoriasis and psoriatic arthritis: insight from the VALORE database network. Expert Opin Biol Ther. 2024;24(5):399-409. doi:10.1080/14712598.2024.2357381
  2. Wu B, Muser E, Teeple A, et al. Treatment adherence and persistence of five commonly prescribed medications for moderate to severe psoriasis in a U.S. commercially insured population. J DermatolTreat. 2021;32(6):595–602. doi: 10.1080/09546634.2019. 1687828