AB0475 The influence of switching from etanercept originator to its biosimilar on effectiveness and and the impact of shared decision making on retention and withdrawal rates

Background With biological patents expiring, biosimilars are becoming a realistic, less costly alternative to their originator. The data from numerous randomised clinical trials support that it is safe, effective and cost saving to switch to a biosimilar. However, real world data about efficacy, safety, and cost-effectiveness of such a switch are lacking. Since shared decision making (SDM) is a key factor in the treatment of rheumatic diseases, a non-mandatory open label transitioning from Etanercept originator to its biosimilar was performed at the rheumatology department of Bernhoven. Objectives The first goal of this study was to investigate the effect of switching from Etanercept originator to its biosimilar on the effectiveness of treatment. The second aim was to analyse the effect of SDM on the 1 year retention rates and reasons for withdrawal in daily clinical practice. Methods All patients with rheumatoid arthritis (RA), axial spondyloarthritis (SpA) and psoriatic arthritis (PsA) that were using Etanercept originator between 01–06–2016 and 23–10–2017 were informed by letter of the possibility to switch to its biosimilar. During the next outpatient visit with their rheumatologist the possibility to switch was discussed. Patients had the opportunity to ask questions regarding biosimilars and the switch to a biosimilar. If patients agreed the switch was made, with the reservation that they could switch back to the originator if they encountered difficulties with the biosimilar. Using the registry of the rheumatology department at Bernhoven data were collected on disease activity (DA), medication use and adverse events from the moment of switch till 23–10–2017. As measure for DA the DAS28 was used for RA and PsA, the ASDAS was used for SpA. Stop reasons for biosimilars were verified using the health record system of the hospital. Reasons for change in disease activity and discontinuation of biosimilar treatment were assessed. Results Between 01–06–2016 and 23–10%–2017 80% (69 patients) of the Etanercept originator users switched to its biosimilar. These patients switched to biosimilar after a median time of 5.1 (IQR 2.8–8.3) years. By 23–10–2017, median follow-up of 307 (IQR 196–357) days, the mean DA did not significantly differ from the DA at baseline, 3.1 (95%>CI 2.5–3.7) vs. 2.8 (95%>CI 2.5–3.1). At end of follow-up 25% of the patients had discontinued there treatment and either switched back to originator (18%), switched to another biological (3%) or stopped treatment with biologicals (4%). Reasons for switching back to originator were adverse events (58%), lack of effect (17%) and “adverse event and lack of effect” (25%). Only one serious adverse event was reported. This was a drug hypersensitivity reaction. After the patient was recovered, the originator was restarted without any difficulties. Conclusions An open label non-mandatory switch from Etanercept originator to its biosimilar showed that around 80% of the patients is willing to perform this switch. Switching did not affect effectiveness of treatment during one year follow-up. 75% of the patients were able to continue biosimilar therapy. In the 69 patients that switched only one serious adverse effect occurred. Disclosure of Interest None declared