Cycling versus swapping strategieswith TNF-α inhibitors and IL-17 inhibitors in psoriatic arthritis in clinical practice

The availability of a number of bDMARDs with different mechanism of action increases potential treatment pathways in psoriatic arthritis (PsA). In clinical practice, following the failure of one bDMARD, it is normal to consider which options are the best for switching strategy. In most cases this choice involves IL17i and TNFi. The main aim of this study was to compare the effectiveness of cycling (from TNFi to another TNFi) and swapping (from TNFi to IL17i or vice versa) strategies. In this monocentric retrospective observational study, all PsA patients treated with TNFi or IL17i between January 2016 and January 2022 were enrolled. The prescriptions were clustered in one cycling group (CG), and two swap groups: from TNFi to IL17i (SG1) and from IL17i to TNFi (SG2). The Kaplan–Meier method and Cox regression models were applied to compare the drug retention rates and to identify factors affecting treatment persistence. A total of 122 patients were enrolled. The CG, SG1 and SG2 2-years retention rates were 51%, 58% and 34% (p = 0.1), respectively. SG1 strategy (HR 0.53; CI 0.31–0.89; p = 0.02), age (HR 0.98; CI 0.96–0.99; p = 0.003), Disease Activity PsA (HR 1.11; CI 1.08– 1.13; p < 0.0001), year of switch (HR 1.78; CI 1.39–2.22; p < 0.0001) influenced the retention rate. The findings of this real-world study, even if burdened by bias related to its observational nature, support the hypothesis that in PsA patients swapping from TNFi to IL17i might be more effective than cycling TNFis