Changes in Drug Survival of Adalimumab Over Time in Patients with Psoriasis – A Nationwide Cohort Study

Background Drug survival of older biologic therapies is thought to be influenced by the availability of newer biologic therapies and lower-cost biosimilars. However, there is limited data examining changes in drug survival over time. Objectives To examine the drug survival of adalimumab over the past two decades. Methods This observational, retrospective, multicenter cohort study analysed data from patients with moderate-to-severe psoriasis treated with adalimumab registered in the Danish nationwide registry, DERMBIO. Patients were stratified into two distinct time periods based on initiation date: an early period (2007-2016) and a late period (2019-2024). Kaplan-Meier curves were used to present unadjusted drug survival curves. A multivariable adjusted Cox proportional hazards model was used to compare the risk of drug discontinuation between the two periods. Results A total of 2,336 patients were included: 861 in the early period and 1,475 in the late period. We found a significantly lower risk of drug discontinuation in the late period compared to the early period (adjusted hazard ratio: 0.78, 95% CI: 0.68-0.90, p <0.001), despite the concurrent availability of newer and more effective biologic therapies. Conclusions This study found that the increased number of available biologic therapies did not have a negative impact on the drug survival of adalimumab. On the contrary, discontinuation risk was significantly lower in 2019–2024 compared with 2007-2016. The concurrent introduction of lower-cost biosimilars and the associated rise in dose escalation may have contributed to the improved drug survival observed in the later period.