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.