Characteristics and safety outcomes of rheumatoid arthritis patients treated with AMGEVITA® in the United Kingdom using data from a national register

Over the past decade, rheumatoid arthritis (RA) management in the UK has evolved with increased use of biologic and targeted synthetic Disease-Modifying Anti-Rheumatic Drugs (DMARDs). The introduction of biosimilars, including AMGEVITA®, has expanded treatment options and improved access for patients. This study aims to (1) describe the clinical characteristics and serious adverse events (SAEs) in RA patients treated with AMGEVITA®, and (2) similarly, describe the incidence of these outcomes from the British Society for Rheumatology Biologics Register for Rheumatoid Arthritis (BSRBR-RA) anti-tumor necrosis factor (anti-TNF) comparison cohort. The BSRBR-RA is a national registry for patients with RA receiving biologic treatments, including anti-TNF inhibitors (e.g., adalimumab) and non-anti-TNF biologics, designed to evaluate the long-term safety and effectiveness of these agents in clinical practice. SAE analyses derived from an interim pharmacovigilance report on a subset of all AMGEVITA® and anti-TNF patients in the BSRBR-RA based on the Manchester Template Report. Eligible participants were ≥ 16 years of age with RA who registered in the registry within 6 months of initiating AMGEVITA®. Descriptive statistics were calculated for all variables of interest. From 01/01/2019 to 31/03/2022, 288 RA patients initiating AMGEVITA® were enrolled. Follow-up ended 30/11/2023. The mean (SD) age was 59.7 (12.0) years; 86 (28.0%) were 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 initiation. The crude incidence rate of SAEs in the AMGEVITA® cohort was 9.6 per 1,000 patient-years (95% CI: 3.1–22.4), including 37.5 serious infections per 1,000 patient-years (95% CI: 95% CI: 23.2–57.3). For context, the anti-TNF comparator cohort had a crude SAE rate of 13.3 per 1,000 patient-years (95% CI: 10.6–16.5) and a serious infection rate of 49.1 per 1,000 patient-years (95% CI: 43.8–54.8). The crude incidence rates of SAEs and serious infections among AMGEVITA® users were within the range observed for the anti-TNF comparator cohort. These findings provide supportive real-world safety data, although differences in baseline characteristics and the absence of adjusted analyses should be considered when interpreting results.