PO:01:004 | Real-world retention of il-17 inhibitors in psoriatic arthritis: impact of prior il-17 exposure across multiple treatment lines in the “birra” multicentre cohort

AIM OF THE STUDY Several studies have explored cycling versus switching strategies in Psoriatic Arthritis (PsA) when TNF- inhibitors are used as biological DMARD (bDMARD). Conversely, real-world evidence regarding cycling strategies within other bDMARD classes is lacking. In this study, we aimed to evaluate the retention rate of interleukin-17 inhibitors (anti-IL17) in patients with PsA, focusing on the differences between those receiving their first anti-IL17 agent and those previously exposed to anti-IL17 therapy. METHODS This was a multicentre, retrospective, observational study. All consecutive patients with PsA treated with an anti-IL17 bDMARD were included. The baseline assessment encompassed demographic and clinical characteristics, including disease domains and activity scores, IL-17 exposure status, number of prior bDMARD lines, and concomitant therapies. The primary outcomes were: a. the retention rate of anti-IL17 agents in IL-17 naïve versus IL-17 experienced patients; b. predictors of treatment discontinuation. RESULTS A total of 868 patients were included (59.3% female; median age 56 [48-63] years). The majority were receiving their first anti-IL17 agent (89.3% IL17 naïve vs 10.7% IL17 experienced). Secukinumab was the most frequently prescribed bDMARD (70.8%), followed by Ixekizumab (28.6%), and Bimekizumab (0.6%) (Figure 1.A.). At baseline, IL17 experienced patients more commonly exhibited axial involvement compared to IL17 naïve patients (59.1% vs 35.4%) and had received a higher median number of previous bDMARDs (4 [3-5] vs 2 [1-3] lines, respectively). Secukinumab was more frequently prescribed in IL17 naïve patients (76.9% vs 20.4%), whereas Ixekizumab was preferentially used in IL17 experienced individuals (Figure 1.A.). Median follow-up for the overall cohort was 15.2 [7.0-33.8] months, for a total exposure of 20’014 patient-months. At 12 months, the estimated retention rate was 77.6% vs 77.0% in naïve vs experienced patients respectively, dropping at 61.7% vs 54.0% at 24 months. Although Kaplan–Meier curves suggested a numerically lower persistence among IL17 experienced cases, this difference did not reach statistical significance (log-rank p = 0.068) (Figure 1.B.). In multivariable Cox regression analysis, male gender, a lower number of prior bDMARDs, and treatment with Secukinumab were associated with higher odds of drug survival, whereas axial involvement increased the risk of discontinuation. Prior IL17 exposure was associated with a non-significant trend towards a lower risk of discontinuation (Figure 1.C.). CONCLUSION Our findings suggest that, in the real-world PsA clinical practice, prior exposure to an IL17 inhibitor may not compromise the retention of a subsequent agent from the same class. Conversely, drug survival was influenced by gender, axial involvement, the specific bDMARD prescribed, and the cumulative number of prior bDMARDs. Recycling within the IL17 inhibitor class may represent an effective strategy. Nevertheless, further studies are warranted to better define the clinical contexts in which this approach could be most appropriate.