Association between biological immunotherapy for psoriasis and time to incident inflammatory arthritis: limitations and opportunities.

Psoriatic arthritis (PsA) is a chronic inflammatory immune-mediated disease that affects approximately 30% of psoriasis patients. In most cases, skin disease clearly precedes the musculoskeletal disease. Some studies suggest that targeted treatment may intercept the disease course and prevent psoriasis patients from developing PsA. A recent population-based retrospective analysis in 15 501 psoriasis patients evaluated the association between different biological treatment strategies and time to incident inflammatory arthritis based on data in a US electronic health records database. A cumulative incidence of 2.6 PsA cases per 100 person-years was determined. The multivariable regression analysis revealed a significantly lower risk of developing inflammatory arthritis in patients who had been prescribed interleukin (IL)-12/23 or IL-23 inhibitors compared with tumour necrosis factor (TNF) inhibitor-treated patients, whereas there was no significant difference in risk for patients prescribed inhibitors of IL-17 versus TNF. Although the analysis was based on a large set of clinical data and the findings were rigorously evaluated, there are some limitations in interpretation due to the study design. Prospective clinical trials are missing, and retrospective data analyses from clinical trials or population-based studies show conflicting results. Overall, the recent data on prevention of PsA in patients with psoriasis support the high need to characterise biomarkers of increased risk and perform prospective clinical trials to give a clear guidance on possibilities for disease interception in psoriatic disease.