The predictors of paradoxical reactions, especially psoriasis, to biologic therapy-findings from the TReasure database: a 5-year follow-up study

Objectives The objectives of this study were to assess the clinical characteristics, predictive factors, and practical algorithms of paradoxical reactions (PRs), specifically paradoxical psoriasis (PP). Methods The TReasure database is a web-based prospective observational cohort comprised of patients with RA and SpA from 17 centres around Turkey since 2017. A cohort study and a case-control study nestled within the cohort were identified. Results In total, 2867 RA and 5316 SpA patients were evaluated. The first biologic agent was found to have caused PRs in 60% of the 136 patients (1.66%) who developed the PRs. The median time interval between the PRs and biological onset was 12 months (range 1-132 months, mean 21 months). The most common types of PP, constituting 92.6% of PRs, were pustular (60.3%) and palmoplantar (30.9%). Adalimumab (30.9%), infliximab (19%) and etanercept (17.4%) were the most common agents causing the PP. In the treatment of most PP patients (73.2%), switching biologic agents was favoured, with TNF inhibitor (TNFi) chosen in 46.03% and non-TNFi in 26.9% of cases. The three most frequently selected drugs were etanercept (24.6%), secukinumab (9.5%) and adalimumab (8.7%). Only 5.17% of patients who switched to another TNFi showed progression. The odds ratios (s) for SSZ, HCQ, and LEF use were significantly higher in RA controls than in PP patients (P = 0.033, OR = 0.15; P = 0.012, OR = 0.15; and P = 0.015, OR = 0.13, respectively). In the PP group with SpA, the number of smokers was significantly higher (P = 0.003, OR: 2.0, 95% CI: 1.05, 3.81). Conclusion Contrary to expectations based on earlier research suggesting that paradoxical reactions develop with the class effect of biological agents, the response of patients who were shifted to another TNFi was favourable.