ADA_ETA_BIO2021: real-world evaluation of adherence, persistence, and cost-effectiveness of originator and biosimilar biologic drugs in the treatment of rheumatoid arthritis: a multicenter study in Italy.

Objectives: The objective was to assess the adherence, persistence, and costs of bDMARDs through a multicentre study of nine Italian hospital pharmacies.
Methods: The drugs analysed were Abatacept, Adalimumab, Certolizumab, Etanercept, Golimumab and Tocilizumab.Adult subjects with Rheumatoid Arthritis were considered in the analysis.In this study, we calculated the following metrics: Adherence to treatment was evaluated as dose-intensity, which is the ratio between the amount of medication received and probably taken by the patient at home (Received Daily Dose, RDD) and the amount prescribed by the clinician (Prescribed Daily Dose, PDD). Persistence was calculated as the number of days between the first and last dispensing of the same drug. Lastly, costs were assessed based on persistence to treatment and normalized for adherence.
Results: Adherence to treatment was found to be above 0.8 for all drugs studied. The median persistence for a 5-year treatment period was 1.4 years for Abatacept, 1.7 years for Adalimumab, 1.8 years for Certolizumab, 1.4 years for Etanercept, 1.3 years for Golimumab, and 1.6 years for Tocilizumab.
Conclusions: This multicentre retrospective observational study of bDMARDs used in the treatment of RA showed that, for all the drugs studied, there was no problem with adherence to treatment but rather a difficulty in maintaining treatment with the same drug over time.