Real-world evidence of biologic treatments in psoriatic arthritis in Italy: results of the CHRONOS (EffeCtiveness of biologic treatments for psoriatic artHRitis in Italy: an ObservatioNal lOngitudinal Study of real-life clinical practice) observational longitudinal study

Background Biologics have demonstrated efficacy in PsA in randomized clinical trials. More evidence is needed on their effectiveness under real clinical practice conditions. The aim of the present work is to provide real-world evidence of the effectiveness of biologics for PsA in the daily clinical practice. Methods CHRONOS was a multicenter, non-interventional, cohort study conducted in 20 Italian hospital rheumatology clinics. Results 399 patients were eligible (56.9% females, mean (SD) age: 52.4 (11.6) years). The mean (SD) duration of PsA and psoriasis was 7.2 (6.9) and 15.3 (12.2) years, respectively. The mean (SD) duration of the biologic treatment under analysis was 18.6 (6.5) months. The most frequently prescribed biologic was secukinumab (40.4%), followed by adalimumab (17.8%) and etanercept (16.5%). The proportion of overall responders according to EULAR DAS28 criteria was 71.8% (95% CI: 66.7-76.8%) out of 308 patients at 6 months and 68.0% (95% CI: 62.7-73.3%) out of 297 patients at 1 year. Overall, ACR20/50/70 responses at 6 months were 41.2% (80/194), 29.4% (57/194), 17.1% (34/199) and at 1-year were 34.9% (66/189), 26.7% (51/191), 18.4% (36/196), respectively. Secondary outcome measures improved rapidly already at 6 months: mean (SD) PASI, available for 87 patients, decreased from 3.2 (5.1) to 0.6 (1.3), the proportion of patients with dactylitis from 23.6% (35/148) to 3.5% (5/142) and those with enthesitis from 33.3% (49/147) to 9.0% (12/133). Conclusions The CHRONOS study provides real-world evidence of the effectiveness of biologics in PsA in the Italian rheumatological practice, confirming the efficacy reported in RCTs across various outcome measures.