P232 Effectiveness of adalimumab biosimilar switching: real world data from a London rheumatology centre

Abstract Background Biologic drugs have revolutionised the management of many rheumatological diseases with remission or low disease activity now the realistic targets for treatment. However, given the chronic nature of most rheumatological disease and the need for long term treatment, there has been a significant increase in the cost associated with disease treatment. The advent of biosimilars offers an attractive target in reducing drug costs for payers. Biosimilar medications are thought to be equally efficacious as originator drugs. Real world data in adalimumab biosimilar switching is limited. In this audit we aim to examine the real-world outcomes from switching from originator Humira to biosimilar Amgevita in a London teaching hospital. Methods A list of all adult rheumatology patients on Amgevita was obtained through pharmacy records. All patients had been switched from Humira to Amgevita from February 2019. Using clinic letters and an in-house biologics database, data was collected on the underlying disease and the date of switch. Outcomes reviewed were disease activity scores pre and post switch, documented side effects and flare of disease activity following switch including decision to revert to originator Humira or change treatment. Results There was a total of 289 adult patients on Humira who switched to Amgevita. Of these patients, 28 in total discontinued treatment - 13 with rheumatoid arthritis, 10 with psoriatic arthritis and 5 with ankylosing spondylitis. 22 had to be switched back to Humira, with a further 4 patients approved to switchback and awaiting to restart. Two additional patients were switched to alternative biologic therapy due to inefficacy. A further 3 patients refused to switch onto Amgevita. Sixteen patients had documented flares, with one requiring admission and ten requiring local or systemic corticosteroid therapy to control activity. Seven patients had documented side effects which included chest pain, headache, rash and site reactions and one patient developed shingles post switch. Conclusion A total of 9.6% of patients switched to Amgevita had disease flare or side effects resulting in a switchback to Humira or alternative biologic therapy. For a biosimilar to be approved, efficacy and safety profiles needs to be comparable to the originator biological therapy and usually looks at two treatment naïve groups, rather than direct switch. Thereby, data on switches in therapy is limited. One systematic review looking at 11,053 patients with inflammatory arthritis treated with Etanercept and switched to Benepali, found 768 reverting to original therapy giving a lower total of 6.9%. We find that although no previous data of Amgevita, our figure of 9.6% appears high in the context of previously controlled inflammatory disease with Humira. Disclosures S. Vigneswaran None. M. Galloway None. S. Hanlon None. A. Tynan None. A. Singh None.