Biological therapy utilization, switching, and cost among patients with psoriasis: retrospective analysis of administrative databases in Southern Italy

Francesca Guerriero, Valentina Orlando, Valeria Marina Monetti, Veronica Russo, Enrica Menditto Center of Pharmacoeconomics (CIRFF), University of Naples Federico II, Naples, Italy Purpose: The aim was to describe the current use of biological therapies among patients affected by psoriasis and to analyze a drug utilization profile in naïve patients in terms of switching and treatment costs in a Local Health Unit (LHU) of Southern Italy. Methods: We conducted an observational retrospective cohort analysis using the health-related administrative databases of a LHU in Southern Italy covering a population of about one million inhabitants. All subjects with a main or secondary diagnosis of psoriasis who received at least one prescription of biological therapies between January 1, 2010 and December 31, 2014 were analyzed. Switching rate was evaluated in naïve patients within the first year of treatment. Drug cost was calculated for all drugs prescribed and comprised both costs for psoriasis drugs and costs for other treatments. Results: About 20% of patients identified with a diagnosis of psoriasis were under treatment with biological drugs. Among 385 subjects treated with biological therapy, 51.2% were in treatment with etanercept and 33% with adalimumab. Among naïve patients, switching rate to a different biological drug, within the first year of treatment, was 7.3%. The per patient yearly drug cost was €10,536: 96.8% for psoriasis-related drugs and 3.2% for other pharmaceutical treatments. The annual average cost per patient switching from the initial treatment was €13,021, while for those who did not switch from the initial treatment, the annual average cost was €10,342, with a significant difference of about €2,680 per patient per year (p=0.002). Conclusion: Our data may be useful in exploring the dynamics that characterize the use of biological therapy within a specific context and to optimize the use of resources for a better management of the disease. Keywords: drug utilization, biological drugs, psoriasis, administrative databases, treatment cost, switch therapies