Background and Importance As the access to biosimilars at competitive prices increases, it is necessary to evaluate multiple switches to provide data on their interchangeability. Recently, the European Medicines Agency (EMA) has notified that medicines approved as biosimilars in the EU may be prescribed interchangeably.

Aim and Objectives The objective is to assess the efficiency and safety of switching from innovator adalimumab (Humira®) to biosimilar adalimumab (Imraldi®) and successive to another biosimilar (Hyrimoz®) in a real-life setting.

Material and Methods Retrospective observational study conducted in a 200-bed hospital. We included all patients who had been treated with the innovator adalimumab between 1-September-2019 and 31-March-2022 and switched to two adalimumab biosimilars. Variables analysed: clinical prescribing service, disease, patients who discontinued treatment with biosimilar and reason. Clinical and economic data were obtained from electronic medical records and management programs.

Results The first switch from innovator adalimumab to the first biosimilar adalimumab included 114 patients: 47.4% prescribed by the rheumatology department, 28.0% by the digestive unit and 24.6% by dermatologists.

The most frequent disease was rheumatoid arthritis (26.3%), following by Crohn’s disease (23.7%), psoriasis (17.5%) and psoriatic arthritis (13.2%).

The percentage of patients that discontinued the first biosimilar was 15.8%. While 61.1% of patients discontinued due to inefficacy, 38.9% had adverse effects. A total of 96 patients switched twice. The retention rate after the second switch was 96.9%. No major changes in disease activity were observed.

In the first switch (January 2019), the acquisition cost in our hospital of one unit of the original drug was €431.10, while that of the biosimilar (Imraldi®) was €176.80. In the second switch (August 2019) the price of Imraldi® was the same and for Hyrimoz® was €158.0. If we consider the most frequent posology in our patients (a dosage every two weeks), the first switch resulted in annual savings of €753,745.20 and the second switch resulted in €46,949.76. The multi-switching of 96 patients resulted in a total saving of €681,682.56.

Conclusion and Relevance The retention rate after multiple switches from innovator adalimumab to adalimumab biosimilars is high. Considering this multi-switching successful experience with biosimilars regarding safety and economic impact, interchangeability between biological medicinal products should be common in clinical practice.

Conflict of Interest No conflict of interest