P120 Characteristics and safety outcomes of rheumatoid arthritis patients treated with Amgevita® in the UK using data from a national register

Background/Aims Rheumatoid arthritis (RA) is a chronic inflammatory disease that can cause joint damage and impair quality of life. Research advances have led to seven adalimumab (ADL) biosimilars approved in the EU, making it crucial to understand their long-term benefit-risk profiles. This study aims to 1) estimate the clinical characteristics, serious adverse events (SAEs), and outcomes in patients with RA exposed to Amgevita® and 2) to estimate the incidence rates for the same outcomes from the British Society for Rheumatology Biologics Register for Rheumatoid Arthritis (BSRB-RRA) antitumor necrosis factor (TNF) comparison cohort. Methods Results from a crude pharmacovigilance report sent to Amgen on a subset of all Amgevita patients in the BSRBR-RA are presented. The BSRBRRA is a nationwide prospective study for patients with RA receiving biologic treatments, including anti-TNF inhibitors (i.e., adalimumab) and non-TNF biologics, that seeks to evaluate the long-term toxicity of these agents in clinical practice. Eligible participants were men and women ≥16 years of age with RA who registered in the study within 6 months of initiating Amgevita to comprise study cohort (these patients represent one-third of all Amgevita patients recruited into the BSRBR-RA). Descriptive characteristics were calculated for all variables of interest. Summary statistics for continuous variables include the number of patients, mean, median, SD or standard error, minimum, and maximum. Results From 01/01/2019 to 31/03/2022, 307 RA patients treated with Amgevita were enrolled in the registry. The follow-up period for this cohort ended 30/11/2023. The mean (SD) age of the population was 59.7 (12.0) years, 86 (28.0%) of patients identified as male, and mean (SD) disease duration at initiation was 9.9 (9.8) years. Two-thirds of Amgevita patients were biologically naïve and 9.8% were using steroids at Amgevita initiation. Non-adjusted incident rates of SAEs per 1,000 patient years by patient cohort are presented in Table 1. Conclusion These results show crude safety incidence rates for Amgevita patients in the BSRBR-RA, with point estimates similar to the anti-TNF cohort, though the confidence intervals are large due to small patient numbers. Ongoing monitoring of biosimilars is essential to optimize RA treatment and patient care. Disclosure A.E. Servin: Corporate appointments; Amgen. Shareholder/stock ownership; Amgen. M. Lillie: Corporate appointments; Amgen. Shareholder/stock ownership; Amgen. L.C. Coates: Consultancies; AbbVie, Amgen, Bristol Myers Squibb, Celgene, Eli Lilly, Gilead, Galapagos, Janssen, Moonlake, Novartis, Pfizer, Takeda, UCB. Grants/research support; AbbVie, Amgen, Celgene, Eli Lilly, Janssen, Novartis, Pfizer, UCB. M. Brunori: Corporate appointments; Amgen. Shareholder/stock ownership; Amgen. L. Krishnamoorthy: Corporate appointments; Amgen. Shareholder/stock ownership; Amgen. F. Humby: Consultancies; Roche, AbbVie, Genentech, UCB, Novartis. Honoraria; Roche, UCB, Novartis. Member of speakers’ bureau; UCB, Novartis.